Epidemiological Survey of Zoonotic Parasites in Rats and House Shrews in Selected Areas of Dar es Salaam, Tanzania

Abstract

Rodents are known carriers of intestinal parasites that pose significant risks to human health. In Tanzania, little is understood about the prevalence of parasitic zoonoses in rodents inhabiting human dwellings and the public awareness of these diseases. This study assessed the prevalence of intestinal and ectoparasites in rats and house shrews and the awareness of parasitic zoonoses among residents of Dar es Salaam. Rats and house shrews were captured from urban households in Ubungo and peri-urban households in Kivule. Ectoparasites were collected using fur-rubbing toothbrushes, while intestinal contents were examined microscopically for parasites. The study further investigated the knowledge and practices related to parasite transmission risks among household heads in houses where rats and shrews were captured using the questionnaire. The parasite prevalence was analyzed using a chi-square test and intensities with t-test. A total of 200 rats were examined (88 from Kivule and 112 from Ubungo), revealing a 96% overall prevalence of intestinal parasites. Prevalence was 100% in Kivule and 93% in Ubungo. Between two wards, Hymenolepis nana (64.3%) and Hymenolepis diminuta (60.7%) were predominant in Ubungo (p < 0.008), while Ascarid sp. (50%) and Strongyloides sp. (40.9%) were more common in Kivule (p < 0.02). Co-infections among Ascaris spp., H. nana, H. diminuta, and Strongyloides sp. were observed, with the most common combination being H. nana and H. diminuta (18%). Co-infections involving three species occurred in 4% and those with four species in 2% of cases. Ectoparasites, including fleas, mites, and ticks, were infrequent. Among 200 respondents from households where rats or shrews were captured, 76% saw them visit clean dishes, and 69% did not re-wash the dishes. Only 45% were aware of rodent-borne diseases, and 61% reported frequent childhood diarrhoea. These findings highlight the significance of rats and house shrews as reservoirs and vectors of zoonotic and non-zoonotic parasites in urban and peri-urban settings.