PRIMER REGISTRO DE HENNEGUYA LACUSTRIS (MYXOZOA, MYXOBOLIDAE) EN BUENOS AIRES, ARGENTINA

YASMIN CROCI; YAMILA RESHAID; JORGE BARNECHE; SERGIO R. MARTORELLI; MARTIN M. MONTES

Congreso; XI Congreso Internacional de Parasitología Neotropical; 2023

The genus Henneguya (Thélohan 1892) is one of the most specious genera within the Myxozoa subphylum, including more than 200 described species. Certain species have been identified as pathogens, capable of inducing diseases such as cardiac henneguyosis and gill lamellar deformation in their hosts. These pathogenic effects have been observed to result in notable economic losses in certain instances. Henneguya lacustris was described for the first time parasitizing Psalidodon lacustris, from the Tietê River, State of São Paulo, Brazil. During the period from April 2018 to December 2020, 300 fish were collected in Juan Blanco Stream, La Plata, Buenos Aires. The gills of the specimen were partially covered by white sac-like structures. The examination of the content of these structures showed they were plasmodia of H. lacustris containing numerous mature spores and developmental stages of the parasite. Spores were measured according to standard procedures and observed microscopically. Myxospores of the parasites were found in the gills of Psalidodon lacustris with 9% prevalence of infection. The myxospores were oval and presented as measures: total length 17.7 ± 2 μm, body length 10.2 ± 1.3 μm, body width 4.7 ± 0.7 μm, tail length 7 ± 2.1 μm. The length of the polar capsule measured 4.7 ± 0.1 μm, while its width was determined to be 1.2 ± 0.4 μm. This finding represents the first record of H. lacustris for the Buenos Aires region of Argentina. Future studies on this group of organisms in the region will allow us to demonstrate their dispersal mechanisms and their ubiquity in the freshwater ecosystems of the Pampa.