First evidence of Cichlidogyrus Paperna, 1960 (Monogenea: Ancyrocephalidae) in Oreochromis spp. cultures from Ecuador

Objective. To provide evidence of the presence of two species of monogeneans of the genus Cichlidogyrus that cause damage to gill tissue, in tilapia (Oreochromis spp.) grown in Ecuador. Materials and methods. The gills were placed in a Petri dish with boiling water so that the parasites relax, and later they were fixed in 4% formalin. The samples were checked under a stereoscope microscope. The parasites were counted and preserved in 70% ethanol for their taxonomic identification according to their morphological characteristics. The infection parameters (prevalence, mean abundance, and mean intensity) were calculated for each species of parasite. For the description of histological damages, fragments of parasitized gills were fixed in 10% neutral formalin and processed by the histological paraffin embedding technique. Results. Cichlidogyrus sclerosus showed highest infection parameters: prevalence of 65%, mean abundance of 24.24 ± 68.62, and mean intensity of 37.62 ± 82.93. Cychlidogyrus dossoui was observed in a prevalence of 4.5%, mean abundance of 0.13 ± 0.66, and mean intensity of 3 ± 1.41. Both species caused hyperplasia in lamellae. Conclusions. This study constitutes the first report of infestation by Cichlidogyrus sclerosus and C. dossoui in tilapia culture systems of Ecuador.