Development of swim bladder nematodes (Cystidicola spp.) in their intermediate hosts.

Abstract

Listen

Translate article

It has been confirmed experimentally that Cystidicola farionis develops to the infective third-stage in amphipods. The third stage was reached more quickly in Gammarus fasciatus (5 weeks) than in Hyalella azteca (6 weeks) at 12–14 °C and required 7 weeks to develop in Pontoporeia affinis at 5–7 °C. Third-stage larvae were 437 μm long immediately after the second moult and grew up to 4.9 mm long. Cystidicola cristivomeri developed to the third stage in Mysis relicta but not in amphipods. Third-stage larvae were about 720 μm long after the second moult and grew up to 5.7 mm long. Third-stage larvae of C. cristivomeri up to 10.8 mm long were found in 0.8% of M. relicta from a lake where lake trout were infected with the parasite. Third-stage larvae of C. farionis and C. cristivomeri grew considerably in the intermediate hosts and the gonads became well developed. Similar development has been reported in other cystidicolids but suggestions that larvae moult to the fourth stage in the intermediate host cannot be accepted.