Visceral leishmaniasis and malaria prevalence in West Pokot District, Kenya.

The prevalence of visceral leishmaniasis and malaria in the human population of West Pokot district of Kenya was studied in 1986. A total of 2139 people was proportionately screened for the two diseases according to four age categories (0-4, 5-14, 15-44 and greater than 45 years). Diagnostic methods included the enzyme linked immunosorbent assay (ELISA) and Leishmanin skin test for visceral leishmaniasis, and parasitological examination for malaria. The epidemiological value of the spleen rate was evaluated in relation to visceral leishmaniasis and malaria endemicity. A general decline of infection rates with altitude was observed for both diseases. Visceral leishmaniasis was less prevalent than malaria, with less than 2% active cases in any age group and had the same distribution in both sexes. Malaria infection rate was highest in the younger age groups, declining from 21.5% in the 0-4 year old age group to 5.5% in people more than 45 years old. Malaria affected significantly more males than females. The spleen rate was inappropriate for epidemiological survey of either malaria or visceral leishmaniasis due to an overlap in the distribution of the two diseases.

Malaria prevalence and morbidity in relation to the use of permethrin-treated wall cloths in Kenya.

The effect of permethrin-treated wall cloths (Mbu cloth) on malaria parasitaemia prevalences and malaria morbidity, was evaluated in a population of over 10,000 for a period of three years in the Marigat area, Baringo District, Kenya. The use of the treated cloth in 2,000 houses resulted in significantly lower rates of malaria parasite prevalences with an overall reduction rate of 73% (P < 0.001) in the treated area. Control areas had an initial increase in rate of malaria parasite prevalence of 30% and later a reduction of 31%. There was a slight reduction in spleen rates in the control and treated areas but it was not significant for either between the surveys or among the villages.

PIP: The use of pyrethroid-treated fabrics against disease vectors is a well-accepted vector control strategy worldwide. Most studies have assessed the merits of using impregnated bednets, but this prevention strategy is inappropriate for many households in many communities due to incompatible cultural norms, high cost, the lack of conventional western style beds, sleeping arrangements which differ between cultures, and differences between housing construction styles in rural communities. The International Center of Insect Physiology and Ecology recently developed a technology using cotton wall cloth, Mbu cloth, to control vectors of malaria and leishmaniasis in rural communities in Kenya. Other fabrics such as polyester have even improved the technology by making the cloth lighter and cheaper. The authors evaluated the effect of permethrin-treated Mbu cloth on malaria parasitemia prevalences and malaria morbidity in a population of over 10,000 for a period of 3 years in the Marigat area of Baringo District, Kenya. 2000 houses were fitted with the cloth. The prevalence of malaria parasites was reduced an overall 73% in the treated area. Control areas saw a 30% initial increase in the rate of malaria parasite prevalence followed by a reduction of 31%. Slight reductions in spleen rates were also observed in the control and treated areas, but were insignificant between the surveys and among the villages.