LARVAL DIGENEAN COMMUNITY PARASITIZING THE FRESHWATER SNAIL, BIOMPHALARIA PEREGRINA (PULMONATA: PLANORBIDAE), FROM A TEMPORARY POND IN PATAGONIA, ARGENTINA

FLORES V.R.; SEMENAS L.G.; VELEIZÁN A. A.

JOURNAL OF PARASITOLOGY

AMER SOC PARASITOLOGISTS

Año: 2010 vol. 96 p. 652 - 656

0022-3395

Knowledge of infection dynamics of parasites in freshwater snails from South America is scarce. The objective of the present study was to describe the infection dynamics of larval digeneans in the planorbid snail, Biomphalaria peregrina during 2 sampling periods in a Patagonian temporary pond. In total, 1,003 snails were examined. Rediae of Notocotylus biomphalariae and Echinoparyphium sp., sporocysts of Cotylurus sp., and metacercariae of the 2 latter species were found; all with allogenic life cycles. The overall prevalence of digeneans in B. peregrina as first intermediate host was 4%, always as single-species infections in the hepatopancreas. All species exhibited different seasonal prevalence patterns, with Echinoparyphium sp. present in all sampling mo. Metacercariae of Echinoparyphium sp. occurred in heart and kidney, and those of Cotylurus sp. between organs (stomach and liver, and albumin gland and kidney). The overall prevalence of metacercariae was 39.3% with a progressive rise in prevalence from spring to summer for both species. Almost all size classes of B. peregrina were infected with metacercariae of both species, but rediae and sporocysts were present only in snails larger than 3.1 mm. Predictability of the hydroperiod and the physiological tolerance of B. peregrina to drougth produce a similar infection pattern over time. This is the first study in Argentina analyzing the infection dynamics of digeneans of a pulmonate snail from a temporary pond.