Compared to the previous month the amount of spam in email traffic increased by 1.2 percentage points and averaged 80.8 per cent.
In the second half of April, the average figure exceeded 83.6 per cent, suggesting the share of unsolicited mail will continue to grow in the coming month.
Russia continued its slide down the rating of most popular spam sources, being overtaken by South Korea whose contribution to global spam almost doubled compared with March's figure.
Of particular interest in April was the appearance of Packed.Win32.Katusha.n and Trojan-Downloader.
Win32.FraudLoad.hxv in the rating of malicious programs blocked by mail antivirus.
Both malicious programmes are linked to fake AV: the former is used to pack them while the latter downloads them to users' computers.
In April, malicious files were found in 3.65 per cent of all emails, an increase of 0.43 percentage points compared with the previous month.
USA, Russia and UK continued
World's top 20 network ready nations
India's Libya no-vote based on misinformation: US
Cities with world's highest and lowest carbon emission
Are you a technosexual or mouse potato? Find out
Cybercriminals now target companies' trade secrets