Abstract Introduction Malignant catarrhal fever (MCF) is a rare, under-explored lethal viral infection of cattle with gammaherpesvirus aetiological agents. Most often, the disease occurs on farms where cattle and sheep are kept together. However, other trigger mechanisms and environmental factors contribute. This study investigates the causation of MCF. Material and Methods An outbreak of MCF occurred in June - August 2017 in Kharchev village in Irkutsk Oblast, Russia. In this paper, we provide epidemiological (sanitary status of pastures, watering places, and premises) and weather data during the outbreak, and descriptions of the clinical signs and post-mortem changes in cattle. The virus was detected and isolated from pathological material samples and identified by molecular methods. Results Extreme weather conditions, mixed-herd cattle and sheep farming, and unsatisfactory feed quality contributed to the outbreak. A virus related to herpesvirus OvHV2 was isolated and typed (MCF/Irkutsk/2017). Phylogenetic analysis showed its close genetic relationship to isolates from cattle and sheep in Germany, USA, and the Netherlands. Conclusion Sporadic outbreaks of MCF caused by biotic and abiotic factors together are typical for the Russian Federation, and the Irkutsk outbreak epitomised this. Temperature anomalies caused pasture depletion, resulting in feed and water deficiency for grazing animals and dehydration and acidosis. Heat stress in animals ultimately led to the occurrence of MCF in the herd.

中文翻译：

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伊尔库茨克州牛恶性卡他热

摘要 简介 恶性卡他热 (MCF) 是一种罕见的、未被充分探索的牛的致死性病毒感染，带有 gammaherpesvirus 病原体。大多数情况下，这种疾病发生在牛羊一起饲养的农场。然而，其他触发机制和环境因素也有影响。本研究调查 MCF 的病因。材料与方法 2017 年 6 月至 8 月，俄罗斯伊尔库茨克州哈尔切夫村发生 MCF 疫情。在本文中，我们提供了疫情期间的流行病学（牧场、饮水场所和场所的卫生状况）和天气数据，以及对牛的临床症状和死后变化的描述。该病毒是从病理材料样本中检测分离出来的，并通过分子方法进行鉴定。结果极端天气条件，牛羊混群养殖，饲料质量不理想，导致疫情暴发。分离出一种与疱疹病毒 OvHV2 相关的病毒并进行分型 (MCF/Irkutsk/2017)。系统发育分析表明，它与德国、美国和荷兰的牛羊分离株有密切的遗传关系。结论 由生物和非生物因素共同引起的 MCF 零星暴发是俄罗斯联邦的典型特征，伊尔库茨克暴发就是一个缩影。温度异常导致牧场枯竭，导致放牧动物饲料和水缺乏以及脱水和酸中毒。动物的热应激最终导致牛群发生MCF。系统发育分析表明，它与德国、美国和荷兰的牛羊分离株有密切的遗传关系。结论 由生物和非生物因素共同引起的 MCF 零星暴发是俄罗斯联邦的典型特征，伊尔库茨克暴发就是一个缩影。温度异常导致牧场枯竭，导致放牧动物饲料和水缺乏以及脱水和酸中毒。动物的热应激最终导致牛群发生MCF。系统发育分析表明，它与德国、美国和荷兰的牛羊分离株有密切的遗传关系。结论 由生物和非生物因素共同引起的 MCF 零星暴发是俄罗斯联邦的典型特征，伊尔库茨克暴发就是一个缩影。温度异常导致牧场枯竭，导致放牧动物饲料和水缺乏以及脱水和酸中毒。动物的热应激最终导致牛群发生MCF。导致放牧动物的饲料和水缺乏以及脱水和酸中毒。动物的热应激最终导致牛群发生MCF。导致放牧动物的饲料和水缺乏以及脱水和酸中毒。动物的热应激最终导致牛群发生MCF。