Sunday, August 22, 2010

Allergy

Also called: Hypersensitivity

An allergy is a reaction of your immune system to something that does not bother most other people. People who have allergies often are sensitive to more than one thing. Substances that often cause reactions are
  • Pollen
  • Dust mites
  • Mold spores
  • Pet dander
  • Insect stings
  • Food
  • Medicines
How do you get allergies? Scientists think both genes and the environment have something to do with it. Normally, your immune system fights germs. It is your body's defense system. In most allergic reactions, however, it is responding to a false alarm.
Allergies can cause a runny nose, sneezing, itching, rashes, swelling or asthma. Symptoms vary. Although allergies can make you feel bad, they usually won't kill you. However, a severe reaction called anaphylaxis is life-threatening.
NIH: National Institute of Allergy and Infectious Diseases

READ MORE - Allergy

Asthma in Children

Asthma is a chronic disease that causes the airways - the tubes that carry air in and out of your lungs - to become sore and swollen. In the United States, about 20 million people have asthma. Nearly 9 million of them are children. Children have smaller airways than adults, which makes asthma especially serious for them. Children with asthma may experience wheezing, coughing, chest tightness and trouble breathing, especially early in the morning or at night.
Many things can cause asthma, including :
  • Allergens - mold, pollen, animals
  • Irritants - cigarette smoke, air pollution
  • Weather - cold air, changes in weather
  • Exercise
  • Infections - flu, common cold
When asthma symptoms become worse than usual, it is called an asthma attack. Asthma is treated with two kinds of medicines: quick-relief medicines to stop asthma symptoms and long-term control medicines to prevent symptoms.
READ MORE - Asthma in Children

Asthma

Asthma is a chronic disease that affects your airways. Your airways are tubes that carry air in and out of your lungs. If you have asthma, the inside walls of your airways become sore and swollen. That makes them very sensitive, and they may react strongly to things that you are allergic to or find irritating. When your airways react, they get narrower and your lungs get less air. This can cause wheezing, coughing, chest tightness and trouble breathing, especially early in the morning or at night.
When your asthma symptoms become worse than usual, it's called an asthma attack. In a severe asthma attack, the airways can close so much that your vital organs do not get enough oxygen. People can die from severe asthma attacks.
Asthma is treated with two kinds of medicines: quick-relief medicines to stop asthma symptoms and long-term control medicines to prevent symptoms.
NIH: National Heart, Lung, and Blood Institute
READ MORE - Asthma

Anthrax, NIAID Fact Sheet

About the Microbe
Anthrax is an acute infectious disease caused by the spore-forming, rod-shaped bacterium Bacillus anthracis. Predominantly a cause of livestock disease, B. anthracis forms durable spores that can lie dormant in the soil for years. Once eaten by a grazing animal, the spores are activated and the bacteria reproduce. After the bacteria spread, they typically kill the infected animal and return to the soil or water once again as spores.
The bacterium's destructive properties are due largely to toxins, which consist of three proteins: protective antigen, edema factor, and lethal factor.
  • Protective antigen (PA) binds to select cells of an infected person or animal and forms a channel that permits edema factor and lethal factor to enter those cells.
  • Edema factor (EF), once inside the cell, causes fluid to accumulate at the site of infection. EF can contribute to a fatal buildup of fluid in the cavity surrounding the lungs. It also can inhibit some of the body's immune functions.
  • Lethal factor (LF), once inside the cell, disrupts a key molecular switch that regulates the cell's functions. LF can kill infected cells or prevent them from working properly.
About the Disease
People rarely contract anthrax from healthy animals. Contact with infected livestock or their products such as leather and wool does, however, cause a limited number of anthrax cases throughout the world. In the United States, only 236 anthrax cases were reported between 1955 and 1999, an average of about five per year. Most of those cases were occupational exposures in people who work with animal carcasses or products. The treatable cutaneous (skin) form of the disease is most common. Worldwide incidence is unknown, but anthrax occurs more frequently in developing countries, especially those without strong veterinary public health programs. Anthrax is not transmitted from person to person.
Human anthrax occurs primarily in three forms: cutaneous, gastrointestinal, and inhalation.
  • Cutaneous anthrax occurs when the bacteria, usually from infected animal products, enter a break in the skin. The skin reddens and swells, much like an insect bite, then develops a painless blackened lesion or ulcer that may form a brown scab. If left untreated, the infection can spread through the body. Cutaneous anthrax is the most common form of the diseases and responds well to antibiotics. It is rarely fatal if treated before it becomes invasive.
  • Gastrointestinal anthrax may arise when a person eats contaminated food. The infection often causes fever accompanied by gastrointestinal problems such as vomiting, abdominal pain, diarrhea, or loss of appetite. In some cases, lesions may form in the nose and throat instead of the lower digestive tract. In both cases, gastrointestinal anthrax can spread through the body and is often fatal if not treated immediately. This form of anthrax, however, is not known to have occurred in the United States.
  • Inhalation anthrax, sometimes called respiratory or pulmonary anthrax, occurs when the bacterial spores are inhaled. The early symptoms resemble those of a common cold or sore throat. The spores travel from the lungs to immune cells called macrophages in the nearby lymph nodes. There they begin to reproduce and secrete their toxins, causing severe breathing problems and shock. Treatment is difficult once the bacteria have reached that stage, and death often ensues. Naturally occurring inhalation anthrax is rare. Prior to the bioterrorist attack of 2001, the last known case of inhalation anthrax in the United States occurred in 1976 in a California craftsman who apparently contracted the infection from contaminated, imported yarn.
Treatment and Prevention
Antibiotics
Several different antibiotics kill B. anthracis as it reproduces within people and animals. If diagnosed early, anthrax can be treated. Unfortunately, infected people often confuse early symptoms with more common infections and do not seek medical help until severe symptoms appear. At that point the destructive anthrax toxins, which are not affected by antibiotics, have risen to high levels, making treatment difficult. Although cutaneous anthrax has telltale signs and symptoms making diagnosis easy, early stage gastrointestinal and inhalation anthrax are more likely to be mistaken for common maladies.
Vaccine
An anthrax vaccine is licensed for limited use. The vaccine is currently used to protect members of the military and individuals most at risk for occupational exposure to the bacteria, such as abattoir workers, veterinarians, laboratory workers, and livestock handlers. The vaccine consists of filtered proteins and other components of a weakened B. anthracis strain adsorbed to aluminum hydroxide. PA is the major component of the vaccine that provides protection against infection. The vaccine contains no whole bacteria.
Health experts currently do not recommend the vaccine for general use by the public due to the rarity of anthrax and the potential for adverse side effects. Researchers have not determined the safety and efficacy of the vaccine in children, the elderly, and people with weakened immune systems. In addition, the recommended vaccination schedule is 6 doses given over an 18-month period, so the vaccine would likely offer little protection in response to a bioterrorist attack. For these reasons, a new anthrax vaccine is needed.
NIAID Basic Research
Several biologic factors contribute to B. anthracis's ability to cause disease. By uncovering the molecular pathways that enable the bacterium to form spores, survive in people, and cause illness, NIAID hopes to identify new ways to diagnose, prevent, and treat anthrax.
Toxin Biology
Scientists are studying the anthrax toxins to learn how to block their production or action. Recently, NIAID grantees determined the three-dimensional structure of the LF protein as it attaches to its target inside cells. The research showed for the first time that LF uses a long groove on its side to latch onto that target. At the same time, another group of researchers identified a protein receptor on the surface of host cells to which PA attaches. Using a specific fragment of that receptor protein, the researchers were able to block the attachment of PA, thereby preventing formation of the PA channel and inhibiting the toxic effects of LF and EF in test-tube experiments. Other investigators have engineered mutant, inactive PAs that prevent bacteria-produced PAs from forming the channel. The studies of PA and LF should enable researchers to develop small molecules that can be used as therapeutics to treat anthrax by inhibiting its toxins.
The Anthrax Bacterium Genome
The instructions that dictate how a microbe works are encoded within its genes. Bacteria often contain genes at two locations. The bacterial chromosome is a long stretch of DNA that houses most of those genes, but smaller loops of DNA called plasmids also carry genes that can be exchanged between different bacteria. Because plasmids often contain genes for toxins and antibiotic resistance, knowing their DNA sequence is important.
In B. anthracis, the genes for PA, LF, and EF are found on plasmids that have already been sequenced. In addition, researchers recently reported the complete chromosomal DNA sequence of two B. anthracis isolates, including the bacterium that infected a Florida victim of the recent anthrax attack. Genome sequencing of more than a dozen other B. anthracis strains and related bacteria has already begun.
By comparing the DNA blueprints of different B. anthracis strains, researchers hope to learn why some strains are more virulent than others. Small variations among the genomes of different strains may also help investigators pinpoint the origin of an anthrax outbreak. Knowing the genetic fingerprint of B. anthracis might lead to gene-based detection mechanisms that can alert scientists to the bacteria in the environment or allow rapid diagnosis of anthrax in infected people. Variations between strains might also point to differences in antibiotic susceptibility, permitting doctors to immediately determine the appropriate treatment.
DNA sequencing also opens the door to functional genomics, in which the B. anthracis genome will be analyzed to determine the function of each of its genes and how they interact with each other or with host-cell components to cause disease. Genes are the instructions for making proteins, which in turn build components of the cell or carry out its biochemical processes. Knowing the sequence of B. anthracis genes therefore helps scientists discover key bacterial proteins that can then be targeted by new drugs or vaccines.
Spore Biology
B. anthracis spores are essentially dormant and therefore must wake up, or germinate, to become reproductive, disease-causing bacteria. Researchers are therefore studying the germination process to learn more about the signals that cause spores to become active once inside an animal. Efforts are underway to develop models of spore germination in laboratory animals; scientists hope those models will enable discoveries leading to drugs that block the germination process.
Host Immunity
People who contract anthrax produce antibodies to PA, and similar antibodies appear to protect animals from infection. Recent studies also suggest that some animals can produce antibodies to components of B. anthracis spores. Those antibodies, when studied in a test tube, prevent spores from germinating and increase their uptake by the immune system's microbe-eating cells. It therefore might be possible to develop a vaccine that can be given after exposure to fight both the reproductive form of B. anthracis and any spores that may linger in the lungs following antibiotic treatment.
As part of NIAID's strategic plan, researchers will study how both the innate and adaptive immune responses are triggered by a B. anthracis infection. The adaptive immune response consists of B cells and T cells which specifically recognize components of the anthrax bacterium. The innate immune system, however, responds more generally to a wide range of microbial invaders and likely plays a key role in the body's front-line defenses. Scientists will conduct studies of how those two arms of the immune system act to counter infection, including how B. anthracis spore germination affects individual immune responses.
NIAID Therapeutics Research
Following the recent discoveries of how PA and LF interact with their cellular targets, researchers are screening thousands of small molecules in hopes of finding a compound that is practical for use as an anti-anthrax drug. In addition, NIAID is working with the Food and Drug Administration (FDA), Centers for Disease Control and Prevention (CDC), and Department of Defense (DoD) to accelerate testing of collections of compounds for their effectiveness against inhalation anthrax. Many of those compounds have already been approved by FDA for other indications and therefore could quickly be approved for use in treating anthrax should they prove effective.
NIAID is seeking new drugs that attack B. anthracis at many levels. These include agents that prevent the bacterium from attaching to cells, compounds that inhibit spore germination, and inhibitors that block the activity of key enzymes such as anthrax lethal factor. The Institute will also develop the capacity to synthesize promising anti-anthrax compounds in sufficient purity and quantity for preclinical testing.
NIAID Vaccine Research
Researchers are working on new, improved anthrax vaccines that may be more easily given to a diverse population. NIAID is collaborating with DoD to develop a next-generation vaccine based on a laboratory-produced, or recombinant, PA variant. Antibodies to PA also appear to recognize some components of the bacterial spore, making PA-based vaccines promising candidates for broad protection against anthrax. The Institute will supervise phase I and phase II trials of the recombinant PA vaccine in different formulations.
To help move potential vaccines into clinical testing, NIAID will develop the infrastructure to produce pilot lots of promising candidates and expand the Institute's testing capacity. To assist in its vaccine research efforts, NIAID will establish a centralized immunology laboratory to assess the efficacy of different vaccine candidates.
NIAID Diagnostics Research
Research is underway to develop improved techniques for spotting B. anthracis in the environment and diagnosing it in infected individuals. A key part of that research is the functional genomic analysis of the bacterium, which should lead to new genetic markers for sensitive and rapid identification. Genomic analysis will also reveal differences in individual B. anthracis strains that may affect how those bacteria cause disease or respond to treatment.
Anthrax and Bioterrorism
CDC has classified B. anthracis as a Category A agent. Those agents are considered the highest threat to national security due to their ease of transmission, high rate of death or serious illness, and potential for causing public panic.
In October 2001, anthrax spores were sent through the U.S. mail and caused 18 confirmed cases of anthrax (11 inhalation, 7 cutaneous). Five individuals with inhalation anthrax died; none of the cutaneous cases was fatal.
More Information
National Institute of Allergy and Infectious Diseases
National Institutes of Health
31 Center Drive, MSC 2520
Bethesda, MD 20892-2520
http://www.niaid.nih.gov/newsroom/releases/anthraxspec.htm
National Library of Medicine
MEDLINEplus
8600 Rockville Pike
Bethesda, MD 20894
1-800-338-7657
http://www.nlm.nih.gov/medlineplus/anthrax.html
U.S. Centers for Disease Control and Prevention
1600 Clifton Road
Atlanta, GA 30333
1-888-232-3228
http://www.bt.cdc.gov/Agent/Anthrax/Anthrax.asp
World Health Organization
Avenue Appia 20
1211 Geneva 27
Switzerland
(00 41 22) 791 21 11
http://www.who.int/emc/diseases/anthrax/
U.S. Department of Agriculture
Washington, D.C. 20250
http://www.usda.gov/homelandsecurity/anthraxfs.htm
U.S. Food and Drug Administration
Food and Drug Administration
5600 Fishers Lane
Rockville, Maryland 20857
1-888-INFO-FDA (1-888-463-6332)
http://www.fda.gov/oc/opacom/hottopics/bioterrorism.html
Johns Hopkins University Center for Civilian Biodefense Studies
http://www.hopkins-biodefense.org/pages/agents/agentanthrax.html
NIAID is a component of the National Institutes of Health (NIH). NIAID supports basic and applied research to prevent, diagnose, and treat infectious and immune-mediated illnesses, including HIV/AIDS and other sexually transmitted diseases, illness from potential agents of bioterrorism, tuberculosis, malaria, autoimmune disorders, asthma and allergies.
Press releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov.
Prepared by:
Office of Communications and Public Liaison
National Institute of Allergy and Infectious Diseases
National Institutes of Health
Bethesda, MD 20892

