Prevalence and zoonotic potential of Enterocytozoon bieneusi in dogs and cats in Guangdong, China.

Dogs and cats are important reservoirs for the zoonotic pathogen Enterocytozoon bieneusi. In this study, fecal samples from 682 dogs and 424 cats in Guangdong Province, China, were examined for E. bieneusi by PCR targeting the internal transcribed spacer (ITS) of the rRNA gene. The overall infection rate was 31.5 % in dogs and 3.5 % in cats. Significantly higher infection rates were observed in dogs >6 months (31.0 %, 137/442, χ = 33.168, P = 0.000), female dogs (35.0 %, 114/326, χ = 22.669, P = 0.000), purebred dogs (29.7 %, 140/471, χ = 24.464, P = 0.000), dogs from the research center and shelters (52.3 %, 116/222, P = 0.000; 50.7 %, 71/140, P = 0.000). The genotypes detected in dogs included canine-adapted PtEb IX (n = 212) and WW8 (n = 2), and zoonotic Type IV (n = 1). In cats, Type IV was dominant (n = 12), followed by D (n = 2) and PtEb IX (n = 1). The genetic diversity in Type IV and D samples were further assessed by multilocus sequence typing at four microsatellite/minisatellite loci. Twelve multilocus genotypes (MLGs) were identified, suggesting inconsistent genotyping results among the loci. Population genetic analysis of the MLG data generated in this study and those from other hosts in previous studies revealed three distinct subpopulations. Subpopulation 1 and Subpopulation 3 contained E. bieneusi from monkeys and fur animals, respectively. In contrast, Subpopulation 2 contained E. bieneusi from humans and cats. This suggests that E. bieneusi in cats and in humans is genetically related and has the potential for zoonotic transmission.