U.S. regulators on Thursday suspended trading in four small over-the-counter stocks of companies that they said have been touting the development of products to prevent or treat the Ebola virus, and warned investors to beware of similar scams.

The Securities and Exchange Commission said it had suspended trading in the shares of New York-based Bravo Enterprises Ltd., California-based Immunotech Laboratories Inc., Canada-based Myriad Interactive Media Inc. and Wholehealth Products Inc., which is also located in California.

The SEC also issued a warning that "con artists" may be soliciting investors and claiming to be developing treatments or medicine to prevent the deadly virus.