First responders, stranded motorists and passersby wading in knee-length to chest-deep floodwaters — that image is branded in Southeast Texas’ collective psyche.

In most of these cases, walking in the water can’t be avoided. But when a viral video from Lamar University in Beaumont showed some people diving into deep water at an underpass for fun, Dr. Laila Woc-Colburn cringed.

That’s because Woc-Colburn, an associate professor of medicine in infectious diseases at Baylor College of Medicine, says when she sees a video like that, she thinks of what a person can contract in the water: staph, fungal and bacterial infections, vibrio and Leptospira.

In Woc-Colburn’s co-authored 2018 study “Infectious Diseases in the Aftermath of Hurricanes in the United States” she found that hurricanes “facilitate the spread of infectious pathogens through population displacement, flooding, and trauma.”

“If you have chronic infections, liver disease or you’re pregnant, your immune system is low,” Woc-Colburn said. “Then you’re exposed to water in the Gulf Coast area where vibrio is very common because of the (warmer) water temperature. It’s a very rapid infection.”

People who have cuts or open wounds are already more likely to contract vibrio if it’s present in the water, but the bacteria can enter the bloodstream through microabrasions caused by floating debris. It presents as a soft tissue infection that starts by turning the skin red and blistering up, Woc-Colburn said.

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A mild case of vibriosis can be treated and recovery time may take three days with no lasting effects. However, dehydration is typical because of loss of fluids.

Since it’s so fast-acting, a Vibrio vulnificus infection can already be serious by the time a person goes to an emergency room to be diagnosed, Woc-Colburn said. Severe cases call for amputation of the infected areas. About 1 in 5 people with this type of infection will die within a day or two of becoming sick, according to the Centers for Disease Control and Prevention.

For diabetic patients or those with poor blood circulation, infections can spread more quickly and are typically accompanied by redness, blistering, fever and fatigue.

But typically healthy people can also get sick, and much of that has to do with what’s floating in the water itself. Bacteria from agricultural areas, pesticides, animal stool and any number of chemicals can be found in bodies of water around Southeast Texas.

“Another one we do see during flooding is (the bacteria) leptospira,” she said. “Mice and rats carry leptospira in their urine, and it’s found in the water.”

Leptospirosis is a bacterial disease that affects humans and animals and sometimes has no symptoms, according to the CDC. The bacteria enters the body through skin or mucous membranes especially if there’s an existing cut or scratch. Outbreaks of this disease are usually caused by exposure to contaminated water.

The symptoms are flu-like and include high fever, headache, chills, muscle aches, vomiting, jaundice, red eyes, abdominal pain, diarrhea or a rash. Because the symptoms are easily misidentified for other illnesses, it’s important to go to the hospital for further testing if you’ve been exposed to floodwater.

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Another thing to be wary of is debris that gets stuck in the dermis of the skin that can easily cause an abscess or soft tissue infections, Woc-Colburn said. If you accidentally ingest the water, you’re susceptible to immediate diarrhea and vomiting, which can cause dehydration.

Mold is a constant concern in Houston’s humid conditions but especially after major flood events. Woc-Colburn recommends everyone cleaning out their houses to wear respiratory masks.

“If your house took on water, the first thing you’ll want to do is try to get the dry wall out — that space is where the mold goes,” she said. “If you’re helping someone whose house was flooded, you want to use a an N95 mask because the air might be full of mold by that time.”

In the two years since Hurricane Harvey, Woc-Colburn saw patients develop fungal infections six-to-12 months after the storm. These people had minimal flooding of 1-2 inches, she said. People with preexisting asthma and lung conditions experienced increased respiratory infections or asthma attacks.

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Finally, West Nile virus and other mosquito-borne illnesses are still a public health concern. Mosquito problems peak during the late summer months, according to Harris County Public Health.

Dump out standing water from areas around your house and wear DEET insect repellants and long pants if you can.

julie.garcia@chron.com

Twitter.com/reporterjulie

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