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Biomedical subjects

J F Prescott

Publications and source records attributed to J F Prescott.

At least 127 records · Page 7Linked to original sources
PubMed1982

A mild form of strangles caused by an atypical Streptococcus equi.

A mild form of strangles caused by an atypical Streptococcus equi was recognized on a large horse breeding farm. The organism differed from most S equi isolates by disappearance of the mucoid capsule by 24 hours of culture, leaving a matt-type colony. Typically, the clinical signs were a transient (24-48 hour) fever, profuse nasal discharge, and anorexia. In about half the affected animals, there was moderate mandibular lymph node enlargement, and these glands usually ruptured or were drained. The use of a passive hemagglutination antibody test showed that subclinical infection was widespread in horses on the farm.

Animals↗
PubMed1982

Capsular serotypes of Rhodococcus equi.

One hundred strains of Rhodococcus equi from various animal species and sources in Australia were examined for capsular serotype. Eighty-four of the strains fell into the existing 7 serotypes, and just under half of the strains belonged to serotype 1. Isolates from the intestines and faeces of horses, cattle, pigs and other species, and from soil, were found to belong to the same serotypes as those recovered from the lungs of foals with R. equi pneumonia. There was no clear relationships between capsular serotype and source of origin of the isolates.

Actinomycetales↗
PubMed1982

Pathogenicity of Campylobacter jejuni isolates from animals and humans.

Fourteen isolates of Campylobacter jejuni of different serotypes and one Campylobacter coli isolate, from various human and animal sources, were tested for potential pathogenic mechanisms. Enterotoxin production was not detected in the infant mouse test or by calf and piglet ligated intestinal loop studies. Isolates were not invasive by the Sereny test. All isolates associated with and penetrated HeLa cells, although both actions occurred generally in a minor way under the conditions of our study. The C. coli isolate showed extensive HeLa cell association, but three other C. coli isolated tested did not. None of the 15 isolates produced diarrhea or death in 3-day-old chickens inoculated orally and observed for 3 days, nor did they consistently produce diarrhea and death in 9- to 10-day-old infant mice over a 3-day period after oral inoculation. Diarrheal disease and mortality were not observed when 3-day-old gnotobiotic chickens were infected with one of five isolates and observed over a 2-week period.

Animals↗
PubMed1982

Equi factors in the identification of Corynebacterium equi Magnusson.

The production of equi factor(s) by 173 serologically verified Corynebacterium equi isolates was tested by streaking strains at right angles to a culture of Corynebacterium pseudotuberculosis or Staphylococcus aureus on a cattle blood agar plate. All strains produced equi factor(s). This characteristic was more specific than other tests used on the strains.

Animals↗
PubMed1981

The susceptibility of isolates of Corynebacterium equi to antimicrobial drugs.

Fifty-one isolates of Corynebacterium equi recovered from pigs and horses belonging to two capsular serotypes were tested for susceptibility to antimicrobial agents. No clear differences were detected in sensitivity between isolates of different sources or serotypes. All isolates were sensitive to less than 0.25 micrograms/ml of erythromycin and gentamicin. The following minimum inhibitory concentrations (MICs) of antimicrobial agents were determined for greater than or equal to 90% of isolates: methicillin greater than 16 micrograms/ml, clindamycin 1-2 micrograms/ml, tobramycin less than or equal to 1 microgram/ml, cephalothin 8-64 micrograms/ml, kanamycin 2-8 micrograms/ml, amikacin less than or equal to 1-2 micrograms/ml, penicillin 2-greater than or equal to 4 micrograms/ml, ampicillin 2-8 micrograms/ml, trimethoprim-sulfa 4/76-32/608 micrograms/ml tetracycline 1-4 micrograms/ml and chloramphenicol 8-16 micrograms/ml.

Animals↗
PubMed1981

Capsular serotypes of Corynebacterium equi.

Antisera were prepared against 26 isolates of Corynebacterium equi. A capsular antigen preparation was made by washing a heavy suspension of individual C. equi isolates in saline overnight. Ninety-seven isolates from a variety of sources were tested by a double diffusion immunoprecipitin test and seven capsular serotypes identified. The majority of isolates belonged to capsular serotype 1 (59.8%) and 2 (25.8%). No clear relationship was established between capsular serotype and the source of origin of the isolates (disease processes in horses, pigs, man, cattle, dogs or cats).

Animals↗
PubMed1981

Carriage of Campylobacter jejuni in healthy and diarrheic animals.

Feces from normal and diarrheic animals were cultured for Campylobacter jejuni. A clear difference could not be detected in carriage between normal and diarrheic cattle, horses, pigs, and dogs. Too few diarrheic goats, sheep, and rabbits were sampled for conclusions to be made. Carriage rates (%) detected in normal animals were as follows: ducks 88.3, chickens 23.8, sheep 13.6, rabbits 11.3, goats 2.7, cattle 2.5, and dogs 0.5. The organism was not isolated from horses and mink. Carriage rates varied within a species between animals from different sources.

Animals↗
PubMed1981

Campylobacter jejuni colitis in gnotobiotic dogs.

Campylobacter jejuni of human and canine origin was inoculated orally into six gnotobiotically reared Beagle puppies and reactions were compared with two controls. Inoculated dogs developed transient lassitude, inappetence, mild diarrhea and tenesmus during the period 36-72 hours after inoculation. Pairs of dogs killed 43 hours, and five and seven days after inoculation had lesions limited to typhlitis and colitis. Congestion of colonic mucosa, associated loss of goblet cells, attenuation and exfoliation of surface epithelium with microerosions, hypertrophy of glands and neutrophil infiltration of lamina propria were seen during the acute phase. Less severe surface and inflammatory lesions were evident at five and seven days, with hyperplasia of the proliferative compartment in mucosal glands. Campylobacter established at over 10(10) organisms per gram of colonic content but did not invade the mucosa. It was concluded that the gnotobiotic dog may be a suitable model for investigation of the pathogenesis of Campylobacter colitis.

