A survey of the prevalence and genotypes of Giardia duodenalis infecting household and sheltered dogs

Abstract

Giardia duodenalis (syn. G. intestinalis, G. lamblia) is an intestinal protozoan parasite that infects humans and a wide range of mammals that includes dogs. Highly significant genetic heterogeneity has been found within this species, while only genotypes from assemblages A and B have zoonotic potential. Although Giardia infection in dogs has been reported worldwide, there is increasing molecular evidence that dogs may be infected with host-specific genotypes (C and D) as well as zoonotic ones (A and B). Therefore, dogs play a role as a potential source of Giardia infection impacting humans and other Canidae. Fecal samples from privately owned dogs and from dogs kept in two shelters in the west-central region of Poland were examined using a microscope and polymerase chain reaction. The total prevalence of Giardia in specimens was 1.9%. Deoxyribonucleic acid was extracted only from two out of the three Giardia-positive fecal samples. After amplification using the G7 and G759 beta-giardin primers, 753 bp amplicons were obtained, and both amplification products were sequenced. Sequence and phylogenetic analyses showed that both G. duodenalis isolates were dog-specific genotypes (C and D).