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Biomedical subjects

R C Povey

Publications and source records attributed to R C Povey.

At least 19 recordsLinked to original sources
PubMed1995

Prevalence of bovine parvovirus infection in Ontario dairy cattle.

Studies were conducted to determine prevalence and dynamics of bovine parvovirus (BPV) infection. Dairy cows from 29 randomly selected herds in southwestern Ontario were tested twice, one year apart, for the presence of hemagglutination inhibition (HI) antibodies against BPV. Fifty-one percent of 1141 cows tested had BPV-HI titers > 1:32. One year later, the seroprevalence was 83% in 1131 cows from the same farms. The herd mean seroprevalence was 49% and 86% for the year-1 and year-2 samples, respectively. Evidence of BPV infection was found in 96% (27/28) of herds in year-1 and 100% of herds in year-2. A comparison of titers from 716 cows tested twice showed evidence of frequent BPV infection. Sixty-two percent of 326 animals selected in a systematic manner from 40 Guelph area dairy farms had BPV-HI titers > 1:32. The herd mean seroprevalence was 64% Two herds had no animals with titers above the critical titer (1:32) while in one-quarter of the herds all animals exceeded the critical titer.

Animals↗
PubMed1986

Persistent viral infection. The carrier state.

A persistent viral infection is one in which the virus in a replicating or non-replicating form persists in the host beyond the normal recovery and elimination period for that particular viral infection. The clinical significance and mechanisms of persistence, when known, are discussed for the important viral infections of dogs and cats. Particular emphasis is given to feline viral rhinotracheitis, feline calicivirus, canine distemper, and feline leukemia.

Animals↗
PubMed1986

An unusual form of motor neuron disease following a cat bite.

A case of motor neuron disease with clinical and pathological resemblance to amyotrophic lateral sclerosis (ALS) in a woman who was severely bitten on the ankle by a cat is described. Weakness first appeared at the ankles and relentlessly advanced proximally, terminating in death from pulmonary failure in a year. A number of unusual features that are uncharacteristic of ALS were found that included a markedly elevated antinuclear antibody titre in the serum and the presence of prominent oligoclonal bands in the cerebrospinal fluid. The spinal cord showed loss of anterior horn cells and pyramidal degeneration that are characteristic of ALS, but an extraordinary finding was the presence of transmural granulomatous inflammation of numerous small and medium sized vessels, especially veins, in the subarachnoid space around the cord. There were also inflammatory changes in the brainstem and spinal cord consisting of microglial and astrocytic nodules and perivenous cuffing by mononuclear cells. Ill-defined hyaline eosinophilic cytoplasmic inclusions were seen in some remaining anterior horn cells. No viral particles were found by electron microscopy despite an extensive search. Virological studies were inconclusive but there is reason to believe that this patient's illness was caused by an as yet unidentified virus.

Amyotrophic Lateral Sclerosis↗
PubMed1985

Vaccination against feline viral rhinotracheitis in kittens with maternally derived feline viral rhinotracheitis antibodies.

The efficacy of a modified live-virus intranasal vaccine and a killed-virus adjuvanted parenteral vaccine in inducing protective immunity against feline viral rhinotracheitis (FVR) was evaluated in kittens with and without maternally derived FVR antibodies. The intranasal vaccine was given as a single dose to kittens 5 weeks old, and the parenteral vaccine was administered in 2 doses at 5 and 7 weeks of age. Seroconversion was delayed for 5 to 10 days in kittens with maternally derived antibodies, but occurred in all vaccinated kittens by 8 weeks of age. When virulent FVR virus was given, both vaccines provided satisfactory protection against disease but did not prevent infection. The results indicated that the modified live-virus intranasal vaccine or the killed-virus adjuvanted parenteral vaccine can be used successfully in kittens with residual maternally derived FVR antibodies.

Animals↗
PubMed1985

Pathogenesis of canine parvovirus-2 in dogs: haematology, serology and virus recovery.

