Human polyomavirus JC variants in Papua New Guinea and Guam reflect ancient population settlement and viral evolution.

The peopling of the Pacific was a complex sequence of events that is best reconstructed by reconciling insights from various disciplines. Here we analyze the human polyomavirus JC (JCV) in Highlanders of Papua New Guinea (PNG), in Austronesian-speaking Tolai people on the island of New Britain, and in nearby non-Austronesian-speaking Baining people. We also characterize JCV from the Chamorro of Guam, a Micronesian population. All JCV strains from PNG and Guam fall within the broad Asian group previously defined in the VP1 gene as Type 2 or Type 7, but the PNG strains were distinct from both genotypes. Among the Chamorro JCV samples, 8 strains (Guam-1) were like the Type 7 strains found in Southeast Asia, while nine strains (Guam-2) were distinct from both the mainland strains and most PNG strains. We identified three JCV variants within Papua New Guinea (PNG-1, PNG-2 and PNG-3), but none of the Southeast Asian (Type 7) strains. PNG-1 strains were present in all three populations (Highlanders and the Baining and Tolai of New Britain), but PNG-2 strains were restricted to the Highlanders. Their relative lack of DNA sequence variation suggests that they arose comparatively recently. The single PNG-3 strain, identified in an Austronesian-speaking Tolai individual, was closely related to the Chamorro variants (Guam-2), consistent with a common Austronesian ancestor. In PNG-2 variants a complex regulatory region mutation inserts a duplication into a nearby deletion, a change reminiscent of those seen in the brains of progressive multifocal leukoencephalopathy patients. This is the first instance of a complex JCV rearrangement circulating in a human population.

Prevalence of HIV-1 infection and symptomatology of AIDS in severely malnourished children in Dar Es Salaam, Tanzania.

In Dar es Salaam, Tanzania, 200 children with severe malnutrition and controls matched for age, sex, and area of residence were screened for serological evidence of infection with the human immunodeficiency virus type 1 (HIV-1) over 5 months in 1988. The prevalence of HIV-1 antibodies in the malnourished group was 25.5% (51 of 200) compared with 1.5% (three of 200) in the controls. The seroprevalence rate was equally high in malnourished children above the age of 18 months (26 of 102; 25.5%), as in those below this age (25 of 98; 25.5%). The prevalence rate was higher in children with marasmus (38.2%) as compared to children with marasmic-kwashiorkor (12.3%) or kwashiorkor (12.2%). The prevalence of clinical features known to be associated with AIDS was higher in the HIV seropositive malnourished children as compared to the seronegative children. The modified World Health Organization clinical case definition of AIDS in children was also evaluated and found to have a low sensitivity and positive predictive value (62.8 and 57.1%, respectively) but a fairly high specificity (83.9%). It is recommended to routinely rule out HIV infection in malnourished children, especially those with marasmus.

Prevention of cerebral malaria in children in Papua New Guinea by southeast Asian ovalocytosis band 3.

Southeast Asian ovalocytosis (SAO) occurs at high frequency in malarious regions of the western Pacific and may afford a survival advantage against malaria. It is caused by a deletion of the erythrocyte membrane band 3 gene and the band 3 protein mediates the cytoadherence of parasitized erythrocytes in vitro. The SAO band 3 variant may prevent cerebral malaria but it exacerbates malaria anemia and may also increase acidosis, a major determinant of mortality in malaria. We undertook a case-control study of children admitted to hospital in a malarious region of Papua New Guinea. The SAO band 3, detected by the polymerase chain reaction, was present in 0 of 68 children with cerebral malaria compared with six (8.8%) of 68 matched community controls (odds ratio = 0, 95% confidence interval = 0-0.85). Median hemoglobin levels were 1.2 g/dl lower in malaria cases with SAO than in controls (P = 0.035) but acidosis was not affected. The remarkable protection that SAO band 3 affords against cerebral malaria may offer a valuable approach to a better understanding of the mechanisms of adherence of parasitized erythrocytes to vascular endothelium, and thus of the pathogenesis of cerebral malaria.

The correlation between microscopical examination and erythrocyte band 3 (AE1) gene deletion in South-east Asian ovalocytosis.

