ABSTRACT
Prevalence of plasmodium falciparum and plasmodium vivax in the human population; infectivity and DDT resistance of Anopheles mosquitoes were studied on samples collected during the peak malaria season of 1990 from Gambella; South West Ethiopia. Mosquito vectors collected were assorted into species and their infectivity with malaria parasites was determined by the enzyme-linked immunosorbent assay (ELISA). In the human population out of a total of 821 individuals examined from nine villages; 4.1 percent (34) were found to be positive for malaria parasites. Of the 34 positive individuals 5.9 percent (2) were positive for plasmodium vivax and 94.1 percent (32) for plasmodium falciparum. Although relatively high positivity rates for malaria were observed in 1-4 and 5-14 age groups; the difference in rates of positivity was not statistically significant for the whole population (p=0.5077). However; a significant difference in parasite prevalence was detected between the nine localities. Compared to that of 1989; the overall malaria prevalence rate in the human population significantly decreased in 1990. Insecticide susceptibilty studies revealed the presence of DDT resistant Anopheles gambiae s.l. mosquito in Itang. Furthermore; a strong evidence would suspect the vectorial status of A. pharoensis was obtained by detecting salivary gland sporozoite antigens of P. vivax in the head region of two mosquitos. Sporozoite rate of 0.76 percent (P. falciparum) for A. gambiae s.l. and 0.47 percent (P. vivax) for A. pharoensis were determined
Subject(s)
DDT , Malaria/epidemiologyABSTRACT
Ancillary to a community based mass treatment campaign of onchocerciasis with ivermectin; assessment of the drug's effect on various intestinal nematodes was made in Bebeka; Southwest Ethiopia between 23 April and 23 July; 1990. A total of 231 people were invited for the study and all consented. From each; stool specimen was collected before treatment; two weeks and three months after administration of ivermectin at a dose of 150 mcg/kg body weight. Various intestinal parasites were observed in many of the samples; ranging from single parasite up to five mixed infections per slide. Efficacy of ivermectin against Strongyloides stercoralis was 100 percent throughout the observation period. Eggs of Ascaris lumbricoides were found in 74.5 percent of the stool samples collected before treatment and this was reduced to 3.5 percent and 48.9 percent in the post-treatment samples of 15 days and three months; respectively. Similar observation was made for the other geohelminths at a lower cure rate. This finding shows that apart from its primary purpose in the control of onchocerciasis; ivermectin has the added benefit of eliminating ascaris and stronglyloides infection in areas where such parasites are co-endemic. Furthermore; its significant effect on the intensity of the other enteric nematodes will have a great impact on reducing transmission. The public health significance of population based mass chemotherapy with ivermectin is discussed