Can Humans Get Strep Infection from Dogs?

Strep infections in people can cause sore throats, impetigo, cellulitis and, in extreme cases, necrotizing fasciitis. When strep infections occur or recur in certain family members, the cause needs to be found and all family members may need to be treated, including the family dog.

Strep Infections in People

Human strep throat infections are caused by Group A streptococcus, a bacterium that is usually passed between people, both those who are ill with the infection and healthy individuals who carry and spread the bacteria without showing signs of illness themselves.

Although current studies indicate that dogs cannot infect people with strep throat directly, they can serve as carriers of the bacteria within the home, which can create a lengthy cycle of infection, treatment and re-infection.

One of the ways dogs can serve as a carrier is when your pet licks you or another family member. You or the other family member could have strep throat, or you could simply be carrying the bacteria on your skin (Group A strep is present in about 10 percent of healthy children). 

A Zoonotic Form of Strep

A strep infection that both humans and dogs can contract is called streptococcal toxic shock syndrome. Symptoms of this frequently fatal zoonotic (a disease that both people and animals can contract) condition include high fever, cough, shock and clotting abnormalities. In many cases, a dog can be fine in the morning and dead by nightfall, while human mortality may be as high as 80 percent.

Risk factors for developing the canine form of streptococcal toxic shock syndrome include crowded living conditions for dogs, shared food and water bowls or close physical contact with sick animals. To protect your dog from exposure to this disease, keep him out of high-stress, crowded conditions. If he’s a show dog, groom and handle him yourself to minimize handling by a judge, who may be an inadvertent carrier. Consult your veterinarian promptly if one of your dogs becomes seriously ill or dies suddenly.

Strep Infections in Dogs

In dogs, streptococcal infections are primarily caused by Streptococcus canis, which is a Group G strep bacteria. Group B and Group L infections have also been reported in dogs. Still another strep infection, Streptoccocus equi subsp. Zooepidemicus or strep zoo, killed several dogs at Philadelphia-area animal shelters in the past year and in Brooklyn, New York, in 2009.

Although no direct Group A infections have been reported, dogs can still carry the bacteria and pass it on to human family members.

Healthy adult dogs are not as susceptible to strep infections as younger or older dogs are. This may be because a young dog’s immune system has not fully developed, while an older dog’s immune system may be less effective than a healthy adult’s.

Clinical signs of strep infection in dogs can include abscesses, arthritis, coughing, fever, lethargy, pain, pneumonia or problems with swallowing. The dog’s skin, mammary glands and urinary tract may also be infected, or he may have an infected wound.

Treatment plans include antibiotics and fluid therapy to rehydrate a sick dog and cleanse the infection from his body.