ITS2 sequences of Dictyocaulus species from cattle, roe deer and moose in Sweden: molecular evidence for a new species

Total DNA was isolated from adult lungworms of the genus Dictyocaulus, coll ected from cattle, moose (Alces alces) and roe deer (Capreolus capreolus) i n Sweden. The second ribosomal internal transcribed spacer was amplified wi th PCR, and DNA sequences were determined from nine individual worms that a ll came from different hosts in order to avoid analysis of siblings. The se quence data obtained were aligned and compared with similar data derived fr om German lungworm isolates from cattle and fallow deer (Cervus dama). Thes e analyses clearly showed that specimens of the cattle lungworm, Dictyocaul us viviparus; were almost identical irrespective of their geographical orig in. However, when the second internal transcribed spacer sequence of D. viv iparus was compared with that of lungworms from moose and roe deer, major d ifferences were noticed. Although lungworms collected from these cervids ha d identical second internal transcribed spacer sequences, they proved to be genetically different from Dictyocaulus eckerti of German fallow deer, dis playing a 66.5% similarity. In an evolutionary tree, inferred by maximum li kelihood analysis, the Dictyocaulus species from cattle and wild cervids cl ustered as compared with Dictyocaulus filaria from sheep. The study has thu s demonstrated that A. alces and C. capreolus in Sweden are parasitised wit h a Dictyocaulus species that is different from D. viviparus and D. eckerti , indicating that we are dealing with a new species in moose and roe deer. (C) 1999 Australian Society for Parasitology Inc. Published by Elsevier Sci ence Ltd. All rights reserved.