764-W. HIV-1 Group M and Group O Dual Infections in Rural Northwest Cameroon

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Session 100 Poster Session
Molecular Epidemiology
Session Time: 4:30-6:30 pm
Room 4E-F

764-W.

HIV-1 Group M and Group O Dual Infections in Rural Northwest Cameroon
A. Vallari¹, J. Yamaguchi¹, P. Bodelle¹, R. Coffey¹, C. McArthur², S .G. Devare¹, G. Schochetman¹, and C. A. Brennan*¹
¹Abbott Labs., Abbott Park, IL and ²Univ. of Missouri, Sch. of Dentistry

Background: HIV-1 has high genetic diversity and is classified into group M (subtypes A-K, CRFs, mosaics), group N, and group O. HIV diversity was examined in a rural population in the northwest province of Cameroon.
Methods: Patients attending local hospitals (1998-2000) were screened for HIV using Determine HIV-1/2, a rapid test for antibodies to HIV-1 group M and O, and HIV-2. Research assays were used to serotype the HIV infections: MO2N assay (gp41 based), env V3 peptide EIA (PEIA), and env IDR PEIA. RT-PCR followed by sequencing was used to genotype HIV strains.
Results: Determine HIV-1/2-positive specimens (n=3107) were collected and classified by serology as: 8 group O, 3 HIV-1 group M and O dual infections, 1 HIV-2, 2 HIV-1 group M and HIV-2 dual infections, and the remaining as group M. RT-PCR confirmed the presence of group O virus in the 8 group O seroreactive specimens. Using group M or O specific PCR for gag and env, sequences for both group M and group O were amplified from the 3 dual M/O seroreactive specimens. For all 3 specimens, group M PCR amplified sequences that cluster with group M subtype A and group O PCR amplified sequences that cluster with group O. Since both group M and O sequences were obtained for each gene region, the specimens are infected with at least 2 HIV strains. The vast majority (84%) of the group M specimens that were evaluated (n=154) are subtype A (most cluster with CRF02_AG). Subtypes D (2.6%), F2 (2.6%), G (3.9%), and mosaics (7%) were also found.
Conclusions: The HIV diversity in the rural population of northwest Cameroon is lower than was previously observed in the cities of Cameroon. Comparing the data presented here with HIV specimens collected in Yaounde and Douala (1996-1999) shows that both populations are infected with group M subtypes A, D, F2, G, and mosaics. However, subtype prevalence differ in rural vs urban populations: subtype A, 84% vs 66%; mosaics (excluding CRF02_AG), 7% vs 18%. Considering the low prevalence of group O infections in northwest Cameroon (0.35%), it is surprising that 3 of 11 group-O-infected patients are also infected with a group-M virus. Given that most serological screening tools do not easily discriminate between cross-reactivity and dual infections, dually infected individuals (groups M and O) may be more common than expected. Recombination between group M and O may lead to new viral strains with unknown properties.

Š2002 9^th Conference on Retroviruses and Opportunistic Infections