SAN FRANCISCO (Reuters) - Google Inc has bought startup VirusTotal, picking up a fledgling but widely used cybersecurity industry player in a move that could beef up protection for its Internet services.

The acquisition of VirusTotal, which aggregates warnings on submitted files and websites from most antivirus solutions, including Intel Corp's McAfee and Symantec Corp, could significantly shore up the search giant's ability to weed out infectious content from Gmail, social network Google+ and even the pages it shows search users.

VirusTotal operates by accepting requests for virus checks, running every available protection software on the questioned document or pages, then distributing the results to security vendors.

Because those results include the documents and websites submitted, the service is considered a valuable source of information by the security industry about emergent threats and potential targets.

"VirusTotal will continue to operate independently, maintaining our partnerships with other antivirus companies and security experts," the startup said in a blogpost announcing the acquisition.

"We've worked hard to ensure that the services we offer continually improve. But as a small, resource-constrained company, that can sometimes be challenging."

Google did not disclose the amount it paid, and did not respond to requests for comment.

(Reporting by Joseph Menn and Edwin Chan; Editing by Gary Hill)