Aching joints. Pounding head. Running in sweat. These are signs anyone who's had a fever will be familiar with. But what exactly is a fever and why do they happen?
A fever is when the body's temperature is raised above normal. This is usually the result of an infection and is part of the body's defense mechanism.
The invading bacteria are recognized by the immune system's white cells, which set about fighting the bug. To do this, they release substances called pyrogens, which are a chemical messenger that resets the body's thermostat to a higher setting. This makes the body a more hostile place for the bacteria and aids the work of the immune system.
So, if infection is the main cause of fever in people, is your dog at risk of catching it from you?
Can Dogs Get a Fever from Humans?
No, the vast majority of the bacteria and viruses that make people sick, stick to making humans unhappy. Likewise with dogs, the majority of fever inducing bugs that make our canine companions sick, stay with that species.
Dogs can get a fever, but it's most commonly a result of a dog-to-dog infection.
Does My Dog Have a Fever?
Let’s imagine your dog is acting unwell. You check their temperature and the thermometer reads 102.4. Does the dog have a fever? No, they do not.
This is a trick question because while this is high for a person, it's normal for a dog. People and dogs have a different range of 'normal'. Whereas 102.4 is well above normal for a person, for our fur friend this is perfectly acceptable. Here are those ranges for reference:
Human: 97.8 to 99.1°F, considered a fever above 100.4°F
Dog: 100.5 to 102.5°F, considered a fever above 103°F
Now we've got that straight, if the dog is feverish after all, what could be the possible causes?
Bacterial or viral infection: Many common infections are linked to fever as one of the symptoms
Inflammation: Conditions such as pancreatitis, with severe inflammation of the pancreas, can cause a dog to be feverish
Encephalitis: Inflammation can reset the brain's thermostat to a higher setting
Heat Stroke: The body cannot lose enough heat to stay cool
Cancer: Some tumors give off pyrogens, which elevate body temperature
To learn more about the symptoms and diagnosis of each condition, follow the link to a detailed guide.
How Do I Treat My Dog's Fever?
It's important that any dog with a fever sees a vet. While most pets cope well with a fever for a short period of time, there is a risk of dehydration, or worse, if the dog remains feverish for a long time.
Ideally, the cause of the fever is identified and treated directly. For example:
Pancreatitis: Pain relief, antiemetic medications, intravenous fluids
Infections: Antibiotics where appropriate, and anti-fever medications
Sepsis: Internal infection, such as pus in the womb (pyometra) of female dogs requires hospitalization
Encephalitis: Antibiotics or steroids as appropriate for the causative agent
Cancer: Chemotherapy medications.
In addition, keep the dog in a cool (but not cold) place, with a choice of places to lie so they can regulate their own temperature. Make sure drinking water is freely available and talk to your vet about medications to reduce the fever.
How Is a Fever Similar in Dogs and Humans?
In much the same way we feel lousy when running a fever, the same is true for dogs. They will:
Tend to lack energy
Lose interest in food
Seem listless and have difficulty settling
How is a Fever Different in Dogs and Humans?
Fever is different in people in the following ways:
Dogs don't sweat; a person with a fever tends to be bathed in sweat, this doesn't happen for dogs
Don't use human 'normal' reference ranges of temperature to decide if your dog has a fever
A pet parent is worried about his female Poodle who is listless and drinking a lot, but refusing to eat. He checks her temperature, which is 103.5F. Thinking she might have a bug, he takes his dog to the vet. An examination raises suspicion of a womb infection called 'pyometra'. Blood tests point toward sepsis and an ultrasound scan of the womb shows it to be distended and full of fluid. At exploratory surgery a large pyometra is confirmed and the womb removed. The dog takes a course of antibiotics while recuperating from surgery and happily makes a full recovery.