Studies On The Pathogenesis Of Contagious Ecthyma In Goats And Sheep
Local contagious ecthyma viruses isolated from sheep (Lb) and goats (GV 1 and GV 2) were used in a series of infection trials in kids and lambs to compare the pathogenesis, virus virulence and host susceptibility. Caprine contagious ecthyma isolate (GV 1) was able to establish infection in kids...
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| Format: | Thesis |
| Language: | English English |
| Published: |
1994
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/12309/1/FPV_1994_2_A.pdf |
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| Summary: | Local contagious ecthyma viruses isolated from sheep (Lb) and goats (GV 1
and GV 2) were used in a series of infection trials in kids and lambs to compare the
pathogenesis, virus virulence and host susceptibility.
Caprine contagious ecthyma isolate (GV 1) was able to establish infection in
kids and lambs, producing typical lesions. When rechallenged, the infected kids and
lambs developed rapid but milder lesions followed by rapid resolution. The clinical
and histopathological changes in the primary and secondary infections were similar
but were more severe in the former. The third infection, however, failed to establish
any lesions.
Secondary bacterial infection appeared to have complicated the contagious
ecthyma lesions resulting in a marked reduction in body weight and occasional
death. The inoculation of Corynebacterium pyogenes into the contagious ecthyma
lesions resulted in much more severe lesions resembling those observed in field cases of complicated contagious ecthyma. This finding suggests that in natural cases,
contagious ecthyma virus probably acts synergistically with other agents to produce
severe and generalised lesions.
Although the kids and lambs appeared to have similar disease, the kids
developed more severe lesions. Severity of the lesions produced were compared
statistically between the viral isolates and between the animal species. The caprine
GV 2 isolate was found to produce lesions in both kids and lambs with similar
severity whereas the ovine isolate (Lb) produced milder lesions in lambs but severe
lesions in kids. These observations correlated well with the development of antibody
response. In general, the lambs showed better antibody response than the kids,
reaching significantly high level on day twenty-two, coinciding with recovery from
the disease. The kids infected with Lb virus responded poorly leading to the severe
disease and longer recovery period. |
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