|ASCHENBROICH, SOPHIE - University Of Georgia|
|NEMETH, NICOLE - University Of Georgia|
|RECH, RAQUEL - Embrapa|
|Briggs, Robert - Bob|
|SANCHEZ, SUSAN - University Of Georgia|
|BROWN, CORRIE - University Of Georgia|
Submitted to: Journal of Comparative Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2013
Publication Date: 4/10/2013
Citation: Aschenbroich, S., Nemeth, N., Rech, R., Briggs, R.E., Sanchez, S., Brown, C. 2013. Mannheimia haemolytica A1-induced fibrinosuppurative meningoencephalitis in a naturally-infected Holstein-Friesian calf. Journal of Comparative Pathology. 149(2-3):167-171.
Interpretive Summary: Mannheimia haemolytica is a bacterium associated with pneumonia in domestic cattle, sheep, and goats. In cattle, M. haemolytica disease is almost exclusively confined to the lungs or mammary gland wherein systemic multi-organ disease is extremely rare. Here is reported a case in a weaned Holstein-Friesian calf of disease in the brain as well as the lung associated with recovery of pure cultures of M. haemolytica from both tissues. This is the first report of disease in the brain caused by this organism.
Technical Abstract: Mannheimia haemolytica is an opportunistic bacterium that is widely recognized among the bovine respiratory disease complex as the predominant pathogen associated with pleuropneumonia in cattle. Among the characterized M. haemolytica serotypes, A1 is the major cause of severe pulmonary lesions in cattle. Rarely, M. haemolytica has been reported to lead to extra-pulmonary systemic infections with multi-organ spread. The current report describes post-mortem findings from a Holstein-Friesian calf that included pinpoint and ecchymotic hemorrhages with associated fibrin strands and cloudy leptomeninges overlying the cerebrum, brainstem, and cerebellum. Microscopically, the meninges over the brainstem and cerebellum were expanded by neutrophils and fibrin, with intralesional bacterial coccobacilli. Occasional vessels within the midbrain and cerebellum contained fibrin thrombi at different stages of development. Bacterial culture yielded M. haemolytica from cerebellum and lung, and rapid plate agglutination confirmed the isolate as serotype A1. The accompanying fibrinonecrotizing and hemorrhagic pleuropneumonia in this calf was consistent with typical mannheimiosis due to serotype A1. While Mannheimia haemolytica has been reported to produce localized infections in specific organs, such as the meninges, in ruminants, no published case reports exist on M. haemolytica-associated fibrinosuppurative meningoencephalitis in cattle.