RESUMEN
The response of six calves to subcutaneous inoculation with louping-ill virus was studied. All developed viraemia of low intensity which lasted two to four days followed by the appearance of haemagglutination inhibiting serum antibody. IgM was the predominant class of antibody until day 14. Only one calf developed clinical signs; following a brief period of incoordination on day 7 it became recumbent and was killed on day 12. Severe meningoencephalitis was detected in this calf and mild changes were observed in one of the five survivors which were killed on day 14 or 20. These findings are discussed in relation to the epidemiology of louping-ill and the diagnosis of the disease in cattle.
Asunto(s)
Enfermedades de los Bovinos/diagnóstico , Meningoencefalomielitis Ovina/diagnóstico , Animales , Anticuerpos Antivirales/análisis , Bovinos , Enfermedades de los Bovinos/inmunología , Enfermedades del Sistema Nervioso Central/diagnóstico , Enfermedades del Sistema Nervioso Central/veterinaria , Meningoencefalomielitis Ovina/inmunología , Masculino , OvinosRESUMEN
The usefulness of the double immunodiffusion test for the diagnosis of louping ill infection was investigated. Whereas louping ill viral antigen was not detected in brain material from field cases of the infection, its presence was readily confirmed in suckling mouse brain isolates of the virus. The double immunodiffusion test was found to be unreliable as a serological test for the retrospective diagnosis of louping ill infection in the horse.
Asunto(s)
Enfermedades de los Caballos/diagnóstico , Inmunodifusión , Meningoencefalomielitis Ovina/diagnóstico , Animales , Antígenos Virales/análisis , Encéfalo/inmunología , Bovinos , Enfermedades de los Bovinos/microbiología , Virus de la Encefalitis Transmitidos por Garrapatas/inmunología , Virus de la Encefalitis Transmitidos por Garrapatas/aislamiento & purificación , Enfermedades de los Caballos/microbiología , Caballos , Meningoencefalomielitis Ovina/microbiología , Ratones , OvinosRESUMEN
Studies were made to find evidence of louping-ill virus infection in free-living red grouse and relate this to their breeding success. In areas where ticks were abundant 61 (84%) adult grouse had antibody to the virus compared with 1 (10%) in areas where ticks were relatively scarce. Of 162 chicks tested 25 were shown to be viraemic. Infected chicks were of significantly less weight than comparably aged uninfected birds and the probability that they died was much greater than that of uninfected birds. It is concluded that the relatively poor breeding success in areas of high tick numbers was principally due to infection with louping-ill virus. The susceptibility of the red grouse to infection is discussed.