What you need to know about tick-borne disease in our area and how to protect your pets
Most people by now have heard about the rising problems of ticks in our area. These external parasites are attracted to mammals as they survive off of blood meals they take when biting and attaching to their hosts. These small arachnids can carry bacteria that cause disease, as well. While this post is focusing primarily on dogs, it is important to note that ticks can cause disease in many species, including humans. If you think you have been bitten by a tick, it is advised that you seek care with your primary care physician.
But back to dogs - let's talk about the diseases we see most commonly in this area, what to do if your dog is ill, and how to prevent tick-borne disease.
A Problem We See All Year
Before we get into the nitty-gritty details, it's important we talk about a few facts. First, in upstate New York, ticks are everywhere. It seems to be well understood that ticks are abundant in woodlands and tall grass, but as the years have passed, ticks have even been found in suburban and urban areas. They're adapting, and not only to their terrain, but also to the weather. Clients commonly tell us they don't worry about ticks through the colder months, but we find ticks on pets year-round. I suspect this has a lot to do with ticks adapting to a colder climate, but it is also important to remember how ticks find their next meal. Ticks go on a quest, like Nicholas Cage looking for national treasure. Just kidding. But they do perform a behavior called "questing" where they seek out heat to find their host. Heat means blood and blood means food! During the colder months, a warm body walking by stands out dramatically against the chilly air, making a host much more noticeable. This is an anecdotal observation I've made through noting that tick bites seem to increase as temperatures decrease, but this could also be due to lower client compliance with prevention and a multitude of environmental factors.
So why do we even care about ticks? Read through the whole post or select a specific tick-borne disease below to learn more.
Lyme Disease
There are three main tick-borne diseases we commonly see in upstate New York; Lyme disease, anaplasmosis, and ehrlichiosis.
Lyme disease seems to be one that most people are familiar with around here. Caused by a bacteria called Borrelia burgdorferi and spread by the Deer Tick, this disease causes varying clinical signs. The most common ailment appears as a shifting lameness between limbs that can come and go. Other signs include fever, anorexia, lethargy, generalized discomfort or ability to settle, and behavioral changes. It has been noted that Lyme disease can potentially contribute to neurologic abnormalities as well. A primary concern for me when it comes to Lyme disease is that some cases effect the kidneys and damage done there cannot be reversed. This process, called Lyme nephritis, has a guarded to grave prognosis.
Lyme disease is diagnosed through blood testing. We use an Elisa SNAP test (you'll be hearing about that a lot here!) which identifies antibodies created only by Borrelia burgdorferi. This test is great for screening for exposure, meaning that the dog was bit by a tick carrying the bacteria at some point. What this test cannot tell us is whether or not this bacteria is causing disease at that time. For example, a dog treated for Lyme disease years ago may still show up as positive despite no longer being actively infected. When a dog shows up as positive in my clinic, I recommend further testing called a C6. Simply put, this test quantifies exposure, or assigns a number to their exposure. For dogs who's value comes back higher than 30, we consider this an active infection and treatment is recommended (if a dog has clinical signs and is SNAP positive, I often start treatment while waiting for the C6 results to come back). We also often send out a urine sample to evaluate the kidneys to be sure no damage is evident there.
Treatment for Lyme disease is a 4 week course of doxycycline, an antibiotic. For patients with Lyme nephritis, doxycycline is still used to clear the bacteria from the body, however the damage to the kidneys remains, and these patients must be treated as any dog with chronic kidney disease. Some cases of Lyme nephritis are extremely severe and do result in euthanasia despite treatment efforts.
Prevention is two-fold for Lyme disease. In our area, I recommend year round flea/tick prevention (yes, even in the Winter! See above!) as well as the Lyme vaccine. This vaccine comes alone or in combination with our other recommended vaccines. Years ago, this vaccine was noted to have somewhat increased adverse reactions such as soreness, swelling of the injection site, vomiting, or lethargy, and while any vaccine can potentially cause a reaction to an individual, new products have come to market that are much less reactive than in the past. For dogs with sensitivities, I will often recommend Benadryl prior to their vaccine appointment. This vaccine is given every year.
Lyme disease in dogs can be a complicated topic. Those who are infected and treated do not develop any immunity, so I recommend all dogs be vaccinated regardless of negative or positive status. I do recommend dogs still be tested yearly to screen for potential infection despite preventative measures. Dogs who test positive and are confirmed, treated, and vaccinated, are likely to show up positive for years to come. Unless they show clinical signs, I do not recommend treating them again each year as the vaccine makes it very unlikely they are exposed again. If clinical signs are noted, or there is a lapse in vaccination, I recommend testing the C6 value again. We compare the two values and depending on the findings will discuss if treatment is necessary again. For many vaccine companies, dogs who are tested prior to vaccination and become infected after vaccination, there is often a guarantee on their product that they stand by. This varies between companies, so it is important to discuss this with your veterinarian.