South-east Asian ovalocytosis status was determined by microscopical examination of peripheral blood samples collected from 137 individuals in Papua New Guinea. The examination was performed separately by 2 microscopists, one of whom was very experienced in examining peripheral blood films for the diagnosis of south-east Asian ovalycytosis and the other was recently trained. The samples were also analysed by polymerase chain reaction (PCR) to determine ovalocytosis status by demonstrating a 27 base pair deletion in erythrocyte band 3 protein of the affected individuals. The microscopists were unaware of each other's results and of those obtained by PCR. Generally, there was very good agreement between the results obtained by both microscopists and the PCR. Although there was considerable inter-observer variation in the final ovalocyte count between the 2 microscopists, this did not affect their ability to discriminate between ovalocytic and normocytic individuals. Taking the PCR results as the standard, for the first, more experienced observer, the most efficient ovalocyte count cut-off point was around 50%. At this ovalocyte count the sensitivity and specificity of microscopical examination were 93.6% and 92.2%, and the positive and negative predictive values 86.3% and 96.5%, respectively. The second microscopist generally underscored the ovalocyte counts and his most efficient cut-off point was 20%, with sensitivity and specificity of 85.1% and 93.3% and positive and negative predictive values of 87.0% and 92.3%, respectively.

Occurrence of the erythrocyte band 3 (AE1) gene deletion in relation to malaria endemicity in Papua New Guinea.

South-east Asian ovalocytosis status was determined in 1629 individuals originating from 12 different geographical areas of Papua New Guinea, representing different ethnic groups and degrees of malaria endemicity. This was achieved by using polymerase chain reaction amplification to demonstrate a 27 base pair deletion in the erythrocyte band 3 (AE1) gene. By using this method, the prevalence of erythrocyte band 3 gene deletion was determined to range from zero in both the lowland inland area of Wosera, East Sepik Province and the highland region of Goroka, Eastern Highlands Province to 35% on the north coast of Madang Province. In general, the prevalence correlated well with altitude, being highest on the coast where malaria transmission is high, intermediate in the lowlands, and lowest in the non-malarious highlands. However, Wosera, a lowland area in the Sepik River Plains, which is hyperendemic for malaria, was an exception in that no ovalocytosis was detected. These results largely confirm the prevalence rates that have been reported in the past using microscopy. In keeping with the autosomal dominant mode of inheritance, the male:female ratio was 1.02 and no homozygote was detected, indicating that homozygosity for the ovalocytosis band 3 gene deletion is lethal.

Ketotifen in African children.

Twenty-six asthmatic children, 16 boys and 10 girls with a mean age of 4.9 years, were given ketotifen, an oral prophylactic drug against asthma. Both the number of acute asthmatic attacks and their severity were reduced over a period of three months. Also reduced was the concomitant use of bronchodilators in these children. Only minimal side effects were noted. It is concluded that ketotifen has beneficial effects in childhood asthma.

Cerebral palsy in Dar Es Salaam.

Between December 1985 and July 1986 a study on cerebral palsy was undertaken among the inpatients and outpatients of the department of Paediatrics and Child Health, Muhimbili Medical Centre Centre, Dar Es Salaam. The objective of the study was to determine the clinical pattern of cerebral palsy and its associated handicaps. During this period, 100 children with cerebral palsy 56 boys and 44 girls ranging in age between four months and 10 years were seen. The commonest type of cerebral palsy seen was spastic tetraplegia which occurred in 36 percent of the cases followed by spastic diplegia and hemiplegia seen in 20 and 15 percent of the cases respectively. In 70 children the cerebral palsy was associated with other severe handicaps, the commonest being epilepsy which occurred in 35 percent of the children followed by deafness, speech disorders and blindness. Birth asphyxia, convulsions of undetermined causes, low birth weight, meningitis and cerebral birth trauma were found to be the leading causes of cerebral palsy. As these conditions are largely preventable or amendable to treatment, it is suggested that improvement of antenatal and perinatal care is important in the reduction of the incidence of cerebral palsy.

HLA-DQA1 genotyping by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and restriction endonuclease digestion in Papua New Guinea.

We have used PCR-SSCP, a technique based on the conformation of single-stranded DNA, to characterize the HLA-DQA1 gene in four geographically diverse population groups in Papua New Guinea. Among the 294 individuals that were studied from Goroka, north coast of Madang, Kimbe and Wanigela, we detected 5 of the 20 known variants of this gene locus. These included alleles 0101, 0102, 0103, 0301 and 0501. Furthermore, variable mobility shifts observed for alleles 0301 and 0501 from Madang suggested a further 3 variants. All 15 combinations of the 5 confirmed alleles were detected and their respective gene frequencies found to be consistent with the groups' ethnic and linguistic diversity. In respect to their frequencies and the observed overall allelic heterozygosity, the distribution in Kimbe showed some similarity to that in the north coast of Madang while Madang and Goroka were the most different. The distribution of alleles 0102 and 0501 was observed to be similar for Goroka and Wanigela as was 0301 for Madang and Wanigela. Our results, confirmed by endonuclease digestion, show PCR-SSCP to be a highly sensitive technique that can be used to characterize HLA-DQ antigens. In addition, the simplicity of the method provides an opportunity for large-scale typing of HLA antigens.

