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.

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.

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.

Ischemia in isolated interventricular septa: mechanical events

1976 ◽  
Vol 231 (4) ◽  
pp. 1225-1232 ◽  
Author(s):  
KI Shine ◽  
AM Douglas ◽  
N Ricchiuti
Keyword(s):  
Nitrogen Atmosphere ◽  
Ischemia And Reperfusion ◽  
Mechanical Function ◽  
Maximal Rate ◽  
Temperature Dependent ◽  
Tension Development ◽  
Time To Peak ◽  
Rate Of Decline ◽  
Rate Limiting ◽  
Mechanical Recovery

Isolated blood-perfused rabbit interventricular septa were adapted for studies of global ischemia by enclosure in a constant-humidity nitrogen atmosphere. During ischemia, developed tension (DT) and maximal rate of relaxation (-dP/dt) declined monoexponentially, lambda = 0.39 min-1 at 37 degrees C and 72 beats/min with a Q10 of 1.4 for DT and a Q10 of 1.9 for -dP/dt. After a 60- to 90-s delay the maximal rate of tension development (+dP/dt) declined at the same rate as DT. Time-to-peak tension (TPT) shortened immediately with ischemia but action potential duration shortened after 60-90 s. Calcium at a concentration of 5 mM slowed the rate of decline of +dP/dt to lambda = 0.26 min-1. Upon reperfusion after 10 min of ischemia the rates of recovery of DT, +dP/dt, and -dP/dt were similar, lambda = 0.21-0.23 min-1, and were not temperature dependent. The magnitude of recovery was 10-17% less at 37 degrees C than 28 degrees C. Potassium at a concentration of 10 mM did not alter the rate of decline of mechanical function, but significantly (P less than 0.01) increased the magnitude of mechanical recovery. The results suggest depletion and/or repletion of single compartments as the rate-limiting steps in ischemia and reperfusion.

Methodology of Relative Sugar Preferences in Laboratory Rats and Deer Mice

1966 ◽  
Vol 64 (2) ◽  
pp. 151-158 ◽  
Author(s):  
Mahlon W. Wagner ◽  
J. Timothy Rowntree
Keyword(s):  
Deer Mice ◽  
Laboratory Rats

Immunological aspects ofGiardia murisandSpironucleus murisinfections in inbred and outbred strains of laboratory mice: a comparative study

Parasitology ◽  
1982 ◽  
Vol 85 (1) ◽  
pp. 85-99 ◽  
Author(s):  
Sara J. Brett ◽  
F. E. G. Cox
Keyword(s):  
Small Intestine ◽  
Anterior Part ◽  
Inbred Mice ◽  
Laboratory Mice ◽  
Parasite Resistance ◽  
Villus Height ◽  
Rate Of Recovery ◽  
Outbred Mice ◽  
Epithelial Lymphocyte ◽  
Giardia Muris

SUMMARYThe intestinal flagellates,Giardia murisandSpironucleus muris, cause similar infections in CBA mice as determined by trophozoite and cyst counts. Both parasites occur all along the small intestine withG. muris, being mainly present in the anterior part andS. muristowards the posterior. The early stages of infection are similar in all strains of mice examined and peak levels of both trophozoites and cysts occur 1–2 weeks after infection. All strains of mice overcome the infection but the rate of recovery varies considerably between strains, being most rapid in BALB/c and slowest in A and C57BL.B10. Outbred mice are more variable in their recovery than inbred mice. After recovery, mice are partially resistant to reinfection with the homologous but not the heterologous parasite. Resistance to reinfection withS. murisis greatest in those strains that eliminate the primary infection most rapidly.Giardia murisandS. muriscause similar changes in the mucosa of the small intestine of BALB/c mice with increased intra-epithelial lymphocyte counts from 3 weeks onwards corresponding with the start of the elimination of the parasites from the gut. A reduction in villus height and increase in crypt depth is also characteristic of these infections.

An Assessment of the Potential Target Specificity of 1080 Predator Baiting in Western-Australia

1989 ◽  
Vol 16 (6) ◽  
pp. 625 ◽  
Author(s):  
MC Calver ◽  
DR King ◽  
JS Bradley ◽  
JL Gardner ◽  
G Martin
Keyword(s):  
Western Australia ◽  
Mus Musculus ◽  
Rattus Norvegicus ◽  
National Park ◽  
Lethal Dose ◽  
Potential Hazard ◽  
Laboratory Mice ◽  
Laboratory Rats ◽  
Sminthopsis Crassicaudata ◽  
Approximate Lethal Dose

The potential hazard of 1080 baiting for predators to 14 species of non-target mammals in the pastoral areas of Western Australia and a further six from Western Australia's Fitzgerald River National Park, was assessed by comparing projected doses of 1080 (based on consumption of non-toxic bait by captive animals in the absence of alternative food) with the approximate lethal dose of 1080 for each species. These figures suggested that individuals from 12 species were potentially at risk from crackle baits, while only individuals from Dasyurus hallucatus, Ningaui spp., Sminthopsis crassicaudata, Planigale maculata, one population of Leggadina forresti and one population of Sminthopsis ooldea were potentially endangered by meat baits. Tests using the native mammals Zyzomys argurus and Pseudomys hermannsbergensis and laboratory mice (Mus musculus) and laboratory rats (Rattus norvegicus) showed that individuals of all species reduced their consumption of toxic bait relative to non-toxic bait, although this did not prevent three of five rats and one of three P. hermannsbergensis from being killed.

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