Gris Anderson H, Alves Raquel S, Camargo Laura J, Baumbach Letícia F, Menegatt Jean C O, Silva Emanoelly M S, Perosa Fernanda F, Lima Rafael P, Bertolini Marianna, Fiúza Aparecida T L, Watanabe Tatiane T N, Canal Cláudio W, Driemeier David
Faculdade de Veterinária, Setor de Patologia Veterinária, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Faculdade de Veterinária, Laboratório de Virologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Transbound Emerg Dis. 2023 Dec 7;2023:6582778. doi: 10.1155/2023/6582778. eCollection 2023.
Encephalomyocarditis virus (EMCV) is a zoonotic disease caused by a highly pathogenic virus that affects wild and domestic animal species, with rodents as its reservoir. Most recently, in South America, this virus was detected in an outbreak affecting humans in Peru. In Brazil, EMCV infection was described in some wild species, in horses, and once in farrowing pigs. The aim of this study is to report the reemergence of EMCV in commercial growing-finishing pigs from two different farms that experienced sudden pig death in midwest Brazil. This aim was achieved through gross pathology, histologic examination, RT‒PCR analysis, and genetic characterization of the virus. Clinical signs, such as trembling, dyspnea, and squealing sounds shortly before death, were only occasionally observed and were nonspecific. On gross examination, cardiomegaly was observed, along with multifocal pale tan foci in the epicardium extending to the myocardium on the cut surface. Microscopically, there was severe myocardial necrosis, dystrophic mineralization, fibrosis, and lymphoplasmacytic and histiocytic myocarditis. Gross and microscopic examinations of the rats were unremarkable. The RT‒PCR analyses of the pig and rat organs were positive for EMCV, and the phylogenetic analysis of the VP1 gene showed that the samples from pigs and rats contained similar strains that had their closest relatives identified in humans in Peru. This is the first genetic characterization of EMCV in Brazil, and the other findings confirm the reemergence of the disease that was transmitted from rats to pigs.
脑心肌炎病毒（EMCV）是一种由高致病性病毒引起的人畜共患病，可感染野生动物和家畜，以啮齿动物为储存宿主。最近，在南美洲，秘鲁的一次疫情中检测到了这种病毒感染人类的情况。在巴西，已在一些野生动物、马匹以及一例分娩母猪中发现了EMCV感染。本研究的目的是报告在巴西中西部两个不同猪场的商品育肥猪中再次出现EMCV，这两个猪场出现了猪突然死亡的情况。该目标通过大体病理学检查、组织学检查、逆转录聚合酶链反应（RT-PCR）分析以及病毒的基因特征分析得以实现。临床症状，如死前偶尔出现的颤抖、呼吸困难和尖叫等，并不具有特异性。大体检查时，发现心脏肿大，心外膜有多处浅褐色病灶，切面延伸至心肌。显微镜下可见严重的心肌坏死、营养不良性矿化、纤维化以及淋巴细胞浆细胞性和组织细胞性心肌炎。对大鼠的大体和显微镜检查未发现异常。对猪和大鼠器官进行的RT-PCR分析结果显示EMCV呈阳性，对VP1基因的系统发育分析表明，猪和大鼠的样本含有相似的毒株，其亲缘关系最近的毒株在秘鲁的人类中被鉴定出来。这是巴西首次对EMCV进行基因特征分析，其他研究结果证实了该疾病从大鼠传播至猪并再次出现。
