A Wisconsin man made international headlines this week after a dog lick led to a rare infection resulting in the amputation of part of his legs and arms.
Greg Manteufel, 48, was diagnosed with a blood infection from capnocytophaga canimorsus, a bacteria found in dog and cat mouths. Doctors believe Manteufel became infected after a dog licked him.
Manteufel’s case was serious, but experts say most people have an extremely small risk of contracting a similar infection from their pet ― and it’s certainly no reason for anyone to give up a beloved companion.
“I would never, ever think that somebody should give up their dog or cat,” said Jennifer McQuiston, a veterinarian and epidemiologist for the Centers for Disease Control and Prevention.
What is capnocytophaga canimorsus, exactly?
Capnocytophaga is a bacteria commonly found in the mouths of dogs, cats and even humans, and is considered “normal oral flora,” according to the CDC. Up to 74 percent to dogs and 57 percent of cats have some form of capnocytophaga in their mouths.
There are many species of capnocytophaga. One of those species ― capnocytophaga canimorsus, commonly found in dog and cat mouths ― can potentially cause serious infection when transmitted to humans.
It’s possible to test pets for the presence of the bacteria, but such tests usually aren’t very helpful because an animal might have the bacteria one day but not have it the next, according to the CDC. And it’s not practical to treat animals with medicine to get rid of the bacteria because it’s a normal part of their biology.
How do people get it?
People typically contract capnocytophaga canimorsus from an animal bite, usually a dog bite. Some people, like Manteufel, become infected without a bite, if an animal carrying the bacteria licks them and the saliva comes into contact with a mucous membrane or an open area on the skin, like a cut.
Since the bacteria is so common, should I be worried?
Generally, no. The bacteria is common, but becoming seriously ill from an infection is not.
“It’s just really, really, really rare,” said Scott Weese, a professor at Ontario Veterinary College’s Centre for Public Health and Zoonoses. “The risk posed by a dog is really low. Most dogs are carrying this bug in their mouth, but few people get sick.”
Experts don’t know exactly how many people get infected with capnocytophaga annually because there’s no centralized record of cases. But all agree that serious infections are extremely uncommon.
That said, some people are more at risk than others.
Who is most at risk?
People who have lost their spleen and people who are immunocompromised are more likely to get sick from the bacteria.
Anyone in those groups should be more aware of the possibility of infection from animal bites. For instance, a person without a spleen should go to a doctor for any dog bite, even a “little nip” that most people wouldn’t need to worry about, Weese said.
And anyone with a weakened immune system should talk to their doctor about extra precautions they should take around animals in general and come up with a plan for if they do get sick.
What is an infection like?
Symptoms can include redness, swelling or pus around the bite wound, fever, diarrhea, stomach pain, vomiting, headache, muscle pain or joint pain. Ultimately, it can lead to gangrene that necessitates amputation, or sepsis, organ failure or death. The CDC notes that 3 out of 10 people who get the infection die.
“Part of [the fatality rate] is, it’s just a really nasty bug,” Weese said. “People go from healthy to really sick really quickly.”
Doctors also may not recognize the illness, since the early symptoms can be confused with more common ailments like the flu. Patients often don’t realize it’s relevant to tell doctors about factors like not having a spleen, and doctors often don’t ask about recent contact with animals.
Weese added that it’s possible the illness isn’t as deadly as the fatality rate suggests. The rate is based only on statistics from people who have been diagnosed, and there may be people who get a mild infection and recover without ever determining the real cause.
“If it causes a sporadic flu-like illness, that’s never going to get diagnosed,” he said.
OK, are you sure I shouldn’t panic over this?
Every so often, a news story involving a rare but scary illness ― often one that leads to amputations ― starts making the rounds. But usually, these incidents are not something that should cause most people to panic.
“Sometimes people can really get scared when they see media reports,” McQuiston said. “What we don’t want to see is people overreacting to such rare events.”
Whether such stories are helpful or harmful really depends on the message readers take away from them.
It’s bad if people “look at their dog and think it’s going to kill them” after reading about capnocytophaga, Weese said. But he said it’s good if they become generally aware that animals can transmit illness and that it’s good to take some common-sense precautions like avoiding animal bites and not letting pets lick open wounds or broken skin.
Both Weese and McQuiston have pets, and both emphasized that the risk of capnocytophaga is not a major concern for most people. For them, the benefits of having pets in their lives far outweigh the risks of any kind of animal-borne illness.
“I think pets are really important parts of many of our lives, and they bring us really positive health benefits in addition to companionship,” McQuiston said.