Permethrin-impregnated curtains and bed-nets prevent malaria in western Kenya.

The effectiveness of permethrin-impregnated (0.5 g/m2) bed-nets and curtains as malaria control measures was evaluated in Uriri, Kenya in 1988. One hundred five families were randomly assigned to 1 of 3 study groups (control, bed-net, or curtain). All participants were cured of parasitemia with pyrimethamine/sulfadoxine. Selective epidemiologic and entomologic parameters were measured weekly, while knowledge, attitude, and practices surveys were conducted at the beginning and end of the 15 week study. Plasmodium falciparum infections per person week at risk were significantly higher in the control group than in either the curtain group (5.42 vs. 2.35 cases/100 person weeks risk) or the bed-net group (5.42 vs. 3.77 cases/100 person weeks risk). The curtain group had fewer infections per person week at risk than the bed-net group (2.35 vs. 3.77 cases/100 person weeks risk). A difference was found in clinical malaria among the groups: 45% of persons in the bed-net and curtain groups vs. 30% of those in the control group reported no episodes of fever and chills (chi 2, P less than 0.05). Indoor resting Anopheles gambiae or An. funestus were found on 94 occasions in the control houses, but only twice in the treated houses during weekly visits to each house over the study period (chi 2 P less than 0.001). The pyrethrum knockdown method produced similar results with a total of 195, 23, and 3 An. gambiae and An. funestus collected in the control, bed-net, and curtain houses during the same period, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies to Plasmodium falciparum ring-infected erythrocyte surface antigen and P. falciparum and P. malariae circumsporozoite proteins: seasonal prevalence in Kenyan villages.

Two cross-sectional surveys of 954 persons in Asembo Bay and Got Nyabondo, western Kenya, were performed in August-September 1986, after long rains, and in February-March 1987, after a comparatively dry season. Serologic testing was performed using an ELISA with synthetic peptides representing repeat amino acid sequences of the Plasmodium falciparum ring-infected erythrocyte surface antigen (RESA), (EENV)5, (EENVEHDA)4, and (DDEHVEEPTVA)2 and repeat sequences (PNAN)5 and (NAAG)5 of the P. falciparum and P. malariae circumsporozoite proteins. In 1986, 45%, 73%, 72%, 85%, and 59% of the persons in Asembo Bay had antibodies to the respective peptides. In Got Nyabondo, the rates were 44%, 67%, 56%, 36%, and 41%, respectively. All positivity rates increased with age. When next determined in 1987, the positivity rates and levels of reactivity were generally unchanged in Asembo Bay, but were decreased in Got Nyabondo.