Although most people have heard of Lyme Disease, not many know about another dangerous tick-borne illness that can cause serious complications in our dogs – Tick Fever.
Tick Fever, also known as Ehrlichiosis, is found worldwide and has been reported in almost every state in the U.S. It’s caused by a tiny organism called rickettsia, which is a type of bacteria that has evolved to behave more like a virus, in that it can actually take over living cells and grow inside them.
The 2 most common forms of rickettsia causing Ehrlichiosis in dogs and their wild wolf cousins are Ehrlichia canis (which is transmitted by the Brown Dog tick, and is by far the most prevalent) and Ehrlichia ewingii (transmitted by the Lone Star tick).
How Do Dogs Become Infected With Tick Fever?
When ticks feed on an animal infected with Ehrlichia, they also become infected. Ehrlichia can remain alive in the tick for up to 5 or 6 months before being passed on to another host.
When an infected tick bites a dog, it immediately begins injecting its saliva into the dog’s skin. This saliva not only has an anesthetic effect (which allows the tick to bite without its host noticing), it also contains a cement-like material to keep the tick stuck to the skin AND an anticoagulant to keep the dog’s blood from clotting so the tick can continue to feed for days. All this is very bad news for the dog, since it only takes 3-6 hours for the Ehrlichia to be transmitted through the tick’s saliva into the dog’s bloodstream. Sadly, it only takes a single bite for a dog to become infected.
Once in the bloodstream, the organism begins to multiply and spread. From there, it can take between 8 and 20 days for the dog to show the first signs of Tick Fever.
Tick Fever Symptoms
Symptoms of Tick Fever can be vague and mild at first. The disease is typically divided into 3 distinct stages:
The Acute Phase
During the earliest stage of Tick Fever, dogs may suffer from low-grade fever, swollen lymph nodes, unexplained bruising, loss of appetite, joint pain, nasal discharge, or difficulty breathing. This stage can last anywhere from 2 to 4 weeks, at which point the dog can appear to recover.
The Subclinical Phase
During this phase, the organism is still present, but it’s not causing any signs of infection. It takes up residence in the dog’s spleen, where it remains quietly dormant. The dog can remain in this phase for anywhere from several months to years, during which he appears to be back to normal and healthy. It’s at this stage that some dogs are actually able to fight off the organism and make a true recovery.
The Chronic Phase
If the dog is not able to fight off the disease, the chronic phase begins. During this time, the dog is at risk of serious complications, including:
- Anemia (not enough red blood cells, which carry oxygen)
- Bleeding episodes caused by a massive decrease in platelets, the blood-clotting cells
- Eye inflammation (including uveitis, retinal disease, damaged corneas, and hemorrhages inside the eye)
- Swollen legs
- Tender abdomen, usually due to an enlarged liver
- Kidney problems
- Neurological issues
- Bone marrow failure
Since the bone marrow manufactures all the blood cells needed to sustain life (including red blood cells, white blood cells, and platelets), if the bone marrow fails, the dog will most likely die.
Diagnosing Tick Fever
Tick Fever can be notoriously difficult to diagnose, especially during the early stages. Most dogs don’t make it to a veterinarian until they are already in the chronic stage of the disease, when the symptoms are at their most severe.
Diagnosis is usually made based on a history of tick exposure, what symptoms are present, blood work that shows a low platelet count, and a separate blood test that shows whether specific antibodies against the disease are present.
Since a dog’s immune system takes at least 2 to 3 weeks to produce antibodies against Tick Fever, early blood tests may come back falsely normal. Because of this, veterinarians often recommend doing a second test several weeks later to make sure the initial negative result is still negative.
This is why many veterinarians recommend that if you see an engorged tick (one that is full of blood) on your dog, you should have your dog tested for Tick Fever around 8 weeks after finding and removing the tick.
Treating Tick Fever
The treatment for Tick Fever depends on how severe the symptoms are at the time of diagnosis. Dogs who are experiencing severe bleeding problems may need IV fluids and a blood transfusion to help make them strong enough to continue treatment. For dogs with eye diseases caused by Ehrlichia, corticosteroids can be prescribed to help decrease inflammation in the eyes.
The only way to truly get rid of the Ehrlichia organism is with an antibiotic. The current drugs of choice for treating Tick Fever are Doxycycline and Tetracycline, which are usually given for 3 weeks to several months.
Dogs who receive treatment in the acute (early) phase usually show improvement within 24 to 48 hours after starting treatment. For dogs in the chronic phase, it can take up to several months for them to visibly recover.
What’s The Prognosis For Dogs With Tick Fever?
As with most diseases, early detection and treatment can greatly improve a dog’s chances of surviving Tick Fever. Dogs with good immune systems can make a full recovery, although they may still remain susceptible to reinfection.
Older dogs, those with weak immune systems, or those who are experiencing bone marrow problems have a much more guarded prognosis. Interestingly, German Shepherds and Doberman Pinschers seem to have more severe reactions to Tick Fever, and tend to have a poorer prognosis than other breeds of dogs.
Fortunately, however, a dog who recovers from Tick Fever can go on to lead a normal, healthy life, as long as he doesn’t become reinfected from the bite of another infected tick.
Preventing Tick Fever
Unfortunately, at this time there is no vaccine to prevent Ehrlichiosis. However, there are several things you can do to lower your dog’s risk of developing Tick Fever.
Unlike other ticks that feed on many different types of hosts, the Brown Dog tick only feeds on dogs and thrives in areas where dogs hang out. Therefore, getting rid of the ticks on your dog and in your dog’s environment is the most effective form of protection.
There are many ways to reduce the number of ticks on and around your dog. These include:
- Using veterinary spot treatments that are placed directly on the dog’s skin. These not only repel ticks, they also kill any ticks that may already be on your dog. Be sure to ask your veterinarian which products are the safest for your dog.
- Using tick repellents such as tick sprays, shampoos, and dips.
- Periodic use of household and lawn tick treatments, such as sprays and granules. Several non-chemical options, such as Diatomaceous Earth, are safer than chemical sprays and very effective at killing both ticks and fleas.
- Keeping your yard as inhospitable to ticks as possible by mowing your lawn very short, keeping bushes trimmed, and removing piles of vegetation and debris.
- Diligently safety-checking your dog for ticks after being outside in parks or wooded areas, and immediately removing any ticks that you find.
For a more complete list of how to protect your dog against ticks, including a step by step guide on safely removing ticks, please check out my article “10 Ways To Get Ticks Off Your Dog.”
Can Humans Get Tick Fever From Dogs?
The good news is, you can’t catch Ehrlichiosis directly from your dog. However, you CAN catch it if an infected tick bites you, so keeping ticks off your dog will not only protect him, but will help protect you as well. Ticks are notoriously hardy and can live both indoors and out, so keep a diligent eye out for any signs of tick activity in your environment.
Remember, the longer a tick is attached to your dog’s skin, the greater the risk of him developing Tick Fever. If you find a large, engorged tick on your dog, remove it immediately and let your veterinarian know. It may be a good idea to have him tested for Ehrlichiosis about 8 weeks later to make sure he is free of disease.
Has your dog ever been diagnosed with Tick Fever? Please share your story with us in the comments below!