Infections with blood parasites in the small British rodentsApodemus sylvaticus,Clethrionomys glareolusandMicrotus agrestis

Abstract

SUMMARYThree populations of small wild British rodents were studied by capture–recapture methods over a period of 3 years, a fourth group was studied for 1 year and a fifth was sampled annually for 4 years. Blood smears were taken from 3 species of rodents: the woodmouseA podemus sylvaticus, the bank voleClethrionomys glareolus(and an island sub-speciesC.g. skomerensis) and the short-tailed voleMicrotus agrestis. The smears were examined microscopically. Four genera of haemoparasitesBabesia, Hepatozoon, TrypanosomaandGrahamellawere detected.Babesiawas absent fromC.g. skomerensis, Hepatozoonwas rarely found inA. sylvaticusandM. agrestisandTrypanosomawas rare inA. sylvaticus. More males were infected than females but the difference was only statistically significant for the infection withHepatozoonin adultC.g. skomerensis. Infections withBabesiaandHepatozoonwere more prevalent in adult animals and infections withTrypanosomawere more prevalent in younger individuals. Only inC.g. skomerensiswas there a significant difference between age classes in the prevalence of infection withGrahamella– there being more adults infected. Concurrent infections were detected,Hepatozoonbeing the parasite most commonly involved. The prevalence of infections was found to be approximately proportional to the number of animals known to be alive, regardless of the season.