Outbreak of Aeromonas hydrophila associated with the parasitic infection Ichthyophthirius multifiliis in pond of African catfish (Clarias gariepinus) fingerlings at Sebeta, Ethiopia

Outbreak of a disease was observed on African catfish (Clarias gariepinus) fingerlings manifested by white nodules all over the body and hemorrhage in the skin that occurred on June 20, 2011 in an earthen pond at Sebeta, Ethiopia. The outbreak was investigated by using a combination of methods that included clinical observations, gross and histopathology examination and bacterial isolation. On histopathological examination co-infection of Aeromonas hydrophila with Ichthyophthirius multifiliis a holotrichous ciliate, was found to be the cause of the outbreak. In order to control the outbreak, the fish density was reduced and the fish were removed and treated with sodium chloride (3%) and moved to another properly disinfected pond that contains fresh and good quality water. The former pond was drained and left empty for two weeks to dry and then lime was added over it before filling it with water. The sick fish got cured after three weeks and no new case was observed; which may be due to development of immunity or the intervention measures taken to control the problem. This intervention protocols need to be further investigated in a properly designed experiment as a possible control of co-infection of these two pathogens in catfish fingerlings.Keywords: Aeromonas hydrophila, Co-infection, Ethiopia, Ichthyophthirius multifilii