Health care officials recommend that volunteers take the time to be checked out by a doctor after going down to South Louisiana to help residents muck out their flooded houses.
That's because they could be sick.
There are dangerous toxins in the floodwaters, and those waters standing stagnant worsens the situation, said Holly Lyles, injury prevention coordinator at University Health in Shreveport.
"There's things in the floodwaters that we wouldn't normally walk through," she said.
"Bacteria and viruses get pushed in there. Chemicals from household items get pushed in there. Sewage gets pushed in there.
"When you start feeling bad is really when you should go see a doctor," Lyles continued.
One example, she said, is the rise in Hepatitis A cases recorded among people coming back from volunteering after Hurricane Katrina in 2005.
Keeping your shots up to date is important; and people should ensure they are before volunteering, Lyles said.
"You want the best immunization and for your immune system to be built up before you go in. We did a big push of the Hepatitis A vaccines after Katrina. So, hopefully, people are still immune to that."
Volunteers returning from South Louisiana also could be contagious; so that's another reason they should be cleared by a doctor, Lyles said.
"With certain viruses and bacteria, you can be contagious for a couple of weeks after and not even show any symptoms. So you want to make sure that you maintain good hygiene and stuff like that after coming into contact with the floodwaters."