DAO 47:151-157 (2001)  -  doi:10.3354/dao047151

Experimental infection of white spot syndrome virus in freshwater crayfish Pacifastacus leniusculus

Pikul Jiravanichpaisal*, Eakaphun Bangyeekhun, Kenneth Söderhäll, Irene Söderhäll**

Department of Comparative Physiology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
*Present address: Marine Biotechnology Research Unit, National Centre for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Ministry of Science, Technology and Environment, Bangkok 10400, Thailand **Corresponding author. E-mail:

ABSTRACT: The signal freshwater crayfish Pacifastacus leniusculus was found to be susceptible to infection with white spot syndrome virus (WSSV). Histopathological observations of various tissues of virus-injected crayfish showed similar symptoms to those from WSSV-infected penaeid shrimp, but no appearance of white spots on the cuticle or reddish body colour were observed, although these are the prominent gross signs of white spot disease in shrimp. A gene probe for detecting WSSV was developed in order to detect the virus in affected cells and tissues using in situ hybridisation. Strong signals were observed in cells of virus-injected crayfish, but not in control-injected crayfish. The number of granular haemocytes in virus-injected crayfish was significantly higher than in sham-injected and non-injected crayfish from Days 5 to 8 (p ≤ 0.05) and Days 3 to 8 (p < 0.01) postinjection, respectively. The proportion of granular haemocytes in virus-injected crayfish was also significantly higher than in sham-injected controls from Days 3 to 8 (p < 0.01). These results indicate that WSSV has a significant effect on the proportion of different haemocyte types in the freshwater crayfish.

KEY WORDS: White spot syndrome virus · WSSV · Crayfish · Pacifastacus leniusculus ยท In situ hybridisation

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