A new virus that send messages under the guise of the Harvard e-mail server spread through computers across campus yesterday, forcing the temporary removal of about 56 people from the University’s network.

“I don’t think we’ve ever seen the kind of intensity in virus proliferation as we’re now seeing,” said Todd van Stolk-Riley ’06, a user assistant (UA) at Harvard Law School.

Kevin S. Davis ’98, the director of residential computing, said that 70 percent of the Faculty of Arts and Sciences’ Computer Services help desk work yesterday was related to the virus, which is called Bagle.J.

Davis said last night that system administrators put a block on all incoming e-mail with the Bagle.J signature and that students should begin seeing a decrease in the amount of virus-infected e-mails they are receiving.

Although the MyDoom and SkyNet Internet viruses have been spreading through University e-mail accounts like wildfire for weeks, the new virus, Bagle.J, sends what appear to be legitimate notes from system administrators at a Harvard.edu account.

Yesterday, the virus also began to appear to come from the Office of Career Services summer employment list-serve.

“This virus really isn’t new,” said Imran M. Saleh ’07, a UA. “It’s just another variant of the viruses we’ve been seeing.”

Davis said the virus is spreading so rapidly because “it’s smart enough to be able to customize itself for sites.”

“It tries to make it look customized for its site,” Davis said.

Van Stolk-Riley thought that Harvard was particularly vulnerable to Bagle.J because students’ computers are directly connected to the Internet via University servers.

Students have had a hard time distinguishing between malignant and benign e-mails, and many download the virus thinking it to be a safe attachment from the Harvard administration.

“I just got back from rehearsal [two nights ago] and downloaded it. I didn’t know what to except,” said Joseph N. Fasano ’04-’05. “Apparently everyone else figured out it was a virus. I don’t know what I was thinking.”

“I am apparently that stupid guy,” Fasano joked.

“These viruses do masquerade,” said Davis. “They do pretend to be people you know.”

Once a student downloads the virus, Davis said, a computer could send thousands of e-mails without the student’s knowledge.