Abstract：
Native to South America, the coypu (Myocastor coypus) is an invasive alien species (IAS) of Union concern. It was introduced to Germany a hundred years ago and is considered established in all German federal states. Between January and February 2021, ground temperatures below -10° Celsius were recorded in Lower Saxony, Germany, for approximately two consecutive weeks. Five male and five female coypus, harvested between 23 February and 31 March 2021, received a post-mortem examination. Nutritional status was poor in six cases, moderate in three and good in one case. Pregnancy was observed in two females. In all the animals, lesions were predominantly found on the distal limbs (n = 7) and/or tail (n = 10), involving the skin and soft tissue with occasional exposure or loss of bones. The histological findings consisted of chronic, ulcerative to necrotizing dermatitis and occasional ulcerative-suppurative dermatitis, necrotizing myositis, thrombosis, granulation tissue, fibrosis and intralesional dystrophic mineralization. Intralesional bacteria were present in six and fungal spores in one animal. Determination of the exact cause was not possible; however, considering the local weather conditions and the distribution of lesions, frostbite injuries have to be considered as the most likely cause. The intralesional bacteria and fungal spores most likely represent secondary contaminants. Interestingly, lesions of this kind have not been reported in coypus in Germany so far. Therefore, frostbite should be considered as a potential cause of disease in coypus, warranting further investigation.
摘要：
原产于南美洲，coypu（Myocastorcoypus）是联盟关注的外来入侵物种（IAS）。它在一百年前被引入德国，并被认为在所有德国联邦州建立。在2021年1月至2月之间，下萨克森州的地面温度低于-10摄氏度，德国,大约连续两周。五只雄性和五只雌性,在2021年2月23日至3月31日期间收获，接受了验尸。6例患者的营养状况较差,三个人中等，一个人好。在两名女性中观察到怀孕。在所有的动物中，病变主要出现在远端肢体（n=7）和/或尾部（n=10），涉及皮肤和软组织，偶尔暴露或骨骼丢失。组织学发现包括慢性，溃疡性至坏死性皮炎和偶尔的溃疡性化脓性皮炎，坏死性肌炎,血栓形成,肉芽组织,纤维化和病灶内营养不良矿化。六只动物中存在侵内细菌，一只动物中存在真菌孢子。无法确定确切原因；然而，考虑到当地的天气条件和病变的分布，冻伤必须被认为是最可能的原因。病灶内细菌和真菌孢子最有可能代表次级污染物。有趣的是,到目前为止，德国的coypus还没有报告这种病变。因此,冻伤应该被认为是一种潜在的疾病的原因，保证进一步调查。
