Genotypes and public health potential of Enterocytozoon bieneusi and Giardia duodenalis in crab-eating macaques

Abstract

Background: Enterocytozoon bieneusi and Giardia duodenalis are common human and animal pathogens. Studies have increasingly shown that non-human primates (NHPs) are common hosts of these two zoonotic parasites. However, few studies have explored the genetic diversity and public health potential of these pathogens in laboratory monkeys. In this study, we examined the genetic diversity of the two pathogens in crab-eating macaques (Macaca fascicularis) in a commercial facility in Hainan, China.

Results: Enterocytozoon bieneusi and G. duodenalis were detected by PCR analysis in 461/1452 (31.7%) and 469/1452 (32.3%) fecal specimens from the animals, respectively. Significantly higher detection rates of E. bieneusi were detected in males (36.5%, 258/706) than in females (26.7%, 160/599; χ² = 14.391, P = 0.0001), in animals with loose stools (41.4%, 151/365) than those with normal stool (28.5%, 310/1087; χ² = 20.83, P < 0.0001), and in animals of over 3 years of age (38.6%, 135/350) than those of 1-3 years (29.6%, 326/1,102; χ² = 9.90, P = 0.0016). For G. duodenalis, the detection rate in males (33.4%, 236/706) was higher than in females but not statistically significant (30.2%, 181/599; χ² = 1.54, P = 0.2152), in monkeys with loose stools (41.1%, 150/365) than those with normal stools (29.3%, 319/1087; χ² = 17.25, P < 0.0001), and in monkeys of 1-3 years of age (36.6%, 403/1102) than those over 3 years (18.9%, 66/350; χ² = 38.11, P < 0.0001). Nine E. bieneusi genotypes were detected in this study by DNA sequence analysis of the internal transcribed spacer of the rRNA gene, namely Type IV (236/461), Peru8 (42/461), Pongo2 (27/461), Peru11 (12/461), D (4/461) and PigEbITS7 (1/461) previously seen in NHPs as well as humans, and CM1 (119/461), CM2 (17/461) and CM3 (3/461) that had been only detected in NHPs. DNA sequence analyses of the tpi, gdh and bg loci identified all G. duodenalis specimens as having assemblage B. Altogether, eight (4 known and 4 new), seven (6 known and 1 new) and seven (4 known and 3 new) subtypes were seen at the tpi, gdh and bg loci, leading to the detection of 53 multi-locus genotypes (MLG-B-hn01 to MLG-B-hn53). Most of them were genetically related to those previously seen in common Old-World monkeys.

Conclusions: Data from this study indicate a common occurrence of zoonotic genotypes of E. bieneusi and assemblage B of G. duodenalis in farmed crab-eating macaques in Hainan, China.

Keywords: Crab-eating macaques; Enterocytozoon bieneusi; Genotypes; Giardia duodenalis; Multi-locus genotyping.

Fig. 1

Phylogenetic relationship of multilocus genotypes (MLGs) of Giardia duodenalis assemblage B inferred by the maximum likelihood analysis of concatenated tpi, gdh and bg nucleotide sequences using genetic distances calculated by the general time reversible model (GTR). Reference sequences (MLG1-15, isolates Sweh001, Sweh059, Sweh074, Sweh107, Sweh136, Sweh158, ECUST1710, ECUST5414, ECUST4064 and ECUST981) used are from the studies by Lebbad et al. [51], Karim et al. [18] and Wang et al. [27]. Bootstrap values greater than 50% from 1000 replicates are shown on nodes. MLGs identified in the present study are in bold. The scale-bar indicates 50 nucleotide substitutions per 100 nucleotides