Objective: To assess the impact of livestock keeping on the human biting rate (HBR)of anopheline mosquitoes and malaria transmission around Ziway in the middle courseof the Ethiopian Rift Valley.Design: As a passive experiment, man landing captures were done in homesteads withmixed dwelling, separate cattle shed and without livestock; and as an active experiment,captures were in experimental tukuls (huts) of cattle, goats, and without livestock.Parasite and spleen rates of children were compared among those residents undervariable living conditions mentioned for passive experiment.Subjects: For entomological study, human-baits were used for man-landing captures ofmosquitoes. Study subjects for parasitological and clinical studies were children below10 years old.Main outcome measures: Human-biting rate (HBR) of anopheline mosquitoes; and theparasite and spleen rates of the study subjects in different living conditions.Results: In the passive experiment, the mean HBR of Anopheles arabiensis in mixeddwelling, separate cattle shed and without livestock was 8.45, 4.64 and 5.97, respectively.Similarly, the HBR of An. pharoensis was 2.88, 1.79 and 1.61, respectively. In the activeexperiment, the mean HBR of An. arabiensis in tukuls with cattle, goats, and withoutlivestock was 3.50, 3.38 and 1.43 respectively; while that of An. pharoensis was 0.37,0.70 and 0.55 respectively. Parasitologically, mean parasite rates of 26.67%, 15.05% and23.85% were, respectively, recorded from children living under the above conditionsstated for passive experiment. Similarly, the mean spleen rates of 50.0%, 26.9%, and47.37% were recorded, respectively.Conclusion: These observations in the present study indicate that the presence of cattlein homesteads tends to increase the man biting rate of An. arabiensis, althoughdifferences in the mean HBR of vector mosquitoes were not statistically significant forall groups. In contrast, cattle keeping in separate cattle sheds outside of the humandwellings tends to reduce the man biting rate of An. arabiensis and malaria transmissionin the study area