U.S. Department of Health and Human Services
READ MORE - Anthrax, NIAID Fact Sheet

Saturday, August 21, 2010

HIV Infection in Minority Populations

Overview
Minority populations in the United States, primarily African Americans and Hispanics, constitute 57 percent of the more than 700,000 cases of AIDS reported to the U.S. Centers for Disease Control and Prevention (CDC) since the epidemic began in 1981. African Americans make up almost 38 percent of all AIDS cases reported in the United States, yet according to the U.S. Census Bureau, they comprise only 12 percent of the U.S. population. Hispanics represent 19 percent of all AIDS cases. Including residents of Puerto Rico, they represent 13 percent of the population in this country. According to CDC
  • As of June 2001, African Americans and Hispanics represented 51 percent of AIDS cases reported among males and 77 percent of those in females.
  • As of June 2001, 58 percent of all women reported with AIDS are African American and 20 percent are Hispanic
  • African American children represent 58 percent of all pediatric AIDS cases.
  • Of the 194 pediatric AIDS cases reported between July 2000 and June 2001, 163 (84 percent) were in African Americans and Hispanics.
  • In 1999, AIDS accounted for an estimated 50 percent of deaths among African Americans and 18 percent among Hispanics. It is the leading cause of death among African-American men ages 25-44.
  • Injection drug use is a major factor in the spread of HIV in minority communities. Through June 2001, injection drug users accounted for 20 percent of all AIDS cases among both African Americans and Hispanics.
NIAID Research on HIV Infection and AIDS
The National Institute of Allergy and Infectious Diseases (NIAID), the lead component for AIDS research at the National Institutes of Health (NIH), is at the forefront of the war against this continuing health crisis, which disproportionately affects minority populations.

NIAID supports scientific research at universities, medical schools, hospitals and research institutions, both in the United States and abroad, aimed at preventing, diagnosing, and treating HIV infection and AIDS and other infectious diseases as well as allergic and other immune system disorders.

NIAID's AIDS research agenda includes conducting clinical trials that address the specific needs and concerns of minority populations, ensuring that minority patients have access to all clinical trials and sharing the latest information on AIDS treatment and prevention. In addition, NIAID's Office of Special Populations Research and Training encourages research aimed at improving the health of minority populations. The office also works to increase the effectiveness of outreach and education programs.

Through its Office of Communications and Public Liaison and the Dale and Betty Bumpers Vaccine Research Center, NIAID works with community-based organizations to disseminate information about HIV infection and AIDS and NIAID research activities to minority communities.

Clinical Research
NIAID programs and/or networks evaluate promising therapies to fight HIV infection and its associated complications, as well as approaches to reconstitute HIV-damaged immune systems. These include the Adult AIDS Clinical Trials Group (AACTG),the Pediatric AIDS Clinical Trials Group(PACTG), the Terry Beirn Community Programs for Clinical Research on AIDS (CPCRA), the HIV Prevention Trials Network (HPTN), the Acute Infection and Early Disease Research Program (AIEDRP), and the Division of Intramural Research Clinical Program.

Together, these programs represent the largest AIDS treatment and prevention initiative in the United States. Recruiting minorities into clinical trials is a priority for NIAID to ensure that research results will apply to all populations affected by HIV. With the epidemic moving swiftly into minority communities, inclusion of these patients is particularly urgent.

