PREVALENCE OF THE PARASITIC INFECTIONS AND HISTOLOGICAL CHANGES IN THREE PARASITIC-INFECTED TILAPIA SPP. FROM FAYOUM GOVERNORATE, EGYPT

Parasitic infections pose serious threats to fish populations and the sustainability of aquaculture, as they can inflict substantial tissue damage, and may ultimately result in host mortality. This study sought to survey/characterize parasites, document their prevalence/intensity, and evaluate their histopathological impacts on the general health of three freshwater fish species of tilapia (Oreochromis niloticus, Coptodon zillii, and Oreochromis galileus) in Fayoum Governorate, Egypt. Between October 2022 and November 2023, a total of 190 O. niloticus, 50 C. zillii, and 50 O. galileus were collected from fish market in Fayoum Governorate, and assessed for parasite diseases. The findings revealed that 111 out of 190 O. niloticus (58.4%) were infected with five parasite species – four Trematoda spp. (Gyrodactylus funduli, Cichlidogyrus sp., Prohemistomum sp., and Clinostomum sp.) and one Nematoda sp. (Contracaecum sp.). In C. zillii, 28 of 50 (56%) harbored one Trematoda sp. (Prohemistomum sp.) and one Nematoda sp. (Contracaecum sp.); while, in O. galileus, 23 of 50 (46%) carried two Trematoda spp. (Prohemistomum sp. and Clinostomum sp.). Concerning seasonal fluctuations, the highest infection rates in O. niloticus occur in summer (77.9%), with the lowest in winter (30%). For C. zillii, the peak infection rate was recorded in summer (90%), with the lowest in autumn (38.4%). Conversely, O. galileus exhibited the highest infection rate in winter (92.3%) and the lowest in summer (12.5%). The parasitic infection caused severe tissue destruction in tilapia fishes. In conclusion, the general health of tilapia spp. of Fayoum governorate could be affected by trematode and nematode infections.