Pornographic spam dropped to an all-time low in February, as spammers concentrated on health-related products and other general product pitches, according to a report from vendor Symantec Corp.

And similar to software, spam is also increasingly being localized. The Symantec report on spam also said that there was a rise in gambling-related spam in German, Italian and French, while previously it was only mostly in English.

Symantec drew the conclusions from its own data, as do many security vendors that publish trend reports based on their own monitoring methods.

Pornographic spam comprised just 3 percent of the total amount of spam last month, the lowest figure ever recorded, Symantec said. Overall, about 70 percent of the e-mail messages monitored by Symantec were spam, half of which originated from computers in North America.

Improvements in blocking and filtering methods have driven spammers to use new techniques to get into inboxes. Some 38 percent of the spam sent in February used images in messages, which makes it more difficult for security software. Messages appear to be more unique, allowing them to bypass a filter.

Spammers also are using text slanted at upward or downward angles. The method hampers optical character recognition technology, which tries to read the text within images, Symantec said.