Pathogen index in freshwater drum (Aplodinotus grunniens R.) from the usumacinta river in southeastern mexico (Aplodinotus grunniens R.) from the usumacinta river in southeastern mexico

Objective: Determine infestation rates and identify parasites in the fresh-water drum (Aplodinotus grunniens R.) from the Usumacinta River. Design/methodology/approach: A total of 17 specimens were reviewed during the months of April-May 2022 and dissected in the Aquaculture Health Laboratory of Universidad Juárez Autónoma de Tabasco, Rios Di-vision, for the search and extraction of pathogens under conventional methods and techniques. Results: Two pathogen groups were recorded and taxonomically classi-fied: Nematodes: larvae of Contracaecum sp. (n = 139) and adult Rhabdochona sp. (n = 9) and Trematodes: metacercaria of Aus-trodiposmotum sp. (n=19) and Clinostomum sp. (n=1). The larvae of Con-tracaecum sp. presented the highest infestation rates with a Prevalence (P) of 41.1%, Mean Intensity (MI) of 19.8, and Abundance (AB) of 8.1. The lowest rates were for the metacercaria of Clinostomum sp. with a P of 5.8%, MI of 1.0, and AB 0.05. Limitations on study/implications: From a parasitic zoonosis point of view freshwater drum is a potential disease vector due to the consumption of raw or undercooked fish. Findings/conclusions: The parasitofauna recorded in freshwater drum from the lower basin of the Usumacinta River includes 4 species of para-sites belonging to two groups: Trematodes and Nematodes.