Lymnea stagnalis as experimental intermediate host for the protostrongylid nematodeElaphostrongylus rangiferi

Abstract

The aquatic snail species,Lymnea stagnalis was examined as experimental intermediate host for the nematodeElaphostrongylus rangiferi, a neurotrophic parasite of reindeer,Rangifer tarandus. All juvenile snails exposed to first-stage larvae ofE. rangiferi became infected, but the mean number of larvae per snail ($\bar x$) was higher when snails were exposed in water ($\bar x$=14.3) than when exposed on filterpaper moistened with a suspension of larvae ($\bar x$=8.1), an efficient method of infecting terrestrial snails. Juvenile snails had a significant higher mean number of larvae ($\bar x$=17.2) than adults ($\bar x$=1.4). The development of the parasite, in both juvenile and adultL. stagnailis, was comparable to the most susceptible terrestrial snails. At 21 days postinfection about 40% of the larvae had reached the infective L3 stage, whilst 80% were in the third stage at 29 days postinfection. When kept at 12°C, larvae remained infective toL. stagnalis for about 100 days, but the period of infectivity was reduced to about 17 days when larvae were kept at 20° C.L. stagnalis is a good experimental host forE. rangiferi, and may be of epidemiological significance in transmitting the parasite to reindeer.