Parasitic nematodes in the mayan cichlid Mayaheros Urophthalmus sold in Ciudad del Carmen, Campeche: potential implications for public health

Abstract

The Mayan cichlid, Mayaheros urophthalmus (Günther, 1862), is a euryhaline fish used for local consumption in southeastern Mexico. This study characterized larval anisakid nematodes in fish sold at a market in Ciudad del Carmen, Campeche, and assessed their potential relevance to food safety. Fifteen fish obtained from market vendors were transported on ice and examined for external and internal parasites. Nematodes were cleared in glycerin and identified morphologically. Contracaecum sp. occurred in 3 of 15 fish (prevalence = 20.0%), Anisakis sp. morphotype I in 5 of 15 (33.3%), and Anisakis sp. morphotype II, tentatively assigned to the A. simplex sensu lato complex, in 2 of 15 (13.3%). At least one anisakid larval morphotype occurred in 8 of 15 fish, yielding an overall larval prevalence of 53.3%. Free nematode eggs were observed in 4 of 15 fish (occurrence = 26.7%) and were reported separately because they could not be assigned to a taxon. Larvae were recovered from the mesenteries and peritoneum, where they were generally encapsulated, and from the external surface or wall of the stomach and intestine. Because the edible musculature was not examined separately and species-level identification was not confirmed molecularly, consumer exposure and the probability of human infection cannot be estimated. The findings document anisakid larvae in fish sold for consumption and support molecular identification, systematic examination of edible muscle, prompt evisceration, and parasitological surveillance of local fishery products.