Anaplasmosis
Anaplasmosis is caused by the bacteria Anaplasma phagocyotophilum which gets into the blood from the bite of a Deer Tick and hangs out in the white blood cells (Anaplasma platys is another cause of Anaplasmosis spread by the Brown Dog Tick, but is less common here than the other form). Many cases of anaplasmosis show no clinical signs and often don't require treatment, but those who are effected can appear quite ill. Signs most commonly include fever, lethargy, decreased appetite, and joint swelling or stiffness. A common symptom also includes thrombocytopenia, or low platelets, a cell necessary to stop bleeding. This can be severe and require additional therapies, depending on the case.
This disease can also be screened for using the same Elisa SNAP test mentioned above. When a patient shows up as positive in my clinic, but has no clinical signs, we often evaluate a blood smear to confirm the platelet levels are normal. If all is normal, we do not treat these patients, but monitor for any clinical signs at home and recheck a platelet count each year they show up positive. Like Lyme disease, a dog can show up as positive on a test for years after they've been exposed. If owners report that the dog has clinical signs, or we see changes to the blood smear, we often will treat them. Treatment consists of administering the antibiotic doxycycline for 2 weeks.
Unfortunately, no vaccine exists for this disease. Flea and tick prevention for pets is recommended to help reduce the risk of exposure. Ideally, all pets in the home should be treated. Even indoor-only pets can be exposed if a person or other animal carries a tick inside on their fur or clothing.
Ehrlichiosis
Ehrlichiosis is caused by the bacteria Ehrlichia canis and spread by the Brown Dog Tick. This disease has three phases, the acute phase, the sub-clinical phase, and the clinial phase. The acute phase can sometimes show no clinical signs, but when it does it can appear similar to those above including intermittent lameness or joint stiffness, neurologic signs, general malaise and fever, easy bruising or difficulty clotting blood when bleeding. If no signs are noted and the dog is truly infected, they can pass to the sub-clinical phase where the body either fights off the bacteria on it's own or develops into the clinical phase where signs of illness occurs. The illness in the clinical phase can vary dramatically, such as bleeding disorders, neurologic abnormalities, or ocular damage, to name a few.
This disease is noted less commonly in our clinic than anaplasmosis or Lyme disease. Like the others previously mentioned, we screen for Ehrlichiosis using the ELISA SNAP test. Again, this demonstrates exposure and not active infection. Currently, if our clinic finds a positive that was not positive in the past, we ask about potential clinical signs and recommend lab work to look for abnormalities suggestive of infection. If none are noted, we monitor the dog for any signs of illness and remember the patient will likely test positive for years to come in the future, just like anaplasmosis. Determining a new infection from an old exposure on the test requires careful monitoring of clinical signs and lab changes.
Treatment for this disease is also with the antibiotic doxycycline, typically for a 4 week course. There exists no vaccine for Ehrlichiosis, so again, prevention is the best measure to avoid infection.
Some Final Thoughts
Tick-borne illness can be complicated and I always recommend reaching out to your veterinarian with any concerns or questions. In this area, I do recommend vaccinating for Lyme disease and using year-round flea and tick prevention (as well as Heartworm Prevention - but we will talk about that some other time!). After discussing with a few other veterinarians in the area, we have all noticed a decreased efficacy with some of the over the counter products that have been around for years. It's suspected this is due to parasites developing a resistance to those medications. Your veterinarian will have the most up-to-date information regarding recommended products at this time.
I also wanted to take a moment to talk about cats. As mentioned above, this post is geared towards dogs, but cats can be effected to. Research conducted by Cornell University Hospital for Animals suggests that Lyme disease has limited effect on cats, though it is not entirely understood why at this time. Ehrlichiosis also does not seem to effect them nearly the way we see it effect dogs. A few cases of Anaplasmosis reported suggests that it could be serious in cats, though testing for this is much less routine and there are far more common ailments causing similar clinical signs. More research is certainly needed here, but prevention is still recommended for cats due to the poorly understood effects of ticks on cats as well as the fact that they can carry these parasites into the home on their fur, thus exptemplate-the-ultimate-guide-to-writing-the-ultimate-guideosing other members of the home.
We love hearing feedback on our posts as well as subjects you'd like us to talk about in the future! Follow us on Facebook to stay connected or send us an email at info@romanacresvet.com
Comments