EN
The purpose of the study was to establish the influence of canine herpesvirus (CHV), Mycoplasma sp. and Toxocara canis on new-born fox mortality. 25 new-born foxes died at the age of up to 5 days. They were derived from 5 blue and silver fox farms. Virologic investigations were done by means of direct IF method and virus isolation attemps. Hepatic, splenic and renal tissue suspensions were inoculated into monolayers of cell lines: A-72, MDCK, Vero, RK-13. PPLO (Difco) medium was used to isolate mycoplasmas. Parasitological examinations were performed by means of the larvoscopy technique. At autopsy lung congestion was observed in the all the examined pups. Renal haemorrhages in subcabsular region of the kidney were found in some pups. No microorganisms were isolated from basic bacteriological examinations of the pups. Females were free from brucellosis, leptospirosis and listeriosis. Low levels af antibodies against CHV were determined in some vixens. Histopathologically interstitial pneumonia was found in the all examined foxes. Canine herpesvirus was not isolated from any of the cases, as well as no Toxocara canis larvae were observed in lungs and livers. Mycoplasmas were isolated from the lungs of 5 pups derived from 2 farms. This suggests that mycoplasmas may cause interstitial pneumonia in new-born foxes.