The threats listed in the August virus chart have had a much smaller impact and claimed fewer victims than the previous months. Sophos's research shows that 1.99%, or one in 50 emails, circulating during the month of August were viral - a significant drop when compared to the May results of one in 38 emails.

"Rather than being a sign that virus writers are giving up trying to infect computers, the reason for this decrease is most likely due to August being a favourite holiday time for many people," explained Theriault. "While people are enjoying a cocktail of sun, sea and sand, a large number of computers are switched off and therefore immune to infection".

In order to minimise exposure to viruses, Sophos recommends that companies deploy a policy at their email gateway which blocks unwanted executable attachments from being sent into their organisation from the outside world. Companies should also run up-to-date anti-virus software, firewalls and install the latest security patches.

Sophos identified and protected against 1,626 new viruses in August. The total number of viruses Sophos now protects against is 109,244.

The top ten hoaxes reported to Sophos during August 2005 were as follows (percentage of reports in brackets:

1. Hotmail hoax (13.5%)
2. Bonsai kitten (10.0%)
3. Meninas da Playboy (9.8%)
4. Budweiser frogs screensaver (8.8%)
5. ICE virus hoax (6.9%)
6. A virtual card for you (5.7%)
7. WTC Survivor (4.7%)
8. Jamie Bulger (3.8%)
9. Mobile phone hoax (1.9%)
10. Bill Gates fortune (1.8%)
    

Though the Hotmail hoax is now in its 14th month at the top of the chart, it has fallen in volume by 20% from July - though this may be explained by the reduction in user activity," added Theriault. "With London still recovering from last month's bombings, it is not surprising that the ICE virus hoax, which exploits a genuine 'In Case of Emergency' campaign, has risen several places in the chart."