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.

Clinical manifestations of HIV infection in Melanesian adults.

PIP: By mid-1995, a total of 308 HIV cases had been reported in Papua New Guinea. The majority (74%) of these cases were diagnosed in Port Moresby. This article describes the clinical characteristics of HIV infection in 67 adults who presented to Port Moresby General Hospital in 1990-95. The median age at presentation was 27 years in men and 28 years in women, with an equal distribution of cases by sex. The major presenting symptoms were wasting and weight loss exceeding 10% of body weight (94%), chronic diarrhea (47%), prolonged fever (77%), and oropharyngeal candidiasis (66%). Pulmonary tuberculosis was diagnosed on the basis of chest X-ray and history in 37 patients (56%), but only 3 had sputum positive for acid-fast bacilli. Anemia was present in 75%. 65 patients (97%) fulfilled the World Health Organization criteria for AIDS. The inpatient mortality rate in this series was 43%, and 13 of these 29 patients died within a month of their first presentation.^ieng

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%.

Age-specific prevalence of hepatitis B surface antigenaemia in hospitalized children at Port Moresby, Papua New Guinea (a cross-sectional study with implications for the Hepatitis B Control Programme).

A cross-sectional analysis of the prevalence of hepatitis B surface antigenaemia in cord blood from 50 newborn babies and in blood from 415 children admitted to the children's ward of Port Moresby General Hospital indicates that perinatal vertical transmission is likely to be important and that there is a high rate of horizontal transmission in the 1st few years of life. Thirteen per cent of infants aged 3-5 months and 29-30% of those over 2 years of age were strongly positive for hepatitis B surface antigen. Open sores and poor hygiene are likely to play a significant role in the high level of horizontal transmission of hepatitis B virus (HBV) in our context. Our findings give support and urgency to the current active immunization policy against HBV, beginning as soon as possible after birth.

Hepatitis B surface and e antigen seropositivity in mothers and cord blood at Port Moresby General Hospital: implications for a control program.

Analysis of 100 unselected paired maternal and cord blood samples showed 11 mothers to be HBsAg positive and 6 of these to be also HBeAg positive. 5 cord blood samples were HBsAg positive and 3 were HBeAg positive. Assuming a protective efficacy rate of 75%, the present plasma-derived hepatitis B virus vaccine control program is likely to prevent the perinatal acquisition of the hepatitis B virus carrier state in 27 per 1000 children. The addition of immunoglobulin prophylaxis would be likely to reduce this by another 5 per 1000, but its use does not appear practicable at the present time.

PIP: 100 mother-infant pairs were tested for hepatitis B surface and e antigen and the results used to estimate effectiveness of the current vaccination program in Papua New Guinea. The 100 mothers and neonates born at the Port Moresby General Hospital in May-June 1990 were tested for HBsAg and HBeAg with the reversed passive hemagglutination technique (Green Cross Corp., Japan). 11 mothers were positive for HBsAg, and 6 of these for HBeAg. 5 cord bloods were positive for HBsAg, and 2 of these for HBeAg. 1 infant was positive for HBeAg only. All 3 infants positive for HBeAg were born of HBeAg mothers. It is assumed that HBsAg in infants is from passive transfer from the mother. HBeAg is indicative of a highly infectious state in a mother, and active infection in a newborn. It was calculated that the currently used plasma-derived vaccine, which has a protective efficacy rate (PER) of 75%, would be expected to protect 25/1000 children from becoming carriers, compared to 5/1000 more if immunoglobulin were given in addition. The higher costs of the new recombinant vaccine and of the plasma vaccine plus immunoglobulin were considered impractical.

Geographical distribution of subjects seropositive for human T-cell leukemia virus type 1 in Papua New Guinea.

Of 1471 sera collected from 1986 to 1989 in Papua New Guinea (PNG), 2.2% were found to be positive for anti-HTLV-1 antibody by successive particle agglutination and immunofluorescence tests. The seropositive rate varied in different provinces and was higher in the coastal areas of the main island and in neighboring small islands than in the highlands of PNG. The frequency of HTLV-1 infection of children was higher, but the age-dependent increase in antibody positivity, generally observed in other HTLV-1 endemic areas of the world, was not clear in PNG. No difference was observed in antibody prevalence in males and females in this study.

Molecular defect of the band 3 protein in southeast Asian ovalocytosis.

BACKGROUND: Southeast Asian ovalocytosis is a form of hereditary elliptocytosis in which the red cells are rigid and resistant to malaria invasion. The underlying molecular defect is unknown. METHODS AND RESULTS: We studied the red cells of 54 patients with ovalocytosis and 122 normal controls. We found that ovalocytes contain a structurally and functionally abnormal band 3 protein, the principal transmembrane protein of red cells. The structural lesion of ovalocyte band 3 was revealed by limited proteolytic cleavage of the protein, which produced fragments of abnormal size that were derived from the cytoplasmic domain of the protein. The structural lesion was present in all the subjects with ovalocytosis but none of the controls. This region of band 3 serves as the principal binding site for the membrane skeleton, a submembrane protein network composed of ankyrin, spectrin, actin, and protein 4.1. The structural defect is dominantly inherited, being tightly linked with the inheritance of ovalocytosis (the probability of linkage is in excess of 10 million to 1). Ovalocyte band 3 bound considerably more tightly than normal band 3 to ankyrin, which connects the membrane skeleton to the band 3 protein. This tight binding of ovalocyte band 3 to the underlying skeleton containing ankyrin was directly confirmed in intact cells by the finding that ovalocyte band 3 had markedly reduced lateral mobility in the membrane. CONCLUSIONS: The red cells in Southeast Asian ovalocytosis carry a structurally and functionally abnormal band 3 protein. This molecular defect may underlie the increased rigidity of the red cells and their resistance to invasion by malaria parasites.

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.

The parasites of the Purari people of Gulf Province, Papua New Guinea.

A survey of parasites of the Purari people of the Gulf Province of Papua New Guinea is reported. Hookworm was the commonest helminth encountered, whereas ascaris and trichuris were less frequently noted. Strongyloides (species unidentified) were detected in the inland Wabo area. In the latter area, a small survey revealed that filariasis and malaria were prevalent. Improvement in the standards of health of the Purari people should be an integral part of any plans to develop this region.

Malaria and hereditary ovalocytosis.

Hereditary ovalocytosis in Papua New Guinea is restricted to areas of endemic malaria and may confer increased resistance to the disease. The incidence of malaria was investigated in 1616 Melanesiams of known red cell morphology and severity of infection determined in a smaller subsample. Ovalocytics tended to be more resistant to severe malarial infections than normocytics. The ratio of parasitaemia in 112 ovalocytics compared with 741 normocytic children was 1.05 for P. falciparum; 0.90 for P. vivax; 0.54 for P. malariae, and 0.91 for infection with any species. The difficulties in conclusively demonstrating any selective advantage of the condition are discussed.