Pathological and histopathological findings in lungs following experimental infection of calves with Histophilus somni.

Histophilus somni (former name: Haemophilus somnus) is a Gram-negative, fastidious, facultative patogenic bacterium, that can cause local or generalised diseases in cattle: thromboembolic meningoencephalitis - TEME -, septicaemia, reproductive problems, mastitis, respiratory diseases, as well, as asymptomatic carriage on the mucous membranes of respiratory and genital tract can also occur. The authors carried out the pathological and histopathological evaluation of lungs of 12 conventionally reared 3-month-old Holstein-Friesian calves after aerosol infection with H. somni. All animals were exterminated and gross pathological examination was carried out on 15(th) day after infection. Ten calves developed acute catarrhal bronchopneumonia, while there was one subacute, as well as, one chronic case. This is the first article in Hungarian on pathological and histopathological findings of pneumonic lesions caused by experimental infection of calves with H. somni.