Infestation of Argulus sp. associated with bacteriosis in ornamental carp - case report

The aim of this study was to diagnose the causative agent of carp (Cyprinidae) mortality in an artificial lake used for recreation in Jaragu & aacute; do Sul, state of Santa Catarina, in February 2018. The fish showed symptoms, including skin ulceration, hemorrhages on the surface of the body, loss of scale and increased mucus production. Through the proteomic profile, using the MALDI-TOF technique, three bacterial isolates were identified as Aeromonas veronii, A. hydrophila and Citrobacter freundii. In addition, in the mucus scraping, a large number of the ectoparasite Argulus was observed. A blood collection was carried out to verify the hematological indices of the animals and a decrease in the the hematocrit value, erythrocyte count, and differential leukocyte count was observed. These findings indicate that Argulus infection increases the carp's susceptibility to bacterial diseases and contributes to the suppression of the innate immune system and consequent increase in mortality.