The AACTG investigates therapeutic interventions for HIV infection, AIDS, and complications of HIV-associated immune deficiency in adults. AACTG sites receive additional funding from the National Institute on Drug Abuse (NIDA) to increase participation of injection drug users, who are also hard hit by the AIDS epidemic.

The PACTG evaluates clinical interventions for treating HIV infection and HIV-associated illnesses in neonates, infants, children, adolescents. Both the PACTG and the HPTN are researching approaches to interrupt mother-to-infant transmission in pregnant women. In 2001, 6,186 and 6,426 participants were enrolled in AACTG and PACTG studies respectively. In the AACTG, 26 percent were African American, 19 percent were Hispanic, and 3 percent were Asian/Pacific Islander or Native American. In the PACTG, 47 percent were African American, 25 percent were Hispanic, and 1 percent Asian/Pacific Islander or Native American.

The HPTN is a global multicenter network dedicated to non-vaccine prevention research with a focus on HIV endpoints. They have directed their educational outreach efforts to minority communities working to increase trial volunteerism.

CPCRA is a network of community-based health centers and clinics which support clinical research in community settings by conducting large comparative studies that examine how to use available therapies more effectively as well as the long-term consequences of different treatments. Currently, CPCRA trials are under way in 17 cities at 18 units. In 2001, 4,244 people participated in CPCRA studies. Of those, 49 percent were African American, 13 percent were Hispanic, and 1 percent were Native American or Asian/Pacific Islander.

NIAID also supports clinical research on vaccine and non-vaccine strategies to prevent HIV infection. Vaccine studies are carried out through the HIV Vaccine Trials Network (HVTN) and non-vaccine prevention studies are conducted by the HPTN. The HVTN is a global network of clinical sites which evaluate preventive HIV vaccine in all phases of clinical trials. They allow for studies that examine differences in HIV diversity and genetic background , all of which may prove crucial to developing an effective vaccine for use around the world. Through close collaborations and education outreach programs with communities where vaccines will be tested, the HVTN hopes to enroll a diversified population in its clinical trials, ensuring access and representation of populations most affected by and vulnerable to HIV spread.

The HVTN and HPTN opened in 2000 and have enrolled thousands of study participants. In 2001, 383 and 9,517 people participated in the HVTN and HPTN, respectively. Of those in the HVTN, 21 percent were African American, 3 percent were Hispanic, and 1 percent Native American or Asian/Pacific Islander. In the HPTN, 57 percent of participants were African American, 7 percent Hispanic, and about 3 percent Native American or Asian/Pacific Islander.

In addition, NIAID supports two major programs to enhance basic and clinical HIV research performed at minority institutions: Research Centers in Minority Institutions and AIDS Clinical Trials Infrastructures in Minority Institutions.
Epidemiologic Research
NIAID conducts and supports research on HIV infection in a variety of population groups, including minority populations. These studies are conducted through the Women and Infants Transmission Study (WITS/WITS II), the Women's Interagency HIV Study (WIHS), and the Multicenter AIDS Cohort Study (MACS). Inner-city women, children, and injection drug users are the focus of WITS/WITS II. Eighty-four percent of the women in this study are from minority populations.

Similar populations of women are the focus of the WIHS, which NIAID established and awarded funds to six U.S. sites in 1993 to investigate primarily the impact of HIV infection on women. Several other NIH institutes also collaborate on WIHS and provide funds for various components. They include NIDA, the National Cancer Institute, National Institute of Child Health and Human Development, and National Institute of Dental and Craniofacial Research.

Active community involvement through the WIHS sites and the WIHS National Community Advisory Board helps encourage minority women to participate in the studies. More than 80 percent of the women currently enrolled in WIHS are from minority populations.

In the United States, the Multicenter AIDS Cohort Study (MACS) and WIHS are the two largest observational studies of HIV/AIDS in homosexual or bisexual men and in women, respectively. These studies have made major contributions to understanding how HIV is spread, how the disease progresses, and how it can best be treated. Over the past year, these studies expanded their enrollment to increase the size of the study groups by 60 percent and increase the number of minority participants. The enlarged groups will focus on contemporary questions regarding HIV infection and treatment.
More Information
For information about Food and Drug Administration-approved HIV-related clinical trials being conducted throughout the United States, contact the AIDS Clinical Trials Information Service.
1-800-TRIALS-A (1-800-874-2572)
301-519-0459 (International)
1-888-480-3739 (TTY/Deaf Access)
http://actis.org

For federally approved treatment guidelines on HIV/AIDS, contact the HIV/AIDS Treatment Information Service:

1-800-HIV-0440 (1-800-448-0440)
1-888-480-3739 (TTY/Deaf Access)
301-519-0459 (International)
http://hivatis.org

Both services operate from 12 p.m. to 5 p.m. Eastern Time, Monday through Friday. Spanish-speaking specialists are available.

To receive materials or to talk with a Health Communication Specialist, contact the CDC National HIV and STD Hotline. This service is available 24 hours a day.

1-800-227-8922
1-800-342-2437
1-800-243-7889 (TTY/Deaf Access)

To get information specifically about clinical trials conducted by the NIAID Intramural AIDS Research Program, call 1-800-243-7644 (http://clinicaltrials.gov).

NIAID is a component of the National Institutes of Health (NIH). NIAID supports basic and applied research to prevent, diagnose, and treat infectious and immune-mediated illnesses, including HIV/AIDS and other sexually transmitted diseases, illness from potential agents of bioterrorism, tuberculosis, malaria, autoimmune disorders, asthma and allergies.

Press releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov.

Prepared by:
Office of Communications and Public Liaison
National Institute of Allergy and Infectious Diseases
National Institutes of Health
Bethesda, MD 20892

U.S. Department of Health and Human Services
June 2002

READ MORE - HIV Infection in Minority Populations

HIV Infection in Infants and Children

Overview

The National Institute of Allergy and Infectious Diseases (NIAID) has a lead role in research devoted to children infected with the human immunodeficiency virus (HIV), the virus that causes the acquired immunodeficiency syndrome (AIDS).

NIAID-supported researchers are developing and refining treatments to prolong the survival and improve the quality of life of HIV-infected infants and children. Many promising therapies are being tested in the Pediatric AIDS Clinical Trials Group (ACTG), a nationwide clinical trials network jointly sponsored by NIAID and the National Institute of Child Health and Human Development (NICHD). Scientists also are improving tests for diagnosing HIV infection in infants soon after birth so that therapy can begin as soon as possible.

Epidemiologic studies are examining risk factors for transmission as well as the course of HIV disease in pregnant women and their babies in an era of antiretroviral therapy. Researchers have helped illuminate the mechanisms of HIV transmission as well as the distinct features of pediatric HIV infection and how the course of disease and the usefulness of therapies can differ in children and adults.

Researchers also are studying ways to prevent transmission of HIV from mother to infant. Notably, Pediatric ACTG investigators have demonstrated that a specific regimen of zidovudine (AZT) treatment, given to an HIV-infected woman during pregnancy and to her baby after birth, can reduce maternal transmission of HIV by two-thirds.1 Many consider this finding to be one of the most significant research advances to date in the fight against HIV and AIDS.

A Global Problem

According to UNAIDS (The Joint United Nations Programme on HIV/AIDS) and the World Health Organization (WHO),2,3 at the end of 1998, an estimated 1.2 million children worldwide under age 15 were living with HIV/AIDS. Approximately 3.2 million children under 15 had died from the virus or associated causes. The number of children who had lived with HIV from the start of the epidemic through 1997 was estimated to be 3.8 million. As HIV infection rates rise in the general population, new infections are increasingly concentrating in younger age groups.

Statistics for the year 1998 alone show that
  • 590,000 children under age 15 were newly infected with HIV.
  • One-tenth of all new HIV infections were in children under age 15.
  • Approximately 7,000 young people aged 10 to 24 became infected with HIV every day-that is, five each minute.
  • Nine out of 10 new infections in children under 15 were in sub-Saharan Africa.
  • An estimated 510,000 children under 15 died of AIDS-related causes, up from 460,000 in 1997.
More than 95 percent of all HIV-infected people now live in developing countries, which have also suffered 95 percent of all deaths from AIDS. In countries with the longest-lived AIDS epidemics, some doctors report that children ill from HIV occupy three-quarters of pediatric hospital beds, and childrens' life expectancy has been shortened dramatically. In Botswana, for example, because of AIDS, the life expectancy of children born early in the next decade is just over age 40; without AIDS, it would have been 70. In Namibia, the infant mortality rate is expected to reach 72 deaths per 1000, up from a non-AIDS rate of 45 per 1000.

