Bartonella henselae is a type of bacteria that can cause infections in humans. It is primarily transmitted through scratches or bites from infected cats, particularly kittens. This bacterium is known for causing cat scratch fever, which can lead to symptoms like fever, swollen lymph nodes, and fatigue. In most cases, infections caused by Bartonella henselae are mild and resolve without treatment. However, in some individuals, especially those with weakened immune systems, it can lead to more serious health issues. Diagnosis typically involves blood tests, and treatment may include antibiotics if necessary.