The epidemiology of infections with Giardia species and genotypes in well cared for dogs and cats in Germany

BACKGROUND: Giardia is now considered the most common enteric parasite in well cared for dogs and cats in developed countries. The ecology, epidemiology and clinical impact of infections with this parasite in such animals is still not fully understood due to variable results across different studies. METHODS: Faecal samples were collected between 2009 and 2012 from privately owned cats and dogs in Germany presented to local veterinarians for a variety of reasons. Giardia positive samples were identified by microscopy and coproantigen methods. Total faecal DNA was extracted from Giardia positive samples and multilocus genotyping methods (18S rDNA, β-giardin, GDH) were applied. Relationships between host age, sex, and breed, season of presentation and the different species of Giardia detected were assessed. RESULTS: A total of 60 cat and 130 dog samples were identified as Giardia positive. Potentially zoonotic Giardia was identified in both animal species. Cats had a similarly high rate of infection with the G. duodenalis and G. cati. Cats less than 1 year were more likely to have G. duodenalis than cats older than 1 year. Pure breed cats demonstrated a greater proportion of zoonotic species than mixed breed cats. In samples from dogs, G. canis (C and D genotypes) were identified most commonly. Male dogs were more likely to have G. canis (genotype D) than female dogs. The 18S rDNA PCR protocol was the most successful followed by the β-giardin and GDH (amplifying from 92%, 42% and 13% of samples respectively). CONCLUSIONS: The potentially zoonotic species G. duodenalis and G. enterica were found in cat and dog samples, with G. duodenalis found in greater numbers; however, this may be due to the detection techniques utilised. Cats appeared to show a relationship between G. duodenalis and G. cati with age and breed, which may be explained by different housing habitats for pure and mixed breed cats. The different success rates for the three loci utilised highlights the usefulness of the 18S locus as a screening tool, as well as the importance of using multiple loci for genotyping to fully determine the level of multiple infection of Giardia present.