Prevalence of Eimeria spp. in calves from dairy farms in northern Paraná state, Brazil

Abstract Bovine coccidiosis is a disease of major importance in cattle herds across the world. The disorder mainly affects young calves, and E. bovis and E. zuernii are considered the most pathogenic species of the genus, however, E. alabamensis have been described in grazing calves. In this study, the prevalence of Eimeria spp. was evaluated in calves on dairy farms in the northern region of the state of Paraná, Brazil. Four hundred calves on 44 dairy farms were tested for the presence of coccidian oocysts. The positives were re-examined and the oocysts were morphometrically analyzed for species identification. All the farms were contaminated and 205 animals (51.25%) presented Eimeria spp. oocysts. Among these, 146 animals (71.22%) were co-infected by two or more species of coccidia. Ten species of Eimeria were identified: E. bovis (in 30.25% of the positive samples), E. alabamensis (26.75%), E. zuernii (22.00%), E. ellipsoidalis (18.50%), E. auburnensis (13.75%), E. canadensis (8.00%), E. cylindrica (7.25%), E. subspherica (5.00%), E. bukidnonensis (3.00%) and E. brasiliensis (0.75%). This study demonstrates the high prevalence of Eimeria spp. in the northern region of Paraná, Brazil, and detection for the first time in our region the pathogenic species E. alabamensis.

摘要 牛球虫病是全球牛群中危害最为严重的疫病之一。该病主要侵害犊牛，其中牛艾美耳球虫（E. bovis）和楚尔艾美耳球虫（E. zuernii）被认为是艾美耳球虫属（Eimeria spp.）中毒性最强的虫种，不过已有研究在放牧犊牛中检出阿拉巴马艾美耳球虫（E. alabamensis）。本研究针对巴西巴拉那州北部地区奶牛场的犊牛，开展了艾美耳球虫属感染率的调查评估。研究共对44家奶牛场的400头犊牛进行了球虫卵囊检测，对检测呈阳性的样本进行复检，并通过形态计量学分析卵囊以完成虫种鉴定。所有受调查奶牛场均存在球虫污染，其中205头犊牛（占比51.25%）检出艾美耳球虫属卵囊。在上述阳性个体中，146头（71.22%）存在两种及以上球虫混合感染。本次研究共鉴定出10种艾美耳球虫：牛艾美耳球虫（E. bovis，阳性样本占比30.25%）、阿拉巴马艾美耳球虫（E. alabamensis，26.75%）、楚尔艾美耳球虫（E. zuernii，22.00%）、椭球形艾美耳球虫（E. ellipsoidalis，18.50%）、奥本艾美耳球虫（E. auburnensis，13.75%）、加拿大艾美耳球虫（E. canadensis，8.00%）、圆柱艾美耳球虫（E. cylindrica，7.25%）、亚球形艾美耳球虫（E. subspherica，5.00%）、布基农艾美耳球虫（E. bukidnonensis，3.00%）以及巴西艾美耳球虫（E. brasiliensis，0.75%）。本研究证实，巴西巴拉那州北部地区艾美耳球虫属感染率较高，且首次在本地区检出致病性虫种阿拉巴马艾美耳球虫（E. alabamensis）。