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13th International AIDS ConferenceDurban, South Africa - July 9-July 14, 2000 |
Int Conf AIDS 2000 Jul 9-14; 13:35 (abstract no.. LbPeA7015)
York D, Singh B, Gopaul W, Smith A
University of Natal, Department of Virology, Congella, South Africa. Fax: +27 31 360 3744, E-mail: york@med.und.ac.za.
BACKGROUND: KwaZulu-Natal (KZN) is regarded as the epicenter of HIV in Southern Africa. HIV prevalence data suggests that the epidemic is leveling off at just above 31% in the province. In 1999 the prevalence was 31.5% down from 32.5% in 1998. In high prevalence areas there is a need for a simple routine procedure that can distinguish recently infected samples from older ones. The use of a desensitised "detuned" commercial assay has been reported that can identify recently infected HIV-1 patients (within 109-149 days following infection). We have used this assay to estimate the incidence of HIV in KZN and Gauteng which is about two years behind the epidemic in KZN.
METHOD: A total of 3551 serum samples were collected from ante natal attendees in KwaZulu-Natal as part of a National survey. All HIV positive samples were tested using a modified EIA (Abbott 3A11-LS) as described by Janssen et al 1998. CDC calibrators determined the cut off values. All EIA negative samples and early sero converters were tested for p24 antigen. An additional 233 HIV positive samples from Gauteng province were also tested using the detuned assay.
RESULTS: The HIV sero prevalence in the KZN samples was 31.5%. Of the positives 8.5% (91/1073) were determined to be recent infections using the detuned assay. Of the recently infected positives 11.8% (9/76) were antigen positive compared to 0.16% (4/2431) of the negatives. The percentage early seroconverters in the Gauteng samples was 14.6% (34/233) by the detuned assay.
CONCLUSIONS: The increased percentage early seroconverters in the Gauteng samples was expected for a region not as far advanced in the epidemic as KZN. The true value of the assay will be confirmed using a pedigreed panel of known seroconverters from KZN which recently become available.Jansen et al., 1998 JAMA 280, 1 42-48.
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