Observations on Giardia Infection in Dogs from Veterinary Clinics in Germany

Abstract

Recent studies have shown that dogs in Germany harbour different genotypic assemblages, predominantly C and D, but also the assemblage A, which has been confirmed as a pathogenic human genotype. To determine the prevalence of assemblage A, a first study was conducted in dogs which showed clinical signs of diarrhoea or other symptoms indicating a possible infection with Giardia. A total of 92 dogs were identified positive for Giardia by a coproantigen test, of which 65 samples were positive for cysts of Giardia using theMIFC technique.These samples were genotyped, 50 Giardia isolates were identified as assemblage D, 33 as assemblage C and eight as a mixture of both. One dog harboured a mixture of assemblage D and A. It was concluded that the predominant dog-specific assemblages C and D in this first study might be more commonly associated with GI disorders than the zoonotic genotype A. Alternatively the coproantigen test used in this study might select assemblages C + D in dogs. Therefore, in a second study randomly selected dogs presented at local veterinary clinics were examined for cysts of Giardia using theMIFC technique. A total of 58 samples of Giardia-positive dogs were genotyped: 57% belonged to assemblage D, 36% to assemblage C and 7% could be identified as the zoonotic genotype assemblage A. Comparing the 65 MIFC-positive samples from the first study with the 58 samples of the second study a significantly higher prevalence of assemblage A (P = 0.0467) was found in randomly selected dogs.