A longitudinal study on the occurrence of Cryptosporidium and Giardia in dogs during their first year of life

Background: The primary aim of this study was to obtain more knowledge about the occurrence of Cryptosporidium and Giardia in young dogs in Norway. The occurrence of these parasites was investigated in a longitudinal study by repeated faecal sampling of dogs between 1 and 12 months of age ( litter samples and individual samples). The dogs were privately owned and from four large breeds. Individual faecal samples were collected from 290 dogs from 57 litters when the dogs were approximately 3, 4, 6, and 12 months old. In addition, pooled samples were collected from 43 of the litters, and from 42 of the mother bitches, when the puppies were approximately 1 and/ or 2 months old. Methods: The samples were purified by sucrose gradient flotation concentration and examined by immunofluorescent staining. Results: 128 ( 44.1%) of the young dogs had one or more Cryptosporidium positive samples, whilst 60 ( 20.7%) dogs had one or more Giardia positive samples. The prevalence of the parasites varied with age. For Cryptosporidium, the individual prevalence was between 5.1% and 22.5%, with the highest level in dogs < 6 months old, and declining with age. For Giardia, the individual prevalence was between 6.0% and 11.4%, with the highest level in dogs > 6 months old, but the differences between age groups were not statistically significant. Significant differences in prevalences were found in relation to geographic location of the dogs. Both parasites occurred at low prevalences in Northern Norway. Conclusion: Both Cryptosporidium and Giardia are common in Norwegian dogs, with Cryptosporidium more prevalent than Giardia. Prevalences of the parasites were found to be influenced by age, geographical location, and infection status before weaning.