Bovine cryptosporidiosis in Denmark. 2. Cryptosporidia associated with neonatal calf diarrhea.

: In recent years cryptosporidia have often been identified in diarrheic calves of under one month old, either as the sole pathogenic agent or in combination with other diarrhea-causing infectious agents. In 203 cases of bovine cryptosporidiosis, recorded over a period of two years, cryptosporidia were present in such great numbers that they would seem to be of causal significance. The calves were from three days to five weeks old. In 111 cases (55%) a monoinfection with cryptosporidia occurred, while in the rest of the cases mixed infections with other agents associated with calf diarrhea were demonstrated, especially rotavirus (61 cases) and coronavirus (32 cases); in addition, mixed infections with ETEC (four cases), septicaemic E. coli (two cases), salmonellosis (11 cases), and BVD and coccidiosis (one case each) were seen. In 87 (10%) of 849 4-21-day-old dead calves a massive occurrence of cryptosporidia was demonstrated. Extreme emaciation was noted in 36 of 122 autopsied calves. Most of these calves were more than 14 days old, and mono-infection with cryptosporidia was demonstrated in two thirds of them. In younger calves, more acute cases of cryptosporidiosis were commoner, often in connection with concomitant infections with rota- or coronavirus.