R Sadeghi Limanjoob - Islamic Azad University of Kazeroon
M Zamani Rad
N Siahmard

Objective: The pathogencity of white spot syndrome virus (WSV) in Litopenaeus vannamei with average weight 10 to12 grams, was studied experimentally with challenge exposure of two hundred shrimps. Method & Materials: Shrimps were examined with IQ2000 detection Kit for WSV before introducing. The Fenneropenaeus indicus that showed the clinical sign and PCR positive of white spot disease (WSD) was used as the source of WSV. The challenge exposure were accomplished by feeding minced tissue of F. indicus for 24 hours. The shrimps that showed sign of disease were collected for histopathology in Davidson fixator and a part of samples preserved in ethyl alcohol %75to %90 for PCR. Results & Conclusion: The results showed that L. vannamei after three days revealed the clinical sign of WSD, the PCR examined was positive and all shrimps died after ten days. The histopathology showed that the effect of virus and Cowdry type A inclusion body can be seen in all tissue except hepatopancreas. The PCR also indicate the virus infected the shrimp after 3 days. The SOI and ROI determined the severity of infection and rate of infection in different tissue

Litopenaeus vannamei, white spot disease, Histopathology, Polymerase chain reaction, Severity of infection, Rate of infection, pathogencity