The incidence and significance of bovine herpesvirus (infectious bovine rhinotracheitis) antibodies in the sera of aborting cattle

The results of bovine herpesvirus (IBR-IPV) neutralization tests conducted on the sera of 463 animals with a prior history of undiagnosed abortion and 331 control animals with no history of abortion are reported. One hundred and thirty-one (28.3 per cent) of the aborting and 105 (31.7 per cent) of the control animals, were found to harbour antibody to this virus. No significant seasonal or gestational incidence could be determined but some variation in the annual incidence was apparent. On the basis of these results it appears unlikely that this virus is responsible for a significant proportion of the undiagnosed cases of bovine abortion in Quebec and Ontario, where the animals tested were located. The problems involved in substantiating a diagnosis of abortion due to bovine herpesvirus are briefly discussed.

Some observations on the diagnosis and epidemiology of leptospirosis in swine

The results of combined epidemiological, clinical, serological, bacteriological and histopathological studies following an outbreak of disease caused by L. pomona on a farm stocked with cattle, sheep, pigs, goats and horses maintained for experimental purposes, are reported.The incidence of infection was high in horses, cattle and pigs. A few low titres were seen in sheep. The goats were not infected. Apart from a single bovine abortion all the clinical symptoms observed occurred in pregnant sows. Seven of these aborted or gave birth to stillborn pigs within a six week period. Fifteen species of wildlife were trapped or shot on the farm during the year following the outbreak. L. pomona was isolated from four skunks and a porcupine. Epidemiological studies indicated that wildlife reservoir hosts were the primary source of infection for the domestic livestock. Leptospiruria and the serological response were studied in a group of eight infected sows. Microscopic agglutination titres of 10(2) or less could not be associated with leptospiruria and the duration of leptospiruria was found to range from a few weeks to over two years in individual sows. Direct dark-field examination of urine proved superior to guinea-pig inoculation as a method of detecting leptospiruria and it is suggested that the former technique could be adopted with advantage as a routine aid to diagnosis.

Isolation and Identification of a Leptospire of The Hebdomadis Serogroup (L. Hardjo) From Cattle in Canada

During the summer of 1961 an outbreak of atypical mastitis in a small herd of dairy cattle was investigated. The clinical findings, which included a single abortion, were suggestive of leptospirosis and serological studies indicated that a serotype other than the usual L. pomona was the causative agent. A fastidious leptospire recovered from the urine of one cow has been identified as L. hardjo, a member of the hebdomadis group. The difficulties encountered in isolation, adaptation to standard media and serotyping are described.

Dalmeny Disease. An Infection of Cattle Presumed to be Caused by an Unidentified Protozoon

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Studies on Pathogenic Porcine Enteroviruses: II. Isolation of Virus in Tissue Culture from Brain and Feces of Clinical Cases

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Studies on Pathogenic Porcine Enteroviruses: 1. Preliminary Investigations

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Observations On Leptospirosis In Swine

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An Outbreak Of "Inclusion-Body" Rhinitis In Pigs

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