Media for Medical/UIG/Getty Images

Story highlights

In Mobile County, two infections were caused by exposing open wounds to water and two others by eating raw shellfish

A fifth case of a Vibrio infection was reported in Baldwin County after a woman went fishing on a pier

CNN —  

Four people have been infected with the illness-causing bacteria Vibrio vulnificus, according to health officials in Mobile County, Alabama.

One case happened in March when someone went out of state, ate raw oysters and became infected with Vibrio, said J. Mark Bryant, the public information officer for the Mobile County Health Department.

Another case occurred in April after a local resident consumed raw oysters in Mobile County.

“Then in June, we had two people that went into the waters south of Mobile County and also were infected,” Bryant said.

Vibrio vulnificus is a natural bacterium found in coastal gulf waters, particularly when water temperatures are warm. Other types of Vibrio bacteria that can live in the water are Vibrio parahaemolyticus and Vibrio alginolyticus.

Infection with any form of these Vibrio bacteria causes vibriosis, the symptoms of which include watery diarrhea, abdominal cramping, nausea, vomiting, fever and chills. If Vibrio infects an open wound, it can cause pain, redness and swelling. Skin rashes have also been reported.

Most people contract the infection by consuming raw oysters and other shellfish harboring the bacteria, or when open wounds are exposed to brackish or salt water where the bacteria are present.

Symptoms can be especially severe in people with weakened immune systems and those who have cancer, diabetes, liver disease or other chronic conditions.

Bryant said all four cases in Mobile County were mild because they were identified and treated early.

A fifth case was reported recently in a Mississippi woman who contracted the infection while fishing on a pier in Baldwin County, Alabama.

Dr. Karen Landers, assistant state health officer for the Alabama Department of Public Health, said that despite the infection occurring in Alabama, it is being investigated by the Mississippi State Department of Health.

Dr. Paul Byers, Mississippi state epidemiologist, wrote in an email that “the Mississippi State Department of Health does not provide specific details regarding individual cases to protect personal information and to avoid patient identification.”

But Byers confirmed that the Mississippi State Department of Health recently received notice of a new Vibrio case, bringing the total number of cases reported in Mississippi in 2017 to nine.

The Alabama Department of Public Health has reported 30 cases of vibriosis there in the past 12 months. The US Centers for Disease Control and Prevention estimates that 80,000 people become ill and 100 people die from vibriosis each year nationwide.

Landers said the most important thing people can do to avoid Vibrio infections is to be “wound and water aware,” especially during the summer months, when Vibrio bacteria in the water are at a higher concentration.

“The overarching message is that we must have a specific awareness for our own health and our own safety,” she said. “Let’s say you sustain a wound in the water. You need to watch for signs and symptoms of illness.”

Landers asks that anyone showing signs of infection, such as redness or swelling, wash the wound and then immediately see their health care provider.

Follow CNN Health on Facebook and Twitter

  • See the latest news and share your comments with CNN Health on Facebook and Twitter.

“Even though Vibrio is not very common, if treated early, severe illness can be avoided,” she said.

The Alabama Department of Public Health and the Mississippi State Department of Health advise anyone with open wounds or cuts to stay out of the water and those with compromised immune systems or chronic conditions to avoid eating raw shellfish.