Disease patterns in field and bank vole populations during a cyclic decline in central Finland

摘要: Abstract Declining field vole ( Microtus agrestis ) and bank Clethrionomys glareolus populations were sampled (117 voles 34 voles) in south-central Finland during the winter of 1988–89. The last surviving caught April February. A subsample (16) taken live to laboratory for immunosuppression. histopathology main internal organs presence aerobic bacteria certain parasites studied. In lungs, an increase lymphoid tissue, probably caused by infections, was most common finding (52% all individuals). prevalences voles, whole material, Chrysosporium sp. Pneumocystis carinii lungs 13 10% 9 0% respectively. Cysts Taenia mustelae (9 27%) pathological changes liver. Enteritis also rather (14 34%). Frenkelia brain Sarcocystis leg muscles low (both 6%). Bordetella bronchiseptica commonly (31%) isolated from Listeria monocytogenes intestines (34%). Salmonella spp. could not be found. dynamics abundance inflammations intestines, as well B. isolations indicate that obvious epidemics took place declining populations. Of Luhanka 16 brought April, one died listeriosis, two , five unknown reasons. Even if small mustelids are driving force microtine cycles, it is possible diseases contribute decline.