title: High level of HIV-2 false positivity in KwaZulu-Natal province: a region of South Africa with a very high HIV-1 subtype C prevalence.
abstract: Human immunodeficiency virus 2 (HIV-2) is found predominantly in West Africa. It is not unlikely, however, that HIV-2 may also be found in South Africa, due to the influx of immigrants into this country. It is important to distinguish between HIV-1 and HIV-2 since the clinical courses and treatment responses of these viruses are different. Routine serological methods for diagnosing HIV do not differentiate between HIV-1 and -2 infections, while rapid tests, viral load quantification and PCR are HIV-type--specific. The objective of this study was to describe the seroprevalence and molecular epidemiology of HIV-2 in KwaZulu-Natal, one of the regions with the highest HIV prevalence in the world and home of the two largest harbors in South Africa. HIV-1 positive samples were screened for antibodies against HIV-2, using a rapid test. The confirmation of HIV-2 positive samples was done by PCR. Of the 2,123 samples screened, 319 (15%) were identified as positive by the rapid test. None of these samples were confirmed positive by PCR. To explore this discrepancy in the results, a subset (n = 52) of the rapid HIV-2 positive samples was subjected to Western blotting. Thirty-seven (71%) of these were positive, yielding an overall HIV-2 seroprevalence of 10.6%. Three out of 28 (10.7%) Western blot positive samples were positive by a Pepti-LAV assay. This discrepancy between serological and molecular confirmation may be attributed to non-specific or cross-reacting antibodies. The use of rapid tests and Western blots for HIV-2 diagnosis in South Africa should be interpreted with caution.
authors: Department of Virology, National Health Laboratory Service, University of KwaZulu-Natal, Durban, South Africa.
authors: Lavanya
authors: L
authors: Singh
authors: Raveen
authors: R
authors: Parboosing
authors: Justen
authors: J
authors: Manasa
authors: Pravi
authors: P
authors: Moodley
authors: Tulio
authors: T
authors: de Oliveira
mesh_terms: D005189:False Positive Reactions; D015658:HIV Infections / Q000175:diagnosis / Q000453:epidemiology*; D015528:HIV Seroprevalence; D015497:HIV-1 / Q000145:classification*; D015498:HIV-2 / Q000145:classification*; D006801:Humans; D015995:Prevalence; D013019:South Africa / Q000453:epidemiology
keywords: HIV-2; South Africa; diagnosis; prevalence; serology