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A placebo-controlled chemoprophylaxis trial was carried out in 1980 in 318 semi-immune school children in the Madang area of Papua New Guinea, where there was a high prevalence of strains of Plasmodium falciparum resistant to 4-aminoquinolines. Since prophylaxis with amodiaquine at 5 mg/kg weekly had failed, amodiaquine at a dose of 10mg/kg weekly and Maloprim (half a tablet or one tablet depending on body weight, which gave ranges of dapsone of 1.7-3.3mg/kg and pyrimethamine 0.2-0.4 mg/kg) weekly were tried. Neither regimen was completely successful in preventing parasitaemia, though after 13 weeks of prophylaxis the slide positivity rate was 16% for the amodiaquine group and 2% for the Maloprim group, which was in each case significantly lower than the normal baseline rate in the controls of 42%. Amodiaquine was completely successful in suppressing Plasmodium vivax infections. Breakthrough parasitaemia occurred, with either P. falciparum or P. vivax, in 5% of subjects on Maloprim at some time during the 13-week period of prophylaxis. Significantly more children in both the amodiaquine and Maloprim groups than in the placebo group showed a reduction in spleen size. All groups showed an unexplained fall in haemoglobin level over the study period but the fall was significantly less in both the prophylaxis groups. There was no adverse effect on white cell counts by either drug regimen. Chemoprophylaxis as a component of an integrated malaria control program should not be overlooked, provided that compliance can be maintained. However, in this particular case the principal purpose of the study had been to evaluate the proposed chemoprophylactic regimens in school children before embarking on an intervention study in young children. As a result of this study it was decided not to go ahead with the chemoprophylactic intervention in young children but to adopt an approach based on early presumptive treatment.

In Papua New Guinea, Plasmodium falciparum and P. vivax are common causes of acute malaria in children and P. malariae an uncommon cause. The increasing prevelance of chloroquine-resistant strains of P. falciparum in Papua New Guinea has prompted the search for alternatives to chloroquine as standard presumptive treatment. Sulfadoxine-pyrimethamine, either alone or in combination with a single dose of chloroquine, was compared with chloroquine alone for treatment of acute vivax malaria in children in Madang. Fever resolution was slowest in the group treated with sulfadoxine-pyrimethamine alone, and time to clearance of parasitemia was significantly longer in this group (P less than 0.001). Where possible, species identification should be undertaken in acute malaria and cases of P. vivax treated with chloroquine.

As part of a multi-disciplinary malaria research programme in a rural area of Madang Province, the Papua New Guinea Institute of Medical Research (PNG IMR) in 1982 established a village-based intervention programme of presumptive treatment of fever in 35 villages (population about 5,200). Seventy-four villages aides, selected by people from their own village, attended two-week training courses conducted by PNG IMR staff, and were trained to dispense three-day courses of amodiaquine (for children) or chloroquine (for adults) to anyone presenting with fever (presumptive malaria). The majority of village aides, who were voluntary workers, were married men and women between the ages of 20 and 35 years, who had had up to six years' schooling. In 1983, 5,075 fever cases were treated by village aides, which represents a quarter of the number of fever episodes estimated to occur each year in this area. Utilization of village-aide services was variable, the most important determining factors being the personality and standing of the village aide, and the distance (walking time) to the village aide's house from the patient's house. The village aides' role was expanded to include taking blood slides, dispensing other medicines (aspirin and dressings), treatment of diarrhoea by oral rehydration, and registration of vital demographic events in the village. Regular supervision, currently undertaken on a two-weekly basis by PNG IMR staff, regular refresher courses, and, probably, some sort of compensation (not necessarily monetary) are important for the long-term continuation of the programme, which may serve as a model for other areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Islets of Langerhans have been enclosed in polycarbonate diffusion chambers and transplanted intraperitoneally to syngeneic streptozotocin diabetic rats. Direct implantation of 1100--1400 islets in these chambers failed to reverse diabetes during a period of 12 weeks, and viable islet tissue was not recoverable at the end of this period. Islets placed in chambers which had been implanted 3--12 weeks previously similarly failed to lower blood glucose of diabetic recipients, as a result of lack of survival of the islets. Insulin infusion into chambers previously implanted in vivo, I125 insulin diffusion studies in chambers recovered 6--8 weeks after implantation, and scanning electron microscopy of the recovered membranes all indicated that the pores were not totally occluded. The failure of islet transplantation via chambers in this simple syngeneic model has discouraging implications for their use as a means of avoiding allograft rejection.

Much of the present knowledge of the status of malaria in Papua New Guinea stems from a few studies carried out in the past. In the present situation there are many areas of uncertainty not least the effects of poor acceptance of residual spraying programmes and the emergence of chloroquine-resistant falciparum malaria. New anti-malarials are being developed, new methods of vector control may become useful and immunization may soon become possible. In order to assess the impact of these measures it is essential that they are studied in an area with a well defined population and where the current epidemiological situation is known.

Chloroquine-resistant Plasmodium falciparum malaria is increasing in prevelance in Papua New Guinea and alternative therapies for acute malaria are being sought. A trial of sulfadoxine-pyrimethamine for the treatment of acute falciparum malaria in children has been carried out in Madang, Papau New Guinea. Eighty-five children were treated with sulfadoxine-pyrimethamine, either alone or in combination with a single 10 mg/kg dose of chloroquine. Of 78 children completing 28-days follow-up, treatment failures occurred in 15 (19.2%) and of these, 8 (10.3%), are believed to be sulfadoxine-pyrimethamine resistant; the others remain equivocal. There was no advantage in this study in combining a single dose of chloroquine with sulfadoxine-pyrimethamine; indeed, this combination was associated with an increased incidence of vomiting. It is argued that sulfadoxine-pyrimethamine should not become the standard presumptive treatment for acute malaria in Papua New Guinea.

A village-based programme of presumptive treatment of fever, using voluntary village aides to dispense oral chloroquine or amodiaquine, was established in 1982 by the Papua New Guinea Institute of Medical Research (PNG IMR) in 35 rural villages or hamlets near Madang, on the north coast of PNG. In the course of the following two years, village aides became an established health resource in many of those villages, although in others they were poorly utilized. In attempting to evaluate the impact of the programme on village health, a number of parameters were investigated. These included malaria-related mortality and morbidity, and the prevalence of parasitaemia and splenic enlargement in children in the study area. Deaths attributable to malaria, which accounted for 11% of deaths in the under-10 year age-group, and cerebral malaria cases were too few to be useful as parameters to evaluate the programme. No reduction in spleen or parasite rates occurred in children as a result of the village aide programme. In two villages, there was an unexplained increase in spleen rate following the introduction of a village aide. A study of malaria-related morbidity, by investigation of all fever cases occurring in a two-week recall period, was conducted in mid-1984. House-to-house interviews were carried out in 19 villages: 9 control villages, where there was no village aide, 6 where the village aide was well utilized, and 4 where the village aide was poorly utilized. The study showed that village aides had a measurable impact on morbidity due to fever in villages where they were well utilized, primarily by reducing the duration of fever through early treatment. The results also suggested that children benefitted even in the villages where the overall utilization of village aides was low. It is felt that such a programme would have had an even greater impact in areas where access to existing health services is more difficult than in the study area.