Diagnosis and Monitoring of HIV-1 Group O-Infected Patients in Cameroun

Objective: To define a routine algorithm for the specific diagnosis and complete follow-up of HIV-1 group O (HIV-O) infections in Cameroun. Methods: During 18 months, samples referred to Centre Pasteur du Cameroun for HIV testing or viral monitoring were screened for HIV-O infection with an in-house serotyping assay HIV-O viral load was quantified by real-time polymerase chain reaction in the LTR gene and resistance genotyping was performed on pol and env sequences. Results: Of the 7030 samples tested, 78 HIV-O infections (1.1%) were identified, including 7 M and O dually seroreactive samples (9%). All treatment-naive patients and 59% of the patients receiving HAART had detectable vital loads. Analysis of pol sequences from 15 treatment-naive patients revealed a high number of polymorphisms in the protease region, with natural residues implicated in genotypic resistance to tipranavir and saquinavir for HIV-1 group M according to the Agence Nationale de Recherches Sur le Sida et les Hepatites virales algorithm. Six patients (40%) harbored the 181C mutation conferring natural resistance to nonnucleoside reverse transcriptase inhibitors. Among anti retroviral-treated patients, major resistance mutations described for HIV-1 group M were found. Conclusions: HIV-O prevalence remains relatively low in Cameroun. The cocirculation of groups M and O in this country leads to replicative dual infections. HIV-O-infected patients in this region can now benefit from effective and specific tools for a complete monitoring of infection. However, further studies are needed to understand long-term response to antiretrovirals of these complex variants.