Robert Koch redux: malaria immunology in Papua New Guinea.

Over a century ago, the malaria expedition of the brilliant microbiologist Robert Koch to the Dutch East Indies (Indonesia) and German New Guinea (now Papua New Guinea, or PNG), resulted in profound observations that are still central to our current understanding of the epidemiology and acquisition of immunity to the malaria parasite Plasmodium. The tradition of malaria research in PNG pioneered by Koch continues to this day, with a number of recent studies still continuing to elucidate his original concepts and hypotheses. These include age and exposure-related acquisition of immunity, species-specific and cross-species immunity, correlates of protective immunity and determining the prospects for anti-malaria vaccines.

Mosquito nets for the elderly?

Nine-year follow-up (ending 1999) of survival of 3738 individuals in a malaria-endemic area of Papua New Guinea found that the use of mosquito nets was associated with a large reduction in mortality in people aged > or = 40 years as well as in children aged < 5 years. There may be substantial benefits of malaria transmission reduction for older people, that have been overlooked in public health programmes and burden of disease calculations.

Regional patterns of birthweights in Papua New Guinea in relation to diet, environment and socio-economic factors.

Regional differences in mean birthweight in rural Papua New Guinea (PNG) and the importance of differences in family diet and maternal education and socio-economic status on such patterns were explored using birthweight data collected by the 1982/83 PNG National Nutrition Survey. A total of 6137 birthweight measurements from 85 PNG districts were available, representing 22% of all children included in the survey. The nature of possible selection biases are assessed and their implications discussed. Hierarchical Bayesian spatial models based on conditional autoregressive (CAR) priors were used to model spatial patterns in birthweights and their relation to different sets of covariates. Birthweights were found to exhibit striking geographical differences. Children from the central PNG highlands and from affluent lowland areas had the highest birthweights, while they were lowest in the (largely lowland) Sepik, Western, Madang and Milne Bay Provinces and in remote highland fringe areas. Maternal education, socio-economic status and diet were all important predictors, but only differences in family diet were correlated with the observed spatial patterns. The results of the present study highlight the importance of nutrition and socio-economic status in explaining differences in birthweights in PNG. Besides improving maternal health, interventions for improving birthweights in PNG should therefore aim at strengthening the economic base of rural populations and promote the cultivation and consumption of high quality foods.

Serum lipid levels in diabetic Papua New Guineans.

We have investigated 78 type 2 diabetic patients (mean age 46.7 years and duration 4.6 years) and 59 non-diabetic controls (mean age 44.6 years) for their serum levels of total cholesterol and triglyceride. Total cholesterol, triglycerides, glycosylated haemoglobin and glucose were significantly elevated in the diabetic patients. Amongst the diabetic subjects, 10 (13%) had hypercholesterolaemia, 19 (24%) hypertriglyceridaemia and 6 (8%) combined hyperlipidaemia. By comparison none of the controls had elevated lipid levels. There were no significant differences in the lipid concentrations of diabetic patients treated or not treated with insulin; both subgroups were similar in respect of age, body mass index (BMI) and glycaemic control. No significant correlations were observed between serum lipid levels and glycosylated haemoglobin, BMI, age or duration of diabetes. Our data suggest that diabetic patients from Papua New Guinea may probably be at an increased risk for developing macrovascular disease.