Common occurrence of divergent Cryptosporidium species and Cryptosporidium parvum subtypes in farmed bamboo rats (Rhizomys sinensis)

Abstract

Background Bamboo rats are widely farmed in southern China for meat, but their potential in transmitting pathogens to humans and other farm animals remains unclear. Methods To understand the transmission of Cryptosporidium spp. in these animals, 709 fecal samples were collected in this study from Chinese bamboo rats (Rhizomys sinensis) on nine farms in Jiangxi, Guangxi and Hainan provinces, China. They were analyzed for Cryptosporidium spp. using PCR and sequence analyses of the small subunit rRNA gene. Cryptosporidium parvum, C. parvum-like and C. ubiquitum-like genotypes identified were subtyped by sequence analysis of the 60 kDa glycoprotein (gp60) gene. Results Altogether, Cryptosporidium spp. were detected in 209 (29.5%) samples. The detection rate in samples from animals under two months of age (70.0%,105/150) was significantly higher than in samples from animals above 2 months (18.6%, 104/559; χ2 = 150.27, df = 1, P < 0.0001). Four Cryptosporidium species/genotypes were identified: C. parvum (n = 78); C. occultus (n = 1); a new genotype that is genetically related to C. ubiquitum (n = 85); and another new genotype that is genetically related to C. parvum (n = 44). Among them, C. parvum (27,610 ± 71,911 oocysts/gram of feces) and the C. parvum-like genotype (38,679 ± 82,811 oocysts/gram of feces) had higher oocyst shedding intensity than the C. ubiquitum-like genotype (2470 ± 7017 oocysts/gram of feces) and the C. occultus (1012 oocysts/gram of feces). The C. parvum identified belonged to three subtypes in two rare subtype families, including IIpA9 (n = 43), IIpA6 (n = 6) and IIoA15G1 (n = 9), while the C. parvum-like and C. ubiquitum-like genotypes generated very divergent gp60 sequences. Conclusions Results of the present study suggest that bamboo rats on the study farms were infected with diverse Cryptosporidium species and divergent C. parvum subtypes, which probably had originated from their native habitats. As similar C. parvum subtypes have been recently detected in humans and farmed macaques, attentions should be paid to the potential role of these new farm animals in the transmission of zoonotic pathogens.

Cryptosporidium Species and C. parvum Subtypes in Farmed Bamboo Rats

“…in present study. This is similar to observations of two previous studies [24,25]. However, bamboo rat genotype III, commonly found in bamboo rats in Guangxi and Hainan [24], is rare in the present study.…”

“…In contrast, it is lower than several reports of Cryptosporidium spp. in farmed bamboo rats sampled in Guangxi (20.9% or 100/477), Jiangxi (33.3% or 51/153), and Hainan (69.6% or 55/79) [24]. Among six farms, the detection rate of Cryptosporidium spp.…”

“…They are commonly infected with Cryptosporidium spp. Several Cryptosporidium species and genotypes have been identified in these animals, including C. parvum, C. parvum-like genotype, C. occultus, and Cryptosporidium bamboo rat genotypes I and II [24,25]. Thus, the distribution of Cryptosporidium spp.…”

“…In contrast, bamboo rats in southern China are seemingly infected with rare IIo and IIp subtype families of C. parvum [25,27]. Most of data on these two C. parvum subtype families in bamboo rats, however, were from a study of animals in Jiangxi, Guangxi, and Hainan [24].…”

Diversity of Cryptosporidium spp. in wild rodents from the Canary Islands, Spain

“…More than 40 Cryptosporidium species have been described as valid worldwide [ 12 – 14 ], and around 20 species and genotypes have been reported in humans, such as Cryptosporidium meleagridis , Cryptosporidium felis , Cryptosporidium canis , Cryptosporidium ubiquitum , Cryptosporidium cuniculus , Cryptosporidium viatorum , Cryptosporidium muris , Cryptosporidium andersoni , Cryptosporidium suis , Cryptosporidium bovis , Cryptosporidium xiaoi , Cryptosporidium erinacei , Cryptosporidium fayeri , Cryptosporidium scrofarum , Cryptosporidium tyzzeri , chipmunk genotype I, horse genotype, skunk genotype and mink genotype [ 12 , 15 ].…”