Humoral immunity and output of first-stage larvae of Elaphostrongylus rangiferi (Nematoda, Metastrongyloidea) by infected reindeer, Rangifer tarandus tarandus.

The use of an indirect immunofluorescence technique demonstrated that serum from reindeer, Rangifer tarandus tarandus, infected with Elaphostrongylus rangiferi (Nematoda, Metastrongyloidea) contained antibodies directed against antigen(s) on the cuticle of the parasites first-stage larvae (L1). Output of L1 from the male reindeer was low in the period June to August, but increased to a higher level during the rutting season (September to October). The titre of specific antibody showed an inverse pattern. In the female reindeer, larval output remained high throughout the sampling period from January to July. During this period antibody titre was low. A relationship between stress (rutting season or calving period), immunity and larval output is suggested.