Abstract
Enterocytozoon bieneusi is an obligate intracellular parasitic fungi that infects a wide range of mammalian hosts. However, the literature is lacking information regarding the presence and diversity of E. bieneusi genotypes in domesticated dogs in Northwestern China. Fecal samples from 604 pet dogs were obtained in 5 cities (Urumqi, Korla, Hotan, Aksu, and Shihezi) in Xinjiang. Screening for E. bieneusi was performed, and isolates were genotyped via nested-PCR amplification of the internal transcribed spacer (ITS) of nuclear ribosomal DNA. The infection rate of E. bieneusi was 6.3% (38/604). The prevalence of E. bieneusi infections in adult animals (>1 year, 10.3%, 15/145) was higher than that in younger (≤1 year) dogs (5.0%, 23/459), which was statistically significant (p = 0.021). No significant difference was observed between the different collection sites or between sexes. Eight distinct genotypes were identified, including 5 known genotypes (PtEb IX, EbpC, D, CD9, and Type IV) and 3 novel genotypes (CD11, CD12, CD13). The most prevalent was genotype PtEb IX, being observed in 50.0% (19/38) of the samples, followed by EbpC (31.6%, 12/38), D (5.3%, 2/38), and the remaining genotypes (CD9, Type IV, CD11, CD12, and CD13) were observed in 1 sample (2.6%, 1/38) each. These findings suggest that genotypes PtEb IX and CD9 are canine host-adapted, and likely pose little risk of zoonotic transmission. Moreover, known zoonotic genotypes EbpC, D, and Type IV represent a public health concern and should undergo further molecular epidemiological investigation.
Highlights
Microsporidia are diverse and ubiquitous obligate intracellular parasitic fungi, with diverse hosts ranging from protists to vertebrates, up to and including humans [16, 27]
Among the collected 604 fecal samples collected from pet dogs, 6.3% (38/604) were positive for E. bieneusi
A higher prevalence of E. bieneusi infections was observed in Aksu (13.6%, 2/22), Shihezi (12.2%, 5/41), and Urumqi (9.9%, 18/191)
Summary
Microsporidia are diverse and ubiquitous obligate intracellular parasitic fungi, with diverse hosts ranging from protists to vertebrates, up to and including humans [16, 27]. Of the 17 microsporidian species known to be human pathogens, Enterocytozoon bieneusi is the most prevalent one that infects the gastrointestinal tract and is responsible for 90% of human microsporidiosis cases reported globally [16]. First detected in 1985, E. bieneusi was isolated from a Haitian AIDS patient suffering from severe diarrhea [8]. Y. Cao et al.: Parasite 2021, 28, 57 an emerging infectious agent, E. bieneusi infection is characterized by acute or chronic diarrhea, malabsorption, and/or wasting [17, 26]. Immunocompetent individuals with asymptomatic infections are commonly reported worldwide [23, 27]. E. bieneusi has been detected in animals. Some zoonotic genotypes are commonly identified both in humans and synanthropic animals, which suggests a potential for zoonotic transmission [13]
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