Sensitization with Eustrongylides sp. (Nematoda: Dioctophymatidae) antigens induce production of specific IgG and IgE in murine model

Fish consumption plays an important role in human diet. Hoplias malabaricus, commonly known as traíra, is a freshwater fish widely appreciated in several Brazilian states and frequently infected by Eustrongylides sp. fourth-instar larvae (L4). The aim of the present study was to evaluate allergenic potential of Eustrongylides sp. L4 crude extract (CEE). BALB/c mice were immunized intraperitoneally (IP) by 10 μg CEE with 2 mg of aluminum hydroxide on days 0 and 35. Specific IgG and IgE antibody levels were determined after immunization and cellular immunity was evaluated by assessing intradermal reaction in ear pavilion. Epicutaneous sensitization was performed in dorsal region by antigen exposure using a Finn-type chamber containing 50 μg of CEE or saline solution, followed by evaluation of specific antibody levels. IP immunization resulted in a gradual increase in IgG antibody levels and transitory IgE production. Significant increase in ear thickness was observed in cellular hypersensitivity reaction. In case of antigen exposure by epicutaneous route, CEE was able to induce meaningfully increased levels of specific IgG and IgE antibodies as well as heightened cellular immunity. Both intraperitoneal immunization and epicutaneous contact with Eustrongylides sp. larval antigens were observed for first time to be capable of inducing immunological sensitization in mice.

Monogenoidea (Dactylogyridae, Gyrodactylidae) from Red River Pupfish, Cyprinodon rubrofluviatilis (Cyprinodontiformes: Cyprinodontidae), from Kansas and Texas, USA

BACKGROUND

The gills of Red River Pupfish (Cyprinodon rubrofluviatilis) collected from Kansas and Texas, U.S.A., were found to be infected with three monogenoideans, Fundulotrema prolongis, Gyrodactylus rubrofluviatilae n. sp., and a species of Salsuginus.

RESULTS

Gyrodactylus rubrofluviatilae n. sp. appears to be a member of a group of six closely related species possessing hamuli with mesially folded roots and a linguiform ventral bar shield, and parasitizing closely related species of Cyprinodon of the North American Gulf Coast and inland waters of the Southwestern United States and northern México. Gyrodactylus rubrofluviatilae n. sp. differs from its close congeners in the morphology of the hamuli, ventral bar, ventral bar shield, and marginal hooks. Because the morphology of the male copulatory complex was not determined of what we believe will eventually be a new species of Salsuginus, a species description is deferred. This is the first report of any parasite from this host.

CONCLUSIONS

Many North American species currently recognized within the Cyprinodontiformes have not yet been surveyed for species of Fundulotrema, Gyrodactylus, or Salsuginus. This, coupled with the high host specificity generally recognized for these monogeneans, portends there are likely additional new species yet to be discovered. When possible, to help augment morphological data, further studies should employ comprehensive intra- and interspecies molecular analyses to help resolve host-parasite phylogenies.