The first study of molecular prevalence and species characterization of Cryptosporidium in free-range chicken (Gallus gallus domesticus) from Brazil

Abstract Rearing free-range chicken is based on grazing feeding patterns, and these animals could be potential environmental contaminants of Cryptosporidium oocysts for humans and other animals. Therefore, the present study aimed to evaluate the molecular prevalence of Cryptosporidium spp. in free-range chickens from Brazil. A total of 351 fecal samples from chickens were examined from 20 farms. For detection of Cryptosporidium spp., 18S rRNA gene fragments were amplified using a nested PCR reaction. Positive samples were sent for sequencing. The overall prevalence of Cryptosporidium was 25.6% (95% CI = 21.2% - 30.6%). Sequencing of the amplified fragments allowed for the identification of three species: C. meleagridis in 57 (62.6%), C. baileyi in 15 (16.4%), C. parvum in 3 (3.2%) samples, and a new Cryptosporidium genotype (C. genotype BrPR1) in 3 (3.2%) samples. Cryptosporidium genotype BrPR1 has not yet been classified as a species, and its host spectrum is not known. Cryptosporidium, including zoonotic species, exists at a high prevalence in free-range chickens within the region studied.

摘要：散养肉鸡采用放牧饲喂模式开展养殖，此类畜禽可成为隐孢子虫卵囊（Cryptosporidium oocysts）污染人类与其他动物的潜在环境污染源。有鉴于此，本研究旨在评估巴西散养肉鸡中隐孢子虫属（Cryptosporidium spp.）的分子流行率。本研究从20个养殖场采集共计351份肉鸡粪便样本进行检测。针对隐孢子虫属的检测，采用嵌套聚合酶链式反应（nested PCR）扩增18S rRNA基因片段，将扩增阳性样本送至测序环节。隐孢子虫的总体流行率为25.6%（95%置信区间：21.2%~30.6%）。对扩增片段的测序结果可鉴定出3种隐孢子虫：57份（62.6%）样本检出火鸡隐孢子虫（C. meleagridis），15份（16.4%）样本检出贝氏隐孢子虫（C. baileyi），3份（3.2%）样本检出微小隐孢子虫（C. parvum），另有3份（3.2%）样本检出一株新型隐孢子虫基因型（C.基因型BrPR1）。隐孢子虫基因型BrPR1尚未被归类为正式物种，其宿主范围尚不明确。本次研究区域内的散养肉鸡中，包括人兽共患物种在内的隐孢子虫流行率较高。