According to press reports, city health officials are investigating a potential outbreak in Brooklyn of campylobacter, a bacterial infection that causes flu-like stomach symptoms. 

Campylobacter is a gastrointestinal bug that can come from eating raw or undercooked poultry or something that comes in contact with it, according to the Centers for Disease Control and Prevention. People can also get it from drinking contaminated water or contact with animals that carry the bacteria.

In Brooklyn, health officials said approximately 50 cases have been reported in the borough since the start of the month. A spokesperson for the city’s Department of Health and Mental Hygiene (DOHMH) declined to detail which neighborhoods have seen the spike. 

One health expert said it’s likely that far more cases have gone undiagnosed. 

“Whenever you have an outbreak of some type of foodborne illness, most likely, when you see the actual number of reported cases, it underestimates, and in some cases, greatly underestimates, the actual number of cases that have occurred,” said Dr. Bruce Y. Lee, a professor at the CUNY Graduate School of Public Health & Health Policy.

People suffering from diarrhea (often bloody) or fever — key symptoms of Campylobacter — might not go to a doctor. And even if they do, the medical professional might not test their stool for the bacteria. That’s the primary way doctors detect the genetic material of the bacteria.