Researchers at the School of Public Health have found that while Thailand has mounted an effective program for preventing the sexual transmission of the human immunodeficiency virus, many HIV-infected persons there have progressed to full-blown AIDS. And these persons with AIDS are now being diagnosed with wasting, tuberculosis, pneumonia and other opportunistic infections that for the past several years have placed a substantial burden on the nation's health care system. The study appears in the March issue of Clinical Infectious Diseases.
Even though few developing countries have created as effective and detailed an AIDS-reporting system as Thailand, few reports before this one have described the most prevalent health problems of AIDS patients in that or any developing country with an HIV/AIDS epidemic. The researchers' analyses of more than 100,000 AIDS cases between 1994 and 1998 in Thailand will give clinicians and public health workers in that country the information they need to mount more focused prevention and treatment efforts.
Senior author Kenrad E. Nelson, a professor of epidemiology at the School of Public Health, said, "These data on officially reported AIDS cases in Thailand allow us to make an estimate of the disease burden due to AIDS and to spell out the specific disorders now affecting persons with AIDS there. These findings should help physicians to suspect and diagnose patients they see with similar symptoms, thereby interrupting the disease's transmission." The authors said that as physicians in Thailand become able to identify more cases of AIDS and furnish more complete and accurate reports on such cases, this information also would assist health officials in Thailand to plan for diagnostic and health care facilities and to formulate prevention strategies for the most frequently seen complications of AIDS.
The researchers analyzed the data from 101,945 persons in Thailand ages 10 and over who were diagnosed with AIDS between January 1994 and December 1998. The study revealed that the number of reported cases of AIDS in Thailand increased from 12,005 in 1994 to 22,542 in 1996 before leveling off at about 24,000 in 1997 and 1998. Although it is too soon to know for certain, the scientists said these findings suggest the epidemic may be slowing, due to an intensive national prevention program directed at decreasing the rate of sexual transmission of HIV, especially during commercial sex. The results also suggested, however, that an increasing proportion of women in regular sexual relationships are becoming HIV-infected.
Overall, 80 percent of persons with AIDS were sexually active males, 83 percent were between ages 20 and 40 years and 87 percent of AIDS cases were acquired through sexual contact. Male homosexuals or bisexuals accounted for only 1.3 percent of those with sexual risks. Throughout Thailand, 6.2 percent of AIDS infections were reported to have occurred through injection drug use.
The study looked at 25 illnesses that are diagnostic of AIDS in HIV-infected individuals and found the most commonly reported AIDS-defining conditions to be wasting syndrome (30 percent of cases), tuberculosis (29 percent), Pneumocystis carinii pneumonia (PCP; 20 percent), cryptococcosis (20 percent) and esophageal candidiasis (6 percent). Interestingly, Kaposi's sarcoma, common among AIDS patients in the West, was rare in Thailand, found in only 0.2 percent of AIDS patients there.
These percentages varied from region to region across Thailand. Tuberculosis, for instance, the most commonly reported opportunistic infection and affecting 29 percent of AIDS cases overall, occurred in only 22 percent of AIDS patients in the north but in 43 percent in Bangkok, probably because of the high numbers of injection drug users in that city. Conversely, patients with risk factors related to sex were more likely to be diagnosed with PCP and cryptococcal meningitis than were patients who injected illicit drugs.
Although public health efforts to prevent HIV infection should continue to be paramount, the authors said, prevention and treatment of AIDS-related opportunistic infections in Thailand are likely to claim a greater percentage of Thailand's public health budget in the coming years.
The other authors of this study were Suwat Chariyalertsak and Thira Sirisanthana, from Chiamg Nai University Faculty of Medicine, and Orapan Seangwonley, from the Ministry of Health.