First report of Enterocytozoon bieneusi in pigs in Brazil

Although Brazil is the world's fourth largest producer and exporter of pork, there is no information on Enterocytozoon bieneusi in pigs. This study was undertaken to determine the presence of E. bieneusi in pigs in the State of Rio de Janeiro, Brazil. Fecal samples were collected from 91 pigs (1- to 12-month-old) in 10 properties and examined by molecular methods. The presence of E. bieneusi was determined by PCR and all PCR positive specimens were sequenced to determine the genotype by nucleotide sequence analysis of the internal transcribed spacer of the rRNA gene. E. bieneusi was found in pigs in all farms. Fifty four (59.3%) samples were E. bieneusi-positive. A wide genetic diversity was found with 21 genotypes identified, 4 previously reported (O, EbpA, CS-1, and H) and 17 novel genotypes named PigEb1-PigEb17. All 17 novel genotypes identified in this study clustered within the previously designated zoonotic Group 1. The most prevalent genotypes were novel genotypes PigEb2 and PigEb4 (16/91, 17.6%, each). Mixed infections with 2 or 3 genotypes were detected in 13 pigs (24.1%). The high prevalence in pigs observed in this study, the description of two known zoonotic genotypes (EbpA and O), and the report of 17 new genotypes of E. bieneusi, represent an important advancement in the study of the wide genetic diversity of this organism, emphasizing the importance of further research, especially in geographical areas where little or no research has been conducted. The zoonotic risk of these novel genotypes and their importance to other animal species is still unknown, but needs to be further evaluated.