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Biomedical subjects

C J Gaskell

Publications and source records attributed to C J Gaskell.

At least 19 recordsLinked to original sources

Characterization of orthopoxviruses isolated from feline infections in Britain.

The biological properties and genomes of orthopoxviruses isolated from cats in Britain were compared with strains of cowpox virus isolated from cows and their handlers. All the isolates tested produced haemorrhagic pocks and A-type inclusions on the CAM, but did not produce pocks above 40 degrees C. Thus the feline isolates behaved as typical strains of cowpox virus. Differences were found in the heat resistance of the virions and in the character of the A-type inclusion which did not correlate with the host from which the viruses were isolated. Analysis of the genomes with a variety of restriction endonucleases showed very close relationship between all the isolates and also failed to separate feline isolates from cowpox virus. However again minor differences, which may prove to be of epidemiological value were detected. We conclude that the orthopoxvirus currently isolated from domestic cats in Britain is cowpox virus and that there is no evidence that a feline variant or subspecies circulates in Britain.

Animals

Induction and enhancement of feline infectious peritonitis by canine coronavirus.

Preexisting antibody to feline infectious peritonitis virus (FIPV) causes acceleration and enhancement of disease on subsequent infection of cats with FIPV. Other workers have shown that canine coronavirus (CCV) can infect cats subclinically, but have found no evidence of enhancement of, or protection against, subsequent FIPV infection. With various isolates of CCV, we determined that 1 strain of CCV can induce transient mild diarrhea in cats and, furthermore, that previous infection with CCV causes acceleration and enhancement of subsequent infection with FIPV. In addition, sequential inoculation of cats with another strain of CCV caused lesions indistinguishable from those of FIP, without exposure at any time to FIPV.

Animals

Canine coronavirus infection in the dog following oronasal inoculation.

The pathogenesis of canine coronavirus (CCV) infection in 10-week-old puppies was studied up to 14 days after oronasal inoculation. Mild diarrhoea was seen from three to 11 days after inoculation, approximately coincident with faecal virus shedding. Virus was initially isolated from the tonsils on day 3, and then from both small and large intestinal tissues up to 14 days after inoculation. Virus was also isolated from liver and lung. Histological changes were not seen in any tissues, but CCV antigen was detected, using a peroxidase antiperoxidase staining technique, mainly in epithelium overlying gut-associated lymphoid tissue. Virus neutralising antibody was first detected on day 10. Specific anti-CCV IgM was first detected in plasma three days after inoculation and IgG on days 4 to 7. Small amounts of anti-CCV IgG, IgM and IgA were detected in duodenal secretion, but none in bile.

Animals

Studies on the role of feline calicivirus in chronic stomatitis in cats.

Two groups of cats were inoculated oro-nasally with one of two isolates of feline calicivirus (FCV) from clinical cases of chronic stomatitis. All cats developed signs typical of acute FCV infection; namely, ocular and nasal discharge, conjunctivitis, and marked oral ulceration. None of the cats shed virus beyond 28 days. Seronegative control cats were then infected with a lower dose of one isolate, but again only acute signs were seen and no carriers produced. The original cats were then re-infected with the heterologous isolate. As before, only signs of acute disease were seen, but the range of clinical signs and severity was reduced. Virus shedding patterns in one group were similar to those seen originally, but in the other the duration was reduced. No chronic stomatitis developed over the 10 months of the study. Serum virus neutralising and serum and salivary class specific immunoglobulin responses were investigated. Although long-term carriers were not induced, no relationship between cessation of virus shedding in an individual animal and systemic and local antibody responses was seen.

Acute Disease

Effect of primary-stage feline immunodeficiency virus infection on subsequent feline calicivirus vaccination and challenge in cats.

The effect of experimental primary-stage feline immunodeficiency virus (FIV) infection on feline calicivirus (FCV) vaccination and challenge in cats was studied. Clinical signs of acute FCV disease were more widespread in the cats which were infected with FIV than in those which were not. FIV infection also prolonged shedding of FCV, with more of the FIV-infected cats becoming chronic carriers. Although vaccination induced protection against acute FCV disease, this was to a lesser degree in FIV-infected cats. Vaccination by itself also appeared to enhance long-term virus shedding. There was evidence of an impaired anamnestic FCV-neutralizing antibody response in FIV-infected cats following FCV challenge.

Animals

Neutralisation patterns among recent British and North American feline calicivirus isolates from different clinical origins.

