Tick-Borne Illnesses in Animals

Tick-Borne Illnesses in Animals

General Information

Prevention is the key in eliminating the risk of tick borne illnesses in pets. Lyme affects pets differently; some show symptoms and others exhibit no symptoms at all. Always do tick checks or groom your pets to find attached and non attached ticks before the pet is allowed inside. Symptoms of Lyme disease are hard to recognize and, as in humans, can mimic other illnesses or advanced age.

Observation of your pet is the only way to discover your pet has contracted a tick-borne illness if you don’t find a tick on your pet.

Prevention Tips:
1. Daily tick checks (between toes, around eyes, ears, and skin folds).
2. Remove ticks carefully (don’t squeeze the body of the tick) and clean bite area with soap and water or antiseptic.
3. Reduce tick population around your home by making it into a tick free zone.
4. Reduce exposure by keeping pets out of brushy areas and leaf piles.
5. Keep cats inside.
6. Use veterinary approved prevention and tick control products on your pet.


Limping that progresses over 3-4 days from mild discomfort to more extreme joint and muscle pain that the animal may not move; swollen lymph nodes in the affected limb; unexplained shifting leg lameness; loss of appetite; fever. The bacteria can also affect the heart muscle, nerve tissue, eyes and kidneys. In serious cases, paralysis and kidney damage (glomerular disease) can occur sometimes with fatal results. Treatment for Canine Lyme disease is administering antibiotics for 4-6 weeks. Treatment within the first week of symptoms leads to a rapid response. This prevents permanent nerve or joint damage from occurring.


Listlessness, depression, high fever, loss of appetite, cough, conjunctivitis, breathing difficulties, leg swelling, joint and muscle pain, uveitis, unstable gait, altered mental state, seizures, and heart muscle inflammation (myocarditis) causing cardiac arrhythmias. Treatment is with 2-3 weeks of antibiotics as soon as Rocky Mountain Spotted Fever is suspected. Mortality is high if treatment is delayed.


Three Phases of symptoms are found in this disease:
1. Acute Phase: Fever, depression, loss of appetite, shortness of breath, enlarged lymph nodes, occasionally encephalitis (symptoms can also be from Rocky Mountain Spotted Fever, Lyme Disease, or Canine Distemper).
2. Subclinical Phase: Two to four weeks after the acute phase, the dog enters a subclinical phase that can last weeks to months with the possibilities of eliminating the infection or progressing to the chronic phase.
3. Chronic Phase: May occur 1-4 months after the tick bite. Symptoms may include weight loss, fever, anemia, a hemorrhagic syndrome with spontaneous bleeding and nose bleeds. Limb swelling and other neurological signs may also occur.
Treatment is with antibiotics administered for 1 month. Supportive treatment can include intravenous fluids and blood transfusions. Response is excellent
as long as treatment is started before the Chronic Phase.


Lyme disease in cats is less common as a result of their grooming habits which remove the ticks before they attach to the body. Indoor cats are not immune but are less likely to contract Lyme disease because of reduced exposure. Lyme is not a major threat to cats, but it can be dangerous because it may go unnoticed and undiagnosed. For outdoor cats, everyday tick checks are recommended
for the cat’s protection and also for their human companions protection. Great care needs to be taken when cleaning the litter box, especially if the cat has outdoor exposure.


Lethargic for days at a time (unwilling to move and may cry when handled).
Hesitant about jumping or climbing stairs.
Shifting leg lameness.
Muscle and joint pain.
Fatigue, fever, loss of appetite.
Eye damage.
Unusual breathing.
Heart Problems (rare, but includes complete heart block).
Nervous system complications (rare).
If Lyme is not treated: kidney problems (glomerulonephritis).
Treatment is with antibiotics started as soon as symptoms are observed.
Cats can become re-infected with further tick bites.


