Parasitology

Biography

Biography: Galina A Yakovleva

Abstract

The study focused on the quantitative assessment of the trematode Apophallus muehlingi (Jagerskiold, 1899) infection in gull species living on Lake Ladoga shores (61°12′N; 32°54′E). A. muehlingi is actively dispersing northwestwards and metacercariae of this species can cause epizootic events in fish. Gulls (81 specimens) were surveyed in spring and autumn in the period between 2010 and 2015. The sample set included 7 species: Larus argentatus, L. canus, L. fuscus, L. minutus, L. ridibundus, Sterna hirundo, S. paradisaea. Mature trematodes A. muehlingi were detected only in L. canus and L. minutes in spring, instantly after their return from wintering grounds. The highest infection rates were found in Common Gull, which yielded 12% prevalence and mean intensity 5.1, whereas the rates in Little Gull were 6% and 0.7, respectively. The birds examined in autumn were free of the trematode infection, suggesting that A. muehlingi cannot yet complete its life cycle along Ladoga shores because local waters lack the snail Lithoglyphus naticoides (the first intermediate host of parasite). Over the past 50 years this snail from the Black Sea has spread from the downstream Volga up to Rybinskoye impoundment reservoir. If L. naticoides continues dispersing at the current rate, the mollusk may soon reach the waters in the Onego and Ladoga catchments. This intervention would generate the conditions required for A. muehlingi to complete life cycle and thus results in epizooty of local fish species with trematode metacercariae.