Lungworm (Otostrongylus circumlitus) infections in ringed seals (Phoca hispida) from eastern Arctic Canada

Abstract

Otostrongylus circumlitus, a metastrongyloid nematode found in the lungs of ringed seals (Phoca hispida) and other pinnipeds, may affect the health of seals and reduce diving capacity. Of five sites sampled in eastern Arctic Canada (190 seals examined), Salluit, Que., is an important enzootic zone (prevalence 48.2%, n = 27). Maximum intensity of O. circumlitus was 32 worms. Infection is restricted to young-of-the-year seals and may have an impact on recruitment of the population. Local geographic conditions may influence transmission of the parasite and thus prevalence and intensity of O. circumlitus among populations of ringed seals. No condition index used showed any significant relationship to infection, but prevalence and intensity were related to sternal blubber thickness (0.01 < p < 0.05) indicating that this parasite may have an effect on the physical condition of seals. Otostrongylus circumlitus may have an indirect effect on seals by modifying their diving behavior. Severe infections may lead to death, but light infections could be lost after a certain time with subsequent development of protective immunity.