A 15-year-old girl in a rural community has swollen, painful lymph nodes in her right axilla. Physical examination reveals multiple scratches on her right arm with a papule associated with one of the scratch marks. She states that the scratches occurred about 5 days ago. What type of animal is the most likely source of the infection?
This patient has the classic symptoms of cat scratch disease caused by the bacillus Baonella henselae. The disease is self-limited with the onset of symptoms occurring 3-10 days following an inoculating scratch. The organism can be isolated from kittens, typically less than 1 year of age, or from fleas. A history of a new kitten in the house and the papule at the site of a scratch with regional painful adenopathy defines the classic scenario. Chickens can harbor Salmonella spp. producing a gastroenteritis or enterocolitis. Chicken guano is also a orable environment for the fungus Histoplasma capsulatum. The mycelial phase thrives in the rich soil. The human disease is a granulomatous infection involving the lungs and mimicking tuberculosis. Dogs or puppies carry Capnocytophaga canimorsus as pa of the normal flora of the oral cavity. Infections from licking or biting range from a self-severe infections are those with asplenia, alcoholism, or hematologic malignancies. This organism is also associated with cat bites, but the patient develops cellulitis and fulminant septicemia, especially in asplenic patients. Pasteurella multocida is another pathogen that colonizes the nasopharynx and gastrointestinal tract of cats and dogs. Cats have the highest rate of colonization (50-90%), followed by dogs (50%), swine (50%), and rats (14%). P. multocida most commonly causes a localized soft tissue infection or cellulitis after an animal bite, but systemic symptoms may be present in about 40% of the cases. These symptoms include osteomyelitis, septic ahritis, or tenosynovitis. Horses and horse manure have been associated with a pulmonary oppounistic infection with cavitation caused by Rhodococcus equi that resembles tuberculosis in immunocompromised patients. Burkholderia mallei (the cause of glanders) is characterized by non-caseating granulomatous abscesses of skin, lymphadenopathy, and pronounced involvement of the lungs. Ref: Levinson W. (2012). Chapter 20. Gram-Negative Rods Related to Animal Sources (Zoonotic Organisms). In W. Levinson (Ed), Review of Medical Microbiology & Immunology, 12e.
Cat or kitten
Chicken
Dog or puppy
Horse