Department of Food and Environmental Virology, National Veterinary Research Institute, Al. Partyzantów 57, 24-100, Puławy, Poland.
BMC Vet Res. 2022 Jul 6;18(1):263. doi: 10.1186/s12917-022-03328-y.
Cryptosporidium parvum (C. parvum) is a cosmopolitan parasite that infects various livestock animals including cattle. Microsatellite typing tools for identification of C. parvum subtypes are currently employed to better understand the species-specific epidemiology of cattle cryptosporidiosis. The aim of this study was to analyse the population genetics of C. parvum strains infecting cattle and recognise geographical distribution and time-span correlations in subtype prevalence in Poland. In total, 1601 faecal samples were collected from 2014 to 2018 from healthy cattle from dairy, meat and mixed breeds at the age of 1 week to 4 months. The 267 farms visited were randomly selected and represented all Polish provinces. PCR-RFLP based identification of C. parvum at the 18 small subunit ribosomal RNA (SSU rRNA) locus was performed, followed by strain subtyping by GP60-PCR. RESULTS: The overall prevalence of C. parvum in Polish cattle was estimated at 6.2% (100/1601). Animals below the age of 1 month were the major host for this parasite. Excluding one breed, that of dairy-meat mixed, there were no significant differences observed between breed and presence of C. parvum infections (95% TPI: 1.67-73.53%; POPR = 0.05-0.95). Infected animals were detected in 15 out of 16 Polish provinces, with significant regional prevalence diffrences (Kruskal-Wallis rank sum test, Kruskal-Wallis χ = 13.46, p < 0.001). When the population genetics of C. parvum strains were analysed, 11 parasite subtypes from the IIa and IId genetic families were identified. Compared to other parasite strains, IIaA17G1R1 and IIaA17G2R1 appeared at statistically significantly higher frequency (F-test, F = 3.39; p = 0.0003). The prevalence of C. parvum subtypes in cattle was breed-related (Chi-squared test, χ = 143.6; p < 0.001).
The analysis of the population genetics of C. parvum subtypes showed that strains from the IIa subtype family predominated in the tested cattle population. However, relations in changes of subtype prevalence and circulation over time were observed. They were associated with the disappearance of some strains and emergence of new variants from the same genetic family in different geographical locations.
微小隐孢子虫（C. parvum）是一种世界性寄生虫，感染包括牛在内的各种家畜。目前，微卫星分型工具用于鉴定微小隐孢子虫亚型，以更好地了解牛隐孢子虫病的种特异性流行病学。本研究的目的是分析感染牛的微小隐孢子虫株的种群遗传学，并识别波兰的亚型流行的地理分布和时间跨度相关性。 2014 年至 2018 年，从年龄为 1 周至 4 个月的奶牛、肉用牛和混合品种的 1601 份粪便样本中采集了 1601 份粪便样本。随机选择了 267 个农场，代表了波兰所有的省份。使用基于聚合酶链反应-限制性片段长度多态性（PCR-RFLP）的 18S 核糖体 RNA（SSU rRNA）基因座鉴定微小隐孢子虫，然后通过 GP60-PCR 进行菌株亚分型。 结果：波兰牛微小隐孢子虫的总流行率估计为 6.2%（100/1601）。小于 1 个月大的动物是这种寄生虫的主要宿主。除了一个奶牛-肉用牛混合品种外，品种和微小隐孢子虫感染之间没有观察到显著差异（95% TPI：1.67-73.53%；POPR=0.05-0.95）。在波兰的 16 个省份中都检测到了感染的动物，并且存在显著的地区流行差异（克鲁斯卡尔-沃利斯等级和检验，Kruskal-Wallis χ=13.46，p<0.001）。当分析微小隐孢子虫株的种群遗传学时，从 IIa 和 IId 遗传家族中鉴定出了 11 种寄生虫亚型。与其他寄生虫株相比，IIaA17G1R1 和 IIaA17G2R1 的出现频率明显更高（F 检验，F=3.39；p=0.0003）。牛微小隐孢子虫亚型的流行与品种有关（卡方检验，χ=143.6；p<0.001）。 结论：微小隐孢子虫亚型的种群遗传学分析表明，来自 IIa 亚型家族的菌株在测试的牛群中占主导地位。然而，观察到亚型流行率随时间变化的关系。它们与某些菌株的消失以及同一遗传家族在不同地理位置出现新变体有关。
