Two studies supported by the National Institute of Allergy and Infectious Diseases (NIAID) provide important new information about the HIV/AIDS epidemic in India, the country with the single largest number of HIV-infected persons in the world. One study identifies risk factors and describes clinical symptoms associated with newly acquired HIV infections. The other sheds light on how the virus is transmitted from high-risk to low-risk populations in India. Both are published in the Dec. 17 issue of the Journal of the American Medical Association (JAMA).
By advancing our understanding of risk factors, signs and symptoms of acute HIV infection and the dynamics of HIV transmission, these studies should help scientists and physicians in India develop better strategies to prevent HIV infection," says NIAID Director Anthony S. Fauci, M.D. "This information also should be useful to investigators studying HIV/AIDS in other developing countries, which bear the brunt of the global AIDS pandemic."
A recent report by the United Nations and the World Health Organization estimates that 16,000 people worldwide are newly infected with HIV each day, mostly in sub-Saharan Africa and Asia. The report also estimates that between 3 million and 5 million people in India already are infected with HIV, more than in any other country. In one of the JAMA studies, scientists from NIAID, The Johns Hopkins University School of Hygiene and Public Health in Baltimore, Md., and the National AIDS Research Institute (NARI) in Pune, India, identified individuals with newly acquired HIV infections among patients at sexually transmitted disease clinics in Pune. Patients who tested negative for HIV antibodies were screened for p24 antigen, an HIV core protein. Because p24 antigen can be detected in HIV-infected blood several weeks before HIV antibodies first appear, its presence serves as an indicator of acute infection.
Patients who test positive for p24 antigen are likely to have been infected with HIV within the last two to three weeks," explains senior author Thomas Quinn, M.D., of NIAID's Laboratory of Immunoregulation. "Most investigations of acute HIV infection have studied individuals who have been infected with HIV for as long as several months. With p24 antigen screening we can identify HIV infections much sooner after they occur and thus get a more accurate picture of risk factors and symptoms of acute HIV infection."
The researchers found that p24 antigen-positive patients were five times more likely to have had unprotected sex with commercial sex workers and three times more likely to have an active genital ulcer than were p24 antigen-negative controls. Clinical symptoms that distinguished p24 antigen-positive patients from controls included fever, night sweats and joint pain. However, symptoms such as enlarged lymph nodes, oral thrush, diarrhea and rash, which previous studies have linked to acute HIV infection, were not clearly associated with the presence of p24 antigen in patients' blood.
Our data suggest that many of the previously described signs and symptoms of acute HIV infection may be relatively nonspecific, particularly in developing country settings where other endemic diseases with similar symptoms are more common," Dr. Quinn and his colleagues conclude.
In the second study, Dr. Quinn and scientists from NARI and Johns Hopkins assessed the prevalence of, and risk factors for, infection with HIV in women who were sex workers and women who were not. The 916 women enrolled in the study were attending sexually transmitted disease clinics in Pune, India.
The researchers detected HIV in nearly 50 percent of the sex workers and more than 13 percent of the women who were not sex workers. Inconsistent condom use and genital ulcer disease or genital warts were factors associated with HIV infection in the sex workers. The only significant HIV risk factor noted for the other women, however, was sexual contact with a partner having a sexually transmitted disease.
More than 90 percent of these women reported having only one lifetime sex partner," says Dr. Quinn, "and an equal proportion reported that their partners had not used condoms with them within the past three months. It is therefore likely that the unexpectedly high rate of HIV infection seen among women who are not sex workers is due to transmission of the virus from infected partners. Many of these women may erroneously believe themselves to be at low risk of infection because of a presumably monogamous relationship."
The researchers note that, as in much of the developing world, women in India likely have little ability to discuss or negotiate condom use or reduction of the number of their partners' sexual contacts. This, they conclude, warrants implementation of condom distribution programs and educational efforts aimed at increasing condom acceptance. Development and availability of effective vaginal microbicides, they add, also would enable women to protect themselves in situations where men refuse to use condoms.
Funding for these studies was provided by NIAID, the Fogarty International Center (FIC) and the National Center for Research Resources (NCRR), each of which are components of the National Institutes of Health (NIH). NIAID supports research on AIDS, malaria, tuberculosis and other infectious diseases, as well as allergies and immunology. NIH is an agency of the U.S. Department of Health and Human Services.References:
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