The United States has a relatively small percentage of the world's children living with HIV/AIDS. From the beginning of the epidemic through the end of 1998, 5,237 American children under age 13 had been reported to the Centers for Disease Control and Prevention (CDC) as living with HIV/AIDS.4 Three hundred eighty-two cases of pediatric AIDS were reported in 1998.5 There are many more children who are infected with HIV but have not yet developed AIDS. Half of all new HIV infections reported to the CDC have been in people younger than 25.6 One encouraging fact is that the number of pediatric AIDS cases estimated by the CDC fell by two-thirds from 1992 to 1997 (947 to 310 cases).7

The U.S. cities that had the five highest rates of pediatric AIDS during 1998 were New York City; Miami, Florida; Newark, New Jersey; Washington, D.C.; and San Juan, Puerto Rico.8 The disease disproportionately affects children in minority groups, especially African Americans.9 Out of 8,461 cases in children under 13 reported to the CDC through December 1998, 58 percent were in blacks/not-Hispanic, 23 percent were in Hispanics, 17.5 percent were in whites/not-Hispanic, and 5.33 percent were in other minority groups.10

According to 1996 data, the latest available, HIV infection was the seventh leading cause of death for U.S. children through 14 years of age.11 However, the CDC reported a drop of 56 percent from 1994 to 1997 in the estimated number of children who died from AIDS.12 New anti-HIV drug therapies and promotion of voluntary testing are having a major impact.

Transmission

Almost all HIV-infected children acquire the virus from their mothers before or during birth or through breast-feeding. In the United States, approximately 25 percent of pregnant HIV-infected women not receiving AZT therapy have passed on the virus to their babies. The rate is higher in developing countries.

Most mother-to-child transmission, estimated to cause over 90 percent of infections worldwide in infants and children,13,14 probably occurs late in pregnancy or during birth. Although the precise mechanisms are unknown, scientists think HIV may be transmitted when maternal blood enters the fetal circulation, or by mucosal exposure to virus during labor and delivery. The role of the placenta in maternal-fetal transmission is unclear and the focus of ongoing research.

The risk of maternal-infant transmision (MIT) is significantly increased if the mother has advanced HIV disease, increased levels of HIV in her bloodstream, or fewer numbers of the immune system cells -- CD4+ T cells -- that are the main targets of HIV.

Other factors that may increase the risk are maternal drug use, severe inflammation of fetal membranes, or a prolonged period between membrane rupture and delivery. A study sponsored by NIAID and others found that HIV-infected women who gave birth more than four hours after the rupture of the fetal membranes were nearly twice as likely to transmit HIV to their infants, as compared to women who delivered within four hours of membrane rupture.15

HIV also may be transmitted from a nursing mother to her infant. Studies have suggested that breast-feeding introduces an additional risk of HIV transmission of approximately 10 to 14 percent among women with chronic HIV infection.16 In developing countries, an estimated one-third to one-half of all HIV infections are transmitted through breast-feeding.17 The WHO recommends that all HIV-infected women be advised as to both the risks and benefits of breast-feeding of their infants so that they can make informed decisions. In countries where safe alternatives to breast-feeding are readily available and economically feasible, this alternative should be encouraged. In general, in developing countries where safe alternatives to breast-feeding are not readily available, the benefits of breast-feeding in terms of decreased illness and death due to other infectious diseases greatly outweigh the potential risk of HIV transmission.

Prior to 1985 when screening of the nation's blood supply for HIV began, some children were infected through transfusions with blood or blood products contaminated with HIV. A small number of children also have been infected through sexual or physical abuse by HIV-infected adults.
Preventing Maternal-Infant Transmission (MIT)
In 1994, a landmark study conducted by the Pediatric ACTG demonstrated that AZT, given to HIV-infected women who had very little or no prior antiretroviral therapy and CD4+ T cell counts above 200/mm3, reduced the risk of MIT by two-thirds, from 25 percent to 8 percent.18 In the study, known as ACTG 076, AZT therapy was initiated in the second or third trimester and continued during labor, and infants were treated for six weeks following birth. AZT produced no serious side effects in mothers or infants. Long-term follow-up of the infants and mothers is ongoing. Pediatric ACTG protocol 185 tested an AZT regimen and was reported in 1999 to have lowered MIT to about 5 percent.19 Combination therapies have been shown to be beneficial in the treatment of HIV-infected adults, and current guidelines have been designed accordingly.20 In HIV-infected pregnant women, the safety and pharmacology of these potent drug combinations need to be better understood, and NIAID is conducting studies in this area.

Researchers have shown that this AZT regimen has reduced MIT in other populations in which it has been used. Observational studies in the past few years in the United States and Europe indicate that similar reductions can be achieved by using this regimen in regular clinical care settings. In the U.S., the number of MIT-acquired AIDS cases reported to the CDC fell 43 percent from 1992 to 1996, probably because of providing AZT to HIV-infected mothers, better guidelines for prenatal HIV counseling and testing, and changes in obstetrical management.21,22

Recent studies have shown that short regimens, too, of AZT can be beneficial in cutting back on MIT. In March 1999, researchers reported on a randomized study in Thailand on the short-term use of AZT during late pregnancy and labor in a group of non-breast-feeding women (the drug was not given to infants). They concluded that the treatment was safe and effective and can reduce the rate of MIT by 50 percent.23 Another recent study using a short-term AZT regimen (including post-partum) in groups of women in Ivory Coast and Burkina Faso, Africa, while limited, supported this finding.24

Following up on the success of ACTG 076, the Pediatric ACTG has begun new HIV prevention trials that build on the AZT regimen. These trials include other antiviral agents and multidrug combinations in an attempt to reduce MIT even more than that achieved by AZT alone. Also, in early 1999, a study sponsored by UNAIDS of a combination regimen of AZT plus lamivudine (3TC) in three African countries showed promising results.25

The AZT regimen used in ACTG 076 is not available in much of the world because of its high cost (approximately $1000 per pregnancy, not counting counseling or testing) and logistical demands. The cost of a short-course AZT regimen is substantially lower, but is still prohibitive in many countries. International agencies are studying whether there may be innovative ways to provide AZT at lower cost, e.g., through reductions in drug prices to developing countries, partnerships with industry, etc. NIAID is pursuing a global strategy that assesses whether simpler and less costly regimens to prevent mother-to-infant HIV transmission can be effective in various settings.

In September 1999, an NIAID-funded study (HIVNET 012) demonstrated that short-course therapy with nevirapine lowered the risk of HIV-1 transmission during the first 14-16 weeks of life by nearly 50 percent compared to AZT in a breastfeeding population.26 This simple, inexpensive regimen offers a potential cost-effective alternative for decreasing mother-to-child transmission in developing countries.27.

The International Perinatal HIV Group reported in April 1999 that elective caesarean section delivery can help reduce vertical transmission of HIV, though it is not without risk to certain women.28 When AZT treatment is combined with elective caesarean delivery, a transmission rate of 2 percent has been reported.29

Because a significant amount of MIT occurs around the time of birth, and the risk of maternal-fetal transmission depends, in part, on the amount of HIV in the mother's blood, it may be possible to reduce transmission using drug therapy only around the time of birth. NIAID has planned other studies that will assess the effectiveness of this approach as well as the role of new antiretrovirals, microbicides and other innovative strategies in reducing the risk of MIT of HIV.
Diagnosis
HIV infection is often difficult to diagnose in very young children. Infected babies, especially in the first few months of life, often appear normal and may exhibit no telltale signs that would allow a definitive diagnosis of HIV infection. Moreover, all children born to infected mothers have antibodies to HIV, made by the mother's immune system, that cross the placenta to the baby's bloodstream before birth and persist for up to 18 months. Because these maternal antibodies reflect the mother's but not the infant's infection status, the test is not useful in newborns or young infants.
In recent years, investigators have demonstrated the utility of highly accurate blood tests in diagnosing HIV infection in children 6 months of age and younger. One laboratory technique called polymerase chain reaction (PCR) can detect minute quantities of the virus in an infant's blood. Another procedure allows physicians to culture a sample of an infant's blood and test it for the presence of HIV.

Currently, PCR assays or HIV culture techniques can identify at birth about one-third of infants who are truly HIV-infected. With these techniques, approximately 90 percent of HIV-infected infants are identifiable by 2 months of age, and 95 percent by 3 months of age. One innovative new approach to both RNA and DNA PCR testing uses dried blood spot specimens, which should make it much simpler to gather and store specimens in field settings.
Progression of HIV Disease in Children
Researchers have observed two general patterns of illness in HIV-infected children. About 20 percent of children develop serious disease in the first year of life; most of these children die by age 4 years.

The remaining 80 percent of infected children have a slower rate of disease progression, many not developing the most serious symptoms of AIDS until school entry or even adolescence. A recent report from a large European registry of HIV-infected children indicated that half of the children with perinatally acquired HIV disease were alive at age 9. Another study, of 42 perinatally HIV-infected children who survived beyond 9 years of age, found about one-quarter of the children to be asymptomatic with relatively intact immune systems.

The factors responsible for the wide variation observed in the rate of disease progression in HIV-infected children are a major focus of the NIAID pediatric AIDS research effort. The Women and Infants Transmission Study, a multisite perinatal HIV study funded by NIH, has found that maternal factors including Vitamin A level and CD4 counts during pregnancy, as well as infant viral load and CD4 counts in the first several months of life, can help identify those infants at risk for rapid disease progression who may benefit from early aggressive therapy.
Signs and Symptoms of Pediatric HIV Disease
Many children with HIV infection do not gain weight or grow normally. HIV-infected children frequently are slow to reach important milestones in motor skills and mental development such as crawling, walking and speaking. As the disease progresses, many children develop neurologic problems such as difficulty walking, poor school performance, seizures, and other symptoms of HIV encephalopathy.

