Sinnott Devinn M, Miller Melissa, Arranz-Solís David, Rodriguez Felipe, Saeij Jeroen P J, Batac Francesca, Greenwald Katherine, Young Colleen, Harris Michael D, Gomes Mary, Shapiro Karen
Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America.
Marine Wildlife Veterinary Care and Research Center, California Department of Fish and Wildlife, Santa Cruz, California, United States of America.
PLoS One. 2025 Sep 10;20(9):e0332223. doi: 10.1371/journal.pone.0332223. eCollection 2025.
Fatal infections with the rare COUG strain of the zoonotic parasite Toxoplasma gondii were recently detected for the first time in four southern sea otters (Enhydra lutris nereis) exhibiting severe protozoal steatitis. The objectives of this study were to describe new COUG strain infections in sea otters, investigate the potential contributory role of a recently discovered parasite-infecting narnavirus (Apocryptovirus odysseus) in these infections, assess the potential contribution of vitamin E deficiency in the development of systemic steatitis, and explore the utility of serotyping for strain-specific diagnosis of T. gondii infections in sea otters. Since initial reporting, six additional sea otters died due to fatal COUG strain T. gondii infections. Five animals exhibited lesion patterns resembling the prior case definition including severe, widespread steatitis. The final case died due to severe T. gondii-associated meningoencephalitis with no grossly or microscopically apparent steatitis. In contrast with a recent report utilizing a cougar-derived parasite isolate, A. odysseus RNA was not detected in sea otter-derived COUG strain isolates, suggesting that this narnavirus is not associated with fatal COUG strain infections in sea otters. Serotyping using dense granule (GRA) peptides to distinguish between T. gondii strains infecting sea otters suggests that Type X, Type II, and COUG strains exhibit different peptide-reactivity profiles that may allow them to be distinguished serologically. COUG strain T. gondii infections are an emerging threat to southern sea otter population health, and this strain has the potential to infect other animal and human hosts that share their environment and food sources with sea otters. Additional studies are needed to clarify the environmental sources, epidemiology, pathophysiology, and premortem serodiagnosis of COUG strain T. gondii infections in southern sea otters and other susceptible hosts.
最近，在4只表现出严重原生动物脂肪炎的南海獭（Enhydra lutris nereis）中首次检测到由罕见的人畜共患寄生虫刚地弓形虫COUG株引起的致命感染。本研究的目的是描述海獭中新出现的COUG株感染，调查最近发现的一种感染寄生虫的纳病毒（奥德修斯隐病毒）在这些感染中的潜在促成作用，评估维生素E缺乏在全身性脂肪炎发展中的潜在作用，并探索血清分型在海獭刚地弓形虫感染菌株特异性诊断中的实用性。自最初报告以来，又有6只海獭因感染致命的刚地弓形虫COUG株而死亡。5只动物表现出与先前病例定义相似的病变模式，包括严重的广泛性脂肪炎。最后一只病例死于严重的刚地弓形虫相关性脑膜脑炎，未出现明显的大体或显微镜下脂肪炎。与最近一份使用美洲狮来源的寄生虫分离株的报告不同，在海獭来源的COUG株分离物中未检测到奥德修斯隐病毒RNA，这表明这种纳病毒与海獭中致命的COUG株感染无关。使用致密颗粒（GRA）肽进行血清分型以区分感染海獭的刚地弓形虫菌株，结果表明X型、II型和COUG株表现出不同的肽反应谱，这可能使它们能够通过血清学进行区分。刚地弓形虫COUG株感染是对南海獭种群健康的一种新出现的威胁，并且该菌株有可能感染与海獭共享其环境和食物来源的其他动物和人类宿主。需要进一步的研究来阐明南海獭和其他易感宿主中刚地弓形虫COUG株感染的环境来源、流行病学、病理生理学和生前血清学诊断。
