Zidovudine with nevirapine for the prevention of HIV mother-to-child transmission reduces nevirapine resistance in mothers from the Western Cape, South Africa.

In the Western Cape province of South Africa, an intensified regimen for the prevention-of-mother-to-child-transmission-of-HIV consisting of zidovudine (AZT) from 34 weeks of pregnancy plus single dose (sd) nevirapine (NVP) during labor was instituted in 2004. The newborn baby receives a single dose of NVP and AZT for 7 days. Similar strategies in Thailand and Africa have been shown to be more effective in reducing transmission than NVP alone. The use of sd NVP only for the prevention-of-mother-to-child-transmission-of-HIV has a high risk of inducing resistance (25-69%) with an average of 35.7% by a recent meta-analysis and has been shown to adversely affect non-nucleoside reverse transcriptase inhibitor (NNRTI)-based antiretroviral therapy when initiated within 6 months. In this study the prevalence of resistance to NVP and AZT in mothers who had received the intensified regimen was measured. Specimens collected from mothers were genotyped by in-house PCR and sequencing. In specimens obtained within 60 days of delivery, acquired NVP resistance mutations were detected in 13 of 76 patients (17.1%, 95% confidence interval: 8.7-25.6%), which appears to be lower than in studies with sd NVP alone (37.5%, 95% confidence interval: 23.0-50.6%).

Simian immunodeficiency viruses (SIVs) from eastern and southern Africa: detection of a SIVagm variant from a chacma baboon.

Simian immunodeficiency viruses (SIVs) have been shown to infect many Old World African primate species. Thus far, no work has been published on southern African primates. In this study we investigated the genetic diversity between SIV strains from Kenyan and South African vervets (Cercopithecus aethiops pygerythrus). We amplified and sequenced a 1113 bp region of the env gene. Phylogenetic analysis of these sequences showed that all strains clustered with members of the vervet subgroup of SIVagm. The SIVs from South African vervets differed by 7% from each other and by 8-14% from the Kenyan SIV strains, while the Kenyan SIV strains differed by 10-21% from SIVagm of other east African vervets. We also isolated and sequenced, for the first time, a SIV strain from a healthy chacma baboon (Papio ursinus), caught in South Africa. Phylogenetic analysis of the env region showed the virus to be closely related to the South African vervet SIV strains, while analysis of its pol region confirmed the virus to be a SIVagm variant.

Identification of env subtypes in fourteen HIV type 1 isolates from south Africa.

PIP: All subtypes of HIV-1 have been identified in Africa. The envelope glycoprotein of the HIV-1 is the most variable region of the virus, with the third variable region, including the V3 loop, a major target of vaccine research. This paper reports the identification of the HIV-1 subtypes present in 14 viral strains, isolated between 1984 and 1992 in South Africa. HIV-1 strains were isolated routinely at Tygerberg Hospital in the Western Cape region, with genomic DNA isolated from virus-infected cultures. After presenting the distance calculations and describing the tree constructions and bootstrap analysis, the authors emphasize the need for ongoing molecular epidemiological analysis of HIV-1 subtypes to track the current epidemic in South Africa. More rapid methods will facilitate subtyping to monitor the circulation and spread of HIV-1 subpopulations in the country.^ieng