The aim of this study was to investigate the use of the anaesthetic 2-phenoxyethanol on the transmission factors of gyrodactylid and to ascertain how this may affect in the colonisation of new hosts using the Gyrodactylus gasterostei Gläser, 1974 - Gasterosteus aculeatus L. model which is a simple and successful system to examine aspects of transmission of parasites from live and dead fish. Laboratory experiments include determining the maturity (presence of male copulate organ) and reproductive (presence of daughter) status of transmitting worms, in order to consider the factors that influence parasite option to migrate to a new individual of the same host species. This study demonstrates that parasites with a Male Copulate Organ (MCO) present are more likely to abandon the host and attempt a host transfer. The use of the anaesthetic 2-phenoxyethanol does not affect transmission of gyrodactylids which leave the host to colonise a new host. Finally, the use of other anaesthetic although its relative importance with respect to transmission remains uncertain.
M. I. Grano-Maldonado, F. Rubalcava-Ramirez, A. Rodriguez-Santiago, F. Garcia-Vargas, A. Medina-Jasso and M. Nieves-Soto
The aim of this investigation was to identify the parasites present in the largely understudied pleasure oyster Crassostrea corteziensis in Sinaloa state in the northwestern Mexican Pacific coast. Inspection of twenty-eight oysters collected on “Ceuta” lagoon revealed the presence of the digenean Stephanostomum sp. (Digenea: Acanthocolpidae) cysts. Metacercariae were found encapsulated and embedded in the digestive gland and mantle tissue of oysters. The prevalence of infection revealed that 84.6 % were infected, the abundance was 13.62, with a mean intensity of 16.09 per host. The members of this genus are characterized by a double crown of spines in the cephalic region surrounding the buccal opening of the worm. Significantly, we report the first incidence of the digenean Stephanostomum sp of the family Acanthocolpidae parasitizing Crassostrea corteziensis. Further we report that this bivalve is now considered a new intermediate host, and the northwestern Mexican Pacific coast is a new geographical distribution area for this digenean. The findings contribute to our understanding of the biology, biodiversity and host preference of these parasites, with implications for health risks posed by human consumption of the pleasure oyster.
D. J. López-Peraza, M. Hernández-Rodríguez, B. Barón-Sevilla, L. F. Bückle-Ramírez and M. I. Grano-Maldonado
The occurrence of the parasitic marine leech Stibarobdella moorei (Oka, 1910) (Hirudinea: Piscicolidae) along the northwest Mexican Pacific coast is described for the first time. This ectoparasite was collected from the skin of the Octopus bimaculatus (Verril, 1983) (Mollusca: Octopodidae). Stibarobdella loricata (Hardig, 1924) is synonymized with S. moorei as this species resembles other species of the genus based on tubercle patterns and the presence of papillae and a marginal fringe on the oral sucker. The present finding throws new light on the biodiversity and host preference of the ectoparasite and suggests a successful migration to unusual host. The coast of the Pacific Ocean, particularly in the Bay of Los Angeles, Baja California, Mexico is a new geographical distribution area for S. moorei, and O. bimaculatus is a new host reported for this leech. The morphology of this ectoparasite is briefly described.