title: Potential interactions between metazoan parasites of the Mayan catfish Ariopsis assimilis and chemical pollution in Chetumal Bay, Mexico.
abstract: The effect of pollutants on the intensity of infection of metazoan parasites in the Mayan catfish, Ariopsis assimilis was investigated. Data were collected on pollutants and metazoan parasites from 76 catfish from five localities in Chetumal Bay in October, 1996. Nineteen pollutants (pesticides, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs)) were found in the catfish livers. Heavy metal content was not determined. Nineteen metazoan parasite species were recovered. After controlling for fish length and sampling station, there was a significant negative linear relationship between the intensity of the larval digenean Mesostephanus appendiculatoides and 1,1,1,-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) concentrations. This negative relationship may be explained either by the effect of the pesticide on the mortality of (i) free-living larval forms, (ii) metacercariae in the fish, (iii) infected fish or (iv) intermediate host snails. There were significant differences between fish parasitized and not parasitized with M. appendiculatoides with respect to their DDT concentrations. There were also significant differences between the variances of the mean Clark's coefficient of condition values between catfish parasitized and not parasitized by M. appendiculatoides, with the variance of non-parasitized catfish being significantly larger. The results provided statistical evidence that DDT has a detrimental effect on M. appendiculatoides infection intensity. Furthermore, the significantly larger variance value of Clark's coefficient for non-parasitized fish suggested that DDT affects both the parasite and general host condition.
authors.affiliation: Laboratories of Parasitology and Marine Geochemistry, Center for Research and Advanced Studies, National Polytechnic Institute (CINVESTAV-IPN), Carretera Antigua a Progreso Km. 6, C.P. 97310 Mérida, Yucatan, Mexico. vvidal@mda.cinvestar.mx
authors.forename: V M
authors.initials: VM
authors.lastname: Vidal-Martínez
authors.forename: M L
authors.initials: ML
authors.lastname: Aguirre-Macedo
authors.forename: E
authors.initials: E
authors.lastname: Noreña-Barroso
authors.forename: G
authors.initials: G
authors.lastname: Gold-Bouchot
authors.forename: P I
authors.initials: PI
authors.lastname: Caballero-Pinzón
mesh_terms: D000818:Animals; D001822:Body Burden; D002397:Catfishes / Q000469:parasitology*; D003634:DDT / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D005393:Fish Diseases / Q000469:parasitology* / Q000635:transmission; D005399:Fishes; D007306:Insecticides / Q000032:analysis; D008099:Liver / Q000737:chemistry; D008800:Mexico; D010271:Parasites / Q000302:isolation & purification; D010273:Parasitic Diseases, Animal / Q000175:diagnosis* / Q000635:transmission; D011078:Polychlorinated Biphenyls / Q000032:analysis; D012623:Seawater; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis; D014877:Water Pollution, Chemical
chemical_list: D007306:Insecticides; D014874:Water Pollutants, Chemical; D003634:DDT; D011078:Polychlorinated Biphenyls