Identification of zoonotic Enterocytozoon bieneusi genotypes in pre-weaned Korean native calves

Abstract Background: Enterocytozoon bieneusi is the most common species of microsporidia that can infect humans and various animals worldwide. To date, information on the prevalence and genotypes of E. bieneusi infection in cattle in the Republic of Korea is limited. Therefore, in this study, we aimed to investigate the prevalence and genotypes of E. bieneusi circulating in pre-weaned Korean native calves and determine the age pattern of E. bieneusi infection and the relationship between E. bieneusi and diarrhea. Results: The overall prevalence of E. bieneusi was 16.9% (53/314) in pre-weaned calves by PCR. The prevalence of E. bieneusi was the highest in September (36.2%), followed by March (28.3%). E. bieneusi infection (c 2 = 5.82, P = 0.016) was associated with diarrhea in calves. The present results indicated that E. bieneusi infection was statistically associated with calf age (c 2 = 11.61, P = 0.003); the prevalence of E. bieneusi was significantly higher in calves aged 21-40 days (odds ratio = 2.90, 95% confidence interval: 1.54-5.45; P = 0.001) than in those aged 1-20 days. Interestingly, E. bieneusi infection showed an association with diarrhea only in calves aged 1-20 days (c 2 = 5.82, P = 0.010). Five genotypes, BEB4 ( n = 12), BEB8 ( n = 23), CHN6 ( n = 1), I ( n = 1), and J ( n = 16), were identified, and all these genotypes belonged to Group 2. The genotype BEB8 was the most prevalent in all age groups regardless of diarrhea. On the other hand, the genotype I was identified only in one calf aged 10 days with diarrhea. Except for CHN6, the four other genotypes were mostly observed in cattle, and all of them have zoonotic potential. Conclusions: This is the first report of the genotypes BEB4 and CHN6 in pre-weaned Korean native calves. The results revealed the presence of zoonotic E. bieneusi in pre-weaned Korean native calves, demonstrating that cattle may play an important role as a reservoir host in E. bieneusi transmission to humans.