Comparative studies of Giardia spp. in small mammals in southern Ontario. I. Prevalence and identity of the parasites with a taxonomic discussion of the genus

1978 ◽  
Vol 56 (6) ◽  
pp. 1348-1359 ◽  
Author(s):  
David R. Grant ◽  
Patrick T. K. Woo
Keyword(s):  
Rattus Norvegicus ◽  
Microtus Pennsylvanicus ◽  
Deer Mice ◽  
Laboratory Mice ◽  
Meadow Voles ◽  
Southern Ontario ◽  
Laboratory Rats ◽  
Wistar Strain ◽  
Brown Rat ◽  
Giardia Muris

Giardia microti Kofoid and Christiansen, 1915 was identified in 98.8% (322 of 326) of meadow voles (Microtus pennsylvanicus) and G. peromysci Filice, 1952 emend, in 98% (48 of 49) of deer mice (Peromyscus maniculatus) that were livetrapped at six locations in southern Ontario. One feral brown rat (Rattus norvegicus) was infected with Giardia simoni Lavier, 1924 and Giardia muris Grassi, 1881. Laboratory rats (Wistar strain) harboured only G. simoni and laboratory mice (C3H strain) were infected with G. muris. Golden hampsters (Mesocricetus auratus) were infected with Giardia mesocricetus Filice, 1952 emend.Giardia spp. were separated into two morphologically distinct groups. Trophozoites of G. muris and G. mesocricetus were almost as wide as long and had round or oval centrally situated median bodies. Trophozoites of G. microti, Giardia peromysci, and G. simoni were elongate with long curved median bodies lying perpendicular to the long axis of the trophozoite.Further differentiation of species was not possible by comparing trophozoite morphology but was accomplished by comparing the average lengths and widths of trophozoites.

Comparative studies of Giardia spp. in small mammals in southern Ontario. III. Duration and cyst production in natural and experimental infections

1979 ◽  
Vol 57 (2) ◽  
pp. 307-313 ◽  
Author(s):  
David R. Grant ◽  
Patrick T. K. Woo
Keyword(s):  
Small Mammals ◽  
Deer Mice ◽  
Meadow Voles ◽  
Southern Ontario ◽  
Laboratory Rats ◽  
Experimental Infections ◽  
Cyst Production ◽  
Faecal Samples ◽  
Giardia Muris ◽  
Rats And Mice

Experimental infections of Giardia-free laboratory rats and mice with their respective parasites (Giardia simoni in rats and Giardia muris in mice) demonstrated that the infections persisted for the duration of the study period (4 months). Similarly, naturally infected meadow voles (with Giardia microti) and deer mice (with Giardia peromysci) retained their infections during their captivity (6 months). Rigorous precautions were taken to prevent contamination and coprophagy. The relative numbers of cysts in consecutive faecal samples varied considerably and there were periods when the numbers of cysts were extremely low. The excretions of cysts were cyclical and there were periods of 7 and 8 days between peaks in laboratory rats and mice infected with G. simoni and G. muris respectively.

Comparative studies of Giardia spp. in small mammals in southern Ontario. II. Host specificity and infectivity of stored cysts

1978 ◽  
Vol 56 (6) ◽  
pp. 1360-1366 ◽  
Author(s):  
David R. Grant ◽  
Patrick T. K. Woo
Keyword(s):  
Deer Mice ◽  
Laboratory Mice ◽  
Temperature Dependent ◽  
Laboratory Rats ◽  
Exponential Decrease ◽  
Brown Rat ◽  
Cross Transmission ◽  
Rate Of Decline ◽  
Giardia Muris ◽  
Cessation Of Treatment

Carefully controlled cross transmission experiments showed that some species of Giardia (Giardia simoni from laboratory rats, Giardia muris from laboratory mice, and Giardia peromysci from deer mice) are highly host specific while others are not. Although Giardia microti infected hamsters, and Giardia mesocricetus infected laboratory rats, these species are morphologically dissimilar from the Giardia spp. which are normally found in these animals. This study also shows that there are two varieties or subspecies of G. muris. Giardia muris from laboratory mice and from a feral brown rat were identical in morphology and dimensions, but differed in host specificity.Infectivity of cysts of G. simoni in faecal suspensions stored at three temperatures was tested using the eosin dye test and by administering portions of suspensions to Giardia-free rats at regular intervals. An exponential decrease in the proportion of cysts that resisted penetration by eosin was observed. The rate of decline was temperature dependent. Rats could not be infected when less than approximately 50% of cysts in suspension were eosin negative.Metronidazole (Flagyl) and quinacrine hydrochloride (Atabrine) did not have a prophylactic effect in rats treated for 7 days. Infections were established in animals inoculated with cysts of G. simoni 24 h after cessation of treatment.

