State Key Laboratory of Bioreactor Engineering, School of Resource and Environmental, East China University of Science and Technology, Shanghai, 200237, China.
Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.
Parasit Vectors. 2019 Jan 17;12(1):41. doi: 10.1186/s13071-019-3310-5.
Cryptosporidium spp., Giardia duodenalis and Enterocytozoon bieneusi are common enteric pathogens in humans and animals. Data on the transmission of these pathogens are scarce from Guangdong, China, which has a subtropical monsoon climate and is the epicenter for many emerging infectious diseases. This study was conducted to better understand the prevalence and identity of the three pathogens in pre-weaned dairy calves in Guangdong.
The occurrence and genetic identity of three pathogens were analyzed by polymerase chain reaction. PCR-positive products were sequenced to determine the species and genotypes. A Chi-square test was used to compare the prevalence of pathogens among sampling dates, age groups, or clinical signs.
The detection rates of Cryptosporidium spp., G. duodenalis and E. bieneusi were 24.0% (93/388), 74.2% (288/388) and 15.7% (61/388), respectively. Three Cryptosporidium species were detected, including C. bovis (n = 73), C. parvum (n = 12) and C. ryanae (n = 7); one animal had concurrence of C. bovis and C. parvum. C. parvum was the dominant species during the first two weeks of life, whereas C. bovis and C. ryanae were mostly seen at 3-9 weeks of age. Sequence analysis identified the C. parvum as subtype IIdA19G1. Assemblage E (n = 282), assemblage A (n = 1), and concurrence of A and E (n = 5) were identified among G. duodenalis-positive animals using multilocus genotyping (MLG). Altogether, 15, 10 and 17 subtypes of assemblage E were observed at the bg, gdh and tpi loci, respectively, forming 49 assemblage E MLGs. The highest detection rate of G. duodenalis was found in winter. Sequence analysis identified genotypes J (n = 57), D (n = 3) and one concurrence of J and D among E. bieneusi-positive animals. The detection rate of E. bieneusi was significantly higher in spring (38.0%; 41/108) than in summer (7.2%; 8/111) and winter (7.1%; 12/169).
These results indicate a common occurrence of C. parvum subtype IIdA19G1, G. duodenalis assemblage E, and E. bieneusi genotype J in pre-weaned dairy calves in Guangdong. More studies are needed to understand the unique genetic characteristics and zoonotic potential of the three enteric pathogens in the province.
隐孢子虫、蓝氏贾第鞭毛虫和肠孢子虫是人类和动物常见的肠道病原体。广东省气候为亚热带季风气候，是许多新发传染病的中心，有关这些病原体传播的数据很少。本研究旨在更好地了解广东未断奶奶牛犊牛中这三种病原体的流行情况和特征。
采用聚合酶链反应（PCR）分析三种病原体的发生和遗传特征。对 PCR 阳性产物进行测序以确定种属和基因型。采用卡方检验比较不同采样日期、年龄组或临床症状的病原体流行率。
隐孢子虫、蓝氏贾第鞭毛虫和肠孢子虫的检出率分别为 24.0%（93/388）、74.2%（288/388）和 15.7%（61/388）。共检测到三种隐孢子虫，包括牛隐孢子虫（n=73）、微小隐孢子虫（n=12）和大鼠隐孢子虫（n=7）；1 只动物同时感染了牛隐孢子虫和微小隐孢子虫。微小隐孢子虫是生命头两周的主要种属，而牛隐孢子虫和大鼠隐孢子虫主要见于 3-9 周龄。序列分析鉴定微小隐孢子虫为亚型 IIdA19G1。采用多位点基因分型（MLG）对蓝氏贾第鞭毛虫阳性动物进行鉴定，发现其组成型为 E（n=282）、A（n=1）和 E 和 A 共存（n=5）。在 bg、gdh 和 tpi 基因座共检测到 15、10 和 17 种 E 组成型，形成 49 种 E MLG。蓝氏贾第鞭毛虫的最高检出率见于冬季。序列分析鉴定出肠孢子虫阳性动物的 J 基因型（n=57）、D 基因型（n=3）和 J 和 D 共存（n=1）。肠孢子虫的检出率春季（38.0%；41/108）显著高于夏季（7.2%；8/111）和冬季（7.1%；12/169）。
这些结果表明，广东未断奶奶牛犊牛中普遍存在微小隐孢子虫亚型 IIdA19G1、蓝氏贾第鞭毛虫组成型 E 和肠孢子虫基因型 J。需要进一步研究以了解该省三种肠道病原体的独特遗传特征和人畜共患潜力。
