Konzo outbreak, in the south-west of the Democratic Republic of Congo, 1996.

In August 1996, cases of poliomyelitis were reported in Kahemba zone, in the south-west of the Democratic Republic (DR) of Congo. The diagnosis was reviewed and charged to Konzo, a spastic paraparesis attributed to food cyanide intoxication. In order to describe the phenomena, a community-based survey took place and found 237 people affected. The highest prevalence was found in the most isolated part of the zone. The patients suffered from an isolated non-progressive spastic paraparesis of abrupt onset. Children and women were the most affected groups, especially women after childbirth. Most of the patients developed the disease after 1990 with 101 cases in 1996. Cassava processing was the same over time and in all the villages. The study did not fully explain the increased number of cases in 1996 but suggested that complementary investigations regarding micronutrient intakes, especially vitamin A, would be necessary.

Permethrin-impregnated bed nets for the prevention of malaria in schoolchildren on the Thai-Burmese border.

A double-blind controlled trial was undertaken from August 1990 to February 1991 among Karen children on the Thai-Burmese border to evaluate the effects on malaria incidence and prevalence of permethrin-treated bed nets. Three hundred and fifty schoolchildren, aged 4 to 15 years, were allocated at random to receive either a permethrin-impregnated net or a non-treated net. The incidence of malaria infections, confirmed by a blood film, was assessed during 6 months. Three surveys were conducted, on admission and 3 and 6 months later, to measure the prevalence of infections and spleen rates. Compliance was assessed by monthly home visiting. The use of permethrin-treated bed nets reduced the number of parasitaemic Plasmodium falciparum infections by 38% and the number of symptomatic episodes by 42%. The number of P. vivax malaria attacks was similar in each group. The prevalence of positive blood films in the 2 groups did not change significantly during the study. A reduction in spleen rate by 50% in both groups at the end of the study period could not be related to the overall use of nets. Compliance was high and no side-effect was reported. The long-term effects on morbidity and mortality need to be assessed after distribution of permethrin treated bed nets at the village level.

Visceral leishmaniasis in southern Sudan.

Reports made by Médecins Sans Frontières in Khartoum on an outbreak of visceral leishmaniasis among displaced people from the western Upper Nile prompted an investigation at Ler Hospital, the second largest in the region. In a 10 d period during April 1989, 100 persons with visceral leishmaniasis were identified. Of these, 82% were men; 67% were aged 20 to 39 years. Except for the absence of ulcerated skin lesions, the clinical features corresponded to those traditionally described in the Sudan. A cross-sectional serological survey was conducted in Kuernyang (400 inhabitants), 40 km north of Ler. The anti-Leishmania antibody prevalence was 18.2%, being higher among those older than 15 years, and higher among adult women (28%) than among men (18%). The overall prevalence of splenomegaly was 16.4%. 33% of seropositive cases presented with splenomegaly, compared with 11.6% of those who were seronegative. Three serological surveys conducted on the eastern side of the Nile showed no seropositive cases. However, 2 autochthonous cases were clinically diagnosed and confirmed by serological assays. The war conflicts and population movements appear to be the main cause of this large outbreak that may have killed thousands of tribespeople in southern Sudan. There is a risk of the disease spreading into other areas with devastating consequences for the population, should energetic measures not be immediately taken.