The pathogenesis of canine parvovirus-2 (CPV-2) was studied in orally inoculated conventional dogs using haematological, serological and virological techniques. Virus was first isolated from mesenteric lymph nodes on day 2 after exposure, tonsil on day 3 and small intestine on day 3. Viraemia occurred subsequently and was present in most dogs on days 4 and 5 after exposure. CPV-2 could be isolated from all tissues during viraemia. Relative pyrexia, lymphopenia and neutropenia occurred on days 5, 6 and 7 after exposure, respectively. Virus excretion in faeces began in most dogs on day 4 and continued despite the appearance of neutralising serum antibody. Specific serum antibody, detected in some dogs as early as day 3 and in all dogs by day 7 after exposure, eliminated viraemia and inhibited virus isolation from tissues in cell culture.

Animals↗
PubMed1985

Pathogenesis of canine parvovirus-2 in dogs: histopathology and antigen identification in tissues.

The pathogenesis of canine parvovirus-2 was studied in orally inoculated conventional dogs using histopathological and peroxidase anti-peroxidase staining techniques. Lymphoid necrosis and depletion of lymphocytes from lymphoid tissues were most notable on days 5 and 6 after exposure. Lymphocyte hyperplasia occurred following day 7. Epithelial cell changes in segments of the small intestine were more severe on days 6 to 9 after exposure in areas associated with Peyer's patches and in the upper segments of the small intestine. The lymphocyte was the primary infected cell. Virus infected cryptal epithelial cells were not detected until 24 hours after the identification of infected cells in lymphoid tissues on day 4 after exposure. The majority of virus infected epithelial cells were found in crypts intimately associated with or adjacent to Peyer's patches in the upper segments of the small intestine.

Animals↗
PubMed1984

Suspected parvovirus infection in porcupines.

During a 142-day period, 6 porcupines died or were killed after becoming moribund. Three had severe acute necrotizing enteritis; two had acute necrotizing myocarditis, one with concurrent lymphocytic-plasmacytic enteritis; and one had chronic enteritis. Histologically, the acute necrotizing enteritis was characterized by villous fusion, blunting, and crypt dilatation. Many dilated crypts contained necrotic debris and were lined by flattened enterocytes. Acidophilic intranuclear inclusions were in colonic epithelial cells in one of these animals. The myocardial lesions consisted of degenerating shrunken myofibers, with infiltrating neutrophils and lymphocytes. Myofiber mineralization was evident in one animal. Though the histologic findings were indicative of parvovirus infection, electron microscopic, serologic, and virologic studies failed to demonstrate parvovirus as the etiologic agent.

Alberta↗
PubMed1984

Feline calicivirus infection in kittens borne by cats persistently infected with the virus.

On the basis of repeated isolation of feline calicivirus (FCV) from oropharyngeal swabs four to eight months after exposure to FCV strain 255, four carrier queen cats were identified. These cats gave birth to 16 kittens. Litters were individually housed with their mothers until nine weeks of age and were monitored virologically and serologically from birth until 15 weeks old. All kittens became infected between three and nine weeks old and shed FCV consistently for periods of three to 11 weeks. Clinical signs of FCV were observed in 11 kittens but none developed severe respiratory disease. At the time of initial infection maternal antibody titres in the kittens ranged from 1:4 to 1:24. Within one to three weeks of infection titres began to rise. The results indicated that kittens of queen cats persistently infected with FCV frequently experience mild or subclinical immunising infections.

Age Factors↗
PubMed1983

Comparison of the viral proteins of canine parvovirus-2, mink enteritis virus and feline panleukopenia virus.

