Infection of skipjack tuna Katsuwonus pelamis (Linnaeus 1758) of Oman Sea with cestode Trypanorhyncha (Diesing 1863)

Numerous reports on existence of white cysts in musculature of skipjack tuna Katsuwonus pelamis and lack of information about the quality of cysts and individual responses of fish to them led the authors to focus on this fish as a commercially valuable species. This study investigated the histopathologic responses of skipjack tuna to highly prevalent cystic larval stages of Trypanorhyncha. Some 92.25% of 400 examined skipjack tuna of Oman Sea (Iran) captured from processing center in Chabahar have been diagnosed infected by Trypanorhyncha Larvae through gross muscle examination. Minimum of 5 to maximum of 19 cysts were observed per each flank flesh with no significant difference between number of cysts from right (9 ± 4) and left flanks (10 ± 4) and also males and females (p>.05, t- student test (spss version 16)). Using hematoxylin and eosin (H&E) staining of 4µm sections of surrounded cysts with muscle and light microscopy observations each metacestode was distinguished encapsulated by surrounding fibrous cyst wall consists of thin inner layer and a thick outer layer with the minimal histopathologic changes around it. The highly prevalent Trypanorhyncha infection in Oman Sea represents the high rate of infection among elasmobranches. The ability of encapsulated parasite to escape from the immune system of the host is assumed as one reason for the observed minimal tissue response in infected fish and the continuation of infection among elasmobranches and teleosts of Omen Sea

In vitro anthelmintic effect of Tobacco (Nicotiana tabacum) extract on parasitic nematode, Marshallagia marshalli

Because of developing resistance to the existing anthelmintic drugs, there is a need for new anthelmintic agents. Tobacco plant has alkaloid materials that have antiparasitic effect. We investigated the in vitro anthelminthic effect of aqueous and alcoholic extract of Tobacco (Nicotiana tabacum) against M. marshalli. For investigating this effect, we prepared three dilutions of aqueous and alcoholic extract of Tobacco (25, 50 and 75 mg/ml). The worms exposed to extracts for 10 h at 25�30 °C. The buffer PBS used as negative control and 50 mg/ml dilution of Levamisole used as standard reference. In each group, 50 worms were examined. We used an inhibition mobility test for our study. Survival analysis with Cox proportional hazard model was used for data analysis. The result showed that compared with Levamisole 50 mg/ml, dilution of 25 and 50 mg/ml of the aqueous extract had the same anthelminthic effects (P > 0.05), but 75 mg/ml dilution of the aqueous extract and dilution of 25, 50 and 75 mg/ml of alcoholic extract had more anthelminthic effect (P < 0.05). Overall, extracts of Tobacco possess considerable anthelminthic activity and more potent effects were observed with the highest concentrations. Therefore, the in vivo study on Tobocco in animal models is recommended. © 2014, Indian Society for Parasitology