[From Tufts January 2010 Issue]
Ever since most dog lovers can remember, they’ve heard that kissing a dog — and being kissed back — is risky. “The dog has germs,” mothers would say.
“If you let him lick you, you’ll get sick.”
That’s a contention that Scott Shaw, DVM, a specialist in emergency and critical care at Cummings School of Veterinary Medicine at Tufts University and head of the school’s infection control committee, disputes. “In most cases, the risk of contracting anything from close contact with a dog is very low,” he says.
The American Veterinary Medical Association has reported that about 60 percent of the 1,461 infectious diseases recognized in humans developed in other species and that animals have transmitted about 75 percent of emerging human infectious diseases in the past three decades. The report didn’t specify the extent of dogs’ role, but they account for only a small fraction of those numbers, Dr. Shaw says. “People should not be afraid of their dogs.”
Protect both species
Still, dogs do give diseases to people — zoonosis is the term for animals’ transmitting infectious diseases to people. What’s more, dogs can contract illnesses from people. Owners need to take steps to protect both themselves and their dogs. Zoonotic diseases range from the bacterium Campylobacter in the feces of puppies, which causes mild to severe diarrhea in people, to some types of mange, which result in an itchy rash in both species, to the more serious methicillin-resistant Staphylococcus aureus.
Here is a partial list of other zoonotic diseases:
– Rabies is transmitted when the saliva of an infected dog passes to a person, as occurs in dog bites. “While uncommon, rabies is usually fatal when contracted by people,” Dr. Shaw says. “Vaccination of the dog is the key to prevention.” If you’re bitten by a dog and you don’t know whether he’s been vaccinated against rabies, you should see a doctor immediately to ask about the need for treatment. Most cases of rabies in the United States are contracted from bats, foxes and skunks.
– Roundworm. is a common parasite with serious implications in young puppies. If children happen to ingest a large volume of eggs from dog feces, larval migration can, on rare occasions, cause liver and eye problems. Transmission is through the puppy’s feces. The best defense is prevention: Keep your yard clean of dog feces, do not handle feces with bare hands, and have puppies examined for worms and, if necessary, de-wormed.
– Hookworm, also a common parasite, can cause a young puppy to have bloody diarrhea and anemia. It also can be passed to children who play with an infected dog or run barefoot through a yard that has not been cleaned of puppy feces. Chances of contracting hookworm decrease dramatically if the puppy receives standard veterinary exams and if children and adults alike exercise common sense: Feces should not be handled with bare hands during yard clean-up, and good basic hygiene should be practiced.
– Ehrlichiosis, Lyme disease and Rocky Mountain spotted fever. Dogs can’t give these diseases directly to people because each requires a tick as the intermediate host, Dr. Shaw says. However, bites from infected ticks can transmit the diseases to both dogs and people. The wide ranging symptoms in dogs include weight loss, lethargy, decreased appetite, unexplained lameness and chronic ear or eye infections that don’t respond to medication.
Veterinarians prescribe antibiotics to treat these diseases. Preventive measures include keeping dogs out of high grasses and low shrubs, where ticks congregate; inspecting your dog for ticks and removing them soon after any exercise in these areas; and — if your veterinarian recommends it — using topical tick treatments.
– Leptospirosis. Several strains of the leptospirosis bacterium can infect dogs. The disease spreads to dogs and humans through the urine of an infected animal, but wildlife contamination of water is the most common source, says Dr. Shaw. Among the symptoms are lethargy, fever, shivering, vomiting and dehydration. Immunization can protect a dog from some strains for up to eight months; other preventive measures include keeping a dog from drinking contaminated water — any stagnant pool of water is suspect. Treatment includes antibiotics, fluid replacement and controlling vomiting.
In humans, the disease occurs in two phases. An abrupt onset of fever, chills, headaches, muscle aches and vomiting characterizes the first stage. A person may recover after a few days but become ill again with complications such as kidney failure and meningitis. Antibiotics are the treatment.
– Ringworm. Technically speaking, ringworm isn’t a worm — it’s a fungal disease easily passed between dogs and people by direct contact, says Dr. Shaw. Petting or otherwise touching a dog with ringworm can cause the transmission of the fungus to people. In dogs, symptoms of the condition are a round, hairless skin lesion that is often itchy and inflammed. In people, the fungus appears as a red or orange ring-like sore. The condition, which is more likely to afflict puppies whose immune systems are not fully developed, runs its course on its own, but a prescription anti-fungal medication will greatly ease your dog’s discomfort.
– Fleas. Endless scratching, red bumps on the skin and telltale brown specks (“flea dirt”) in the fur are signs of flea infestations in dogs. In extreme cases, fleas can be passed to people, also causing intense itching and red bumps on the skin. Keeping your dog healthy and judiciously using flea preventives to break the flea’s life cycle can prevent the condition. If infestation has already occurred, see your veterinarian about treatment and the elimination of fleas from the home.