# Prevalence and Multi-Locus Genotyping of Enterocytozoon bieneusi in Dogs from Fujian Province, Southeast China

## TL;DR

This study found E. bieneusi in 5.93% of dogs in Fujian, China, identifying new genotypes and highlighting zoonotic risks.

## Contribution

New genotypes of E. bieneusi in dogs and insights into their zoonotic potential in Fujian, China.

## Key findings

- E. bieneusi was detected in 5.93% of 506 dog fecal samples.
- Three new genotypes (FJLYD1, FJLYD2, FJSMD) and known genotypes were identified.
- Group 1 genotypes, including zoonotic risks, were prevalent among infected dogs.

## Abstract

Enterocytozoon bieneusi is a prevalent microsporidian pathogen infecting humans and a wide range of animal species. The characteristics of E. bieneusi infection are acute or chronic diarrhea, malabsorption, and emaciation. The objective of this study was to investigate the prevalence and genotypic distribution of E. bieneusi in dogs in Fujian province, southeast China. In this study, 506 dogs’ fecal samples were randomly collected from eight districts in Fujian province, China. We analyzed E. bieneusi infection rate using nested PCR targeting the internal transcribed spacer (ITS) region of the rRNA gene. Multilocus sequence typing (MLST) was performed at three microsatellite loci (MS1, MS3, and MS7) and one microsatellite locus (MS4). These results showed that 5.93% (30/506) of dog samples tested positive for E. bieneusi, including genotypes Ebp C, PigEBITS5, PtEb IX, FJLYD1, FJLYD2, and FJSMD. This study contributes to a deeper understanding of E. bieneusi in dogs, and provides critical data for the development of targeted control strategies in Fujian province.

Enterocytozoon bieneusi is a microsporidian species found ubiquitously in both invertebrate and vertebrate hosts including domestic and wild animals and humans. Enterocytozoon bieneusi typically causes severe or chronic diarrhea, malabsorption and emaciation. This study aimed to investigate the prevalence and genotypic distribution of E. bieneusi in dogs in Fujian province, China. A total of 506 fecal samples from dogs were randomly collected from eight districts in Fujian province, China. The presence of E. bieneusi was confirmed through nested PCR targeting ITS gene. Further multilocus sequence typing (MLST) focused on the three microsatellite loci (MS1, MS3, and MS7) and minisatellite locus (MS4) loci. As a result, the infection rates of E. bieneusi in dogs were found to be 5.93% (30/506). A highly significant difference in the prevalence of E. bieneusi was observed across different urban areas (p < 0.01), with Longyan city exhibiting the highest infection rate (24.62%, 16/65), Zhangzhou and Xiamen the lowest (0.00%). Prevalence also varied significantly by source (p < 0.01), age (p < 0.01), gender (p < 0.05), symptom status (p < 0.01), and season (p < 0.01). Three known genotypes of E. bieneusi were identified in 30 dogs’ positive samples, including EbpC, PigEBITS5 and PtEb IX, whereas FJLYD1, FJLYD2 and FJSMD have been identified as new genotypes. EbpC, PigEBITS5, FJLYD1, FJLYD2, and FJSMD all belong to Group 1, while PtEb IX is assigned to Group 11. Genotypes belonging to Group 1, the first major phylogenetic clade, are considered to possess potential zoonotic risks. None of the positive samples amplified at all four loci, forming a single multilocus genotype (MLG). This study contributes to a deeper understanding of E. bieneusi in dogs, which provides critical data for the development of targeted control strategies in Fujian province.