The quantity of spam originating from the US, says Kaspersky Labs, actually increased by 8.5% on April, having returned to its usual level of 20.7%. Second and third places, respectively, went to India with 7.5% and Russia with 5.4%.

According to the Kaspersky report, May saw major shifts involving China (3.6%) and Brazil (3.7%) who have started to slowly win back their positions.

The 4th and the 5th places in the Top 5 are occupied by Vietnam and the Republic of Korea with 4.8% and 4.1%, respectively.

Germany and Italy dropped out of the 'Top 10' having distributed 2% less spam each compared with the previous month.

The 'newcomer' in May's Top 20, says Kaspersky, is Argentina, distributing 2.1% of the total volume of spam.

Also during May, medication-related spam averaged 30% in pole position in the spam charts, while computer fraud came in second place.

Kaspersky also says that fake DHL notifications abandoned by malicious code distributors have been taken up by fraudulent spam authors.