Many spammers insert weblinks into their messages to trick users into visiting the web page and subsequently infect their PCs. The company warns individuals and businesses to maintain their spam filters to keep potential threats at bay.

"As long as spammers continue to make money from these nasty ruses, the spam plague will continue," said Sophos senior security consultant Carole Theriault. 

"Businesses must wise-up to this threat and recognise the importance of quarantining spam messages before they are delivered to the unsuspecting user.  If the right security measures are put in place, businesses can not only save time and money, but can also protect their users from wider, malicious web-based threats, which commonly originate as spam emails with links to infected sites."

The country sending out the most spam in the first three months of the year was the United States. Russia and Turkey came in at second and third, both countries' contribution to global spam increased significantly in the period. Australia ranked at 34th place.