The patient count in an outbreak of Salmonella infections has more than doubled since first being announced, according to the Food and Drug Administration. The cause of the outbreak remains unknown.

The FDA first announced the Salmonella Javiana outbreak on Nov. 24 and reported it had sickened 19 people. A week later the toll stood at 28. In an updat Dec. 8 the agency reported the count now stands at 42.

As of Dec. 8 the Centers for Disease Control and Prevention had not posted any public information about the outbreak.

In its update, the FDA reported it has begun traceback efforts, but the agency did not indicate what food or beverage is being traced. The agency had not initiated any on-site inspections, sample collection or testing as of Dec. 8.

No information has been released regarding wher the outbreak patients live, their ages, or whether any have required hospitalization.

The FDA continues to investigate two other outbreaks. One involves E. Coli O157 traced to fresh spinach. The other involves Salmonella infections that have been traced to fresh onions from Mexico.

The table below shows ongoing outbreak investigations being managed by FDA’s CORE Response Teams. The investigations are in a variety of stages. Some outbreaks have limited information with active investigations ongoing, others may be near completion. The table below has been abbreviated to show only active investigations.

The Food and Drug Administration will issue public health advisories for outbreak investigations that result in “specific, actionable steps for consumers — such as throwing out or avoiding specific foods — to take to protect themselves,” according to the outbreak table page.

Not all recalls and alerts result in an outbreak of foodborne illness. Not all outbreaks result in recalls.

Outbreak investigations that do not result in specific, actionable steps for consumers may or may not conclusively identify a source or reveal any contributing factors, according to CORE’s outbreak table page. If a source(s) and/or contributing factors are identified that could inform future prevention, FDA commits to providing a summary of those findings, according to CORE officials.