Evolution of human immunodeficiency virus type 1 serotypes in northern Tanzania: a retrospective study

Abstract

The HIV-1 epidemic in Tanzania is characterized by the circulation of heterogeneous virus subtypes. A retrospective study was conducted to determine the changing pattern of circulating HIV-1 subtypes in northern Tanzania. A peptide-binding enzyme immunoassay (PEIA) was employed to analyse 305 HIV-1 positive serum and plasma samples collected between 1985 and 2005. Samples were serotyped using synthetic peptides representing HIV-1 genotypes A-E derived from consensus gp120 V3 sequences. Plasma samples collected in 2005 were V3 genotyped for comparison with PEIA results. In 1985, serotypes A and D were co-circulating while serotype C was first detected in 1990. In 2001 and 2005, serotype C was the most prevalent, serotype A was stable, and serotype D was declining. PEIA is relatively rapid and simple to perform compared to molecular approaches, and is a valuable epidemiological tool in regions with limited resources. HIV-1 classification into serotypes based on antigenic V3 diversity may be a useful screening tool for the identification of HIV-1 variants with regard to diagnosis, treatment, disease progression and candidate vaccine development.

Deciphering the Complex Distribution of Human Immunodeficiency Virus Type 1 Subtypes among Different Cohorts in Northern Tanzania

“…We observed a substantial proportion of recombinant viruses across the three cohorts, with the general population cohort in Kisesa having the highest frequency. However, this was a relatively lower frequency than previously reported [7] . This confirms that re-infection (or superinfection) may occur among people infected with HIV, leading to recombinants that are subsequently transmitted [30] .…”

“…The distribution of HIV-1 subtypes in different regions of Tanzania gives an impression of a genetically more complex and diverse epidemic than some of its neighbouring countries. During the initial phase of the epidemic in Tanzania, HIV-1 subtypes A and D predominated and were found in similar proportions [7] . Subtype C was subsequently introduced during the late 1980s-early 1990s from neighbouring southern African countries [4] , [7] .…”

“…During the initial phase of the epidemic in Tanzania, HIV-1 subtypes A and D predominated and were found in similar proportions [7] . Subtype C was subsequently introduced during the late 1980s-early 1990s from neighbouring southern African countries [4] , [7] . Currently, subtypes A1 and C are the main circulating strains among the general population [8] – [10] and in high-risk groups [9] , [11] .…”

Development of HIV Drug Resistance in a Cohort of Adults on First-Line Antiretroviral Therapy in Tanzania during the Stavudine Era

“…The most prevalent genotypes among the isolates from Tanzanian patients were subtype A, followed by C and D. This is consistent with studies conducted earlier [31][32][33][34][35][36][37][38]. However, we now confirm this in our set of patients.…”

Development of HIV drug resistance in a cohort of adults on first-line antiretroviral therapy in Tanzania during the stavudine era

“…The most prevalent genotypes among the isolates from Tanzanian patients were subtyped A followed by C and D. This is consistent with studies conducted earlier (Arroyo et al, 2004(Arroyo et al, , 2005Hoelscher et al, 2001;Kiwelu et al, 2003;Mosha et al, 2011;Nyombi, Nkya, et al, 2008), but we now con rm this in a higher number of patients. The proportion of unique recombinant forms (URFs) and circulating recombinant forms (CRFs) was substantial at nineteen percent of all isolates.…”