Babesia vesperuginis:natural and experimental infections in British bats (Microchiroptera)

Abstract

SUMMARYBabesia vesperuginisis described from blood of two species of British bat:Pipistrellus pipistrellusandMyotis myslacinus. Reticulocytes appeared significantly elevated in blood films ofP. pipistrellusinfected withB. vesperuginiscompared with uninfected laboratory-maintained bats or apparently uninfected wild-caught bats. Infected captive bats had significantly enlarged spleens.B. vesperuginiswas transmitted by inoculation of infected blood to 5 uninfected captiveP. pipistrellus. The course of infection followed a pattern of a rising parasitaemia accompanied by a rise in reticulocytes, followed by a fall in parasitaemia to low (<0·1%) or undetectable levels. When sacrificed, theBabesia-infected bats had significantly lowered blood haemoglobin, significantly raised white blood cell counts and enlarged spleens compared to uninfected bats. Attempts to transmit the parasite to irradiated and athymic ‘nude’ mice by inoculation of infected blood were unsuccessful. The experimental results and observations of infected wild bats indicate the potential pathogenicity ofB. vesperuginisto bats. It is likely that the vector ofB. vesperuginisisArgas vespertilionisbecause no Ixodid ticks were found onP. pistrellus.