Klez, yet again, is the most-reported viral menace on the Internet.

The virus accounted for 12.7 per cent of support calls in April to AV firm Sophos.

The only new entry on Sophos' April chart is Datemake, a type of malware known as a dialler.

"Datemake is programmed to dial a premium rate telephone line, typically with the intent of gaining access to adult material," explained Graham Cluley, senior technology consultant at Sophos Anti-Virus.

"Businesses should apply strict computing guidelines to prevent getting stung by a huge telephone bill and being embarrassed by these seedy programs."

Sophos detected 475 new viruses, worms and Trojan horses in April. It now protects against 81,437 in toto.

Over at managed security services firm MessageLabs the viral risk barometer is currently low. At the time of writing, only one in 365 emails scanned by MessageLabs is contaminated with viruses.

Like Sophos, MessageLabs reports that Klez-H is the current top threat. ®

Top ten viruses reported to Sophos in April

1. 
   
2. Klez-H
   
3. Lovgate-E (re-entry)
   
4. Bugbear-A
   
5. Sobig-A
   
6. ElKern-C
   
7. Yaha-E
   
8. Yaha-K
   
9. FunLove (re-entry)
   
10. Naith-A
    
11. Datemake-A