How Floodwater Could Put Houston Residents in Harm's Way

While Harvey has already wreaked catastrophic destruction with winds and rain, killing more than 30 people so far, many of its adverse health effects will be felt well after the storm has made landfall. Incidences in illness-causing bacteria like E. coli went up after other severe storms like Superstorm Sandy.

The dirty floodwater, rife with gasoline and bacteria, that has inundated the Houston-area carries many serious dangers including "infectious diseases, chemical hazards, and injuries," according to the Centers for Disease Control and Prevention. While "exposure to flood waters does not increase the risk of tetanus, and tetanus immunization campaigns are not needed," the contaminated water carries other considerable risks to human health.

Experts have warned those in the Harvey affected areas to steer clear of wading in the potentially polluted flood water.

"Our best advice is always to avoid floodwater as much as you can," Chris Van Deusen, a spokesman for the Texas Department of State Health Services told NPR. "Of course, people have had to be in the water — they haven't had a choice."

Here are a list of hazards that experts have warned from Harvey's floodwaters.

1. Intestinal problems, upset stomach, nausea, skin infections

Arch Carson, an assistant professor at University of Texas Health Science Center at Houston, explained to ABC News that "E. Coli and Clostridium difficile" found in floodwaters could lead to gastrointestinal illness and nausea.

"For the most part, these are self-limited and no antibiotic treatment is necessary," he added. "But they can be serious in susceptible people, like the elderly, the infirm, infants and small children."

People with open wounds that wade through the polluted waters risk serious infection. The CDC advises people with these injuries to immediately clean all wounds and cuts with soap and clean water and talk to a doctor or other health professional to find out if more treatment is needed.

"Let's say they walk through [contaminated water] and they have open wounds, all of these microbes can get into the open wounds. So there’s potential risk of infection." Linda Landesman, visiting lecturer of health promotion and policy at University of Massachusetts Amherst, told HuffPost.

Richard Bradley, the chief of the division of emergency medical services and disaster medicine at McGovern Medical School at the University of Texas Health Science Center, told Time Magazine that coming in contact with contaminated water could have negative effects on skin as well.

2. Trench Foot

When feet are submerged in water for a prolonged period of time people become at increased risk for trench foot. USA Today talked to experts that thought that many emergency responders were vulnerable to this health condition.

"That's slang for like when you can't keep your feet dry," Acadian Ambulance Operations Supervisor Jordan Wells explained to the newspaper. "You get that prune-like skin, then the feet are very prone to blisters and layers of skin slough off. It's very painful."

3. Floodwater injuries from debris/horseplay

Health professionals have found that murky water where people are walking may leave them susceptible to possible hurricane damaged debris such as broken glass or jagged metal objects.

Outside of accidents, researchers have also found that people and children horseplaying in floodwater has also led to signficant injuries in the past. According to the Washington Post, an Australian study found that "between the years 1997 and 2008, 1 in 4 flood deaths in Australia were caused by people goofing around, including "swimming, surfing, acting on a wager or some other form of recreation or risky behavior."

4. Exposure to mold

Mold can also be a serious health danger after hurricane-related flooding for indoor air quality. It can leave affected homes uninhabitable. 

According to the World Health Organization, mold causes respiratory symptoms, allergies, asthma, and immunological reactions.

The Atlantic's James Hamblin noted that mold became a major concern for low-income neighborhoods in New Orleans and Brooklyn after severe storms. "Submerging a city means introducing a new ecosystem of fungal growth that will change the health of the population in ways we are only beginning to understand," Hamblin observed.

5. Mosquitoes

Standing water from signficant flooding also allows the populations of disease-carrying mosquitoes to skyrocket. 

Julie Beck from The Atlantic noted that the flooding significantly increases the risk for mosquito-borne diseases like Zika and West Nile Virus to be spread.

Health departments across Texas are urging people to take any actions necessary to prevent the insect from breeding in floodwater.

Hays County Health Department on Wednesday issued a statement calling on residents to drain any standing water if possible, the Austin American-Statesman reported. "Hays County epidemiologists and environmental health specialists are continuing their regularly scheduled mosquito surveillance throughout the county."