SAO PAULO, Brazil (Reuters) - Brazilian (news - web sites) Internet security specialists disagreed on Wednesday on the source of a pornographic e-mail virus that infected computers worldwide and was thought to have originated in Brazil. 

The ``Naked Wife'' virus crippling Microsoft Windows appeared on computers across the United States, Canada and Europe on Tuesday and at least one software company traced it back to Brazil. 

Security software maker Symantec Corp. said the virus appeared to have been written on Monday on a personal computer owned by a company called ``AGF Brasil Seguros'' and registered to a user named ``MH Santos.'' AGF Brasil Seguros is the Brazilian unit of insurance company Centrale des Assurance Generales de France. 

But McAfee.com Corp., a U.S.-based Internet security services firm, said it was certain the virus did not originate in Brazil. The virus ``is from the United States and it does not have any relation with Brazilian companies,'' said Patricia Ammirabile of McAfee's Brazilian unit. 

Marco Antonio Alves Vaquero Bicca of Symantec in Brazil said the information they had received from the United States was that the virus ``could have possibly originated in Brazil'' but he said no specific company was cited. 

Virus Spotted Tuesday 

Dozens of companies reported infections by the virus on Tuesday, but by the afternoon anti-virus companies were already offering cures on their Web sites. 

The destructive worm-type virus appeared on a forwarded e-mail with ``Naked Wife'' in the subject line. Readers who clicked on the attached file would not be greeted by a nude woman, but would instead see a short cartoon followed by a vulgar message, signed by ``BGK (Bill Gates (news - web sites) Killer).'' 

All the while, the virus would be deleting key Windows and system files on the user's computer, leaving it unable to start properly, according to Susan Orbuch, a spokeswoman for anti-virus software maker Trend Micro Inc. 

Similar to earlier worm-type viruses like ``Love Letter'' and ''Melissa,'' ``Naked Wife'' spread quickly by e-mailing itself to everyone in a user's Microsoft Outlook e-mail address book. 

The press department at Sao Paulo-based AGF Brasil said Wednesday: ``The company found out about the incident through press reports and is investigating them now.'' The technical department, which was meeting behind closed doors all morning, said they could have some information in the afternoon. 

Trend Micro said it was still investigating the origin of the virus, while independent security consultant Andre Ptkowski said it was possible AGF Brasil did not know it had a virus in its system, or ``a fox in the henhouse.'' 

All of the security specialists agreed there had not been a single report of the virus in Brazil. 

The Sao Paulo police's computer crime department took the day off as part of the first day of national mourning for the death on Tuesday of Sao Paulo Gov. Mario Covas.