The fallout from the Netsky/Bagle virus war earlier in the year is persisting, according to antivirus companies.

Figures released by Sophos, Kaspersky and Trend Micro for August show variants of Netsky, Bagle and Mydoom all topping the charts.

Although the number of new viruses continues to increase they are less effective at spreading, so general virus activity is down on this time last year.

"We can see that the effects of the 'virus war' between Bagle, Mydoom and Netsky authors are still prevalent, with six of the top 10 threats still relating to these codes," said David Kopp, head of TrendLabs EMEA, in a statement.

"This illustrates the current trend we are facing. The aim of the malware writers is no longer to destroy as many computers as possible, but to obtain access to them to retrieve data."

Variants of the Sasser worm are still in circulation, but better patching has cut their prevalence down from last month's higher placing.

Hungarian worm Zafi.B also appeared widely on the August statistics, despite protection being around for a couple of months. But Kaspersky has speculated that Zafi.B will disappear from lists by next month.