[Mimedefang] [OT] clamd doesn't recognize virus

[Marco Berizzi]

Hello everybody.
I'm using clam 0.87 with mimedefang 2.51.
This morning a virus has been slipped through MD.
This is the output from clamdscan:
/tmp/photo.zip: OK

----------- SCAN SUMMARY -----------
Infected files: 0
Time: 0.143 sec (0 m 0 s)

and this is the output from clamscan:

photo.zip: Trojan.W32.PWS.Prostor.A FOUND

----------- SCAN SUMMARY -----------
Known viruses: 40212
Engine version: 0.87
Scanned directories: 0
Scanned files: 1
Infected files: 1
Data scanned: 0.20 MB
Time: 5.939 sec (0 m 5 s)

Clearly clamd doesn't recognize it as a virus
and MD accept the message.
Hints?