Swollen joints; general stiffness, shifting leg lameness.
Refusal to eat.
Changes in behavior (irritability and refusal to work).
Fever (early infection; may be undulating).
Anterior uveitis.
Less than 10% of infected horses show symptoms.

Treatment for horses is a course of IV antibiotics for 4-6 weeks, administered by a veterinarian. Response is quick if the diagnosis is correct. Other adjunct treatments are anti-inflammatory medications for the pain and stiffness; along with stomach medicine to help deal with the side effects of antibiotic treatment. Probiotics can be helpful here. With horses, the only prevention method is tick control. Ticks are mostly found on the head, throat latch area, neck, stomach and under the tail areas of the horse. Cover your hands (gloves, any kind) when cleaning stalls. Check horses frequently (at the very least, daily) for ticks and remove them carefully. An infected animal is a sign that the area is endemic, so other horses found locally should have tick checks done and be observed for illness. Check with your veterinarian for prevention and tick control products that may be used on the horse.


Babesiosis in dogs and other canines is a tick-borne disease caused by a protozoan blood parasite from the genus Babesia. There are two species of Babesia that can cause disease in dogs in the U.S.: Babesia canis and Babesia gibsoni. Many military dogs had this disease during the VietnamWar, and the disease is often a major problem in areas of the world that don’t have cold winters that reduce tick population. This disease occurs most commonly in dogs, but occasionally is reported in cats. Young animals under age three tend to become infected more often and with more severe symptoms. Greyhounds, pit bull terriers, and American Staffordshire terriers seem to be the most susceptible to infection; with Greyhounds being infected with Babesia canis and terriers with Babesia gibsoni. Mothers can spread this disease to their unborn puppies, so infected females should not be bred. There is also some evidence that babesioisis can be spread through infected dogs biting other mammals. Incubation of the parasite after the infected tick bite is ten days to three weeks. In the United States, this disease is most often diagnosed between March and October, during the periods when ticks are most active. Babesia infections have a wide range of severity; they can be very mild (dogs may not even show symptoms) or very severe (sometimes fatal).

If the acute symptoms are relatively mild or at least nonlethal, a chronic infection can develop. This is usually without symptoms but the dog may continue to be a source of infection to feeding ticks. Relapses can also occur with stress causing the dog’s immune system to allow the protozoa to get out of control again. Previously infected dogs should not be bred or used as blood donors (to prevent spreading the disease).

Symptoms of babesiosis in dogs can include:

Fever, lethargy and weakness, inability to produce urine or red colored urine, excessive thirst, anemia, pale or jaundiced gums, skin, whites of eyes, respiratory distress, enlarged lymph nodes, enlarged spleen, blood tinged frothy nasal discharge, and collapse, seizures or coma. Diagnosis of Babesia can be difficult to confirm and is further complicated by the fact that dogs infected with the disease may also be infected with other tick-borne illnesses, such as Erlichia, Lyme disease, or Rocky Mountain Spotted Fever. Diagnostic tools include a complete blood count, chemistry panel and urinalysis, evaluation of a blood smear, and serology in the form of PCR testing.

Treatment depends on which Babesia species the dog has and can include  Imidocarb Dipropionate (the only drug approve for Babesia in the U.S.), Trypan Blue (used initially in severe cases to suppress the organism in the bloodstream), blood transfusions (in the case of severe anemia) and supportive care. A combination therapy of quinine, azithromycin, atovaquone and/or clindamycin are new therapies that may be useful in the future. Preventing exposure to ticks that carry Babesia is the best means of preventing babesiosis. Veterinarians can recommend tick control products for your dog along with performing regular tick checks after being outside, can reduce the risk of exposure of your pet. Keeping grass and brush trimmed in your yard and in areas where ticks are present along with considering treating the yard and kennel area with a repellent, will reduce the possible exposure to you and your pet to tick-borne illnesses.

TBI in Animals compiled by the JDMLF, Inc. and edited by Dr.
Amy Gerber, D.V.M. (2011).