Key points
- Capnocytophaga bacteria can cause a rare but potentially serious infection.
- People usually get infected if they're bitten by a dog or cat.
- People with weakened immune systems are at higher risk for infection and serious illness.
- People bitten by a dog or cat should call a healthcare provider immediately.
Overview
Many kinds of bacteria are found in the mouths of dogs and cats. One common group of bacteria are called Capnocytophaga. These bacteria sometimes cause opportunistic infections, which means under the right conditions they can cause an infection, such as in a person with a weakened immune system.
Capnocytophaga germs can make people sick if they're bitten or the dog or cat's saliva (spit) gets into an open wound or sore.
Most people who have contact with a dog or cat do not become sick. People with weakened immune systems who have difficulty fighting off infections are at greater risk of becoming sick if they're bitten.
Capnocytophaga infection can cause serious complications, including sepsis, heart attack, kidney failure, and gangrene. Some people may need to have fingers, toes, or limbs amputated.
If you have been bitten by a dog or cat, wash the bite area right away with soap and water. Call your doctor or go to an urgent care clinic. Even if you don't feel sick, dog and cat bites can cause a Capnocytophaga infection and other diseases like Pasteurella, Bartonella (cat-scratch disease), or rabies.
Other types of Capnocytophaga infection
Other Capnocytophaga bacteria can also be found in human mouths. People who have weakened immune systems can sometimes get sick from those bacteria.
People who get sick from the kinds of Capnocytophaga found in people’s mouths can get infections in their eyes, gums and mouth tissues, and respiratory tracts (nose, throat, lungs).
Signs and symptoms
If you have the following symptoms within 14 days of getting bit by a dog or cat, contact a healthcare provider immediately and tell them that you were recently bitten by an animal.
People who are infected with Capnocytophaga can have a range of signs and symptoms:
- Blisters around the bite area
- Redness, swelling, draining pus, or pain at the bite area
- Fever
- Diarrhea and/or stomach pain
- Vomiting
- Headache and/or confusion
- Muscle or joint pain
In all Capnocytophaga infections the bacteria can enter the blood stream, which can lead to infection in various parts of the body (sepsis). Infection can also cause the following:
- Inflammation of the lining of the heart (endocarditis)
- Collections of pus, redness, and swelling in various body tissues (abscesses)
- Inflammation of the eyes, face, lymph nodes, or brain membranes (meningitis)
Who's at risk
Most dog or cat bites do not lead to a Capnocytophaga infection or any illness. But you should take precautions if you have contact with animals, especially if you have a condition that puts you at higher risk of infection. These conditions include:
- Having a weakened immune system (immunocompromise) from conditions like cancer, diabetes, or HIV, among others
- Taking certain medicines that weaken your immune system, such as chemotherapy
- Not having a spleen (asplenic)
- Alcohol use disorders
If any of these conditions apply to you, speak with your healthcare providers about how to be safe around dogs and cats.
Prevention
Preventing Capnocytophaga infection starts with preventing bites from dogs and cats, especially if you have a condition that puts you at higher risk of getting sick.
Treatment
Call your healthcare provider immediately after being bitten by a dog or cat. They may recommend starting antibiotics, especially if you have an higher risk of developing an infection.
If you do get Capnocytophaga from a bite, your doctor can prescribe specific kinds of antibiotics to help you recover. You may need to take more than one type of antibiotic to find the one that works best.