Infectivity of gastrointestinal nematode parasites of sika deer (Cervus nippon) for calves and lambs.

Sika deer, mainly of Japanese origin, have been introduced into the British Isles and central Europe and established free-ranging populations, expanding in several countries. Introduction of the sika deer was associated with the transfer of Spiculopteragia houdemeri which has been reported for the first time in 2003 from Germany and thereafter from sika deer and other cervid species in some countries in Europe. Surveys of livestock parasites have shown that cervid-specific gastrointestinal nematodes of native deer occur in natural infections in cattle and sheep, usually at low level, and infections were experimentally transferred. However, to date there is no such information for sika deer-specific nematodes to livestock. To investigate the establishment of sika deer-derived gastrointestinal nematodes in domestic ruminants, three calves and two lambs were challenged with mixed burdens of infective larvae (~90% ostertagids, ~10% Oesophagostomum) cultured from the faeces of free-ranging sika deer; calves received 20,000 or 30,000 larvae, lambs 12,000 or 13,000. Establishment rate of ostertagids varied from 0.4% to 3.1% in the calves and was 1.3% and 8.4% in the lambs. Spiculopteragia houdemeri, index ostertagid of Japanese sika deer, was the dominant species, recovered from all animals. In addition, Ostertagia leptospicularis and Spiculopteragia boehmi, index ostertagids of native roe deer (Capreolus capreolus) and red deer (Cervus elaphus), respectively, were isolated from calf and lamb and Cooperia pectinata from one lamb. Oesophagostomum venulosum established in the lambs at ~6% but no Oesophagostomum was found in any calf. This investigation indicates that both calves and lambs are permissive to the sika deer-specific S. houdemeri and other deer-derived nematodes which reached maturity, but susceptibility to infections was apparently low.