On the efficacy of ivermectin against the reindeer sinus worm Linguatula arctica (Pentastomida), with a review on ivermectin treatment in reindeer

This field study compared the infection level of Linguatula arctica in 14 treated and 19 control calves of the reindeer host Rangifer tarandus. Eighty calves were each treated subcutaneously with 1 ml (200-250 Mg/kg) ivermectin primo December, to ensure that a sufficient number of treated animals later would be selected by the herders for slaughtering. The target parasite L. arctica was then in the reproductive stage of its life cycle. The reindeer were slaughtered in ultimo February. In the treated group, one reindeer was found infected (prevalence 7.1, relative density 0,1), whereas the infection level for the 19 untreated animals was much higher (prevalence 68.4, relative density 7,3). Our conclusion is that ivermectin is an effective agent against L. arctica, (and possibly against other pentastomids because of their similar arthropodal nerve system). This is the first report of ivermectin treatment against a pentastomid species. Additionally, the study confirmed that ivermectin was fully effective against the nose bot fly Cephenemyia trompe.