Browsing by Author "Okafor, G. O."

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Epidemioogical evidence of recent introduction of HIV-1 subtypes B and O into Nigeria
(2003) Odaibo, G. N.; Olaleye, D. O.; Ruppach, H.; Okafor, G. O.; Dietrich, U.
Peptide based Enzyme Immuno-assay (PELISA) was used to determine HIV-1 subtypes circulating in Nigeria. The synthetic peptide used as the capture antigen were designed from the consensus sequence of the third hypervariable region (V3loop) of 6 HIV-1 subtypes namely A, B, C, D, E and O. A total of 925 ELISA reaactive and western blot confirmed HIV-1 positive plasma or serum samples collected over a 5 year period (1993-1997) from the three broad geographical (south-western, south-eastern and northern) regions of the country were analysed for the stduy. Specific antobodies to the six HIV_! subtypes were identified among the seropositive samples tested. There was an overall increase in the incidence of all the subtypes over the 5 years covered by this study. However, the prevalence of subtypes B and O was relatively low being 2.5% and 2.4% respectively. In addition, subtype B was not detected among HIV-1 positive samples collected before 1995. furthermore, subtypes B and O were not dtected in the samples from the south-eastern and northen regions respectively. Also, the incidence of subtypes B and O decreased with age while there was an increase in the incidence of subtypes E and D with age. On the ohter hand, the incidence of subtypes A and C did not vary significantly with age. Abesence of antibodies to HIV-1 subtypes B among blood samples from confirmed seropositive subjects that were collected during 1993-1994 together with low prevalence of subtypes B and O found in this study indicate their recent introduction. In addition, absence of antibodies to both subtypes in the south-eastern and northen regions respectively and decrease in thier incidence with age are convicing indications f recent introduction of both subtypes into Nigeria. There is therfore a need for continuous monitoring of HIV infection to identify appearance introduction of new variants of the virus into any particular geographical region.
Multiple presence and heterogeneous distribution of HIV-I subtypes in Nigeria
(Klober Academic Publishers, 2001) Odaibo, G. N.; Olaleye, O. D.; Ruppach, H.; Okafor, G. O.; Dietrich, U.
Human immunodefiency virus types I(HIV) subtypes circulating in Nigeria was determined by using the Peptide based Enzymes Immuno-Assay (PELISA) to anlayze sera or plasma samples collected from 925 individuals in southeastern and nothern) of Nigeria. The synthetic peptides used as the capture antigens in the PELISA were design from the consensus sequence of the thrid hypervariable region. (V3 loop) of HIV-I subtypes A, B, C, D, E and O of HIV-I. The assay was initially validated using plasma samples from individuals infected with various genetically identified HIV-I subtypes in Europe and AFrica. Any serum or plasma samples that reacted with more than one peptide was re-tested using the same antigen panel in a limiting ELISA technique. The result co- circulation of multiple HIV-I subtypes including A, B, C, D, E and O in Nigeria. Varying prevalence of specific antibodies to the six HIV-I subtypes included in the PELISA panel were detected among infected individuals (74), B=2.5%(23) and group O, 2.4%(20). Thirty-six (3.9%) of the samples from the northen and southeastern regions reacted with HIV-I subtype O and B peptides respectively. As far as it can be ascertained, this is the first report of dtection of HIV-I subtypes B, D, and E in Nigeria. Furthermore, the result of this work indicated widespread circulation of multiple HIV-I subtypes in Nigeria. Therefore a polyvalent vaccine will be the best option for effective prophylactic immunization against HIV-I infection in Nigeria.