Tanaka Toshiaki, Chatani Mika, Haraguchi Asako, Matsubayashi Makoto, Ikadai Hiromi, Kaneko Takane, Matsuo Tomohide
Kawanabe Livestock Clinic, Kagoshima Agricultural Mutual Aid Association, Kagoshima, Japan.
Laboratory of Parasitology, United Graduate School of Veterinary Science, Kagoshima University, Kagoshima, Japan.
J Vet Med Sci. 2025 Oct 1;87(10):1204-1209. doi: 10.1292/jvms.25-0229. Epub 2025 Sep 3.
Eimeria spp. cause coccidiosis characterized by diarrhea and induce serious economic losses in livestock industries. Although several anti-coccidial drugs are currently available, the emergence of resistant strains and drug residues is problematic; therefore, the development of new drugs is needed. Since sporozoites of Eimeria spp. invade host intestinal epithelial cells and numerous merozoites are formed, drugs that target sporozoites are expected to be useful. We previously used murine Eimeria krijgsmanni as a model to examine anti-coccidial drug susceptibility; however, few studies have conducted drug evaluations against sporozoites. The establishment of excystation protocols is essential for progress in in vitro experiments using sporozoites because oocysts must be isolated from feces using complex techniques before the excystation process. Various artificial excystation protocols have been reported for each Eimeria spp.; however, those for E. krijgsmanni have not yet been examined. Therefore, 4 protocols described in previous studies were herein conducted for E. krijgsmanni. Pepsin was important for excystation in rodent Eimeria spp., and this was also the case for E. krijgsmanni. Excystation rates were higher with the physical disruption of oocyst walls than with pepsin. An incubation in HBSS containing 0.25% (w/v) trypsin and 0.1% (w/v) sodium taurocholate after a physical treatment achieved higher and the most stable excystation rates. Modifications to this method were also examined, and no improvements were observed. The optimal excystation protocol for E. krijgsmanni was elucidated as of now.
艾美耳球虫属可引发以腹泻为特征的球虫病，并给畜牧业造成严重经济损失。尽管目前有几种抗球虫药物可用，但耐药菌株的出现和药物残留问题突出；因此，需要研发新药。由于艾美耳球虫属的子孢子会侵入宿主肠道上皮细胞并形成大量裂殖子，预计靶向子孢子的药物会有作用。我们之前使用小鼠克氏艾美耳球虫作为模型来检测抗球虫药物敏感性；然而，针对子孢子进行药物评估的研究很少。建立脱囊方案对于使用子孢子进行体外实验的进展至关重要，因为在脱囊过程之前，必须使用复杂技术从粪便中分离出卵囊。针对每种艾美耳球虫属都报道了各种人工脱囊方案；然而，克氏艾美耳球虫的脱囊方案尚未得到研究。因此，本文对之前研究中描述的4种方案用于克氏艾美耳球虫进行了实验。胃蛋白酶对啮齿动物艾美耳球虫属的脱囊很重要，克氏艾美耳球虫也是如此。与使用胃蛋白酶相比，通过物理破坏卵囊壁的脱囊率更高。在物理处理后，在含有0.25%（w/v）胰蛋白酶和0.1%（w/v）牛磺胆酸钠的HBSS中孵育可实现更高且最稳定的脱囊率。还对该方法的改进进行了研究，但未观察到改善。目前已阐明了克氏艾美耳球虫的最佳脱囊方案。
