Cat scratch disease is a bacterial infection caused by Bartonella henselae bacteria. Most infections usually occur after scratches from domestic or feral cats, especially kittens. CSD occurs wherever cats and fleas are found. The most common symptoms include fever; enlarged, tender lymph nodes that develop 1–3 weeks after exposure; and a scab or pustule at the scratch site. In the United States, most cases occur in the fall and winter and illness is most common in children less than 15 years old.