The molecular and morphometric identification of Dictyocaulus capreolus in clinically affected roe deer (Capreolus capreolus L.)

Abstract

The poor state of health and increased mortality rate of young roe deer, as reported by South Moravian hunters, caused by the increasing numbers of adult nematodes in the lungs of roe deer prompted us to identify the parasites using a combination of morphological measurements and a phylogenetic SSU rRNA analysis. The study was conducted in a 294 ha game reserve in South Moravia, Czech Republic. Molecular and morphometric techniques were used to identify adult nematodes collected from the respiratory tracts of nine 4–5 months old roe deer in poor health (low body weight of 3–4 kg, poor haircoat quality, and, in some cases, symptoms of diarrhoea). The morphological identification was based on a combination of adult worm characteristics corresponding to Dictyocaulus capreolus. A small subunit rRNA (SSU) partial sequence analysis showed the highest identity scores (99%) corresponding to the sequences of D. capreolus from a roe deer (GenBank: AY168859) from Sweden and the outcomes of the phylogenetic analyses resulted in a tree with a high branch support for two groups, with our sequences forming a well-supported clade with D. capreolus and Dictyocaulus sp. ex Capreolus capreolus (FJ589016) and Dictyocaulus sp. ex Rupicapra rupicapra (FJ589019) sequences from Spain. The examined roe deer have shown symptoms of diarrhoea, anorexia, and respiratory tract inflammation indicating that there might be a connection to the clinical importance of the Dictyocaulus infection.