Canine parvovirus-2 (CPV-2), Mink enteritis virus (MEV) and feline panleukopenia virus (FPV) were produced using identical cell culture and purification techniques. The distributions of the haemagglutinating activity of the three different parvoviruses in a CsCl gradient were similar with haemagglutinating peaks identified at 1.48-1.49, 1.42, 1.36 and 1.30-1.31 g cm-3. The number and distribution of the viral proteins and the equivalent protein molecular weights are similar for all three viruses in SDS-polyacrylamide gels (10%). Four viral proteins were identified and their molecular weights were determined: protein A (77 500-79 500), protein B (63 000-63 500), protein C (61 500-63 000) and protein D (50 000-55 000). The viral protein D although reported for some other parvoviruses has not previously been demonstrated in CPV-2, MEV or FPV.

Animals↗
PubMed1983

Response of mink, skunk, red fox and raccoon to inoculation with mink virus enteritis, feline panleukopenia and canine parvovirus and prevalence of antibody to parvovirus in wild carnivores in Ontario.

Mink virus enteritis, feline panleukopenia and canine parvovirus-2 were inoculated separately into groups of raccoon, mink, red fox and striped skunk. Raccoons were highly susceptible to mink virus enteritis and feline panleukopenia, with animals developing clinical illness, and several dying within six to ten days of inoculation with lesions typical of parvovirus infection. Both viruses were shed in high titre in the feces of infected raccoons, and high antibody titres were stimulated. Raccoons inoculated with canine parvovirus-2 showed no signs; shedding of virus was sporadic though moderate titres of antibody developed. Mink inoculated with mink virus enteritis and feline panleukopenia developed signs and lesions of early parvovirus infection. No signs or significant lesions followed canine parvovirus-2 inoculation. Shedding of virus was heavy (mink virus enteritis) or sporadic (feline panleukopenia and canine parvovirus-2), though good serological responses were elicited to all three viruses. Red fox showed no signs of infection, shed all three viruses only sporadically, and the serological response was strong only to feline panleukopenia. Skunks developed low antibody titres, but no signs, and did not shed virus. Antibody to parvovirus was found in 79.2% of 144 wild red foxes; 22.3% of 112 wild raccoons; 1.3% of 157 wild skunks and 6/7 coyotes in southern Ontario. The likely significance of these viruses to wild and captive individuals and populations of these carnivores is discussed.

Animal Population Groups↗
PubMed1982

Transmission of feline viral rhinotracheitis.

The transmission of feline viral rhinotracheitis (FVR) virus was investigated. Virus could be successfully transmitted between shedding carrier cats and unrelated susceptible kittens, but only if there was intimate contact between them. Studies on the transmission of FVR virus from carrier queens to their kittens showed that although four of 10 queens shed virus in the post partum period, a total of only four kittens from three litters developed a contact infection. All four kittens remained asymptomatic. Two shed for one day only and did not become carriers (as evidenced by corticosteroid treatment) and two shed for 15 days and 25 days and were subsequently shown to have become carriers. None of the remaining kittens tested shed virus. There was no evidence of in utero transmission between FVR-recovered queens and kittens. Passive antibody titres in kittens born to FVR-recovered queens declined to less than 1 in 4 in individual animals by two to 10 weeks of age. Mean titres calculated from a linear regression equation reached less than 1 in 4 and less than 1 in 2 by six and nine weeks of age, respectively. Experiments using a multistage liquid impinger demonstrated that FVR virus was unlikely to be transmitted between cats by aerosol and this was confirmed by the ability of a sentinel cat to withstand virus shedding from carriers over a six month period, although housed in the same air space.

Aerosols↗
PubMed1981

Antibody response to an inactivated vaccine for rhinotracheitis, caliciviral disease, and panleukopenia in nondomestic felids.

