The parasites obtained and bacteria isolated from house rats (Rattus rattus Linnaeus, 1758) caught in human habitations in Ibadan, Nigeria.

A total of 169 house rats were killed in different households distributed within five localities of Ibadan. A wide range of parasites were encountered. The flea, Ceratophylus fasciatus was the commonest ectoparasite found. Trichostrongylus columbriformis eggs were the commonest nematode and Hymenolepis diminuta the only cestode. Escherichia coli was the commonest bacterium found. The incidence of helminthiasis, especially H. diminuta, was generally high among rats trapped in the villages and the indigenous areas of the city. One hundred and twenty eight (128) of the rats possessed Trypanosoma lewisi infection, seventy one (71) had Anaplasma marginale while fifty seven (57) had Babesia microti infection. The public health importance of some of the parasites found is discussed.