Prevalence of Cryptosporidium sp in dairy calves in north-eastern Algeria

Parasitological investigations were carried out in dairy calves in Algeria to determine the prevalence and the intensity of oocyst output of Crytosporidium sp infection according to the age and the relationship with the diarrhoea. Fresh faecal samples were collected from 566 less than 12 month-old dairy calves from 40 cattle herds located in 4 regions of north-eastern Algeria. Faeces were processed through concentration and modified Ziehl-Neelsen staining techniques and the presence of Cryptosporidium sp oocysts was scored semi-quantitatively (0 to 3+). Oocysts were identified in 29 herds out of 40 (herd prevalence: 72.5%) and the within-herd prevalences ranged from 6 to 100%. The overall calf prevalence was 24.7 +/- 1.8%. The prevalence of Cryptosporidium sp infection was strongly correlated with calf age with highest values around 45% being observed in 4-14 day-old and 15-30 day-old animals. Furthermore, the highest faecal excretion scores were observed in same age groups. The overall percentage of diarrhoeic calves was 15.0% and peaked to 59.3% for the 4-14 day-old cryptosporidiosis positive animals. In this age class, the diarrhoea frequency was significantly and positively coupled to the intensity of faecal oocyst excretion. These results show that Cryptosporidium sp infections are highly prevalent in <1 month-old dairy calves in north-eastern Algeria and should be considered in animals with diarrhoea.