Research BriefMolecular characterization of Giardia duodenalis isolates from police and farm dogs in China

•The police and farm dogs have been infected with Giardia duodenalis in Shenyang.•Significantly higher infection rates of farm dogs than police dogs were seen.•The high occurrence of potentially zoonotic subtype AI-1 in dogs is of public health concern.

To assess the potential zoonotic transmission of giardiasis from dogs in China, a total of 205 fecal specimens from dogs were screened for Giardia duodenalis using PCR and sequence analysis of the triosephosphate isomerase gene. The prevalence of G. duodenalis in dogs was 13.2% (27/205). The potentially zoonotic assemblage A and the dog-specific assemblage C was identified in 25 (12.2%) and two (1.0%) dogs, respectively. All assemblage A isolates belonged to sub-assemblage AI, genotype AI-1. Likewise, one subtype was found in assemblage C. The high occurrence of potentially zoonotic G. duodenalis subtype AI-1 in dogs that are in close contact with humans is of public health concern.