Epidemiology of Cryptosporidium spp. and Giardia duodenalis on a dairy farm

Prevalences of Cryptosporidium spp. and Giardia duodenalis in relation to a ge and season were investigated on a dairy farm in The Netherlands over the course of I year. The whole herd was sampled five times, whereas calves yo unger than about 2 months were sampled every 2-3 weeks. Associations betwee n diarrhoea and presence of one or more pathogens (Cryptosporidium spp., G. duodenalis, rotavirus) were investigated. Potential transmission routes of Cryptosporidium spp. were evaluated and positive samples of Cryptosporidiu m spp. and G. duodenalis were identified to genotype level by PCR microsate llite identification and fingerprinting. Shedding of Cryptosporidium spp. w as found in all age categories but peaked in calves 1-3 weeks old (39.1%). Herd prevalence of shedding for Cryptosporidium spp. varied from 2.4% in Ju ne to 22.2% in December. Shedding of G. duodenalis was found in all age cat egories but peaked in animals 4-5 months old (54.5%). Herd prevalence of sh edding for G. duodenalis varied from 0.8% in June to 15.5% in February. Cry ptosporidium spp. and rotavirus appeared to be significantly associated wit h diarrhoea in calves. Microsatellite analysis showed two different subtype s (C3 and Cl) of Cryptosporidium parvum calf strains. Two genotypes of G. d uodenalis were found, one positive by A lineage specific PCR and thus close ly related to human genotypes and one genotype, which was negative by A and B lineage specific PCR. The results indicate that cow-to-calf and indirect calf-to-calf transmission both are important routes for acquiring infectio n with Cryptosporidium spp. (C) 2001 Elsevier Science B.V. All rights reser ved.