Schizotrypanum in British bats.

Two species of Schizotrypanum, T. (S.) dionisii and T. (S.) vespertilionis, were identified from British bats. Laboratory studies on stocks of isolated trypanosomes from 5 species of bat (Pipistrellus pipistrellus, Nyctalus leisleri, N. noctula, Eptesicus serotinus and Myotis brandti) indicated that the predominant species was T. d. dionisii. Collections and dissection of the bat bug Cimex pipistrelli from bat roosts revealed flagellate infection in a total of 12 out of 20 bugs; 7 of these bugs had metacyclic trypanosomes present. C. pipistrelli and the human bed bug, C. lectularius were reared in the laboratory and allowed to feed on wild-caught bats known to be infected with T. d. dionisii. Development occurred in both species of Cimex. Cimex spp. could be used to detect subpatent Schizotrypanum infections by xenodiagnosis. This technique was used to test the parasitological status of bats collected in the wild or reared in captivity. On a single occasion an apparent transmission of T. d. dionisii to an uninfected (by xenodiagnosis) laboratory reared bat was achieved. A stock of Schizotrypanum isolated from a wild-caught C. pipistrelli collected in a N. leisteri roost was identified by DNA buoyant density centrifugation as T. (S.) vespertilionis. A P. pipistrellus known to be infected with T. d. dionisii was found to have cyst-like structures in thoracic skeletal muscle containing amastigotes. The study provided the strongest evidence yet that C. pipistrelli is the vector of Schizotrypanum in British bats.