[ALUG] clamav on etch and cpu usage

Hullo there, Our server is running nearly constantly at 100% cpu usage, the culprit being clamscan. Server is running debian stable, so clamav version is 0.90.1-2 I see a bug reported here http://bugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=425661 which seems to be for a later version so there's not much point in upgrading clamav. Has anyone else had similar? Should I 'downgrade'? Thanks, Jenny