If you cultivate free-range kids, one is likely to bring home a turtle or a frog from the woods one day — maybe even a salamander from a creek.
But parents should resist the urge to pull out an aquarium or shoebox and welcome the animal into the family, veterinarians say.
Turtles — especially those under 4 inches in diameters — are carriers of salmonella, a nasty bacteria that doesn't make reptiles sick, but can give humans diarrhea, abdominal cramping and fever for up to a week.
The Centers for Disease Control and Prevention is warning of four recent outbreaks, affecting 133 people in 26 states, all of which have been traced back to turtles. Forty-one percent of those sickened were age 5 or younger.
Crested geckos (popularized by Geico commercials) have also been blamed for 22 cases in 17 states last year.
But ridding your house of reptiles doesn't mean your family is no longer at risk for zoonotic disease, the term for illness humans contract from animals. Mosquitoes get most of the bad press, and it's true that most cases of zoonoses result from contact with insects or animals in the wild.
Worldwide, it's estimated that at least 60 percent of human diseases are spread by animals, and any contact with animals carries some degree of risk, more so if you are pregnant, older than 65, younger than 6, or have a weakened immune system.
This means parents should take extra care if their children visit a farm or petting zoo, and that some kinds of pets should be off-limits for families with members in a high-risk group.
“I personally don’t like reptiles or turtles (as pets), and I’d stay away from primates of any types; they just shouldn’t be pets,” said Dr. Barry Kellogg, a veterinarian in western Massachusetts and senior adviser for the Humane Society Veterinary Medical Association. “Dogs and cats, potentially ferrets or guinea pigs, are as far as we should go on a household basis, especially if children are involved.”
Children are especially at risk for zoonotic illnesses because their immune systems aren’t fully developed, and because they tend to rub their noses and put things in their mouths — including small turtles.
The Food and Drug Administration banned the sale of small turtles in 1975 because about 280,000 children were being sickened by salmonella every year. But you can still buy them online, and any size turtle can carry salmonella, even the amiable box turtle you stop to help cross the road.
“Wash hands, wash hands, wash hands,” says Kellogg, stressing the most important way to avoid zoonotic illness. But there are other things you should know and do as well.
Be careful what you pick up
Dr. Jason Stull, lead author of a study on reducing risk of zoonotic disease, said that up to 75 percent of American households have contact with at least one pet, and that intimate contact with a pet is common among pet owners, many of whom allow the pet to sleep with them or lick their face. For healthy people between the ages of 6 and 64, this usually presents no problem. For the very young or very old, or for those whose immune system is impaired, that's risky.
“It’s complicated with animals, because a lot of times they don’t get sick themselves from diseases they carry. But just because an animal looks healthy doesn’t mean it can’t make you sick," Stull said.
Salmonella is a problem, not ony with reptiles and amphibians, but with poultry. Children can get it from handling baby chicks or ducklings; in fact, the CDC often has to issue a warning about salmonella outbreaks not long after Easter, when many parents give chicks as pets. "They're so cute; you want to pick them up and hold them, but that's not a good idea," Kellogg said.
Of particular risk to pregnant women is toxoplasmosis, which causes flu-like symptoms that can last for a month, and can cause eye and brain damage in the developing baby. It is contracted from cat feces.
“Pregnant women should not change the litter box,” Kellogg said, adding that because cats could have particles of feces on their paws, they also shouldn't hold cats during pregnancy. (Being obsessive about keeping the litter box clean helps — it takes three to five days for the parasite to become infectious, so changing cat litter every day or every other day greatly reduces the risk.)
Cats, dogs and other mammals can transmit parasites and fungal diseases to humans, including hookworm, tapeworm and roundworm. To avoid these, don't walk barefoot in a yard where a pet defecates, and don't allow young children to clean up after pets in the yard, Kellogg advises.
Bites and scratches are another way people get sick from their pets.
About 4.5 million people in the U.S., most of them under 14, are bitten by animals every year, and dog bites account for a quarter of animal-related visits to emergency rooms, according to Stull’s research.
But a cat bite, too, can cause a nasty infection, because even if you wash the wound afterward, bacteria may have burrowed under the skin. That’s why Kellogg advises that people seek medical attention after any kind of serious bite, even if the animal has been vaccinated for rabies. (A scratch, which is usually superficial, is not as serious, but if it breaks the skin, it can cause cat-scratch disease.)
Sometimes, it's the person who needs training, not the animal, especially when children are involved, Stull said.
“Most young children aren’t really aware of the appropriate way to interact with animals; they think they’re another person — which is, most of the time, the way we treat them in our homes — and they may not realize when a dog is unhappy or frightened,” he said.
In fact, dog experts say that a common expression of affection in humans — the hug — causes stress and anxiety in up to 80 percent of dogs. So, don’t hug your dog, and don’t play rough with cats, which teaches them that aggression is okay. Keep their nails trimmed.
At petting zoos or farms, take along hand-sanitizing wipes, and don't take objects that children will later put in their mouth — like pacifiers, bottles or sippy cups — near animals, Stull said.
And if getting a pet, households with pregnant women or young children are better off with a mature pet, not a young one, he added. That's because animals — like children — are more prone to carrying diseases when they're young. An older animal will have cycled through common illnesses and is less likely to contract and share them, he said.
Even though the list of zoonotic diseases can be unnerving, it shouldn't frighten families away from having pets, which have been shown to reduce depression loneliness, blood pressure and even cholesterol levels. One study even suggested that people who own dogs have healthier hearts than those who don't, according to the National Institutes of Health.
"Thankfully, healthy individuals in the United States are protected by intact immune systems and bolstered by good nutrition, sanitation and hygiene," wrote Dr. Kevin Esch and Dr. Christine Petersen of Ohio State University in their 2013 study on parasites transmitted through pets.
And the most effective way to prevent zoonotic illness is the easiest and the cheapest: water and a bar of soap, or alcohol-based hand sanitizer. "If someone wants to pick up salamanders and pick up frogs, fantastic. Just wash your hands, and don't put your hands in your mouth," Stull said.