Browsing by Author "Karstad, L."
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Item Antibodies to Malignant Catarrhal Fever Virus Antigens in the Sera of Normal and Naturally Infected Cattle in Kenya(1980) Rossiter, P.B.; Jessett, D.M.; Mushi, E.Z.; Karstad, L.; Kenya Agricultural Research Institute, Muguga, PO Box 32, Kikuyu, Kenya; Veterinary Research Laboratory, PO Kabete, Nairobi, KenyaSix different serological tests were used to examine Kenyan cattle sera for antibodies to the herpesvirus of malignant catarrhal fever. Significantly higher levels of indirect immunofluorescent antibody to early and late virus antigens and of complement fixing antibody were found in the sera of 13 naturally infected cattle than in 482 sera collected from four different groups of normal cattle. Virus neutralising and immunoprecipitating antibodies were also found in some infected cattle sera but not in normal cattle sera. Many non-specific reactions occurred using counterimmunoelectrophoresis. These preliminary results indicate that the serological diagnosis of wildebeest-associated malignant catarrhal fever may be possible.Item Isolation And Characterization of a Herpesvirus from Topi (Damaliscus Korrigum, Ogilby)(1981) Rossiter, P. B.; Mushi, E. Z.; Jessett, D.; Karstad, L.; Veterinary Research Department, Muguga: Kenya Agricultural Research Institute: Veterinary Research LaboratoryA cell-associated herpesvirus was isolated from kidney and thyroid cell cultures established from 4 out of 18 topi. The virus isolates were found to be antigenically related to the herpesvirus of malignant catarrhal fever derived from wildebeest. Preliminary studies suggest that this virus is not pathogenic to cattle.Item Malignant Catarrhal Fever Virus Specific Secretory Iga in Nasal Secretions of Wildebeest Calves(1982) Rurangirwa, F.R.; Mushi, E.Z.; Karstad, L.; Kenya Agricultural Research Institute, Veterinary Research Department, P.O. Box 32, Kikuyu, Kenya; Veterinary Laboratories, Kabete, KenyaWildebeest IgA was isolated from nasal secretions and precolostrum. It was identified by cross-reaction with anti-human and anti-bovine IgA sera. Nasal secretions collected from wildebeest calves over 3 months old had malignant catarrhal fever virus neutralizing antibody activity. They also contained specific IgA to the virus as detected by indirect immunofluorescence. It is suggested that production of malignant catarrhal fever virus specific IgA in the nasal cavity, contributes to the elimination and cassation of the virus shed in the nasal secretions of wildebeest calves over 3 months. old.Item Neutralising Antibodies to Rinderpest Virus in Wild Animal Sera Collected in Kenya Between 1970 and 1981(1983) Rossiter, P.B.; Karstad, L.; Jessett, D.M.; Yamamoto, T.; Dardiri, A.H.; Mushi, E.Z.; Veterinary Research Department, Muguga, P.O. Box 32, Kikuyu Kenya; Veterinary Research Laboratories, Kabete, P.O. Kabete Kenya; On leave from the University of Alberta, Edmonton Canada; Plum Island Animal Disease Centre, U.S.D.A., Greenport, New York, NY 11944 U.S.A.Four hundred and twenty-five sera were collected from 18 species of wild mammals in Kenya between 1970 and 1981. Neutralising activity to rinderpest virus (RV) was detected in 35 samples from 13 species. This activity appeared to be specific antibody to RV since it did not neutralise the virus of peste des petits ruminants. It was associated with the serum globulin fraction and it blocked the staining of a rabbit immunofluorescent antibody conjugate to RV. Positive sera were not restricted to any particular area of Kenya. It is possible that strains of RV with low pathogenicity and low transmissibility are still present in wildlife in East Africa, a fact which must be considered when studying the epidemiology and control of rinderpest.Item Persistent Infection of Cattle with the Herpesvirus of Malignant Catarrhal Fever and Observations on the Pathogenesis of the Disease(1976) Rweyemamu, M.M.; Mushi, E.Z.; Rowe, L.; Karstad, L.; East African Veterinary Research Organization, Muguga, P.O. Box 32, Kikuyu, Kenya; Veterinary Research Laboratory, P.O. Kabete, KenyaA case of persistent MCF virus infection is described. A steer was inoculated with attenuated virus and apparently withstood challenge with virulent MCF virus. Five months later it developed a viraemia which persisted for four weeks and the animal died after only one day's fever. Post-mortem and histological studies showed extensive ulcerative, haemorrhagic enteritis and a necrotizing polyvasculitis with mononuclear leucocyte infiltration. Experimental studies have demonstrated viraemia to preceed fever in cases of acute MCF. The pathogenesis of MCF is discussed in the light of these findings and it is concluded that MCF might be an immune complex disease.Item Prevalence of Virus Neutralising Antibodies to Malignant Catarrhal Fever Virus in Oryx (Oryx Beisa Callotis)(1981) Mushi, E.Z.; Karstad, L.; Veterinary Research Department, Kenya Agricultural Research Institute, Muguga, P.O. Box 32, Kikuyu, Kenya; Veterinary Research Laboratory, P.O. Kabete, KenyaVirus neutralising antibodies to malignant catarrhal fever virus were demonstrated in the sera of 50 oryx (Oryx beisa callotis). The mean antibody titre in 42 adult oryx was 10.1.23 Two calves which were 2 weeks’ old had a mean titre of 101.54 but the level of circulating antibody