Investigation of an abortion epidemic due to Neospora caninum in a beef herd on pasture

Authors

  • L. Michelle Arnold University of Kentucky Veterinary Diagnostic Laboratory, College of Agriculture, 1490 Bull Lea Road, Lexington, KY 40511

DOI:

https://doi.org/10.21423/bovine-vol47no1p1-6

Keywords:

abortion, Neospora caninum, beef cattle, brain, diagnosis, disease transmission, epidemiological surveys, epidemiology, fetal death, fetal development, fetal development disorders, herds, immunohistochemistry, outbreaks, pastures, polymerase chain reaction, reproductive disorders, seroprevalence, vertical transmission

Abstract

An outbreak of epidemic abortion in a commercial cow-calf herd was investigated. Within 3 weeks of the index cases, 69 reproductive abnormalities were recorded consisting of abortions, stillbirths, and premature calves born alive but dying within 24 hours. By the conclusion of the calving season, 85 abnormal reproductive outcomes were reported out of 154 cows at risk. The epidemiologic pattern of abortion highly suggested a point-source exposure. Results of diagnostic tests implicated Neospora caninum as the causative agent of abortion. Eleven aborted fetuses were submitted for diagnostic evaluation, and all had lesions consistent with protozoal abortion. The diagnosis was confirmed by polymerase chain reaction assays and immunohistochemical tests performed on brain tissue from 2 aborted fetuses. Once the diagnosis was made, no treatment options were available. Serologic testing was performed to determine the seroprevalence in the herd and the statistical correlation of a positive serum test to an abnormal reproductive outcome. Control measures were instituted to decrease the presence of the organism in the herd and the risk of horizontal and vertical transmission of the organism. Clinically, N. caninum is widely recognized as an important infectious cause of reproductive loss in cattle, and vertical transmission of the protozoan from infected dams to their progeny is considered the major mode of infection and maintenance of the parasite within the population. However, the consequence of a point-source exposure and horizontal transmission in a susceptible population at or near the same vulnerable stage of gestation can be an abortion epidemic, as evidenced by this outbreak.

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Published

2013-02-01

How to Cite

Arnold, L. M. (2013). Investigation of an abortion epidemic due to Neospora caninum in a beef herd on pasture. The Bovine Practitioner, 47(1), 1–6. https://doi.org/10.21423/bovine-vol47no1p1-6

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Articles