Bridging the gap: the odonate naiad as a paratenic host for Halipegus occidualis (Trematoda: Hemiuridae)

• Published in: The Journal of parasitology Vol. 84; no. 1; pp. 94 - 96
• Main Authors: Zelmer, D.A, Esch, G.W
• Format: Journal Article
• Language: English
• Published: Lawrence, KS American Society of Parasitologists 01-02-1998
• Subjects: Animals; Biological and medical sciences; biological development; Crustacea - parasitology; Freshwater; Frogs; Fundamental and applied biological sciences. Psychology; Halipegus; Halipegus occidualis; Helisoma anceps; Insecta - parasitology; Intermediate hosts; Invertebrates; Larvae; Life cycle; life cycle (organisms); Life cycle. Embryology. Development; Life Cycles-Survey; Metacercariae; Nemathelminthia. Plathelmintha; nymphs; Odonata; Ostracoda; Parasite hosts; Parasitology; Paratenic hosts; pathogenicity; Physiology. Development; Rana; Rana clamitans; Ranidae - parasitology; Snails; Trematoda - physiology; Trematode Infections - parasitology; Trematode Infections - transmission; Trematode Infections - veterinary; Worms; Life history; Rana clamitans; Helisoma anceps; Insecta; Amphibia; Plathelmintha; Parasite; Salientia; Gastropoda; Trematoda; Ostracoda; Crustacea; Freshwater environment; Metacercaria; Vertebrata; Pulmonata; Arthropoda; Helmintha; Ranidae; Intermediate host; Odonata; Developmental stage; Invertebrata; Mollusca
• ISSN: 0022-3395; 1937-2345
• DOI: 10.2307/3284536

The temporal and spatial dynamics of the recruitment of Halipegus occidualis by the green frog, Rana clamitans, suggest that infections are acquired through predation on odonates, which become infected by feeding on ostracods. Discrepancies in the literature regarding the life cycle of H. occidualis prompted the investigation of the status of the odonate naiad as an obligate third intermediate host. Infected ostracods were examined at weekly intervals to follow the postcercarial development of the parasite. Four-week-old "mesocercariae" were morphologically similar to metacercariae recovered from natural odonate infections and were infective to green frogs. Passage of the parasite directly from the ostracod to the frog host did not affect the infectivity of the worms or the period of development required to reach the adult stage. Thus, development into the metacercaria takes place within the ostracod, with the odonate acting as a paratenic host. The paratenic transfer of metacercaria is a common phenomenon among hemiurid trematodes, indicating a primitive 3-host cycle for the group, with opportunities for host capture being facilitated by a generalist strategy for the metacercariae.