The neutralisation patterns of 103 recent isolates of feline calicivirus from cats with chronic stomatitis or acute feline calicivirus disease, and from cats with neither oral nor respiratory disease were compared. There were no statistically significant differences between the proportions of isolates from each clinical source neutralised by individual feline calicivirus cat antisera. Different antisera showed widely differing degrees of cross reactivity; antisera to the most widely used vaccine strain F9 being the most cross reactive, neutralising 54 per cent of all the field isolates, and antisera to a field isolate LS015 the next most cross reactive, neutralising 29 per cent of the field isolates. However, the cross reactivity of antisera to early British isolates (A4, 68/40 and 69/1112) was much reduced (overall less than 10 per cent) whereas in the early 1970s 65 per cent of 117 field isolates from clinically normal cats were neutralised by A4 antiserum, and 40 per cent by each of 68/40 and 69/1112 antisera. This suggests a change in the spectrum of antigenicity among feline calicivirus isolates over the past 15 years. However, the cross reactivity of F9 antisera appeared to be similar to that in earlier studies. The relevance of these findings to vaccination is discussed.

Animals

Prevalence of feline calicivirus, feline leukaemia virus and antibodies to FIV in cats with chronic stomatitis.

The prevalence of feline calicivirus (FCV), feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) antibodies were assessed in 78 British and 18 North American household cats with chronic stomatitis and in appropriate controls. In British cats, FCV was significantly (P less than 0.005) more prevalent in both hospital (92 per cent) and general practice (79 per cent) cases compared to their controls (19 per cent in both cases). A similar difference in prevalence of FCV was noted in North American cats where 50 per cent of cases were positive compared to 0 per cent of controls (P less than 0.01). FeLV prevalence was low in all chronic stomatitis populations. A significantly higher prevalence of antibody to FIV was found in British hospital cases (81 per cent) compared with time-matched controls (16 per cent) (P less than 0.001): a similar rate was found in the general practice cases (75 per cent) for which no controls were available. In the North American sample, FIV antibody status was similar in cases (54 per cent positive) and their age, sex and breed matched controls (50 per cent). The possible role of FCV and FIV in the pathogenesis of feline chronic stomatitis is discussed.

Animals

Studies on poxvirus infection in cats.

The development of clinical disease and the pathogenesis of cowpox were studied in domestic cats inoculated by a variety of routes. Intradermal titration in two cats demonstrated that as little as five pfu of cowpox virus caused a primary skin lesion. Intradermal inoculation of greater than or equal to 10(5) pfu cowpox virus resulted in severe systemic disease. Large amounts of virus (greater than or equal to 10(3) pfu/g) were isolated from skin lesions and the turbinates of cats killed at eight and 11 days post-inoculation (dpi). Lesser amounts of virus (congruent to 10(2) pfu/g) were isolated from lymphoid tissues and the lung, and small amounts of virus were isolated from various other tissues. A white cell-associated viraemia was detected from 5 dpi onwards. Skin scarification with 10(3) or 50 pfu cowpox virus enabled reproduction of the naturally-acquired disease. Cat-to-cat transmission was demonstrated from cats inoculated by skin scarification, but caused only subclinical infection in sentinel cats. Oronasal inoculation resulted in transient coryza and milder generalized disease than skin inoculation, and no transmission to sentinel cats. Preliminary investigations showed vaccinia virus (Lister strain) to be of low infectivity in cats while inoculation of ectromelia virus (Mill Hill strain) did not cause any clinical signs.

Animals

Virus shedding and immune responses in cats inoculated with cell culture-adapted feline infectious peritonitis virus.

Eight specific pathogen-free cats were inoculated orally or parenterally with a cell culture-adapted strain of feline infectious peritonitis virus (FIPV). Faeces and oropharyngeal swabs were monitored daily for infectious virus by inoculation of feline embryo lung cells. Virus was recovered from both sites for approximately 2 weeks after inoculation, before clinical signs of disease developed. Peripheral blood lymphocytes collected from these cats were tested in an in-vitro blastogenic assay using concanavalin A (con A) and FIPV antigen. All cats showed a profound suppression of the response to con A which only recovered to pre-inoculation levels in 2 cats, one of which survived. These 2 cats also responded to FIPV antigen on the 21st day after infection, the greater response being in the survivor. The other cats, surviving 16-18 days, developed no response to FIPV antigen. Antibody titres, measured by immunofluorescence and by virus neutralization, rose rapidly to very high levels in all cats, regardless of the route of inoculation.

Animals

Myopathy with core-like structures in a dog.

Core-like structures were seen histologically in many of the fibres of the triceps and biceps femoris muscles of an 18-months-old male Great Dane with muscle weakness and moderate proximal muscular atrophy. The structures were lightly staining and lacked cross-striations. Some contained vacuoles and nuclei. Scattered necrotic and presumably regenerating fibres were also present. Ultrastructurally, the cores contained disarrayed filament bundles attached to thickened Z-lines which were compatible with the rods of rod myopathies. The condition was not fully characterized, but has certain similarities to a group of rare human congenital muscular disorders which includes central core disease.

Actin Cytoskeleton