Cryptosporidium infecting wild cricetid rodents from the subfamilies Arvicolinae and Neotominae

SUMMARYWe undertook a study on Cryptosporidium spp. in wild cricetid rodents. Fecal samples were collected from meadow voles (Microtus pennsylvanicus), southern red-backed voles (Myodes gapperi), woodland voles (Microtus pinetorum), muskrats (Ondatra zibethicus) and Peromyscus spp. mice in North America, and from bank voles (Myodes glareolus) and common voles (Microtus arvalis) in Europe. Isolates were characterized by sequence and phylogenetic analyses of the small subunit ribosomal RNA (SSU) and actin genes. Overall, 33·2% (362/1089) of cricetids tested positive for Cryptosporidium, with a greater prevalence in cricetids from North America (50·7%; 302/596) than Europe (12·1%; 60/493). Principal Coordinate analysis separated SSU sequences into three major groups (G1-G3), each represented by sequences from North American and European cricetids. A maximum likelihood tree of SSU sequences had low bootstrap support and showed G1 to be more heterogeneous than G2 or G3. Actin and concatenated actin-SSU trees, which were better resolved and had higher bootstrap support than the SSU phylogeny, showed that closely related cricetid hosts in Europe and North America are infected with closely related Cryptosporidium genotypes. Cricetids were not major reservoirs of human pathogenic Cryptosporidium spp.

Extension de l’aire de répartition connue du campagnol sylvestre (Microtus pinetorum) : mention la plus nordique au Québec

Le campagnol sylvestre (Microtus pinetorum) occupe la partie est de l’Amérique du Nord. Au Canada, on le trouve dans le sud-ouest de l’Ontario et dans le sud-est du Québec. Compte tenu de sa répartition restreinte et fragmentée ainsi que de sa rareté relative, il a obtenu un statut d’espèce préoccupante au Canada en 1998. Il se caractérise notamment par le fait qu’il soit le seul campagnol fouisseur au pays. Le 28 août 2013, un spécimen a été capturé au lac Mondor à Saint-Jean-de-Matha, dans la région de Lanaudière, au Québec. Cette observation est la plus septentrionale à ce jour, et constitue la première et unique mention de l’espèce au nord du fleuve Saint-Laurent. Cet article propose un état de la situation de cette espèce au Québec et décrit le spécimen capturé ainsi que l’environnement où il a été trouvé afin de bonifier les connaissances scientifiques sur ce micromammifère peu commun.

Mites of the subgenus Microtimyobia (Acariformes: Myobiidae: Radfordia) and their host-parasite relationships with cricetid rodents (Cricetidae)

Myobiid mites of the subgenus Radfordia (Microtimyobia) (Acariformes: Myobiidae) associated with hosts of the subfamilies Arvicolinae and Cricetinae (Cricetidae) are revised. Three new species are described from voles: R. (M.) dinaromys sp. nov. from Dinaromys bogdanovi from Montenegro, R. (M.) golenishchevi sp. nov. from Eothenomys wardi from China (Mekong River), and R. (M.) pitymys sp. nov. from Microtus pinetorum from USA (Virginia). Radfordia (M.) lemnina micromys Fain and Lukoschus, 1976 syn. nov., R. (M.) lemnina mikado Uchikawa et al., 1997 syn. nov., R. (M.) stekolnikovi Bochkov and Mironov, 1998 syn. nov., and R. (M.) stenocrani Bochkov and Mironov, 1998 syn. nov. are synonymized with R. (M.) lemnina (Koch, 1941); R. (M.) rutila Fain and Lukoschus, 1977 syn. nov. and R. (M.) lemnina hata Uchikawa et al., 1997 syn. nov. are synonymized with R. clethrionomys Fain and Lukoschus, 1977; R. (M.) lemnina japonica Uchikawa et al., 1997 syn. nov. is synonymized with R. (M.) rufocani Bochkov, 1995; R. (M.) macdonaldi Gill and Strandtmann, 1977 syn. nov. is synonymized with R. (M.) arctica Fain and Lukoschus, 1977; R. (M.) cricetulus pakistanensis Fain and Hyland, 1980 syn. nov. is synonymized with R. (M.) cricetulus Fain, 1973. The female and male keys to all 21 currently recognized Microtimyobia spp. are provided. The host distribution of Microtimyobia spp. is analyzed. These mites serve as peculiar “markers” of particular host groupings and in many cases are useful tools to test some controversial hypotheses of cricetid phylogeny, including the intriguing problem of phylogenetic relationships of the Palearctic and Nearctic voles of the genus Microtus.

Selective feeding of pine voles on roots of tree seedlings

Previous studies have implicated numerous physical and biotic factors as contributing to the failure of oak to regenerate successfully throughout substantial portions of eastern North America. Recent field evidence in southern Indiana implicated belowground herbivory by pine voles ( Microtus pinetorum (LeConte, 1830)) as a potentially important but overlooked mortality agent for oak seedlings. We used cafeteria-style feeding trials to determine whether selection of hardwood seedlings by captive pine voles differed according to species or age. White oak ( Quercus alba L.) was selected more frequently and experienced a greater proportion of root removal by pine voles than same-age seedlings of the other four species tested. Yellow poplar ( Liriodendron tulipifera L.) was never eaten. White oak seedlings 3 and 6 weeks of age suffered proportionately greater root removal than conspecific seedlings 12 and 15 weeks of age; pine voles removed roughly constant levels of root biomass irrespective of seedling age. Our results confirm that pine voles selectively feed on oak seedlings. In areas where pine voles are abundant, belowground herbivory could limit regeneration of oak by reducing seedling growth and survival. The importance of pine voles as factors influencing the success of oak regeneration warrants closer scrutiny in future field studies.