Like adults with HIV infection, children with HIV develop life-threatening opportunistic infections (OIs), although the incidence of various OIs differs in adults and children. For example, toxoplasmosis is seen less frequently in HIV-infected children than in HIV-infected adults, while serious bacterial infections occur more commonly in children than in adults. Also, as children with HIV become sicker, they may suffer from chronic diarrhea due to opportunistic pathogens.

Pneumocystis carinii pneumonia (PCP) is the leading cause of death in HIV-infected children with AIDS. PCP, as well as cytomegalovirus (CMV) disease, usually are primary infections in children, whereas in adults these diseases result from the reactivation of latent infections.

A lung disease called lymphocytic interstitial pneumonitis (LIP), rarely seen in adults, also occurs frequently in HIV-infected children. This condition, like PCP, can make breathing progressively more difficult and often results in hospitalization.

Children with HIV suffer the usual childhood bacterial infections -- only more frequently and more severely than uninfected children. These bacterial infections can cause seizures, fever, pneumonia, recurrent colds, diarrhea, dehydration and other problems that often result in extended hospital stays and nutritional problems.

HIV-infected children frequently have severe candidiasis, a yeast infection that can cause unrelenting diaper rash and infections in the mouth and throat that make eating difficult.
Treatment of HIV-Infected Children
NIAID investigators are defining the best treatments for pediatric patients. Currently there are 16 drug products approved by the FDA for the treatment of adult HIV infection. Through major contributions by the Pediatric ACTG, 10 antiretroviral agents have pediatric label information, including 3 protease inhibitors.28 While the basic principles that guide treatment of pediatric HIV infection are the same as for any HIV-infected person, there are a number of unique scientific and medical concerns that are important to consider in the treatment of children with HIV infection. These range from differences from adults in age-related issues such as CD4 lymphocyte counts and drug metabolism to requirements for special formulations and treatment regimens that are appropriate for infants through adolescents. As in adults, treatment of HIV-infected children today is a complex task of using potent combinations of antiretroviral agents to maximally suppress viral replication.

Researchers supported by NIAID are focusing not only on the development of new antiretroviral products but also on the critical question of how to best use the treatments that are currently available. Treatment strategy questions designed to identify what the best initial therapy is, when failing regimens should be switched and strategies for how to address the antiretroviral needs of children with advanced disease are examples. Long-term assessment of these children is also a high priority to assess sustained antiretroviral benefits as well as to monitor for potential adverse consequences of treatment.
Problems of Families
A mother and child with HIV usually are not the only family members with the disease. Often, the mother's sexual partner is infected, and other children in the family may be infected as well. Frequently, a parent with AIDS does not survive to care for his or her HIV-infected child.

In the countries hardest hit by the AIDS epidemic, some 8.2 million children under 15 around the world have been orphaned by AIDS - 90 percent of them in sub-Saharan Africa alone.31 The rate is expected to increase. One in three of these orphans is under age five.32 Communities and extended families are struggling with and often overwhelmed by the vast number of AIDS orphans. Many orphans and other children from families devastated by AIDS face multiple risks, such as forced relocation, violence, living on the streets, drug use, and even commercial sex. Other children suffer because sex education and services are not available to them or do not communicate effectively to them. Living in a country undergoing political turmoil or where fathers migrate for work can also raise the risk of a child becoming HIV-infected.

Resources

Note: The UNAIDS and CDC publications referenced in this article may be viewed on the World Wide Web at http://www.unaids.org and http://www.cdc.gov.

AIDS Clinical Trials Information Service. For information about pediatric and adult AIDS clinical trials open to enrollment, call (800) TRIALS-A, 9 a.m. to 7 p.m. Eastern Time, Monday through Friday. Web: http://www.actis.org E-mail: actis@actis.org.

National AIDS Hotline. Staffed 24 hours a day, seven days a week. English Service: 1-800-342-AIDS. Spanish service: 1-800-344-7432. Deaf service (TDD): 1-800-243-7889.

The National Pediatric HIV Resource Center. A non-profit organization that serves professionals who care for children, adolescents and families with HIV infection and AIDS. Phone: 973-972-0410 or toll free: 1-800-362-0071. Web: http://pedhivaids.org/. E-mail: ortegaes@umdnj.edu.

The Pediatric AIDS Foundation. A national non-profit organization dedicated exclusively to supporting reseach for AIDS in children. Phone: 310-314-1459. Web: http://www.pedaids.org E-mail: info@pedaids.org.

The Pediatric Branch of the National Cancer Institute (NCI) conducts clinical trials for HIV-infected children on the NIH campus in Bethesda, Md. Phone: (301) 402-0696. NCI webpage: http://www.nci.nih.gov

References

  1. Connor, E. et al. 1994. Reduction of maternal-infant transmission of human immunodeficiency virus type 1 with zidovudine treatment. N Engl J Med 311:1173-80.
  2. UNAIDS. AIDS Epidemic Update (Dec., 1998):1, 2, 3, 7, 8., 9, 17.
  3. UNAIDS. Report on the Global HIV/AIDS Epidemic (June, 1998):6, 8.
  4. Centers for Disease Control and Prevention. HIV/AIDS Surveillance Report (Dec. 1998) 10(2):7.
  5. Ibid., p. 26
  6. Rosenberg, P., et al. 1994. Declining age at HIV infection in the United States. N Engl J Med 330:789-90.
  7. Centers for Disease Control and Prevention, op cit., p. 36.
  8. Ibid., pp. 10-11.
  9. UNAIDS, Update, p. 6.
  10. Centers for Disease Control and Prevention, op. cit., p. 24.
  11. Centers for Disease Control and Prevention. National Center for Health Statistics. 1998. National Vital Statistics Report 47 (9):26.
  12. Centers for Disease Control and Prevention, HIV/AIDS Surveillance Report, p. 39.
  13. NAIDS, Report.
  14. Quinn, T. 1996. Global burden of the HIV pandemic. Lancet:348:99-106.
  15. Landesman, S., et al. 1996. Obstetrical factors and the transmission of human immunodeficiency virus type 1 from mother to child. N Engl J Med 334: 1617-23.
  16. Monitoring the AIDS Pandemic (MAP) Network. 1998. The status and trends of the HIV/AIDS epidemics in the world:17.
  17. UNAIDS, Report, p. 48.
  18. Connor, E., et al., op. cit.
  19. Stiehm, E., et al. 1999. Efficacy of zidovudine and human immunodeficiency virus (HIV) hyperimmune immunoglobulin for reducing perinatal HIV transmission from HIV-infected women with advanced disease: results of Pedatric ACTG protocol 185. J Infect Dis 179(3):567-75.
  20. Centers for Disease Control and Prevention. 1998. Public Health Service Task Force recommendations for the use of antiretroviral drugs in pregnant women infected with HIV-1 for maternal health and for reducing perinatal HIV-1 transmission in the United States. MMWR Recommendations and Reports 47 (RR-2). May be viewed on the Web at http://www.hivatis.org.
  21. Wilfert, C., et al. 1999. Consensus statement: Science, ethics, and the future of research into maternal infant transmission of HIV-1. Lancet 353 (9155):832-35.
  22. Centers for Disease Control and Prevention. 1997. Update: Perinatally acquired HIV/AIDS-United States, 1997. MMWR 46: 1086-92.
  23. Shaffer, N., et al. 1999. Short-course zidovudine for perinatal HIV-1 transmission in Bangkok, Thailand: A randomised controlled trial. Lancet 353 (9155):773-79.
  24. Dabis, F. et al. 1999. 6-month efficacy, tolerance, and acceptability of a short regimen of oral zidovudine to reduce vertical transmission of HIV in breastfed children in Cote d'Ivoire and Burkina Faso. Lancet 353 (9155):786-92.
  25. Saba, J., The PETRA Trial Study Team. 1999. Interim analysis of early efficacy of three short course ZDV/3TC combination regimens to prevent mother-to-child transmission of HIV-1. Presented at the Sixth Conference on Retroviruses and Opportunistic Infections. Chicago: February 1, 1999.Guay, L, et al. 1999. Intrapartum and neonatal single-dose nevirapine compared with zidovudine for prevention of mother-to-child transmission of HIV-1 in Kampala, Uganda: HIVNET 012 randomised trial. Lancet 354:795-802.
  26. Marseille, E., et al. 1999. Cost effectiveness of single-dose nevirapine regimen for mothers and babies to decrease vertical HIV-1 transmission in sub-Saharan Africa. Lancet 654:803-09.
  27. Riley, L.E. and Green, M.F. Elective caesarean delivery to reduce the transmission of HIV. 1999. N Engl J Med 340:13, 1032.
  28. Mofenson, L.M., Fowler, M.G. In press. Interruption of materno-fetal transmission. Reported in Shaffer, N., op. cit.
  29. HIV/AIDS Treatment Information Service. 1999. Guidelines for the use of antiretroviral agents in pediatric HIV infection. May be viewed on the Web at http://www.hivatis.org/.
  30. UNAIDS, Report, p. 9.
  31. Centers for Disease Control and Prevention. National Center for HIV, STD, and TB Prevention. Divisions of HIV/AIDS. International Projections/Statistics. Web: http://www.cdc.gov/hiv/stats.htm#international
  32. UNAIDS, Update, p. 9.
NIAID is a component of the National Institutes of Health (NIH). NIAID conducts and supports research to prevent, diagnose and treat illnesses such as HIV disease and other sexually transmitted diseases, tuberculosis, malaria, and other infectious diseases as well as asthma and allergies.

