When to start worrying that a dog bite (or lick) might kill you

Most pup interactions are harmless, but serious infections can happen.

You might think your dog’s mouth is gross, and in some ways it is—but it’s not much worse than you own. A moist, warm climate means human and pup maws are both attractive homes for many species of bacteria, and the constant flow of nutritious substances keeps those microbes thriving. But any kind of bite—including one from another human—can prove dangerous, so it’s no surprise that canine-inflicted wounds sometimes turn nasty. Even a simple lick from your precious pup can cause trouble.

An Ohio woman recently contracted a rare infection after her German Shepherd gave her kisses that swept over an open wound. Days later she ended up in the emergency room, delirious, and had such a serious case of Capnocytophaga that doctors amputated her legs and hands.

Capnocytophaga bacteria live in dogs’ mouths naturally, causing no harm to the canine hosts, but they’re pathogenic to humans. There are plenty of these types of bacteria, and yet the majority of dog bites aren’t hazardous, apart from the puncture marks themselves. And licks, of course, are even less likely to cause infection. It’s only when a dangerous microbe gets into a deep wound that folks get sick. Even Capnocytophaga infections mostly cause minor symptoms—the patient in Ohio was an extreme anomaly. It’s generally only people with weakened immune systems who get truly ill from Capnocytophaga.

Most often, nothing terrible will happen to you from contact with a dog, even if they take a nip at you. But if a bite breaks the skin, you should still see a doctor. Serious infections may be rare, but proper prevention is key to keeping that rate low. Here’s what else you should look out for if you get a dog bite—or even a simple kiss.


More than half of all infected dog bite wounds feature Pasturella, making it the most common source of infection. The symptoms are usually pretty localized—think redness, swelling, and tenderness—but there can be more serious complications if left untreated. Swollen lymph nodes and fevers are among the milder ones, but young kids especially can get meningitis or pneumonia.


Methicillin-resistant Staphylococcus aureus is usually something you get in hospitals or from dirty wrestling mats, but it can also sometimes live in dogs’ mouths. It’s not very common, so MRSA isn’t a major concern for bite wounds. The issue is more that if you do get infected, it can become quite serious. Most MRSA infections are limited to the skin and can be treated fairly easily. Doctors start to worry when the bacteria get into the bloodstream, which is much more likely to happen via a deep wound. That can lead to sepsis, which can be deadly.


Though you might think of tetanus as something you get from rusty metal, that’s actually not at all where Clostridium tetani live. The bacteria inhabit dirt and dust—and dogs’ mouths. Tetanus infections aren’t common, but around 10 percent of cases are fatal. If it’s been more than a decade since you last had a tetanus vaccine, you should go get a booster. Clostridium tetani is absolutely everywhere.


Rabies is effectively 100 percent fatal. Let that soak in for a second. With the advent of widespread immunization it’s now exceedingly rare—there were only 125 cases in the U.S. between 1960 and 2018—but it’s still a major concern simply because just about everyone who gets rabies dies, unless they’re given a vaccine dose within a day or so of exposure. That prophylactic measure can save your life, which is why most doctors will give people who come in with dog bites a shot just in case. That’s why you should go see a doctor if you get a skin-puncturing bite, no matter how serious you think it is.

And if you’ve got an open wound or two—scratches, gashes, bug bites you’ve scratched into a bloody mess, or whatever else—consider keeping your pup from slobbering all over you until they heal. If that’s a fate too tragic to bear, then practicing good wound care with antiseptic and wrappings should minimize any risk.