(NewsNation) — As authorities in the path of Hurricane Helene continue to hunt for missing people, the dangers for those who survived the wind and flooding are many, including contaminated water and mold.

“Symptoms from infection with waterborne pathogens can include gastrointestinal upset, diarrhea, nausea, vomiting, fever, and headache,” said Alasdair Cohen, an assistant professor of environmental epidemiology with the Virginia-Maryland College of Veterinary Medicine.

The danger is worse for anyone with any sort of skin break, even a small scrape or a condition like eczema.

“Floodwater with sewage or other harmful contaminants in it can lead to infectious diseases, particularly among people who are already ill, immunocompromised or have open wounds,” epidemiology professor Jennifer Horney at the University of Delaware wrote on the nonprofit news website The Conversation.

In some regions, damaged water treatment plants may not be operational for weeks. A lack of power means that private wells, which require electricity to pump and filter the water, are not a reliable source of safe water.

Another dangerous legacy of Helene’s rain and flooding is mold, which may be especially dangerous to people who rush to clean their homes of storm damage.

“There are multiple health effects from mold exposure,” said Dr. Colin Swenson of Atlanta’s Emory University.

“Probably the best known are those with asthma and other sorts of airway-based diseases,” he told The Atlanta Journal-Constitution.

“Mold can enter your home through open doorways, windows, vents, and heating and air conditioning systems,” according to the Centers for Disease Control and Prevention. “Mold in the air outside can also attach itself to clothing, shoes, and pets (and) can and be carried indoors.”

The site offers several tips on how to clean mold but stresses that “if you see or smell mold, you should remove it. You do not need to know the type of mold. If mold is growing in your home, you need to clean up the mold and fix the moisture problem.”

Swenson adds that while you might not see any mold, your sense of smell will tell the story.

“The best single way to determine if you have mold in the home is ‘the nose knows’ that sort of musty odor that the mold gives off. These are volatile, organic compounds that can oftentimes predate the development of any visual signs,” he said.