Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, Guangdong, China.
Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, Guangdong, China.
Parasit Vectors. 2020 Mar 24;13(1):149. doi: 10.1186/s13071-020-04021-5.
Bamboo rats are widely farmed in southern China for meat, but their potential in transmitting pathogens to humans and other farm animals remains unclear.
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.
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; χ = 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.
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.
在中国南方，竹鼠被广泛养殖以供食用，但它们在向人类和其他农场动物传播病原体方面的潜在风险尚不清楚。
为了了解这些动物中隐孢子虫属的传播情况，本研究从中国江西、广西和海南的 9 个农场采集了 709 份中国竹鼠（Rhizomys sinensis）粪便样本。采用 PCR 方法和小亚基 rRNA 基因序列分析对隐孢子虫属进行分析。通过 60kDa 糖蛋白（gp60）基因序列分析对鉴定出的微小隐孢子虫、微小隐孢子虫样和微小隐孢子虫样基因型进行亚型分析。
共检测到 209 份（29.5%）样本中有隐孢子虫属。2 个月以下动物样本的检出率（70.0%，105/150）明显高于 2 个月以上动物样本（18.6%，104/559；χ²=150.27，df=1，P<0.0001）。鉴定出 4 种隐孢子虫种/基因型：微小隐孢子虫（n=78）；微小隐孢子虫样（n=1）；与微小隐孢子虫关系密切的新基因型（n=85）；与微小隐孢子虫关系密切的另一个新基因型（n=44）。其中，微小隐孢子虫（27610±71911 个卵囊/克粪便）和微小隐孢子虫样基因型（38679±82811 个卵囊/克粪便）的卵囊排放强度高于微小隐孢子虫样基因型（2470±7017 个卵囊/克粪便）和微小隐孢子虫（1012 个卵囊/克粪便）。鉴定出的微小隐孢子虫属于两个罕见亚型家族的 3 种亚型，包括 IIpA9（n=43）、IIpA6（n=6）和 IIoA15G1（n=9），而微小隐孢子虫样和微小隐孢子虫样基因型产生了非常不同的 gp60 序列。
本研究结果表明，研究农场的竹鼠感染了多种隐孢子虫种和不同的微小隐孢子虫亚型，这些亚型可能来自它们的原生栖息地。由于最近在人类和养殖猕猴中也检测到了类似的微小隐孢子虫亚型，因此应该注意这些新型农场动物在传播人畜共患病原体方面的潜在作用。
