Cotton Shrimp disease in the freshwater shrimp Palaemonetes argentinus from La Plata, Argentina

MARTORELLI SERGIO R; MARCOTEGUI, PAULA S

Buenos Aires

Congreso; 45th. Annual Meeting of the Society for Invertebrate Pathology- International Congress on Invertebrate Pathology; 2012

Society for Invertebrate Pathology

Palaemonetes argentinensis is one of the most common palaemonidae shrimp in the freshwater environmental of Argentina and since many years ago has been studied for parasites and pathogens. In a temporary pond from La Plata we found specimens with microsporidian. Infected shrimp showed a whitish coloration with the typical ?cotton shrimp? aspect. The infection was recorded as spore masses embedded in the skeletal muscle. The microsporidian were studied using Interferential Contrast Microscope and TEM. Sporophorous vesicles filled with a large number of mature spores. Unfixed spores measured (4.02?4.99 um) X (2.52? 3.33 m) in size. Under TEM spores were pyriform in shape. The polar tube consists of a straight shaft and a coiled region (11?14 coils) arranged in many rows along the inside periphery of the spore. The polaroplast consisted of an anterior region of closely and loosely packed membranes. According with this features the microsporidian found in P. argentinus seem to belong to Pleistophora. More studies of the developmental stages will be necessary for the final identification. This is the second microsporidian reported from decapods crustaceans in Argentina.