August 02, 2016

Some Feline Respiratory Infections Can Cross Species Lines

Cats can transmit several different respiratory pathogens to humans. Recognizing these diseases can help veterinarians appropriately treat feline patients and counsel clients about preventing zoonotic transmission.

By Amy Karon, DVM, MPH, MA


Bordetella bronchiseptica, the small aerobic coccobacilli that cause kennel cough, can be transmitted from both cats and dogs to humans through respiratory droplet transmission.11,12 However, zoonotic transmission is uncommon, unless human patients are immunocompromised.11 In one review of eight human cases of B. bronchiseptica transmission over a 15-year period, three cases involved cat exposure, including exposure to a coughing cat.11 The human patients typically had serious comorbidities that increased their susceptibility to infection, including chronic obstructive pulmonary disease, cystic fibrosis, and AIDS.11 Symptoms in humans ranged from bronchitis to severe pneumonia, but none were fatal.11


Pasteurella multocida, a gram-negative coccobacillus, is a commensal organism of the oral cavity in cats. However, P. multocida can also cause subcutaneous abscesses, secondary respiratory infections, and pyothorax in cats.13 Humans can acquire P. multocida infection not only from bites or scratches, but also from close contact with secretions or contaminated aerosols.13
In one recent report, three humans developed life-threatening P. multocida infections after providing intensive palliative care for their dying dogs and cats.14 None of these cases involved a known bite or scratch. In one case, an owner became infected after both she and her dying pet consumed honey from the same dropper.
Although such cases are rarely reported, they may be more common than the literature indicates. It is only possible to establish an epidemiologic link by taking a very detailed history, according to Joseph Myers, MD, FACP, FIDSA, professor of internal medicine at Northeast Ohio University, who reported the nonbite pasteurellosis cases.


Cases of cat-human zoonotic respiratory transmission underscore the importance of isolating cats whenever they are in the acute stages of respiratory infection. In addition, veterinarians should reinforce common sense messages about infection control, particularly when owners are caring for ill animals, Dr. Myers emphasized. Pet owners should consistently wash their hands before and after contact with these animals and should avoid exchanging oral secretions with pets.
Dr. Karon earned her doctorate in veterinary medicine and master’s degrees in public health and journalism from the University of Wisconsin-Madison. She was an infectious disease epidemiologist and “disease detective” (EIS officer) with the Centers for Disease Control and Prevention before becoming a full-time medical writer. She lives in the San Francisco Bay area, where she volunteers for the local Humane Society.
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  10. Cesare AD, Castagna G, Otranto D, et al. Molecular detection of Capillaria aerophila, an agent of canine and feline pulmonary capillariasis. J Clin Microbiol. 2012;50(6):1958-1963. doi: 10.1128/JCM.00103-12.
  11. Wernli D, Emonet S, Schrenzel J, Harbarth S. Evaluation of eight cases of confirmed Bordetella bronchiseptica infection and colonization over a 15-year period. Clin Microbiol Infect. 2011;17(2):201-203. doi: 10.1111/j.1469- 0691.2010.03258.x.
  12. Mattoo S, Cherry JD. Molecular pathogenesis, epidemiology, and clinical manifestations of respiratory infections due to Bordetella pertussis and other Bordetella subspecies. Clin Microbiol Rev. 2005;18(2):326-382.
  13. Lloret A, Egberink H, Addie D, et al. Pasteurella multocida infection in cats: ABCD guidelines on prevention and management. J Feline Med Surg. 2013;15(7):570-572. doi: 10.1177/1098612X13489215.
  14. Myers EM, Ward SL, Myers JP. Life-threatening respiratory pasteurellosis associated with palliative pet care. Clin Infect Dis. 2012;54(6):e55-e57. doi: 10.1093/cid/cir975.

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