Prepared by:
Office of Communications and Public Liaison
National Institute of Allergy and Infectious Diseases
National Institutes of Health
Bethesda, MD 20892
Public Health Service
U.S. Department of Health and Human Services
February 2000

Press releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov.

READ MORE - HIV Infection in Infants and Children

HIV Infection and AIDS, An Overview

AIDS - acquired immunodeficiency syndrome - was first reported in the United States in 1981 and has since become a major worldwide epidemic. AIDS is caused by the human immunodeficiency virus (HIV). By killing or damaging cells of the body's immune system, HIV progressively destroys the body's ability to fight infections and certain cancers. People diagnosed with AIDS may get life-threatening diseases called opportunistic infections, which are caused by microbes such as viruses or bacteria that usually do not make healthy people sick.

More than 700,000 cases of AIDS have been reported in the United States since 1981, and as many as 900,000 Americans may be infected with HIV. The epidemic is growing most rapidly among minority populations and is a leading killer of African-American males. According to the U.S. Centers for Disease Control and Prevention (CDC), AIDS affects nearly seven times more African Americans than whites and three times more Hispanics than whites (CDC HIV/AIDS Surveillance Report, Vol. 12, 2000).

Resources
For information about Food and Drug Administration-approved HIV-related clinical trials being conducted throughout the United States, contact the AIDS Clinical Trials Information Service.

1-800-TRIALS-A (1-800-874-2572)
1-888-480-3739 (TTY/Deaf Access)
http://www.actis.org

For federally approved treatment guidelines on HIV/AIDS, contact the HIV/AIDS Treatment Information Service.

1-800-HIV-0440 (1-800-448-0440)
1-301-519-6616
1-888-480-3739 (TTY/Deaf Access)
http://www.hivatis.org

Both services operate from 9 a.m. to 5 p.m. Eastern Time, Monday through Friday. Spanish-speaking specialists are available.

To get information specifically about clinical trials conducted by the NIAID Intramural AIDS Research Program, call 1-800-243-7644 (http://clinicaltrials.gov).

For materials contact the National Prevention Information Network.

1-800-458-5231
1-301-562-1098
1-800-243-7012 (TTY/Deaf Access)
http://www.cdcnpin.org NIAID is a component of the National Institutes of Health (NIH). NIAID supports basic and applied research to prevent, diagnose, and treat infectious and immune-mediated illnesses, including HIV/AIDS and other sexually transmitted diseases, illness from potential agents of bioterrorism, tuberculosis, malaria, autoimmune disorders, asthma and allergies.

Press releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov.

Prepared by:
Office of Communications and Public Liaison
National Institute of Allergy and Infectious Diseases
National Institutes of Health
Bethesda, MD 20892

Public Health Service
U.S. Department of Health and Human Services May 2001

How is HIV transmitted?
HIV is spread most commonly by having unprotected sex with an infected partner. The virus can enter the body through the lining of the vagina, vulva, penis, rectum, or mouth during sex.

HIV also is spread through contact with infected blood. Before donated blood was screened for evidence of HIV infection and before heat-treating techniques to destroy HIV in blood products were introduced, HIV was transmitted through transfusions of contaminated blood or blood components. Today, because of blood screening and heat treatment, the risk of getting HIV from such transfusions is extremely small.

HIV frequently is spread among injection drug users by the sharing of needles or syringes contaminated with very small quantities of blood from someone infected with the virus. It is rare, however, for a patient to give HIV to a health care worker or vice-versa by accidental sticks with contaminated needles or other medical instruments.

Women can transmit HIV to their babies during pregnancy or birth. Approximately one-quarter to one-third of all untreated pregnant women infected with HIV will pass the infection to their babies. HIV also can be spread to babies through the breast milk of mothers infected with the virus. If the mother takes the drug AZT during pregnancy, she can reduce significantly the chances that her baby will get be infected with HIV. If health care providers treat mothers with AZT and deliver their babies by cesarean section, the chances of the baby being infected can be reduced to a rate of 1 percent.

A study sponsored by the National Institute of Allergy and Infectious Diseases (NIAID) in Uganda found a highly effective and safe drug regimen for preventing transmission of HIV from an infected mother to her newborn that is more affordable and practical than any other examined to date. Interim results from the study show that a single oral dose of the antiretroviral drug nevirapine (NVP) given to an HIV-infected woman in labor and another to her baby within three days of birth reduces the transmission rate by half compared with a similar short course of AZT.

Although researchers have found HIV in the saliva of infected people, there is no evidence that the virus is spread by contact with saliva. Laboratory studies reveal that saliva has natural properties that limit the power of HIV to infect. Research studies of people infected with HIV have found no evidence that the virus is spread to others through saliva by kissing. No one knows, however, whether so-called "deep" kissing, involving the exchange of large amounts of saliva, or oral intercourse increase the risk of infection. Scientists also have found no evidence that HIV is spread through sweat, tears, urine, or feces.

Studies of families of HIV-infected people have shown clearly that HIV is not spread through casual contact such as the sharing of food utensils, towels and bedding, swimming pools, telephones, or toilet seats. HIV is not spread by biting insects such as mosquitoes or bedbugs.

HIV can infect anyone who practices risky behaviors such as

* sharing drug needles or syringes
* having sexual contact with an infected person without using a condom
* having sexual contact with someone whose HIV status is unknown

Having a sexually transmitted disease such as syphilis, genital herpes, chlamydial infection, gonorrhea, or bacterial vaginosis appears to make people more susceptible to getting HIV infection during sex with infected partners.

What are the early symptoms of HIV infection?
Many people do not have any symptoms when they first become infected with HIV. Some people, however, have a flu-like illness within a month or two after exposure to the virus. This illness may include fever, headache, tiredness, and enlarged lymph nodes (glands of the immune system easily felt in the neck and groin). These symptoms usually disappear within a week to a month and are often mistaken for those of another viral infection. During this period, people are very infectious, and HIV is present in large quantities in genital fluids.

More persistent or severe symptoms may not surface for a decade or more after HIV first enters the body in adults, or within two years in children born with HIV infection. This period of "asymptomatic" infection is highly individual. Some people may begin to have symptoms within a few months, while others may be symptom-free for more than 10 years.

Even during the asymptomatic period, the virus is actively multiplying, infecting, and killing cells of the immune system. HIV's effect is seen most obviously in a decline in the blood levels of CD4+ T cells (also called T4 cells) - the immune system's key infection fighters. At the beginning of its life in the human body, the virus disables or destroys these cells without causing symptoms.

As the immune system deteriorates, a variety of complications start to take over. For many people, their first sign of infection is large lymph nodes or "swollen glands" that may be enlarged for more than three months. Other symptoms often experienced months to years before the onset of AIDS include

* lack of energy
* weight loss
* frequent fevers and sweats
* persistent or frequent yeast infections (oral or vaginal)
* persistent skin rashes or flaky skin
* pelvic inflammatory disease in women that does not respond to treatment
* short-term memory loss

Some people develop frequent and severe herpes infections that cause mouth, genital, or anal sores, or a painful nerve disease called shingles. Children may grow slowly or be sick a lot.

What is AIDS?
The term AIDS applies to the most advanced stages of HIV infection. CDC developed official criteria for the definition of AIDS and is responsible for tracking the spread of AIDS in the United States.

CDC's definition of AIDS includes all HIV-infected people who have fewer than 200 CD4+ T cells per cubic millimeter of blood. (Healthy adults usually have CD4+ T-cell counts of 1,000 or more.) In addition, the definition includes 26 clinical conditions that affect people with advanced HIV disease. Most of these conditions are opportunistic infections that generally do not affect healthy people. In people with AIDS, these infections are often severe and sometimes fatal because the immune system is so ravaged by HIV that the body cannot fight off certain bacteria, viruses, fungi, parasites, and other microbes.

Symptoms of opportunistic infections common in people with AIDS include

* coughing and shortness of breath
* seizures and lack of coordination
* difficult or painful swallowing
* mental symptoms such as confusion and forgetfulness
* severe and persistent diarrhea
* fever
* vision loss
* nausea, abdominal cramps, and vomiting
* weight loss and extreme fatigue
* severe headaches
* coma

Children with AIDS may get the same opportunistic infections as do adults with the disease. In addition, they also have severe forms of the bacterial infections all children may get, such as conjunctivitis (pink eye), ear infections, and tonsillitis.

People with AIDS are particularly prone to developing various cancers, especially those caused by viruses such as Kaposi's sarcoma and cervical cancer, or cancers of the immune system known as lymphomas. These cancers are usually more aggressive and difficult to treat in people with AIDS. Signs of Kaposi's sarcoma in light-skinned people are round brown, reddish, or purple spots that develop in the skin or in the mouth. In dark-skinned people, the spots are more pigmented.

