Cryptosporidium parvum and Cryptosporidium hominis subtypes in crab-eating macaques

Abstract

Background: Non-human primates are often infected with human-pathogenic Cryptosporidium hominis subtypes, but rarely with Cryptosporidium parvum. In this study, 1452 fecal specimens were collected from farmed crab-eating macaques (Macaca fascicularis) in Hainan, China during the period April 2016 to January 2018. These specimens were analyzed for Cryptosporidium species and subtypes by using PCR and sequence analysis of the 18S rRNA and 60 kDa glycoprotein (gp60) genes, respectively.

Results: Altogether, Cryptosporidium was detected using 18S rRNA-based PCR in 132 (9.1%) sampled animals, with significantly higher prevalence in females (12.5% or 75/599 versus 6.1% or 43/706), younger animals (10.7% or 118/1102 in monkeys 1-3-years-old versus 4.0% or 14/350 in those over 3-years-old) and animals with diarrhea (12.6% or 46/365 versus 7.9% or 86/1087). Four Cryptosporidium species were identified, namely C. hominis, C. parvum, Cryptosporidium muris and Cryptosporidium ubiquitum in 86, 30, 15 and 1 animal, respectively. The identified C. parvum, C. hominis and C. ubiquitum were further subtyped by using gp60 PCR. Among them, C. parvum belonged to subtypes in two known subtype families, namely IIoA14G1 (in 18 animals) and IIdA19G1 (in 2 animals). In contrast, C. hominis mostly belonged to two new subtype families Im and In, which are genetically related to Ia and Id, respectively. The C. hominis subtypes identified included ImA18 (in 38 animals), InA14 (in six animals), InA26 (in six animals), InA17 (in one animal) and IiA17 (in three animals). The C. ubiquitum isolates belonged to subtype family XIId. By subtype, ImA18 and IIoA14G1 were detected in animals with diarrhea whereas the remaining ones were mostly found in asymptomatic animals. Compared with C. parvum and C. muris, higher oocyst shedding intensity was observed in animals infected with C. hominis, especially those infected with the Im subtype family.

Conclusions: Data from the study suggest that crab-eating macaques are infected with diverse C. parvum and C. hominis subtypes. The C. parvum IIo subtype family previously seen in rodents in China has apparently expanded its host range.

Keywords: Crab-eating macaques; Cryptosporidium; Cryptosporidium hominis; Cryptosporidium parvum; Subtypes.

Fig. 1

Phylogenetic relationship of Cryptosporidium parvum and Cryptosporidium hominis subtypes as inferred by a maximum likelihood (ML) analysis of nucleotide sequences of the 60-KDa glycoprotein gene. Bootstrap values were obtained using 1000 pseudo-replicates, with values above 50% being shown on nodes. Bolded sequences are from subtypes found in this study, with specimen IDs being shown before the subtype names and GenBank accession numbers. The tree is rooted with a gp60 sequence (AB539719) from C. meleagridis

Fig. 2

Oocysts per gram of feces in specimens of dominant Cryptosporidium species and Cryptosporidium hominis subtypes in crab-eating macaques in Hainan, China. The sample size (n) for each species or subtype is specified above the bar. None of the differences reached statistical significance (P > 0.05)