Animals↗
PubMed1980

Lymphocyte immunostimulation in the diagnosis of Corynebacterium equi pneumonia of foals.

A lymphocyte stimulation test using antigens of Corynebacterium equi was used to compare the response of peripheral blood lymphocytes from foals with C equi pneumonia with those of clinically normal foals and adult horses. The test clearly distinguished infected foals from normal foals when tested in animals less than or equal to 2 months old. After the 2nd month, stimulation response from individual normal foals sometimes exceed those from infected foals, but mean stimulation response to C equi antigens was significantly (P less than 0.025) greater in 3- to 5-month-old infected foals when compared with mean values of 3- to 5-month-old normal foals. Mean stimulation responses in 5- to 7-month-old foals, which had recovered from C equi pneumonia, could not be distinguished from mean responses of normal foals. The test could still, however, be used diagnostically in foals greater than 2 months of age if stimulation responses were low. The test indicated the great extent of exposure to C equi in the normal horse population.

Animals↗
PubMed1980

Factors associated with mortality in feedlot cattle: the Bruce County Beef Cattle Project.

The design of and the analysis of data from the Bruch County Beef Cattle Project, particularity the field study, are presented and discussed. A major value of the study may lie in its ability to relate laboratory findings to events in the field. The factor most strongly related to mortality was ration, with cattle on hay based rations having a much lower mortality on average than cattle on corn based rations. In general, management activities associated with growing cattle (as opposed to fattening) over the first winter were sparing for mortality. Groups of cattle given prophylactic vaccines or drugs within two days of arrival tended to experience higher mortality (not statistically higher) than those cattle not receiving those measures, or cattle groups recieving the same prophylactics more than 48 hours after arrival. However, these results require validation in the remaining years of the study. Fibrinous pneumonia was the most frequent diagnosis in the calves on postmortem examination.

Animal Feed↗
PubMed1980

Experimental studies on the pathogenesis of Corynebacterium equi infection in foals.

Four month-old foals were infected orally with 75 mL of a suspension of 5.0 x 10(8)Corynebacterium equi per mL. Two foals were killed after ten days and had scanty number of C. equi in the caeco-colic lymph nodes. No C. equi were recovered from the other two foals, killed 20 days after infection. No gross pathological change was detected in these four foals, although mild microscopic lesions were seen in the ileum of one foal. Results of lymphocyte blastogenesis using peripheral blood lymphocytes and C. equi antigens showed, however, that lymphocytes became sensitized to C. equi following this challenge. In a second experiment four month-old foals were given orally the same dose of organisms but on five consecutive days. Two foals were killed ten days after infection and showed mild histological changes in the large bowel mucosa and C. equi could be recovered from all intestinal lymph nodes cultured. In one of these foals moderate numbers of C. equi were present in the bronchial lymph node. Of the other two foals, one died after 22 days with severe ulcerative enterocolitis and intestinal lymphadenitis. Only one small pulmonary abscess was detected despite large numbers of C. equi in the lungs. The other foal developed similar intestinal changes and was euthanized 25 days after infection. No C. equi were detected in the lungs or bronchial lymph node. Lymphocyte blastogenesis in these animals showed a rapid rise in response to C. equi antigens. These studies suggest that C. equi pneumonia in foals does not always arise from an intestinal infection, that minor intestinal infection causes a cellular immune response and that massive exposure of the bowel over a sustained period is necessary to induce intestinal lesions.

Animals↗
PubMed1980

A serological survey of dogs for Brucella canis in southwestern Ontario.

Sera from 2 000 dogs from southwestern Ontario were tested for antibodies to Brucella canis by a rapid slide agglutination test. The 100 positively reacting sera were tested by tube agglutination and immunoprecipitation (gel diffusion) tests. Thirty-one of these sera gave suspicious titres and one a positive titre in the tube agglutination test. Six of the rapid slide test positive sera gave positive reactions in immunoprecipitation tests. One dog was identified which was found to have a history very suggestive of B. canis infection. It was judged that 0.3% of sera tested showed serological evidence of B. canis infection. The complexities of the serological diagnosis of B. canis infection was apparent, in particular the tendency to false-positive results in the rapid slide agglutination test.

Animals↗
PubMed1979

Identification of some anaerobic bacteria in nonspecific anaerobic infections in animals.

Over 200 anaerobic bacterial isolates were recovered in a veterinary diagnostic laboratory from nonspecific infectious disease from 72 specimens originating from ten animal species. The majority of isolates were nonsporeforming bacteria and about half were identified to species. Bacteroides species formed the major group and included B. oralis, B. fragilis, B. corrodens, B. ruminicola subspecies ruminicola, B. ruminicola subspecies brevis and various subspecies of B. melaninogenicus. Gram-positive anaerobic cocci constituted the next major group of isolates and the main species identified in cattle was Peptococcus indolicus. Clostridial species were uncommon. Nine specimens yielded a pure culture of an anaerobe and, in samples containing mixtures of bacterial species, each specimen yielded an average of 3.1 anaerobic and 1.4 aerobic bacterial species. The failure to identify many of the isolates is discussed.

Anaerobiosis↗