What To Know About Capnocytophaga

Animals carry a variety of bacteria in their mouths, some harmful, some not. Our pets are no exception. Capnocytophaga is a type of bacteria found in dogs’ and other animals’ mouths that can cause serious infection, especially for immunocompromised people.

What Is Capnocytophaga?

Capnocytophaga is a type of bacteria commonly found in the mouths of animals, including dogs, cats, and even humans. It is classified as facultative anaerobic, meaning it can use oxygen to make energy if it’s available, but it can also survive in oxygen-free environments. There are a few different species of Capnocytophaga bacteria; some are more commonly found in human mouths, while others are more common in animals’ mouths.

How Is It Transmitted?

Capnocytophaga primarily infects animals such as dogs and cats. Although rare, it can be passed on to a human from a pet or stray animal through a bite or scratch, or even from extended contact with the creature. The bacteria can also be spread by human-to-human contact in the same way. The infection typically enters through a wound, such as a bite, scratch, or cut, or through mucus membranes such as the ones in the mouth and nose.

Do All Dogs Carry Capnocytophaga? No, not every dog carries the bacteria, but a recent study found the bacteria in 69.7% of dogs tested, as well as 54.8% of cats. It doesn’t hurt them or cause any symptoms, so you likely won’t know unless you have your pet tested. Even that doesn’t guarantee they’re uninfected, however, as test results aren’t always accurate and the presence of the bacteria can change all the time. Animals that don’t carry it may still pick it up from contact with other animals. Likewise, if the bacteria is found, it can be treated but may return.

It’s safest to assume any dog or cat is a carrier and treat them accordingly. This doesn’t mean you have to avoid your pets or give them up, even if you’re immunocompromised. You may just need to take some extra precautions to ensure the bacteria isn’t passed to you.

What Are the Symptoms of Capnocytophaga?

Many Capnocytophaga symptoms are consistent with typical bacterial infections. If infected, you can expect to see swelling, redness, or blisters at the injury site, sometimes with pus or abnormal pain. Gastrointestinal symptoms such as diarrhea, vomiting, or a stomach ache may also show up. Other common symptoms include fever, headaches, confusion, and muscle or joint pain.

More severe infections may cause other symptoms or complications, including related conditions such as meningitis, sepsis, gangrene, brain abscesses, aneurysms, respiratory infections, and even heart attacks or kidney failure. People with compromised immune systems or who have had their spleen removed are more likely to experience more severe complications.

How Do You Test for It? The best way to know if you are infected with Capnocytophaga is to be tested. A lab can produce a culture of the infection to determine if the Capnocytophaga bacteria is the culprit. However, because it requires specific growth conditions and often grows slowly, misdiagnosis is possible. Polymerase Chain Reaction, or PCR, testing can also be used to diagnose this type of infection. PCR tests are designed to look for genetic material from certain organisms to tell if an infection is present.

What Are the Risks?

Although Capnocytophaga in humans is uncommon, certain people are at higher risk of infection. Anyone with a compromised immune system should be wary, including people who are pregnant or elderly; people who abuse alcohol or other drugs; or people who have conditions such as cancer, AIDS/HIV, diabetes, or other immunodeficiencies. Infection during pregnancy can also pose a threat to the unborn child.

Animal bites also carry a risk of rabies, so be sure to check with the owner to find out if the pet is up-to-date on their vaccinations. If the animal was a stray, or their shots aren’t current, contact Animal Control to let them know about the bite, and seek medical attention to get a rabies test right away.

How Is Capnocytophaga Treated?

Because Capnocytophaga is a bacterial infection, the most common Capnocytophaga treatment is some kind of antibiotic medication, such as clindamycin. Related symptoms or complications may also be treated separately.

What Can You Do To Prevent Infection?

For people who are not immunocompromised, complications from Capnocytophagia infection are unlikely. However, there are a few things you can do to protect yourself, whether you think you’re at risk or not. Be sure to wash your hands after contact with any animal, but especially an unfamiliar one. If any part of you made contact with the animal’s mouth or saliva, wash those areas as well.

Because most Capnocytophaga transmission comes from bites, take steps to prevent being bitten or scratched. Never approach an unfamiliar dog or cat, even if they seem friendly. If the animal is accompanied by their owner, ask before trying to pet them. Stay away from animals that are scared or angry, and don’t disturb them while they are sleeping, eating, or with their young. If it’s safe to approach, do so slowly and calmly, and give the animal space and time to move away if they don’t want to be touched.

Even if you do these things, you may still be bitten. If that happens, wash the injury with soap and water, and put on antibiotic lotion if you have any on hand. If the wound seems deep or more serious, seek medical attention right away. You should also see a doctor if the injury becomes red or swollen, there is uncontrollable bleeding, or you develop a fever.

If you have pets or frequent contact with animals and are at high risk due to immunodeficiency, talk to your doctor about the best ways to keep yourself safe.