An outbreak of bovine thromboembolic meningoencephalitis in Yucatan, Mexico

Abstract

Seventeen Beef-Master cattle (three calves, one male and thirteen cows) died within a period of two months with neurological signs. A neurological syndrome was evident in the patients characterised by ataxia, incoordination, dysmetria, hyperacusia, muscle tremors and ptyalism. A dysfunction of trigeminal, facial and vestibulocochlear cranial nerves was also observed. At necropsy a septic process was evident. Histopathology of internal organs showed necrosis as a consequence of septicaemia. Complete blood cell count showed leukocytosis due to neutrophilia, lymphocytosis and monocytosis. Macroscopically the brain showed severe congestion and the histology showed a thromboembolic meningoencephalitis and thickening of the meninges. To stop the outbreak, oxytetracycline was provided to the entire herd for 10 days and all susceptible animals vaccinated against Histophilus somni. No other case was presented until a month later when two cows and one calf died with the same symptomatology. Immunosuppression was associated with the development of the disease.