Date of Publication: 30-Nov--0001
Aeromonas hydrophila in Nile tilapia (Oreochromis niloticus) from Brazilian aquaculture: a public health problem
Author: Marianna Vaz Rodrigues, Maria Fernanda Falcone Dias, Claire Juliana Francisco, Gianmarco Silva David, Reinaldo Jose da Silva, Joao Pessoa Araujo Junior
Category: Research Article
Aeromonas hydrophila is a Gram-negative bacterium present in the water, which can cause disease in animals, such as fish, frog, and mammals, including humans. In fish, Aeromonosis occurs when it is immunosuppressed due to the stress of handling, water quality, parasitism or population density. Due the importance of this disease in fish and humans, this study aimed to detect this bacterium by PCR in Nile tilapia (Oreochromis niloticus) of cage fish farms localized in hydro-electrical reservoirs of S__ampersandsignatilde;o Paulo state, Brazil and describe the lesions found in positive fish by necropsy and histopathology. Around 360 samples of Oreochromis niloticus specimens were randomly sampled at six Brazilian fish farms in November 2014 (n = 180) and in March 2015 (n = 180). The identification of A. hydrophila by PCR showed the prevalence since 3.33% to 46.66%. The most common macroscopic lesions were hemorrhage and splenomegaly, and bacteria colonies, coagulative necrosis, hemorrhage, inflammatory process, melano-macrophages, and vacuolar degeneration were microscopic. The pathological and histopathological findings showed the presence of an infectious disease, and employing the molecular technique, it was possible to identify that the analyzed fishes had A. hydrophila. Thus, producers should utilize this information using histopathology and molecular techniques in tilapia to reduce economic losses and avoid disease in consumers.