Genotyping of human immunodefiency virus isolates in Papua New Guinea

There has been considerable escalation in the incidence of HIV infection in Papua New Guinea since the first cases have been reported in 1987.

The study was to identify the genetic subtype in HIV infected patients in Papua New Guinea. It is believed that the result will not only assist in tracing and tracking the sources of the infection, but will also help to evaluate the impact of the genotypes on the natural history of HIV in Papua New Guinea.

Plasma samples from eighty patients were definitively tested for HIV antibodies at PNG Central Public Health Laboratory using Welcome ELISA, Serodia, Immuno Comb and Hexagon. The samples were also tested for Hepatitis B (HBsAG and HBcAG) and Hepatitis C virus antibodies. The HIV positive samples were reconfirmed by the Western Blot analysis; RNA isolation and reverse transcription. DNA sequencing and phylogenetic analysis and determination of HIV subtypes were determined by using representative sequences A-H, J, N and 0 in the Los Alamos Database.

The total number of HIV-1 positive patients' samples was 20 (5 females and 15 males) Out of this, 11 (all males) were successfully subtyped as c (91%) and b (9%) showing the predominant type to be subtype C. Nine isolates were designated not typable. This is attributable to either low viral load or new emerging strains that could not be detected by the database used in phylogenetic analysis.

Data predicts that there is possible emergence of BC circulating recombinant form (CRF) because we also identified subtype B. We suggest that as subtype C remains a guide for tracking the sources of infection in PNG that both subtypes C and B (and any other subtypes that may be identified in future) be included in the future vaccine for use in Papua New Guinea since some potential vaccines work only against particular subtypes assuming that nearly all subtypes identified so far are responsive to ant-retroviral drugs.