It's not just turtles. Pet reptiles in general seem to be suspect. Picture: Centers for Disease Control and Prevention/Washington Post

Washington - Although this may not come as a surprise to anyone suspicious of murky green aquarium water, turtles aren't exactly the healthiest pets.

The health dangers from turtles are so serious that US federal law prohibits selling or distributing turtles with a shell length less than four inches (about 10cm).

The CDC has generally encouraged pet seekers - particularly homes with small children, elderly adults or people with compromised immune systems - to steer clear of shelled reptiles.

All turtles shed salmonella in their droppings, the CDC says, and salmonella can end up on their shells or skin - or in the water they swim in.

Children are especially at risk, because, as The Post's Dina ElBoghdady wrote in 2012, "kids couldn't resist kissing the toylike reptiles or placing them in their mouths, sometimes contaminating themselves with the salmonella commonly found on turtles."

To prevent people from getting sick, the CDC published a handy, kid-friendly fact sheet, telling people "don't kiss or snuggle with your turtle. This can increase your risk of getting sick."

It's not just turtles. Pet reptiles in general seem to be suspect.