Titration of the Iranian White Spot Virus isolate, on Crayfish Astacus leptodactylus and Penaeus semisulcatus

  White Spot Virus (WSV) is currently the most serious viral pathogen of shrimp worldwide it causes mortality up to ۱۰۰% within ۷-۱۰ days in commercial shrimp farms. Infected Indian white shrimp Fenneropenaeus indicus samples were collected from Guatr shrimp site in Sistan and Baluchestan province in south of Iran and WSV infection was confirmed by Nested PCR. WSV was isolated from infected shrimp samples by centrifugation and filtration and multiplied in crayfish by intramuscular inoculation, the isolated virus was called WSV/IRN/۱/۲۰۱۰. In order to determine the dilution resulting in ۹۰-۱۰۰% mortality in Penaeus semiculcatus, diluted virus stock in steps from ۱۰۰ till ۱۰۵ times in sterile PBS was injected intramuscularly to ۱۴ shrimps in each group. Also the virus stock was diluted in steps from ۱/۲ till ۱/۳۲ times in sterile PBS and injected intramuscularly in Astacus leptodactylus crayfish. Therefore the LD۵۰ of live virus stock in Astacus leptodactylus and Penaeus semiculcatus crayfish were calculated by the Karber method ۱۰ ۳.۲۹ /ml and ۱۰ ۵.۳۵ /ml, respectively.

Keywords:

White Spot Virus , Titration , Karber Formula , Astacus leptodactylus , Penaeus semisulcatus