Cat scratch disease is an infectious disease, which came after a cat scratch (which caused a skin lesion), manifested by painful regional lymphadenopathy and persistent (may persist for weeks or months). If the infection disseminates, the patient will present generalized adenopathy, often confused with leukemia disease situation. The symptoms of cat scratch disease is initiated by inoculation of B. henselae bacilli. Since cat is not a natural reservoir for pathogenic species B. quitana, there is clear evidence of the involvement of bacteria in the development of cat scratch disease.

More than half of cases of disease occur in childhood. Risk of infection increases significantly when children are exposed to contact with cats shows asymptomatic bacterium, or are infested with fleas. Usually, bacteria are inoculated through a wound caused by broken, and in rare cases the bite or saliva of cats. Disease incidence increased dramatically in the warm months of the year when fleas develop an intense activity of parasite. Flea plays a significant role in pathogen transmission from a sick to a healthy cat. There is insufficient evidence attesting to human host disease transmitted through flea bites.

-Clinical symptoms of cat scratch disease
Average incubation period of the disease is more than five days. Scratch at the patient shows a popular lesion that later will turn into a pustule (vesicular lesions filled with pus), covered with scabs. At 7 days after pathogen inoculation, regional lymph nodes will be large in volume and become sensitive to touch. After a week of evolving, papulous may resolve spontaneously.

Frequently, solutions of continuity (wounds) caused by scratch it locates the upper limbs and face. The patient may develop simultaneously, a new bacterial infection with staphylococci and other skin pathogens. Regional lymph nodes can increase the discharge volume. Usually the patient has fever, but may present variable systemic symptoms: weight loss, anorexia (lack of appetite) and malaise. If a treatment will be set up quickly, adenopathy can persist for several months and can be confused with adenopathy in leukemia (lymphatic malignant diseases).

Other events occurring in immune-competent patients: encephalitis, convulsions, coma (especially in children), meningitis, myelitis, hepatitis, osteomyelitis and septicemia. If the pathogen is inoculated by conjunctive, the individual will present painful conjunctivitis and preauricular adenopathy.

-Pathology
On anatomic-pathologic examination, the affected tissue will present lesions characteristic of granulomatous inflammation accompanied by necrosis starry. Angiogenesis lesions are absent. Thus, depending on the host's immune status, bacillus B. henselae, infectious diseases can cause two distinct cat-scratch disease and bacillary angiomatosy skin.

-Diagnosis
Cat scratch disease may be suspected when a patient tells the recent history of contact with a potentially sick cat, skin lesions (scratches upper limbs and the face), and adenopathy sensitive to touch, will strengthen the clinical suspicion. Positive diagnosis is confirmed by results of histopathological examination of regional lymph nodes increase the volume. Warthin-Starry stain allows the observation of unit’s pathogen on the optical microscope. Serological tests used to identify antibodies have a sensitivity of 80%. Polymerase chain reaction (PCR) can identify the 16S ribosomal RNA genes of the species B. henselae. It had tried making crops using biological material from the affected nodes, spinal cerebrospinal fluid or other tissues, but they rarely were positive for B. henselae.