A common infectious agent that arrives via a dog or cat bite is an organism called Pasteurella multocida or P. multocida.

A new look is showing one can be infected now without a bite or scratch event occurring.

Rarely is a P. multocida infection from a domestic animal bite reported by health care providers.

They simply treat it and in most cases it resolves. In bite wounds, rarely has the organism been reported to resist antibiotics, so most folks get a course of oral medication.

Untreated, a P. multocida infection usually takes off with a condition called cellulitis, which is a wound and surrounding area that is painful, red, swollen and hot.

The bad news is that left untreated, these wounds can infect deeper soft tissues and become bone infections. Accordingly, a person may need to be hospitalized and receive IV antibiotics, wound care, and perhaps surgical intervention.

Recently though, researchers published a retrospective study of 79 cases of pet-associated P. multocida infections that occurred over a 30-month period and found almost half (34) did not involve a bite from a dog or cat.

So how did these 34 people get infected?

At the American Society of Microbiology’s 2019 Microbe program, Dr. Don Walter Kannangara presented two potential routes of infection: getting dog or cat saliva in a wound and sharing food with their dog.

The man with a diabetic ulcer was admitted with a high fever, chills and shaking. He reported a small wound on his big toe was licked by his dog. Cultures grown from blood samples showed a P. multocida infection.

Dr. Kannangara got permission to scan the records across 10 member hospitals in his employer’s system. He then reviewed the charts of all 79 patients in the sample.

About 63.1 percent of patients were 50 to 80 years old. There were 45 infections associated with a bite. About 29 of those came from cats. The other 16 were dog bite cases. Curiously though, 34 cases stood out as not associated with a bite.

He identified several routes of infection. One was a person with a foot ulcer that remembered stepping in dog drool.

Another contaminated their wound by wearing socks contaminated with cat hair and dander. A third patient fell down while intoxicated and awoke to find his abrasions from the fall being licked by a dog.

Perhaps the capper was a person eating peanut butter and crackers that were left over after a pet dog had had their fill first. Yum, right?

This is not new. In June 2018, a man in West Bend, Wis., lost both hands and lower legs to amputation after being infected with Capnocytophaga canimorsus, acquired through contact with a dog, according to the Milwaukee Journal Sentinel.

C. canimorsus is another bacteria commonly found in the mouths of dogs and cats. It does not make dogs or cats sick and rarely causes disease in humans.

Especially vulnerable are people without their spleens or those that have a weakened immune system: the very young, the very old, those who are pregnant and those who are otherwise immunocompromised.

Also in Wisconsin, a 3 year-old boy had his fingers and toes amputated after being exposed to C. canimorsus, and a woman bitten by her dog developed rapidly progressing flu-like symptoms and eventually died.

The Latin quote that “Lingua canis dum lingit vulnus curat,” or “A dog’s saliva can heal your wound,” is complete nonsense.

So please, don’t cart your skinned-knee children off to wound-licking parties at someone’s house because they have a dog and you think “natural” is better.

Charlie Powell is the public information officer for the Washington State University College of Veterinary Medicine, which provides this column as a community service. For questions or concerns about animals you’d like to read about, email cpowell@vetmed.wsu.edu.

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