Control measures and the outcome of the measles epidemic of 1999 in the Eastern Highlands Province.

In the Eastern Highlands Province (EHP) of Papua New Guinea (PNG) measles outbreaks have occurred regularly every 3 to 4 years since 1980. The latest was between September 1998 and March 2000. Between July 1999 and March 2000 314 children with measles were reviewed at Goroka Base Hospital. The majority of these children were very young: 55% were under 1 year and 27% under 6 months. The median age of the measles cases was 11 months (range 10 days to 13 years). 40% of the children had a verifiable history of having received at least one dose of measles vaccine. The majority were vaccinated during the epidemic and included many children who either were below 6 months of age or who developed measles within 2 weeks of vaccination. Measles complications occurred in 82% of the children, the most common being pneumonia. Serious complications, particularly severe pneumonia, were more common among the unvaccinated children than in those who had received at least a single dose of the measles vaccine. No deaths occurred among 82 children who had received measles vaccine more than 2 weeks before the onset of clinical measles, compared with 10 deaths in 206 children who had never been vaccinated against measles or were vaccinated in the 2 weeks before presentation (p=0.067). The overall case fatality was 4%: 14% among the hospital-acquired and 2.5% in community-acquired measles. Improvement in the measles vaccination coverage and supplementary vaccination campaigns are required to prevent measles outbreaks in PNG. Intensified measles vaccination campaigns, such as the one conducted in EHP in 1999, are recommended during epidemics to minimize deaths due to measles and to rapidly control outbreaks. The efficacy of measles vaccination can only be measured in total mortality, not in the prevention of clinical measles.

Strengthening capacity, collaboration and quality of clinical research in Africa: EDCTP Networks of Excellence.

Developing countries bear 90% of the global disease burden, but only access about 10% of globally available health research funding. Weak south-south networking hampers effective use of limited resources, production of critical mass of quality scientists, career opportunities and incentives to retain the few available scientists. The south must urgently act strategically to accelerate generation of talented scientists, create enabling environment and incentives to retain scientists and attract back those in diaspora. The creation of strong networks of excellence for clinical research among southern academic and research institutions is a novel strategic approach championed by European and Developing Countries Clinical Trials Partnership to achieve the aforementioned goals and mitigate the high disease burden. It will promote strong collaboration, resource sharing and cross-mentorship allowing each partner to grow with complementary capacities that support each other rather than compete negatively. It will enable the south and Africa in particular to participate actively and own the means for solving its own health problems and raise the professional quality and capacity of southern institutions to forge better and equal partnership with northern institutions.

Detection of seven point mutations in the porphobilinogen deaminase gene in patients with acute intermittent porphyria, by direct sequencing of in vitro amplified cDNA.

Direct cDNA sequencing has been performed on asymmetrically amplified transcripts from the human porphobilinogen deaminase gene. Lymphocytes from 30 patients with acute intermittent porphyria were the source of mRNA; of the seven separate point mutations detected, three were silent, whereas four resulted in amino acid changes. Three of these changes involved highly conserved amino acids, and the remaining one a conserved charge. One of these mutations was predicted to cause structural alterations in the protein product. The application of this method to affected families allows the direct identification of these heterogeneous mutations, thus permitting the unequivocal detection of carriers.

Screening for sexually transmitted diseases in rural women in Papua New Guinea: are WHO therapeutic algorithms appropriate for case detection?

The presence of a large reservoir of untreated sexually transmitted diseases (STDs) in developing countries has prompted a number of suggestions for improving case detection, including the use of clinical algorithms and risk assessments to identify women likely to be infected when they present to clinics for other reasons. We used data from a community-based study of STDs to develop and evaluate algorithms for detection of cervical infection with Chlamydia trachomatis or Neisseria gonorrhoeae, and for detection of vaginal infection with Trichomonas vaginalis or bacterial vaginosis. The algorithms were derived using data from 192 randomly selected women, then evaluated on 200 self-selected women. We evaluated the WHO algorithm for vaginal discharge in both groups. The prevalences of cervical and vaginal infection in the randomly selected group were 27% and 50%, respectively, and 23% and 52%, respectively, in the self-selected group. The derived algorithms had high sensitivities in both groups, but poor specificities in the self-selected women, and the positive predictive values were unacceptably low. The WHO algorithms had extremely low sensitivity for detecting either vaginal or cervical infection because relatively few women reported vaginal discharge. Simple algorithms and risk assessments are not valid for case detection in this population.