had started to decline in 2 months old calves. The antibody titres continued to decline only to rise steeply in 9 months old calves. Despite the high prevalence of antibodies in oryx no virus was isolated from blood or nasal secretions inoculated into calf thyroid cell cultures or rabbits.Item Re-emergence of Rinderpest as a Threat in East Africa since 1979(1983) Rossiter, P.B.; Jessett, D.M.; Wafula, J.S.; Karstad, L.; Chema, S.; Taylor, W.P.; Rowe, L.; Nyange, J.C.; Otaru, M.; Mumbala, M.; Veterinary Research Department, Kenya Agricultural Research Institute, Muguga, P PO Box 32, Kikuyu, Kenya. Veterinary Research Laboratories, PO Box Kabere, Kenya. Animal Virus Research Institute, Pirbright, Woking. Veterinary Investigation Centre, PO Box 1068, Arusha, Tanzania. Ministry of Animal Industry and Fisheries, Kampala, Uganda. Centre for Tropical Veterinary Medicine, Easter Bush, Roslin, Midlothian, ScotlandThe evidence for the recent re-emergence of rinderpest as a threat in East Africa is reviewed. East Africa was free from rinderpest in domestic and wild animals from 1966 to 1979 apart from isolated outbreaks of the disease in unvaccinated nomadic cattle and wildlife. However, in July 1979, rinderpest was diagnosed in East African zebu cattle in northeastern Uganda and the disease spread rapidly before being brought under control in November 1981. In July 1980 the disease was confirmed by virus isolation and specific antigen detection among unvaccinated grade and Boran cattle in Muguga, and serological surveys reported in 1982 and 1983 indicated that the virus had infected goats, sheep and wild ungulates in Kenya. In Tanzania, in March 1982, the disease affected buffaloes in the Serengeti National Park and later that year many buffaloes and also giraffes, warthogs and eland in the Ngorongoro Crater area were killed by what is thought to have been the same disease. Serum samples subsequently collected from buffaloes in these latter two areas had a high prevalence of neutralizing antibody to rinderpest virus. In September 1982 detection of virus neutralizing antibody in cattle, sheep and goats in northern Tanzania where a disease resembling rinderpest had been active since 1981 indicated that the rinderpest virus was responsible for this outbreak which was spreading slowly in 1983. It is concluded that the worldwide recession and resultant decrease in the level of vaccination cover have facilitated re-entry of rinderpest to East Africa. Immediate provision of resources to prevent the disease regaining endemic status is called for.Item Re-emergence of Rinderpest as a Threat in East Africa since 1979.(1983) Rossiter, P.B.; Jessett, D.M.; Wafula, J.S.; Karstad, L.; Chema, S.; Taylor, W.P.; Rowe, L.; Nyange, J.C.; Otaru, M.; Mumbala, M.; Veterinary Research Department, Kenya Agricultural Research Institute, Muguga, PO Box 32, Kikuyu, Kenya. Veterinary Research Laboratories, PO Box Kabete, Kenya. Animal Virus Research Institute. Veterinary Investigation Centre, PO Box 1068, Arusha, Tanzania. Ministry of Animal Industry and Fisheries, Kampala, Uganda. Centre for Tropical Veterinary Medicine, Easter Bush, Roslin. Midlothian, ScotlandFollowing the success of the JP15 scheme and subsequent annual vaccination campaigns, East Africa was virtually free of rinderpest after the mid 1960s and the disease was considered beaten. However, economic difficulties have recently reduced the expensively maintained vaccine cover and the disease has reappeared throughout much of the region. In 1979 rinderpest was diagnosed in cattle in north eastern Uganda and caused considerable losses until finally brought under control in 1981. No field outbreaks of the disease in cattle have been seen in Kenya but there is serological evidence that the virus has recently infected unvaccinated sheep and goats and wild ungulates in that country. In 1982 rinderpest was confirmed in the laboratory as the cause of death of large numbers of buffaloes in northern Tanzania and implicated as the cause of a rinderpest-like disease of cattle which is reported to be still active in that area. Substantial aid is essential for further control and research if the virus is not again to become endemic in the region.Item Role of Wildebeest Fetal Membranes and Fluids in the Transmission of Malignant Catarrhal Fever Virus(1983) Rossiter, P.B.; Jessett, D.M.; Karstad, L.; Veterinary Research Department, Kenya Agricultural Research Institute, Muguga, PO Box 32, Kikuyu, Kenya; Veterinary Research Laboratories, PO Box Kabete, KenyaMalignant catarrhal fever virus was not isolated from samples of fetal membranes or fluid collected from 93 calving wildebeest (Connochaetes taurinus) in Kenya Maasai land. Cell-free strains of malignant catarrhal fever virus were very rapidly inactivated when exposed to the sun under field conditions, at least 3.0 log10 units/25 microliter being lost per hour at midday. It is suggested that wildebeest fetal membranes and fluids act as visual markers for areas of pasture which are particularly heavily contaminated with malignant catarrhal fever virus in oculonasal secretions of wildebeest calves. It is possible that starting to graze cattle one to two hours later each morning may be a useful measure for helping to protect cattle from malignant catarrhal fever in areas where they are forced to share pastures with calving wildebeest.
