Occurrence and genetic characteristics of Giardia duodenalis in donkeys in Xinjiang, China

Giardia duodenalis is a common enteric parasite in humans and animals. To examine the occurrence and genetic characteristics of Giardia in donkeys in Xinjiang, China, 758 fecal samples from donkeys were collected, and Giardia was screened via PCR at the SSU rRNA gene. A total of 17.0% (129/758) of samples tested positive for Giardia, with the infection rate in large-scale farm and domestic donkeys being 21.4% (124/580) and 2.8% (5/178), respectively; the infection rates in <1-year-old and ≥1-year-old donkeys were 19.3% (72/374) and 12.7% (41/323), respectively. Three Giardia assemblages were identified, with assemblage B (n = 102) as the prevalent assemblage, followed by assemblage A (n = 23) and assemblage E (n = 4). Of the 129 Giardia-positive isolates, 40, 34 and 59 sequences were obtained at the bg, gdh and tpi genes, respectively. Twenty-one isolates successfully allowed multilocus genotyping (MLG), with four novel assemblage A MLGs, named MLG-AI-1 (n = 1), MLG-AI-2 (n = 1), MLG-AI-3 (n = 1), and MLG-AI-4 (n = 1) and three novel assemblage B MLGs, named MLG-B1 (n = 1), MLG-B2 (n = 14), and MLG-B3 (n = 1). Moreover, two isolates formed two MLG-mixed sequences. The results suggest that donkeys are commonly infected with Giardia in Xinjiang, and there is genetic diversity and host adaptability among the isolates.