Two new species of trypanosomes (subgenus Schizotrypanum) in bats from southern Ontario

1981 ◽  
Vol 59 (3) ◽  
pp. 530-545 ◽  
Author(s):  
Susan M. Bower ◽  
Patrick T. K. Woo
Keyword(s):  
Homo Sapiens ◽  
Myotis Lucifugus ◽  
Deer Mice ◽  
Laboratory Mice ◽  
Southern Ontario ◽  
Laboratory Rats ◽  
Cardiac Muscles ◽  
Fresh Plasma ◽  
Centrifugation Technique

From November of 1976 to May of 1979, the blood of 529 bats from 12 sites in southern Ontario was examined for trypanosomes using the haematocrit centrifugation technique. Trypanosoma hedricki n.sp. was found in 62 of 216 Eptesicus fuscus and Trypanosoma myoti n.sp. in 16 of 313 Myotis lucifugus. Blood forms of both species were morphologically similar to Trypanosoma cruzi. These trypanosomes were readily cultured in diphasic blood–agar medium.Cultures of T. hedricki n.sp. and T. myoti n.sp. were infective when inoculated orally or injected intraperitoneally into laboratory reared E. fuscus and M. lucifugus respectively. Pseudocysts of amastigotes were found in cardiac muscles of both bat species and in the intestinal smooth muscle of M. lucifugus. Trypanosoma hedricki n.sp. was not infective to M. lucifugus nor was T. myoti n.sp. infective to E. fuscus. Unlike T. cruzi, cultures were not infective to Mus musculus, Peromyscus maniculatus, Microtus pennsylvanicus, Mesocricetus auratus, Rattus norvegicus, and Cavia porcellus.After in vitro incubation in fresh plasma from deer mice, hamsters, laboratory rats, guinea pigs, little brown bats, and Homo sapiens, T. hedricki n.sp. could not be cultured. However, positive cultures were obtained after incubation in fresh plasma from E. fuscus and occasionally in fresh plasma from laboratory mice. Positive cultures were always obtained when the plasma was heat inactivated.

Control of Small Mammals on a Hardwood Plantation by Poison-Bait Feeders

1977 ◽  
Vol 53 (2) ◽  
pp. 96-99
Author(s):  
Arthur M. Martell ◽  
Andrew Radvanyi
Keyword(s):  
Small Mammals ◽  
Microtus Pennsylvanicus ◽  
Meadow Vole ◽  
Low Density ◽  
Meadow Voles ◽  
Southern Ontario

Poison-bait feeder stations were placed on a hardwood plantation in southern Ontario in 1973 to attempt long-term control of a meadow vole (Microtus pennsylvanicus) population by continuous dispensing of poisoned grain. Baiting by means of feeders successfully reduced the numbers of meadow voles and maintained them at a low density, about 3-6/ha (1.2-2.4/acre), through April 1976. During the same period, the density of meadow voles on surrounding unpoisoned areas declined from a 1973 peak to about the same as that found on the poisoned plot by fall and winter 1975-76. Despite that low density, less than 4/ha (1.6/acre), severe gnawing and girdling of young hardwoods occurred during winter. Poison-bait feeders are efficient at reducing meadow vole populations from high to low density, but it cannot be assumed that even those low-density populations will not damage hardwood plantations.

Sélection des proies par l'hermine en captivité

1986 ◽  
Vol 64 (9) ◽  
pp. 1973-1980 ◽  
Author(s):  
Michel Raymond ◽  
Jean-Marie Bergeron
Keyword(s):  
Food Preference ◽  
Prey Selection ◽  
Food Preferences ◽  
Microtus Pennsylvanicus ◽  
Deer Mice ◽  
Albino Rats ◽  
Meadow Voles ◽  
Blarina Brevicauda ◽  
Males And Females ◽  
Number Of Individuals

Certain aspects of prey selection were studied in ermines (Mustela erminea) kept in an enclosed arena that simulated a temporary meadow. Four males and eight females were involved in the 12-h experiments. Four types of prey were used: (i) meadow voles (Microtus pennsylvanicus), (ii) deer mice (Peromyscus maniculatus), (iii) short-tailed shrews (Blarina brevicauda), and (iv) young albino rats (Rattus norvegicus). Males were more efficient at catching prey than females, both in number of individuals and number of species captured. Meadow voles and rats were the prey captured most regularly and rapidly by both males and females. Males were more efficient at catching deer mice, but shrews were rarely captured. There was a great similarity in the performance of the four males, but considerable variation was observed among the females. No food preference could be detected in these experiments. The results are discussed in relation to food preferences observed during studies of ermines in a natural environment.[Journal translation]

Latitude affects photoperiod-induced changes in immune response in meadow voles (Microtus pennsylvanicus)

