The infectivity of some nematode parasites of reindeer (Rangifer tarandus L.) and elk (Alces alces L.) for cattle and sheep.

Cross infections were carried out by dosing parasite-free calves and lambs with third stage nematode larvae cultured from the faeces of reindeer and elk. Two lambs each received 20,000 larvae from reindeer, and one lamb 20,000 larvae from elk. One calf received 50,000 larvae from reindeer and one 50,000 from elk. The animals were killed 28 days after infection. Egg output did not differ significantly between the lambs nor between the calves, but in the lambs the output was much higher than in the calves (highest cound 4300 versus 275). Worm counts varied among the animals independent of the origin of the larvae. The highest take was found in the lamb infected with larvae from elk (81.5%) and the lowest in the calf infected with larvae from elk (15.1%). Ostertagia leptospicularis was the dominant species (80% or more) and the only other species present were Skrjabinagia kolchida and Spiculopteragia boehmi. The latter was found in a higher percentage (14.0 and 10.4) in the animals that received larvae cultured from elk faeces. Under natural conditions O. leptospicularis is possibly the only pathogenic species that can play a role in cross contamination to cattle and sheep.