Occurrence of internal nematode parasites and condition factor of Nile tilapia (Oreochromis niloticus) fish species from Agneby river, Cote divoire

The Nile Tilapia Oreochromis niloticus fish is a freshwater cichlid that is indigenous to the Nile basin and is one of the world’s most important food fishes. It is a fish that is very common in Ivorian waters, used for food, and widely utilized in fish farming. However, it is susceptible to infections caused by nematode parasites, which can negatively impact the fish's condition and there are not well known. A study was conducted from February 2023 to March 2024 to determine the epidemiological indices of internal nematode parasites in Nile tilapia in two stations of the Agneby River. The study focused on 450 specimens of this fish, captured using gill nets of various sizes. The gastrointestinal tract fauna of this fish consisted of Capillaria pterophylli, Camallanus polypteri, Eustrongylides sp. and Contracaecum sp. The fish caught in Agboville station were the most parasitized. Seasonal variations in the infestation of this fish by parasitic nematodes have been observed. Generally, the largest and heaviest fish had more parasitic nematodes. The impact of host sex was observed for all nematode parasite load. The study indicated that these parasites have a negative impact on the body condition of this fish. The presence of nematodes causing zoonoses poses a public health risk for people living near this river who have developed the habit of consuming raw or undercooked fish. Therefore, awareness creation activities and control of fish parasites should be conducted in the study river.