Lungworms from the genus Dictyocaulus are the causative agents of verminous pneumonia in domestic and wild ungulates. Recently, in 2017, a new species was isolated from red deer and described as Dictyocaulus cervi; however, little is known about its epidemiology and pathogenicity in other cervids. The aim of our study was to determine the extent of infection with Dictyocaulus nematodes in the moose population in Poland.

Parasitological necropsies were performed in 18 moose and 249 faecal samples were analysed. A combination of multiplex PCR and analysis of the partial SSU, cox1 and cyt B regions revealed the presence of D. cervi infection in two of the necropsied moose. Histopathological examinations revealed changes, including multiple cross sections of larvae of nematodes in alveoli, massive pulmonary fibrosis, mononuclear cell infiltration and diffuse alveolar damage in the lungs of four animals. The lesions were more pronounced when adult Dictyocaulus nematodes were present in the bronchi and bronchioles. Some of the observed pathological changes could be attributed to co-infection by nematodes of the Protostrongylidae, whose larvae were found in all four animals with lung pathologies. In the faeces, Dictyocaulus sp. larvae only occurred together with Protostrongylidae larvae; in addition, higher numbers of Protostrongylidae larvae were excreted in the faeces of animals with dictyocaulosis.

The present study is the first report of the presence of D. cervi in moose, and demonstrates the value of multiplex PCR in the identification of Dictyocaulus nematodes. Our findings indicate that co-infections with multiple species of lung nematodes in moose may be commonplace, and this should be considered as a factor aggravating the course of parasitosis.

网尾虫属的肺虫是家养和野生有蹄类动物蠕虫性肺炎的病原体。最近，2017 年，从马鹿中分离出一个新物种，并将其命名为Dictyocaulus cervi ；然而，人们对其在其他鹿科动物中的流行病学和致病性知之甚少。我们研究的目的是确定波兰驼鹿种群中网尾线虫的感染程度。

对 18 只驼鹿进行了寄生虫尸检，并分析了 249 份粪便样本。多重 PCR 与部分 SSU、cox1 和 cyt B 区域分析相结合，揭示了两只剖检驼鹿中存在D. cervi感染。组织病理学检查显示了四只动物肺部的变化，包括肺泡内线虫幼虫的多个横截面、大量肺纤维化、单核细胞浸润和弥漫性肺泡损伤。当成虫网尾线虫存在于支气管和细支气管中时，病变更加明显。观察到的一些病理变化可能归因于原圆线虫的共同感染，在所有四只患有肺部病变的动物中都发现了原圆线虫的幼虫。在粪便中，网尾菌属sp。幼虫仅与原圆线虫科幼虫一起出现；此外，患有网龙病的动物粪便中排出的原圆线虫幼虫数量较多。

本研究是首次报道驼鹿体内存在D. cervi ，并证明了多重 PCR 在鉴定网尾线虫中的价值。我们的研究结果表明，驼鹿体内多种肺线虫的共同感染可能很常见，这应被视为加重寄生虫病的一个因素。