The efficacy of an inactivated vaccine for the prevention of feline viral rhinotracheitis (FVR), feline caliciviral disease (FCVD), and feline panleukopenia (FPL) was tested in 27 nondomestic adult felids from 7 species. The vaccine was given IM at the standard domestic cat dose in 19 animals and double this dose in 8 others. The animals were vaccinated either 1, 2, or 3 times. Serum-neutralization (SN) antibodies to FVR (mean SN titer, 23) developed in all 15 animals that were previously seronegative, and SN antibodies to FCVD (mean SN titer, 11) developed in 19 of 21 animals that were previously seronegative. There was no significant increase of SN antibody titers by doubling the vaccine dose or by administering a 3rd vaccination. The optimal response could be obtained by using the domestic cat vaccination protocol of a single dose given twice, 4 weeks apart. The critical evaluation of the SN antibody titer for FPL was complicated by preexisting titers to FPL from previous vaccinations, but in 23 animals the titers became higher, whereas they remained unchanged in only 4 animals. The persistence of the SN titers was evaluated 7 to 9 months later and found to be satisfactory for FVR (mean SN titer, 18) FCVD (mean SN titers, 43) and FPL (mean SN titer, 517). Enhanced persistence of titer could not be demonstrated by doubling the dose or administering a 3rd vaccination.

Animals↗
PubMed1980

Immunogenicity and safety of an inactivated vaccine for the prevention of rhinotracheitis, caliciviral disease, and panleukopenia in cats.

An inactivated vaccine for the prevention of feline viral rhinotracheitis (FVR), caliciviral disease, and panleukopenia has been developed. The efficacy of this vaccine for protection against FVR and caliciviral disease was assessed by vaccination of 41 cats and challenge of immunity with rrither FVR virus or feline calicivirus (FCV), strain 225. All vaccinates cats developed serum neutralizing (SN) antibody (mean SN50 1:45.5) to FVR virus, and 95% developed antibody (mean SN50 1:8.1) to FCV, strain 255. Following FVR challenge, the mean cumulative score of clinical signs was 1.1 for vaccinated cats versus 22.2 for controls. Following FCV challenge, the mean scores were 2.7 for vaccinated and 17.5 for controls. Immunogenicity of the panleukopenia fraction was demonstrated by the development of neutralizing antibody titers > 1:8 in all 21 vaccinates that were tested.

Animals↗
PubMed1980

Caliciviridae.

The caliciviruses, as a proposed family Caliciviridae, have a distinct virion morphology with cup-shaped depressions on a spherical capsid surface. The viruses have single-stranded RNA, which has a molecular weight about 2.6 x 10(6) and is infectious. The RNA is covalently linked to a small protein. A single major polypeptide is found in the capsid. A subgenomic RNA, molecular weight about 1 x 10(6), coding for the capsid polypeptide is found in infected cells. Caliciviruses infecting swine, pinnipeds and cats have been characterized. Viruses which are morphologically identical to the known caliciviruses have been identified in human feces; these viruses have been shown to be associated with gastroenteritis, but they have not yet been propagated in the laboratory.

Animals↗
PubMed1980

A comparison of the efficacy of a live and four inactivated vaccine preparations for the protection of cats against experimental challenge with Chlamydia psittaci.

A commercial live feline-chlamydial vaccine and four experimental inactivated preparations were compared on the basis of clinical protection in cats challenged conjunctivally and intranasally with Chlamydia psittaci. Best protection was afforded by the live vaccine. Good results were also obtained using inactivated preparations of a recent feline conjunctival isolate. Protection did not correlate with the development of complement fixing antibodies but may be related to the induction of a cell mediated response as assessed by the lymphocyte blastogenesis test.

Animals↗
PubMed1980

A survey of the conjunctival flora of clinically normal cats and cats with conjunctivitis.

Conjunctival swabs obtained from 39 cats with conjunctivitis and from 50 cats with clinically normal conjunctivae were cultured for bacteria, mycoplasmas, viruses and chlamydiae. Non hemolytic streptococci and Staphylococcus epidermidis were isolated from both groups, but B hemolytic streptococci, rhinotracheitis (feline herpes I) virus, Mycoplasma felis and Chlamydia psittaci were recovered only from cases of conjunctivitis. The isolation rate of microorganisms was low; only two of 50 normal and 14 of 39 diseased cats yielded positive cultures.

Animals↗