AGE AT FIRST INFECTION OF CHERAX-QUADRICARINATUS BY CHERAX-QUADRICARINATUS BACILLIFORM VIRUS AND CHERAX GIARDIAVIRUS-LIKE VIRUS, AND PRODUCTION OF PUTATIVE VIRUS-FREE CRAYFISH

This study determined the age at which Cherax quadricarinatus is first susceptible to infection by Cherax quadricarinatus bacilliform virus (CqBV) and Cherax Giardiavirus-like virus (CGV). The first CqBV infect ed juvenile was diagnosed 2 weeks after the juvenile moulted into stag e 3 (week 2), and the prevalence of CqBV rose steadily to 17.1% at the completion of the experiment (week 7). CGV was first diagnosed at wee k 1 and its prevalence rose dramatically to reach 58% by week 3 and 86 % by week 6. Presumptive virus-free juvenile C. quadricarinatus were p roduced from infected females by removing the eggs at the eyed stage, sterilising and hatching them, and culturing the juveniles in uncontam inated water. These procedures may be used to prevent CqBV and CGV inf ections in aquaculture, or more importantly, prevent translocations of these viruses. (C) 1997 Elsevier Science B.V.