During the course of HIV infection, most people experience a gradual decline in the number of CD4+ T cells, although some may have abrupt and dramatic drops in their CD4+ T-cell counts. A person with CD4+ T cells above 200 may experience some of the early symptoms of HIV disease. Others may have no symptoms even though their CD4+ T-cell count is below 200.

Many people are so debilitated by the symptoms of AIDS that they cannot hold steady employment or do household chores. Other people with AIDS may experience phases of intense life-threatening illness followed by phases in which they function normally.

A small number of people (fewer than 50) first infected with HIV 10 or more years ago have not developed symptoms of AIDS. Scientists are trying to determine what factors may account for their lack of progression to AIDS, such as particular characteristics of their immune systems or whether they were infected with a less aggressive strain of the virus, or if their genes may protect them from the effects of HIV. Scientists hope that understanding the body's natural method of control may lead to ideas for protective HIV vaccines and use of vaccines to prevent the disease from progressing.

How is HIV infection diagnosed?
Because early HIV infection often causes no symptoms, a doctor or other health care provider usually can diagnose it by testing a person's blood for the presence of antibodies (disease-fighting proteins) to HIV. HIV antibodies generally do not reach detectable levels in the blood for one to three months following infection. It may take the antibodies as long as six months to be produced in quantities large enough to show up in standard blood tests.

People exposed to the virus should get an HIV test as soon as they are likely to develop antibodies to the virus - within 6 weeks to 12 months after possible exposure to the virus. By getting tested early, people with HIV infection can discuss with a health care provider when they should start treatment to help their immune systems combat HIV and help prevent the emergence of certain opportunistic infections (see section on treatment below). Early testing also alerts HIV-infected people to avoid high-risk behaviors that could spread the virus to others.

Most health care providers can do HIV testing and will usually offer counseling to the patient at the same time. Of course, individuals can be tested anonymously at many sites if they are concerned about confidentiality.

Health care providers diagnose HIV infection by using two different types of antibody tests, ELISA and Western Blot. If a person is highly likely to be infected with HIV and yet both tests are negative, the health care provider may request additional tests. The person also may be told to repeat antibody testing at a later date, when antibodies to HIV are more likely to have developed.

Babies born to mothers infected with HIV may or may not be infected with the virus, but all carry their mothers' antibodies to HIV for several months. If these babies lack symptoms, a doctor cannot make a definitive diagnosis of HIV infection using standard antibody tests until after 15 months of age. By then, babies are unlikely to still carry their mothers' antibodies and will have produced their own, if they are infected. Health care experts are using new technologies to detect HIV itself to more accurately determine HIV infection in infants between ages 3 months and 15 months. They are evaluating a number of blood tests to determine if they can diagnose HIV infection in babies younger than 3 months.

How is HIV infection treated?
When AIDS first surfaced in the United States, there were no medicines to combat the underlying immune deficiency and few treatments existed for the opportunistic diseases that resulted. Over the past 10 years, however, researchers have developed drugs to fight both HIV infection and its associated infections and cancers.

The U.S. Food and Drug Administration (FDA) has approved a number of drugs for treating HIV infection. The first group of drugs used to treat HIV infection, called nucleoside reverse transcriptase (RT) inhibitors, interrupts an early stage of the virus making copies of itself. Included in this class of drugs (called nucleoside analogs) are AZT (also known as zidovudine or ZDV), ddC (zalcitabine), ddI (dideoxyinosine), d4T (stavudine), and 3TC (lamivudine). These drugs may slow the spread of HIV in the body and delay the onset of opportunistic infections.

Health care providers can prescribe non-nucleoside reverse transcriptase inhibitors (NNRTIs), such as delvaridine (Rescriptor), nevirapine (Viramune), and efravirenz (Sustiva), in combination with other antiretroviral drugs.

More recently, FDA has approved a second class of drugs for treating HIV infection. These drugs, called protease inhibitors, interrupt virus replication at a later step in its life cycle. They include

* ritonavir (Norvir)
* saquinivir (Invirase)
* indinavir (Crixivan)
* amprenivir (Agenerase)
* nelfinavir (Viracept)
* lopinavir (Kaletra)

Because HIV can become resistant to any of these drugs, health care providers must use a combination treatment to effectively suppress the virus.

Currently available antiretroviral drugs do not cure people of HIV infection or AIDS, however, and they all have side effects that can be severe. Some of the nucleoside RT inhibitors may cause a depletion of red or white blood cells, especially when taken in the later stages of the disease. Some may also cause an inflammation of the pancreas and painful nerve damage. There have been reports or complications and other severe reactions, including death, to some of the antiretroviral nucleoside analogs when used alone or in combination. Therefore, health care experts recommend that people on antiretroviral therapy be routinely seen and followed by their providers.

The most common side effects associated with protease inhibitors include nausea, diarrhea, and other gastrointestinal symptoms. In addition, protease inhibitors can interact with other drugs resulting in serious side effects.

Researchers have credited highly active antiretroviral therapy, or HAART, as being a major factor in reducing the number of deaths from AIDS in this country by 47 percent in 1997. HAART is a treatment regimen that uses a combination of reverse transcriptase inhibitors and protease inhibitors to treat patients. Patients who are newly infected with HIV as well as AIDS patients can take the combination.

While HAART is not a cure for AIDS, it has greatly improved the health of many people with AIDS and it reduces the amount of virus circulating in the blood to nearly undetectable levels. Researchers have shown that HAART cannot eradicate HIV entirely from the body. HIV remains present, lurking in hiding places such as the lymph nodes, the brain, testes, and the retina of the eye, even in patients who have been treated.

A number of drugs are available to help treat opportunistic infections to which people with HIV are especially prone. These drugs include

* foscarnet and ganciclovir to treat cytomegalovirus eye infections
* fluconazole to treat yeast and other fungal infections
* trimethoprim/sulfamethoxazole (TMP/SMX) or pentamidine to treat Pneumocystis carinii pneumonia (PCP)

In addition to antiretroviral therapy, health care providers treat adults with HIV, whose CD4+ T-cell counts drop below 200, to prevent the occurrence of PCP, which is one of the most common and deadly opportunistic infections associated with HIV. They give children PCP preventive therapy when their CD4+ T-cell counts drop to levels considered below normal for their age group. Regardless of their CD4+ T-cell counts, HIV-infected children and adults who have survived an episode of PCP take drugs for the rest of their lives to prevent a recurrence of the pneumonia.

HIV-infected individuals who develop Kaposi's sarcoma or other cancers are treated with radiation, chemotherapy, or injections of alpha interferon, a genetically engineered naturally occurring protein.

How can HIV infection be prevented?
Because no vaccine for HIV is available, the only way to prevent infection by the virus is to avoid behaviors that put a person at risk of infection, such as sharing needles and having unprotected sex.

Many people infected with HIV have no symptoms. Therefore, there is no way of knowing with certainty whether a sexual partner is infected unless he or she has repeatedly tested negative for the virus and has not engaged in any risky behavior.

People should either abstain from having sex or use male latex condoms or female polyurethane condoms, which may offer partial protection, during oral, anal, or vaginal sex. Only water-based lubricants should be used with male latex condoms.

Although some laboratory evidence shows that spermicides can kill HIV, researchers have not found that these products can prevent a person from getting HIV.

The risk of HIV transmission from a pregnant woman to her baby is significantly reduced if she takes AZT during pregnancy, labor, and delivery, and her baby takes it for the first six weeks of life.

What research is going on?
NIAID-supported investigators are conducting an abundance of research on HIV infection, including developing and testing HIV vaccines and new therapies for the disease and some of its associated conditions. Investigators are testing 29 HIV vaccines in people, and are developing or testing many drugs for HIV infection or AIDS-associated opportunistic infections. Researchers also are investigating exactly how HIV damages the immune system. This research is suggesting new and more effective targets for drugs and vaccines. NIAID-supported investigators also continue to trace how the disease progresses in different people.

