Genotyping of human immunodefiency virus isolates in Papua New Guinea.

BACKGROUND: There has been considerable escalation in the incidence of HIV infection in Papua New Guinea since the first cases have been reported in 1987. OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Laboratory diagnosis of HIV infection in Papua New Guinea.

In Papua New Guinea, the laboratory diagnosis of HIV infection is based on proof of HIV antibody in the patient's serum. Under the government scheme, the testing is done in 30 laboratories, including the Papua New Guinea HIV Reference Laboratory (NRL), the Red Cross Blood Transfusion Service in Port Moresby, and 19 provincial and 9 district laboratories. An alternative testing strategy was adopted in 1993 based on a WHO recommendation, replacing the classical testing strategy (enzyme immunoassay + Western blot). The alternative testing strategy uses several EIA, rapid or simple HIV antibody assays for the detection and confirmation of the HIV antibody. This approach is faster and cheaper, with the same sensitivity and specificity as the classical testing algorithm. Except for the NRL, the Serodia Fujirebio HIV-1 gelatin particle agglutination assay is used throughout the country as the screening test. The PNG National HIV Reference Laboratory is the only laboratory authorized to perform confirmatory testing and to release positive results. Therefore, all serum samples reactive in the screening assay are sent to the NRL for confirmation by the battery of EIA, rapid or simple assays in accordance with the alternative testing strategy adopted. The paper explains the alternative testing strategy and highlights the principle of each individual test that is employed.

PIP: In Papua New Guinea, HIV antibody testing is performed in 19 provincial and 9 district laboratories, the HIV National Reference Laboratory, and the Port Moresby Red Cross Blood Transfusion Service. Before 1993, enzyme immunoassay and Western blot were used for HIV serotesting and positive findings were sent to Australia for confirmation. Since 1993, the Serodia Fujirebio HIV gelatin particle agglutination assay has been used as the first screening test, followed by the enzyme-linked immunosorbent assay; the third test used for repeatedly reactive samples is generally the Immunocomb. All repeatedly positive results are forwarded to the reference laboratory for confirmation. Results are available within 7 days. In Papua New Guinea, the specificity of the Serodia Fujirebio test is consistently greater than 99%.

Province of origin of hepatitis B surface antigen carriers among blood donors in Port Moresby.

A paper published in the Medical Journal of Australia in 1972 gave a breakdown of Port Moresby blood donors by HBS Ag carrier status and area of origin. It has lately become possible to test whether such geographical subsamples provide reliable evidence of the carrier status in the home areas, and it appears that, except for the Islands provinces, they do not. Traditional lifestyles conduce to the maintenance and spread of the virus, which is much more prevalent in the provinces than in the capital.