2005 ◽  
Vol 83 (10) ◽  
pp. 1271-1278 ◽  
Author(s):  
L M Pyter ◽  
Z M Weil ◽  
R J Nelson
Keyword(s):  
Immune Responses ◽  
Microtus Pennsylvanicus ◽  
Day Length ◽  
Delayed Type Hypersensitivity ◽  
Deer Mice ◽  
Meadow Voles ◽  
Short Day ◽  
Long Day ◽  
Induced Changes ◽  
Short Days

Animals use day length (photoperiod) to time seasonal adaptations to annual changes in their environment. Reproductive adjustments in deer mice (Peromyscus maniculatus (Wagner, 1845)) from high latitudes are more extensive in response to short days than in deer mice from low latitudes. These adjustments may permit individuals to survive the severe seasonal changes (e.g., temperature and food abundance) in high-latitude environments. Immune function is also affected by photoperiod. Short days were predicted to result in elevated immune and reproductive responses in meadow voles (Microtus pennsylvanicus (Ord, 1815)) from the Northwest Territories (NWT), Canada (~62°N), compared with voles from Ohio (OH), USA (~39°N). Male voles from both latitudes were maintained in long or short days for 10 weeks prior to a delayed-type hypersensitivity (DTH) immune challenge. Both populations displayed similar testicular regression and reduction of testosterone concentrations in short days. DTH immune responses, however, diverged between the two populations. DTH immune responses were enhanced in long-day NWT voles and short-day OH voles, but decreased in short-day NWT voles and long-day OH voles. Total and free corticosterone concentrations did not explain the latitudinal differences in immune responses. These results suggest that photoperiod affects reproductive and immune systems differently and that immune responses may reflect other environmental factors.

The comparative epizootiology of Capillaria hepatica (Nematoda) in urban rodents from different habitats of Baltimore, Maryland

1988 ◽  
Vol 66 (12) ◽  
pp. 2769-2775 ◽  
Author(s):  
J. E. Childs ◽  
G. E. Glass ◽  
G. W. Korch Jr.
Keyword(s):  
Age Structure ◽  
Rattus Norvegicus ◽  
Microtus Pennsylvanicus ◽  
House Mice ◽  
Infection Rates ◽  
Intensity Of Infection ◽  
Meadow Voles ◽  
Capillaria Hepatica ◽  
Rats And Mice ◽  
Norway Rats

The prevalence and intensity of Capillaria hepatica infections in four rodent species (Rattus norvegicus, Mus musculus, Microtus pennsylvanicus, and Peromyscus leucopus) trapped from sites in different habitats of Baltimore were examined from 1980 to 1986. Norway rats were frequently infected (87.4%), house mice rarely infected (5.4%), and no lesions were observed in meadow voles or white-footed mice. Rats from residential locations had significantly higher prevalence and intensity of infection compared with rats from parkland locations, findings not related to differences in the age structure of the populations. Prevalence and severity of lesions were positively associated with increasing body mass in rats and mice. No sex-related differences were found. Infection rates were positively correlated with relative densities of rat and mouse populations; results were corroborated by interviews conducted with 87 household residents.

Sexually dimorphic spatial learning in meadow voles Microtus pennsylvanicus and deer mice Peromyscus maniculatus.

1996 ◽  
Vol 199 (1) ◽  
pp. 195-200 ◽  
Author(s):  
L A Galea ◽  
M Kavaliers ◽  
K P Ossenkopp
Keyword(s):  
Breeding Season ◽  
Spatial Learning ◽  
Water Maze ◽  
Microtus Pennsylvanicus ◽  
Group Differences ◽  
Deer Mice ◽  
Sexually Dimorphic ◽  
Meadow Voles ◽  
Spatial Performance ◽  
Males And Females

A number of studies examining developmental, neural and hormonal aspects of sexually dimorphic spatial learning (Morris water-maze) in meadow voles (Microtus pennsylvanicus) and deer mice (Peromyscus maniculatus) are described. We found that, in adult deer mice, female spatial performance decreased during the breeding season relative to the non-breeding season, whereas the reverse pattern was observed in male performance. There was a sex difference favouring males in spatial learning during the breeding season, but not during the non-breeding season. In adult meadow voles, females with low levels of oestradiol and males performed better in the water-maze than females with high levels of oestradiol. Postweaning voles (20 and 25 days after birth) acquired the water-maze task more quickly than preweaning voles (day 10). No sex difference in water-maze performance was evident at any of these juvenile ages. When these same voles were tested again as adults to investigate retention and re-acquisition of the water-maze, both males and females from male-biased litters re-acquired the task better than males and females from female-biased litters. Together, the results of these studies indicate that sexually dimorphic spatial ability is dependent on the organization (in utero) and activational effects of gonadal hormones. These studies provide the first demonstration of the influence of natural changes in reproductive status on spatial learning of deer mice and meadow voles. The results also demonstrate that spatial performance of males and females is differentially affected by changes in reproductive status and that group differences in the laboratory are associated with group differences in space utilization in the wild. These findings help to clarify previous apparently contradictory findings about sex differences in spatial ability.

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