Scientists are investigating and testing chemical barriers, such as topical microbicides, that people can use in the vagina or in the rectum during sex to prevent HIV transmission. They also are looking at other ways to prevent transmission, such as controlling sexually transmitted diseases and modifying people's behavior, as well as ways to prevent transmission from mother to child.
READ MORE - HIV Infection and AIDS, An Overview

Neurological Manifestations Of Aids

What are the neurological manifestations of AIDS?
DESCRIPTION: Acquired immune deficiency syndrome (AIDS) is the result of an infection with the human immunodeficiency virus (HIV). This virus attacks selected cells of the immune, nervous, and other systems impairing their proper function. HIV infection may cause damage to the brain and spinal cord, causing encephalitis (inflammation of the brain), meningitis (inflammation of the membranes surrounding the brain), nerve damage, difficulties in thinking (i.e., AIDS dementia complex), behavioral changes, poor circulation, headache, and stroke. AIDS-related cancers such as lymphoma and opportunistic infections (OI) may also affect the nervous system. Neurological symptoms may be mild in the early stages of AIDS, but may become severe in the final stages. Complications vary widely from one patient to another. Cerebral toxoplasmosis, a common OI in AIDS patients, causes such symptoms as headache, confusion, lethargy, and low-grade fever. Other symptoms may include weakness, speech disturbance, ataxia, apraxia, seizures, and sensory loss. Progressive multifocal leukoencephalopathy (PML), a disorder that can also occur in AIDS patients, causes weakness, hemiparesis or facial weakness, dysphasia, vision loss, and ataxia. Some patients with PML may also develop compromised memory and cognition.
Is there any treatment?
TREATMENT: There is no cure for AIDS but recently developed, experimental treatments appear very promising. Some symptoms and complications may improve with treatment. For example, antidementia drugs may relieve confusion and slow mental decline. Infections may be treated with antibiotics. Radiation therapy may be needed to treat AIDS-related cancers present in the brain or spinal cord.
What is the prognosis?
PROGNOSIS: The prognosis for individuals with AIDS in recent years has improved significantly because of new drugs and treatments, and educational and preventive efforts.
What research is being done?
RESEARCH: The NINDS supports a broad spectrum of basic and clinical research studies on the neurological complications of AIDS. Much of this research is conducted at leading biomedical research institutions across the country.
Where can I find more information?
These articles, available from a medical library, are sources of in-depth information on the neurological manifestations of AIDS:

McArthur, J. "Neurologic Manifestations of Human Immunodeficiency Virus Infection." In Diseases of the Nervous System: Clinical Neurobiology, W.B. Saunders Co., Philadelphia, pp. 1312-1330 (1992).

Mintz, M, and Epstein, L. "Neurologic Manifestations of Pediatric Acquired Immunodeficiency Syndrome: Clinical Features and Therapeutic Approaches." Seminars in Neurology, 12:1; 51-56 (March 1992).

Newton, H. "Common Neurologic Complications of HIV-1 Infection and AIDS." American Family Physician, 51:2; 387-398 (February 1, 1995).

Pajeau, A, and Roman, G. "HIV Encephalopathy and Dementia." Psychiatric Clinics of North America, 15:2; 455-466 (June 1992).

Simpson, D, and Tagliati, M. "Neurologic Manifestations of HIV Infection." Annals of Internal Medicine, 121:10; 769-785 (November 1994).

Additional information or services are available from the following organizations
(last updated April 7, 1998):

American Foundation for AIDS Research
733 Third Ave., 12th Flr.
New York, NY 10017
(212) 682-7440

Pediatric AIDS Foundation.
1311 Colorado Avenue
Santa Monica, CA 90404
(310) 395-9051

CDC National AIDS Clearinghouse
P.O. Box 6003
Rockville, MD 20849-6003
(800) 458-5231

National Institute of Allergy & Infectious Diseases
Building 31, Room 7A50
Bethesda, MD 20892-2520
(301) 496-5717

National Association of People with AIDS
1413 K Street, NW
Washington, DC 20005
(202) 898-0414

AIDS Clinical Trials Information Service
P.O. Box 6421
Rockville, MD 20849-6421
(800) TRIALS-A

Information provided by NIH.

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Friday, August 20, 2010

Swine influenza

Swine influenza (also called pig influenza, swine flu, hog flu and pig flu) is an infection by any one of several types of swine influenza virus. Swine influenza virus (SIV) or S-OIV (swine-origin influenza virus) is any strain of the influenza family of viruses that is endemic in pigs. As of 2009, the known SIV strains include influenza C and the subtypes of influenza A known as H1N1, H1N2, H3N1, H3N2, and H2N3.

Swine influenza virus is common throughout pig populations worldwide. Transmission of the virus from pigs to humans is not common and does not always lead to human influenza, often resulting only in the production of antibodies in the blood. If transmission does cause human influenza, it is called zoonotic swine flu. People with regular exposure to pigs are at increased risk of swine flu infection. The meat of an infected animal poses no risk of infection when properly cooked.

During the mid-20th century, identification of influenza subtypes became possible, allowing accurate diagnosis of transmission to humans. Since then, only 50 such transmissions have been confirmed. These strains of swine flu rarely pass from human to human. Symptoms of zoonotic swine flu in humans are similar to those of influenza and of influenza-like illness in general, namely chills, fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort.

Classification
Of the three genera of influenza viruses that cause human flu, two also cause influenza in pigs, with influenza A being common in pigs and influenza C being rare. Influenza B has not been reported in pigs. Within influenza A and influenza C, the strains found in pigs and humans are largely distinct, although because of reassortment there have been transfers of genes among strains crossing swine, avian, and human species boundaries.

Influenza C
Influenza C viruses infect both humans and pigs, but do not infect birds. Transmission between pigs and humans have occurred in the past. For example, influenza C caused small outbreaks of a mild form of influenza amongst children in Japan and California. Because of its limited host range and the lack of genetic diversity in influenza C, this form of influenza does not cause pandemics in humans.

Influenza A

Swine influenza is known to be caused by influenza A subtypes H1N1, H1N2,H2N3, H3N1, and H3N2. In pigs, three influenza A virus subtypes (H1N1, H1N2, and H3N2) are the most common strains worldwide. In the United States, the H1N1 subtype was exclusively prevalent among swine populations before 1998; however, since late August 1998, H3N2 subtypes have been isolated from pigs. As of 2004, H3N2 virus isolates in US swine and turkey stocks were triple reassortants, containing genes from human (HA, NA, and PB1), swine (NS, NP, and M), and avian (PB2 and PA) lineages.

Surveillance
.
Although there is no formal national surveillance system in the United States to determine what viruses are circulating in pigs, there is an informal surveillance network in the United States that is part of a world surveillance network.


Veterinary medical pathologist, Tracey McNamara, set up a national disease surveillance system in zoos because the zoos do active disease surveillance and many of the exotic animals housed there have broad susceptibilities. Many species fall below the radar of any federal agencies (including dogs, cats, pet prairie dogs, zoo animals, and urban wildlife), even though they may be important in the early detection of human disease outbreaks.

source



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Saturday, August 14, 2010

Avian Influenza (Flu Burung)

(avian influenza) is an infectious disease caused by viruses that normally infect birds and mammals.

Source of infection

Cause of bird flu was type A influenza virus that spreads among birds. This virus was later found to also spread to other species such as pigs, cats, dogs, tigers, and humans.

Influenza virus type A has several subtypes characterized by Hemagglutinin (H) and Neuramidase (N).
There are 9 variants and 14 variants of N. H Bird flu virus is contagious when it is the H5N1 subtype which has a long incubation period of 3-5 days.


Infection Mode

Wild birds and domesticated poultry (livestock) can be a source of H5N1 dispersal. In Southeast Asia most cases of bird flu occurred in poultry transportation routes or instead of wild bird migration routes.

This virus can be transmitted through air or contact through food, drink, and touch. However, this virus will die in high temperatures. Therefore, meat, eggs, and animals should be thoroughly cooked to avoid infection. Personal hygiene should be maintained also by washing hands with antiseptic. Cleanliness of body and clothing also needs to be maintained.

The virus can survive in cold temperatures. Food that is refrigerated or frozen can store the virus. Hands should be washed before and after cooking or touching raw food materials.

Poultry should not be kept in the house or room in which to live. Livestock must be kept away from the housing to reduce the risk of transmission.

Not forever, if infected with the virus will cause illness. However, this can be dangerous in the future because the virus is always mutating, so have the potential pathogen at a time. Therefore, if found in animals or birds that died suddenly the authorities would make the allegation of bird flu. To prevent transmission, the other animals in the surrounding areas need dimusnahkan.dan berkasus prevented the bird flu spreading!


Symptoms and treatment


Common symptoms that can occur are high fever, respiratory complaints, and (probably) the stomach. Viral replication in the body can run fast so that the patient should immediately seek medical attention.

Handling medical and drug administration performed by an authorized medical officer. The drugs commonly given is lowering and anti-virus. Among the antivirus that can be used is the type that inhibit replication of neuramidase (neuramidase inhibitor), among others, Oseltamivir (Tamiflu) and zanamivir. Each of these antivirus has side effects and should be given within a certain time so that the required physician opinion.


Case Avian Influenza

On July 21, 2005, three fatal cases occurred in Tangerang, Indonesia, caused by the H5N1 subtype of bird flu. Unlike other cases in Southeast Asia (Thailand, Cambodia, and Vietnam), this case is considered unique because the victim was not a lot to do with birds.

Until June 6, 2007, WHO has recorded 310 cases with 189 deaths in humans caused by this virus are as follows (see source):

  • Indonesia - 99 cases with 79 deaths.
  • Vietnam - 93 cases with 42 deaths.
  • Egypt - 34 cases with 14 deaths.
  • Thailand - 25 cases with 17 deaths.
  • Republic of China - 25 cases with 16 deaths.
  • Turkey - 12 cases with four deaths.
  • Azerbaijan - 8 cases with 5 deaths.
  • Cambodia - 7 cases with seven deaths.
  • Iraq - three cases with two deaths.
  • Laos - two cases with two deaths.
  • Nigeria - a case with one death.
  • Djibouti - a case without a death.
Description: The number of cases reported to WHO is the number of cases that have been verified by laboratory results.


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