Capnocytophaga questions keep coming in. I guess that’s good in some ways, because I usually get a lot of blank stares when I mention that bacterium. A recent article about the risks of Capnocytophaga and exposure to dog saliva includes some good information about the topic, but the statements below highlight some issues:
It’s important to see a physician if you’ve been bitten by a dog, especially if it hasn’t been vaccinated against rabies.
Not really. Rabies vaccination has very little to do with the response to a bite. Yes, if the dog was vaccinated it reduces the risk that it had rabies, but since it’s not a guarantee, one of two things generally still needs to happen: either the dog needs to be tested (which requires euthanasia) or the dog needs to be observed to make sure it’s still clinically normal 10 days later (meaning it couldn’t have been shedding rabies virus at the time of the bite). Regardless of the rabies risk, there is always some risk of infection from bacteria in the dog’s mouth. Antibiotic treatmemt decisions are based on the location of the bite and the health status of the person. Seeing a physician after a bite is important, from an antibiotic standpoint, in:
- People who are immunocompromised (including pregnant women)
- Bites over the hands, feet, joints, face, bone, surgical implants or the genitals
Severity of the bite is only part of the decision. A very minor bite in a high risk person or a small puncture wound over a joint may pose much more risk than a big flesh wound in an otherwise healthy individual.
Those with weakened immune systems who have difficulty fighting off infections are at greater risk of becoming ill (such as those with cancer, diabetes or an HIV infection).
This may be true, but that’s not the main issue. These groups are at increased risk for various infections in gerenal, but evidence of a major risk from Capnocytophaga specifically is limited. The main risk group for this bacterium, by far, is people who have lost their spleen.
The best way to find out if your dog or cat carries this bacteria is to have a veterinarian run a test. That said, “a negative result may not mean the animal will always be negative, and the same is true for a positive result,”
No/yes. No, testing doesn’t make any sense. Most dogs are carriers and testing isn’t simple. So, a negative result may be a false negative. The correct part of the statement above is that even a true negative result may not mean the animal will always be negative.
When it comes to Capnocytophaga, a few things needto be highlighted:
- Assume all dogs are carrying it in their mouths, so every bite or contact of saliva with broken skin or mucous membranes is a risk for exposure.
- People who are at high risk for Capno infections (most notably splenectomized individuals) need to know that they need antibiotics after any bite or exposure of saliva to broken skin. The risk from Capno is very low in the rest of the population.
- People at high risk for Capno also need to make sure their healthcare provider knows they’re at increased risk if they have signs consistent with Capno infection, especially after a known saliva exposure.
- Healthcare workers need to know this bug exists.
- Healthcare workers need to ask about animal contact routinely and pay particular attention to it when presented with a high risk patient.
- Testing of dogs makes no sense. I’ll do it for free right now:
“your dog is carrying Capnocytophaga.”
- Treating dogs for this bug won’t help. Trying to eliminate a bacterium that has evolved to live in a dog’s mouth is probably futile.
- A little common sense goes a long way. Knowing your risk status, improving dog training and handling to reduce bites, proper bite first aid and some basic awareness by healthcare providers are easy and probably highly effective preventive measures that are often overlooked.
More information about Capnocytophaga and about bites is available on the Worms & Germs Resources – Pets page.