You know all the wonderful things you get from your cherished pet—cuddles, comfort and companionship. But you also can get things you don’t want from your furry, feathered or slippery friend, such as nasty infections. Veterinarian Marcy Souza, DVM, and infectious disease specialist William Schaffner, MD, share what to look out for and how to avoid problems in the first place.


Toxocariasis. This infection is caused by roundworms (Toxocara) that live in the intestines of dogs and sometimes cats. The animals shed roundworm eggs in their feces. Children who play in the dirt and neighborhood sandboxes where dogs like to relieve themselves (and even on beaches where dogs are permitted) are at higher risk for toxocariasis. The eggs live in the soil long after the poop is gone and can infect children if they put their hands in their mouths.

In people, the eggs develop into larvae but don’t grow into mature roundworms. Most of the time the infection doesn’t cause any symptoms and often clears on its own without your ever knowing you had it. However, sometimes a large load of larvae can travel to organs throughout the body and cause fever, coughing or wheezing, or pain in the upper-right belly. If you have any of these signs, your doctor can treat you with antiparasitic drugs.

Encourage your children to regularly wash their hands, and don’t let them play where your dog (or any dog) does its business. (Try to pick up the poop at least every few days.) Remind kids not to play in kitty’s litter box either, and as long as you carefully dispose of kitty litter and wash your hands afterward, your risk is low.  

Symptoms of roundworm infection in your pet—generally in puppies and kittens—includes vomiting and a pot-bellied appearance. Deworming medications, including drugs used to prevent heartworm, can eradicate roundworms. But in general dogs who see their vets regularly won’t have roundworms.

Cat scratch disease. Your playful, adorable kitten can spread this bacterial infection through a scratch or bite that breaks your skin, giving you a mild infection at the site of the wound and possible swelling at the closest lymph node. You may get a fever and be exhausted, similar to feeling as though you have the flu. Keep in mind that a cat with this infection may not show any signs of it, so always wash any bites or scratches you get from Fluffy with soap and water right away. Don’t let your cat or kitten lick any cuts or open wounds you might have as this is another way the infection can be transferred to you.

Cat scratch disease often goes away on its own. If you notice symptoms, talk to your doctor about whether you need treatment. And ask your vet if your cat needs its own treatment.

Toxoplasmosis. Cats can shed the toxoplasma parasite in their feces. In most healthy people, the infection causes no problems. But it can harm an unborn baby and even may result in a miscarriage. You won’t know if your cat is infected because it usually has no symptoms. As a precaution, don’t change the litter box if you’re pregnant or have compromised immunity from cancer or the HIV infection.

Rocky Mountain Spotted Fever (RMSF). Your dog or cat can’t give you this tick-borne bacterial infection directly. But if an infected tick hitches a ride on your pet who then brings it inside, the tick can latch onto you. Symptoms of RMSF in people include a rash and fever. The antibiotic doxycycline can usually clear it up.

Lyme disease. This tick-borne bacterial infection is spread to humans in the same way as RMSF. You may feel like you have the flu and may develop a rash near the bite that looks like a bull’s-eye. Other symptoms include fatigue, headache and body aches. It’s usually successfully treated with an antibiotic, such as doxycycline or amoxicillin, if caught early. Because Lyme disease can have serious complications if not treated, check in with your doctor if you see the bull’s-eye rash or experience other symptoms even if you didn’t remove a tick. (Many people who develop Lyme disease never notice a rash or a tick, so see your doctor if you notice any flulike symptoms that don’t resolve in a few days.)

Tip: Be careful de-ticking your dog. Always use a tissue or gloves (no bare hands!). Firmly grasp the body of the tick, and slowly withdraw it from the skin. Don’t jerk it because the body of the tick can break off and leave the head stuck in the skin.


Mycobacterium Marinum. This bacterial infection is most common in people who keep fish aquariums. Typically, skin gets infected when cleaning out a tank with contaminated water as bacteria enter through a cut in the hand or arm. See your doctor as soon as you notice a skin infection, and be sure to point out if you recently did fish-tank maintenance. You may need an antibiotic to treat the infection. Protect yourself by wearing rubber gloves when cleaning the tank and washing hands afterward. Infected fish may look emaciated and lethargic and usually need to be euthanized rather than treated. Mycobacteria are incredibly resistant to disinfection. Talk to a specialist at your fish store about the latest treatments, but be prepared to drain your tank and start over.

Salmonella Infection. Reptiles such as snakes and turtles and amphibians such as frogs are carriers of salmonella but usually have no symptoms. They shed the bacteria in their stool. People can get infected when handling the animals or cleaning out cages or tanks and then not washing their hands. As with other disease transmissions, young children are more likely to get sick because they often put dirty hands in their mouths. Symptoms include diarrhea, vomiting and stomach cramps. You may not always need treatment with antibiotics, but do call your doctor to find out what’s best for you.

Outbreaks are rare, but they can happen. Between 2009 and 2011, more than 200 people nationwide were sickened with salmonella linked to African dwarf water frogs. Almost 70% of the infections occurred in children under 10, and 30% had to be hospitalized.

A word of caution: Don’t let children under age five handle reptiles or amphibians or play with the rocks and other items in their tanks or cages. A good mantra is: “Look but don’t touch.” Keep in mind that you can get infected from reptiles you catch in the wild—yes, that cute frog or salamander in your backyard.


Psittacosis (parrot fever). Birds in the parrot family can pass this bacterial infection to people. It’s spread by breathing in dried bird droppings that contain the bacteria and causes respiratory symptoms such as coughing and even pneumonia.

Wild birds imported from South or Central America pose the biggest risk. That being said, the US government requires that these birds be held in quarantine for 30 days and treated with antibiotics as a precaution. Make sure you’re buying either a domestically raised bird or, if it’s imported, that the seller is following all appropriate laws.

A word to the wise: Keeping chickens or other backyard birds is becoming more popular as people want to cultivate their own food. If you raise poultry, salmonella is the biggest concern. It’s assumed that all chickens are carriers, but they aren’t treated unless they’re actually sick. Wash your hands, fully cook eggs, and avoid bringing dirty boots into your home to reduce your exposure. Also, don’t let your chickens or other fowl inside your home, even if you do regard them as pets.


The good news: Your risk of getting sick from a pet generally is pretty low, but it is higher for young children, the elderly and anyone with a weakened immune system, such as people with HIV or cancer, because they’re more vulnerable to infection. You can help everyone in the family stay safe with these simple measures…

Wash your hands: Always use soap and water after handling an animal and cleaning out its cage or tank.

Take your pet to the vet: Annual vaccinations and parasite tests and monthly preventive medications help your pets stay healthy. Exactly which ones your pet needs depends on the area of the country where you live and what risk factors your pet has. Your vet knows what illnesses that can transmit to you and can look out for both of you.

Follow your vet’s advice: Be sure your pets get all their vaccinations and any deworming treatments on schedule and be vigilant about using recommended flea and tick prevention.

Say no to raw: Animals that eat a raw diet are more likely to get sick from and pass on bacteria including E. coli and salmonella.

Scoop that poop: Don’t let feces accumulate in your yard, especially if your children or grandchildren play in the grass. Clean up regularly, and don’t let your dog or outdoor cat “go” in a sandbox either. Smart tip: Keep your backyard sandbox covered when not being used to keep out wild animals.

Related Articles