Tick-Borne Disease in Pets
Helping our pets with tick-borne disease is tricky because our pets can’t talk…
Tick-borne disease in Dogs
In our area, most veterinarians screen dogs for heartworm disease yearly. Most commonly, a tick test is bundled with heartworm testing at the same time. The most common test performed combines testing for Canine Heartworm, Lyme Disease, Anaplasmosis, and Ehrlichiosis. The most popular test is called a 4DX by Idexx Laboratories. Because this has been common practice for years, veterinarians have a deep experience with these infections. Carlisle is a location where a very large percentage of the ticks are Ixodes scapularis which is known as the Deer tick. Consequently, a large percentage of dogs have been exposed and will test positive for Lyme and Anaplasmosis. Other ticks are also present but in lesser numbers.
Most local veterinarians find positive dogs every day and will discuss one of the following 4 diseases most commonly:
Lyme Disease: It is caused by the spirochete bacteria, Borrelia burgdorferi farmacie-romania.com. This bacteria is found in the Deer tick and a very high percentage of these ticks carry Borrelia (probably over 50%). It is a commonly diagnosed tick-borne disease of dogs in our area. Clinical disease does not ensue immediately in dogs. In fact, disease will usually occur 2 to 6 months after attachment by an infected tick. The time of disease transmission from tick to dog is not well understood but probably requires 16 to 36 hours of tick attachment. Only a small share of infected dogs (about 10%) will develop clinical signs. Affected dogs become very lethargic and often have inflamed and warm joints due to polyarthritis(inflammation of multiple joints at the same time). They often become lame and are reluctant to move. Most dogs develop a low platelet count. Diagnosis is made by specific blood testing for antibody or by PCR (a test for tick genetic material in the dog’s blood). Happily, dogs typically respond very rapidly to oral doxycycline antibiotic and are usually feeling much better in 24 to 48 hours. Treatment is usually for an entire month. Lyme nephritis is a less common and very serious form of Lyme disease that affects the kidney and carries a poor prognosis.
Anaplasmosis: Anaplasma phagocytophilum is a bacteria also carried by Deer ticks. Thus it is prevalent in areas with dense populations of deer per square mile such as Carlisle. This is a similar pathogen to Lyme, causing lameness, lethargy and low energy in dogs. It can make them very sensitive to the touch and can also affect appetite. It can be transmitted in as little as 3 to 6 hours of attachment to a dog. The organism can infect blood cells within weeks. This bacteria seems to be able to invade a dog’s body and be present for months before it causes disease, if at all. Most of the dogs that test positive for this disease are only showing evidence of exposure and not disease. Infrequesntly, some of the dogs with no clinical signs and positive test(exposure) will later become sick. Antibody testing for Anaplasmosis is part of an annual bundle test performed by veterinarians at the annual physical exam visit. If your dog tests positive for Anaplasma, your veterinarian will probably want to perform a Complete Blood Count to check the platelets and a confirmatory PCR testing is also available. Anaplasmosis also responds very well to doxycycline.
Ehrlichiosis: This is transmitted to dogs by the Brown Dog tick, the American Dog tick, or the Lone star tick. It can be transmitted in as little as 3 to 6 hours of attachment to a dog. We do find positive tests as part of our annual screening but much less commonly. Clinical signs are very similar to Anaplasma and the confirmation would also include performing a CBC and a PCR test. Rapid response to Doxycycline is also expected.
Rocky Mountain Spotted Fever: We know that RMSF is present in our area. Unfortunately, this is not part of our annual screening test and requires an expensive PCR test. Accordingly, we have developed much less information on this disease. It is transmitted primarily by the American Dog tick, but also by the Brown Dog tick, and the Lone Star tick. This disease causes malaise, fever and muscle pain, hemorrhage, and central nervous signs and pain in dogs. Transmission requires 5 to 20 hrs of tick attachment. The time for development of disease varies from a few days to 2 weeks. RMSF will also respond to doxycycline.
It should be said that we suspect many other tick-borne pathogens affect dogs (and probably cats) that are not well understood or tested for. The reason for this assumption is that many lame, tender, sensitive, painful dogs test negative. They may also test negative because they have not produced antibodies (seroconverted) as yet. These cases are difficult for the veterinarian because the dog looks like he has Lyme or another closely related pathogen and he is sick and quite unhappy. In some of these cases, veterinarians will do a 10 day trial of doxycycline and then see a dramatic response within a day or so. As in people, treatment decisions in pets can be a mixture and science and good judgment.
How to prevent Tick-Borne Disease in Dogs
All tick-borne illness in dogs requires tick attachment to the dog and exchange of saliva from the tick mouth parts with the tissue fluid of the dog at the site of the bite. The total time of tick attachment is very important because each bacteria has a different time for transmission of disease.
