HIV serosurveillance in Papua New Guinea.

ABSTRACT

PIP: To determine human immunodeficiency virus-1 (HIV-1) prevalence in low- and high-risk populations in Papua New Guinea (PNG), anonymous unlinked serosurveillance was conducted in government-administered antenatal and sexually transmitted disease (STD) clinics at 6 sites beginning in June 1989. Samples were tested in each local hospital laboratory for syphilis reactivity (VDRL) and for antibodies to HIV-1 (Serodia-HIV, Fujirebio). Positive Serodia specimens were forwarded for enzyme immunoassay (EIA) testing. If positive or indeterminate on EIA testing, Western blot confirmatory testing was conducted. Although 3 of 1233 samples were HIV positive in a pilot study, none of 7948 samples were HIV positive during the first full year of serosurveillance (June 1989-May 1990). HIV-infected people are also identified in Papua New Guinea through clinical diagnostic testing. Although underreporting is probably substantial, 45 HIV-infected people had been identified in Papua New Guinea (population 3.6 million) through diagnostic testing between 1987 and the end of the first serosurveillance year (May 1990). Limited surveillance continued in Papua New Guinea in 1991 and 1992. By June of 1992, 5 of an additional 6035 serosurveillance samples had tested positive. All 5 were among 2000 samples from a single site, the Port Moresby STD Clinic. In addition to surveillance, further clinical diagnostic testing had identified a total of 118 HIV-infected people by June of 1992. In STD clinics, genital sores were found to be common at all sites and in both sexes, occurring in 21% of males and 19% of females. Overall, 7.5% of STD patients had a reactive VDRL, as did 3.5% of antenatal women. Explanations for negative results of serosurveillance may be: 1) the sample size chosen faces a 5% (or higher) chance of failing to detect a case under the likely conditions of this survey; 2) the populations chosen for surveillance may not be those in which HIV is circulating at this early stage of the epidemic; and 3) laboratory error. The first two of these, alone or in combination, are most likely.