Bartonella henselae is a bacterium responsible for a number of illnesses. It is perhaps best known as the agent of cat scratch disease or cat scratch fever, but it can also cause bacillary angiomatosis, bacteremia, endocarditis, and peliosis hepatis. Bartonella is one of the most common genera of bacteria in the world, and Bartonella henselae has a worldwide distribution.
People are usually infested with Bartonella henselae through felines. The bacteria naturally live in cats without causing them any harm. Fleas and ticks are a vector for the bacteria among cats, and humans can also be infected through ticks. Bartonella henselae also lives in the feces of fleas, which can infect humans if it comes into contact with a mucous membrane or a wound, such as a cat scratch.
Cat scratch disease, also known as cat scratch fever or bartonellosis, is usually innocuous and self-limiting, though it may be treated with antibiotics. In some cases, however, the disease can have serious symptoms. Bartonella henselae infection is most common in children who have recently suffered a cat bite or scratch.
Occurrences of cat scratch disease may be classified as classic or atypical. In the classic variety, patients suffer from lymphadenopathy, or swollen, tender lymph nodes. There may also be a papule at the site of infection. Other common symptoms are fever, headache, chills, backache, and abdominal pain, but not all patients experience such systemic symptoms.
Atypical cat scratch fever is a more serious condition. People with compromised immune systems are more likely to develop atypical symptoms following a Bartonella henselae infection. Atypical cat scratch disease may surface as Perniaud's Syndrome, consisting of conjunctivitis and swelling of the lymph nodes behind the ears. It can also cause neuroretinitis, nerve damage and pain in the eyes.
Bacillary angiomatosis is another possible symptom of cat scratch disease in those with compromised immune systems, particularly those with acquired immunodeficiency syndrome (AIDS). Bacillary angiomatosis is characterized by angiomas, or small, benign tumors or lesions. While they most often appear on the skin, the angiomas can also affect the brain, bone, bone marrow, gastrointestinal system, liver, lymph nodes, respiratory system, or spleen. The condition is usually painful and can be fatal if not treated. Bacillary angiomatosis can be cured with antibiotics, or a combination of antibiotics and bactericide if necessary.
A similar condition that can arise from Bartonella henselae infection in immunocompromised individuals is bacillary peliosis, a form of peliosis hapatis. This condition is characterized by numerous blood-filled cavities in the liver, and sometimes in other structures of the body as well. It is also treated with antibiotics.
Bacteremia, or bacteria in the blood, is another possible consequence of Bartonella henselae infection. It can cause blood poisoning, which, if untreated, can lead to multiple organ failure. In the most extreme cases, B. henselae infection can cause endocarditis, an inflammation of the inner layer of the heart, or acute encephalopathy, generalized brain dysfunction. Luckily, any illness caused by B. henselae can usually be completely cured with antibiotics as long as it is caught early enough.