Firstly, removing ticks off of your dog as soon as possible is rule number one! Avoidance of field and forest would be ideal, but definitely not consistent with active human and canine lifestyles. Secondly, monthly tick prevention is mandatory for any dog spending ANY time outside in Carlisle. The reality is that nobody will be able to check every square inch of their dog’s skin every 12-24 hour period, especially in dense-coated breeds. Many people do not understand that ticks DO survive the winter. Because ticks can transmit disease as both adults and nymphs, we need to do YEAR-ROUND monthly tick prevention with an appropriate medication.
Prevention is centered on these three pillars:
- Medical prevention of tick attachment
- Prompt removal
- Vaccination (Lyme disease only at this time)
A. Medications to prevent tick attachment in dog:
Oral medication. These new compounds have really improved tick prevention in dogs over the last 5 years. They are very easy to give by mouth and dogs see them as treats. They kill ticks within the shortest period of time and have been relatively free of side effects in our experience. The veterinary profession has a very positive overall experience with these oral compounds and many dog owners have moved to this method over the last 3-5 years. Most veterinarians believe these products to be relatively free of side effects but some internet and consumer reports say otherwise. Recently, the FDA issued a warning about this oral/isoxazoline class of canine tick preventatives (NexGard, Bravecto, Simparica, Credelio). The FDA continues to believe that these products are safe for the makjority of dogs. They have been associated with gait unsteadiness, tremors, and seizures in a very small number of dogs. The FDA has asked veterinarians to be aware on these side effects and to carefully consider these prior to prescribing. These products are expensive but very effective. Afoxolaner has been reported to be 93% effective at 12 hrs and appears to kills tick much more rapidly than other methods.
Topical medications have been around for over 20 years. They are less expensive and have been fairly effective. Many dog owners do not apply them correctly as they have to reach the skin itself for transdermal absorption and do not work if placed on the hair. Many owners do not like the smell and the greasiness. These medications may take 24 to 40+ hours to kill a tick, which is certainly not fast enough to prevent Anaplasmosis and Ehrlichiosis and may not be adequate for Lyme transmission prevention.
Tick Collars are gaining in popularity. Collars will require 24-48 hours to kill a tick. The most popular brand contains Imidicloprid and Flumethrin and seems effective. Some people object to its use because Imidicloprid is a neonicotinoid involved in the collapse of the bee population. Young mothers also mention that they do not want the chemicals in tick collars near their young children who will have contact with the family dog. Many tick preventive strategies involve the use of the collars combined with an oral product especially in a highly infected area.
There is no product that provides a bubble or shield of protection. There is no product that will prevent a tick bite. We are all hoping for the day when such a shield could be provided. The medical goal is to have the ticks die and fall away from the host before they can cause tick-borne disease. All the products do require the tick to be in contact with the body at some level.
Most veterinarians believe that there are no natural tick preventatives that are effective. Most dog owners and veterinarians would prefer such products but this goal remains elusive.
B. Tick Removal:
Prompt and complete tick removal is very important for the prevention of Lyme as it takes quite a few hours to successfully travel from the mouthparts of the tick to the victim dog. This is especially true for Anaplasma, Ehrlichia, and RMSF because they transmit much more rapidly.
Application of a little alcohol to the tick prior to removal is helpful. Wait a few minutes and remove with forceps or a commercial tick removal tool and try to remove the mouth parts.
C. Vaccination:
There are several vaccines available to prevent Lyme disease in dogs. People often ask if they are effective. There has been research performed to show that dogs may be successfully immunized against Lyme disease. The vaccination does not yield 100% immunity but is an important tool combine with tick removal and tick prevention in the control of canine Lyme Disease. Borrelia is a potent immune suppressor and dogs infected with the disease do not gain long-term immunity and may become infected and ill in a subsequent season.
Currently there are no other vaccinations available for the other tick borne diseases of dogs.
Tick-borne disease in Cats
Carlisle cats are attacked by ticks just as dogs are. In our area, deer ticks predominate but cats can also harbor American Dog ticks and Lone Star ticks. Cats seem to have tick attachment often about the head, sometimes with small nests of several ticks attached in a single location. All life stages can attach to cats including larvae, nymph, and adults. Many veterinarians currently believe that ticks do not cause much disease in cats in our area. However a recent 2018 study in Maine has shown that lyme disease may cause clinical signs in cats. Most veterinarians believe cats to be resistant to Lyme disease but can become ill with Anaplasmosis. Anaplasma causes lethargy, fever, joint issues, and loss of appetite. Cats can respond to doxycycline but it must be administered very carefully to avoid esophageal strictures. Like dogs, we sometimes need to trial doxycycline in cats that are lame and test negative for tick-borne disease to sort things out.
Most importantly, cats can easily bring ticks into the inside space. If the outdoor cat visits under the bedcovers, the people can certainly wake up with an attached Deer tick.
How to prevent Tick-Borne Disease in Cats:
Tick removal is also rule number one in cats. You may remove quite a few at a single event.
Topical products and collars are available for cats. Recently, there has been the addition of Fluralaner topical as well. Please consult your veterinarian for their recommendations as this is a fluid area of medicine at this time.
