April's virus activity was under the sign of the 'evil twins', the now notorious Klez virus which has reached its eighth incarnation, and the Elkern virus which hitches a ride with Klez.
Aside from being a hard hitter in terms of the resources needed to combat it, further problems were caused by Klez's ability to seemingly 'hijack' trusted email addresses.
The virus inserts a random email address from the infected computer's address book into the 'from' line of any infected emails it sends out.
Reported incidents of mistaken identity caused by the virus include a tattoo artist who received a jolly email from a deceased friend entitled "eager to see you", and pornographic images appearing to have originated from a Catholic parish in New York.
Security firm DespatchBox said that "several high profile organisations" have been battling to convince customers that the Klez virus, which hijacks identities, is not actually originating from them.
"As more email is hijacked or impersonated the less people will rely on standard email as a business tool. At the least, hijacking of email can be a nuisance and at the worst can be fraudulent," said Jolyon Jago of DespatchBox.
Graham Cluley, senior technology consultant at Sophos, added: "The success of Klez is damning evidence that computer users are failing to keep their antivirus software up to date."
Experts said that combined infections of Klez and its Elkern twin accounted for well over 90 per cent of all incidents last month, as well as bumping up confirmed infection reports by more than six per cent over those of February and March combined.
Below, vnunet.com gives you the virus top 10 for April.
|Top 10 viruses last month|
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