Prevalence of Cryptosporidium spp. and Giardia duodenalis in Lambs in South-West of Norway: A Longitudinal Study

Abstract

Cryptosporidium spp. and Giardia duodenalis are protozoan parasites that infect a variety of vertebrates, and most of the common farm animals are susceptible to infection. The pathogens have been reported globally with regional variations. Most commonly, it is the youngest animals that show clinical signs of the disease, seen in form of diarrhea. Cryptosporidium parvum is zoonotic and known to be a major cause of diarrhea in calves and is also known to affect small ruminants. Giardia is found in many animals, with zoonotic potential of some of the assemblages. Data were collected from each farm using a questionnaire to identify risk factors. The aim of this study was to investigate Cryptosporidium spp. and Giardia duodenalis infections in lambs in South-West of Norway. A total of 507 fecal samples were collected from 17 different flocks of lambs in South-West of Norway (11 in Sunnhordland and 6 in Dalane) aged from 2 days to 6 weeks. The samples were analyzed using immunofluorescent antibody staining, followed by PCR and sequencing of positive samples for molecular characterization. Of these, 63 (22.4%) were positive for Cryptosporidium spp. and 61 (21,7%) positive for G. duodenalis by IFAT/microscopy. Molecular methods on selected samples identified two species of Cryptosporidium (C. parvum and C. ubiquitum) and Giardia duodenalis assemblage E. Most of our positive samples were from asymptomatic lambs. Cryptosporidium spp. infection peaked at 2-3 weeks of age, while G. duodenalis infection peaked at 6 weeks of age. The finding suggests lambs might be capable of harboring potentially zoonotic Cryptosporidium spp. Further research is needed to better understand the epidemiology of the disease in the study areas.