NEW YORK (CNN/Money) - MSN's Hotmail service, which has almost 200 million users worldwide, will use Trend Micro as its antivirus software, dumping longtime partner McAfee, Trend Micro said in a statement Monday.

Trend Micro (up $4.30 to $54.78, Research) shares jumped more than 8 percent on the report.

E-mails and attachments sent or received by any of Hotmail's 187 million Web mail customers will be scanned in real time by Trend Micro's antivirus software beginning Monday, said the statement.

A Microsoft (down $0.01 to $26.95, Research) spokeswoman said Trend Micro's real-time protection was a new technology that could better protect online customers.

"We are constantly evaluating the needs of our customers as well as our business needs and feel that offering customers a variety of computing experiences further enhances and helps with their online protection. Trend has a proven track record and made technical and business sense for us to work with them," said Phil Holden, director of MSN Global Business.

But Holden added that MSN premium customers would still be protected by McAfee PC antivirus and firewall software, and that the company still has a good relationship with McAfee.

McAfee said that MSN's choice to end the relationship was a business decision and had nothing to do with McAfee technology.

"The revenue impact to McAfee over the decision to no longer scan Hotmail email at the server level will be negligible," Bill Kerrigan, senior vice president of McAfee Consumer, said in an e-mail to CNN/Money.

Shares McAfee (down $1.97 to $26.98, Research) fell nearly 7 percent Monday on the New York Stock Exchange.