Detection of Toxoplasma antibodies in sera of rainbow trout, Oncorhynchus mykiss, in Shahrekord by ELISA

Objective: Toxoplasmosis is a disease caused by the protozoan parasite, Toxoplasma gondii and is one of the most common transmissible parasitic infections of man and other warm-blooded animals. Coastal pollution by freshwater run-off and sewage from humans and pets has been suggested as a source for Toxoplasma infections in marine mammals. Also, filtration and concentration of Toxoplasma oocysts by shellfish can occur, and sporulated oocysts can survive in sea water for an extended period of time. Recent reports of toxoplasmosis in marine mammals raise concern that cold-blooded marine animals are a potential source of T. gondii infection. Toxoplasma antibodies are found in the serum and aqueous humor and its organisms are found in the heart, liver, kidney, skeletal muscles, diaphragm, and other parts of body. The detection of antibodies can be achieved by different serological tests. To determine whether toxoplasmosis has a role in rainbow trout Oncorhynchus mykiss (Walbaum) infection which is the most common sea food in Shahrekord district, this research was carried out on 50 rainbow trout aged 4 to 5 months (weight 200±50 gr). Method & Materials: An enzyme-linked immunosorbent assay (ELISA) was performed on serum samples twice with 2 weeks interval for detecting T. gondii-specific immunoglobulin M (IgM) and immunoglobulin G (IgG). Results & Conclusion: Toxoplasmic antibodies were detected in 5of 50 samples by IgM-ELISA that had cut off value of ≥ 0.183. These results can explain the possible role of T. gondii in rainbow trout infection for the first time in Iran.