It Really Ticks Me Off...
When I started practicing medicine in the dark ages (pre-iPhones) in Chicagoland, the only time I would ever see a tick is after a family came home from a camping trip or a weekend getaway in Wisconsin. Over the past few years, however, ticks have arrived in Chicago.
We have seen several dogs this year with ticks on them, and they haven’t gone farther west than the Kennedy.
Of course, ticks themselves don’t cause the problem: it’s what lurks inside their stomach that can be deadly.
Tick Vomit: Gross and Dangerous
That’s right, tick vomit—or really tick regurgitation into an animal’s bloodstream—is what causes tickborne diseases. A tick attaches to the animal it encounters and embeds its little head into the skin to start their blood meal. When the blood reaches the tick’s stomach, it activates the bacteria that causes the disease. Then the tick regurgitates the bacteria into the animal’s blood.
Depending on the tick and the bacteria, this process can take anywhere from 1 to 2 days. Most preventatives work by killing the tick before it has time to transfer the bacteria into the animal’s bloodstream.
What Does Tickborne Disease Look Like?
There are several different types of bacteria that cause what we call tickborne diseases, but they mostly all belong to the Rickettsial or Borrelia families. The most commonly seen diseases are Lyme, ehrlichiosis, anaplasmosis, and Rocky Mountain spotted fever. There are several other types, though less prevalent in the United States.
These diseases can present in a few different ways. Typically, the pet has fever and lethargy, but these diseases can get into the joints, causing a shifting lameness and puffy joints, a meningitis that can lead to head pressing, or other neurologic signs. They can also cause problems with platelet levels, leading to bruising or more serious issues.
Most of these clinical signs can be resolved with supportive care and the right antibiotic therapy. Unfortunately, dogs can—though rarely—get Lyme nephritis, which can lead to permanent damage of the kidneys and even death.
How Can We Know If Our Animal Was Exposed?
Diagnosis can be a bit tricky. To be honest, experts disagree on the best protocol and test to see if your animal has encountered one of these bacteria.
The most common test that we have in our arsenal is ELISA antibody testing (Idexx 4dx or Antech Accuplex). These tests identify if your dog has antibodies for Ehrlichia, Anaplasma, and Lyme. A positive means that your pet has come into contact with the bacteria, but it doesn’t necessarily mean that have the disease.
A lot of dogs will be able to fight off this disease and will have a positive antibody test, but never become sick. But these bacteria are sneaky little devils. They can lie dormant for months before causing an issue if they don’t cause immediate illness.
It can also take a few weeks if not months for the body to build up an antibody response, so this test may be negative immediately after you find a tick on your pup. We usually recommend getting a baseline test at time of exposure and test again no less than 6 weeks after the tick was found. If we think your dog is sick with a tickborne disease, we may recommend additional tests as well.
When Do We Treat?
This is another topic still being debated in the veterinary community. Some veterinarians believe that any positive test should be treated with antibiotics, while others say only treat when there are clinical signs. Still others say additional testing is needed.
At this time, we recommend treating with antibiotics when there is concern for an active infection, meaning your dog is acting sick. Treatment is usually a course of an antibiotic called Doxycycline.
—Dr. Alyssa Kritzman