What are tick-borne diseases in dogs?
Ticks are intracellular parasites that suck blood from their hosts, and can carry and transmit dangerous bacteria to your dog’s body. These bacteria live inside the cells and can potentially cause many illnesses that infect thousands of dogs every year.
Conditions that result from a tick bite can also cause serious (and in some cases, fatal) long-term damage. That’s why it’s critical to prevent tick-borne diseases and have symptoms treated early by a qualified vet, if your dog does contract a condition.
Though many of the pathogens that cause tick-borne diseases are zoonotic and can infect humans, disease cannot spread between dogs and humans directly.
Pathogens need ticks to complete their lifecycle and become infectious. Therefore, a direct tick bite would be necessary to transmit disease. Here are the most common tick-borne illnesses in dogs across the United States:
Transmitted by black-legged ticks or deer ticks, the bacteria borrelia burgdorferi causes Lyme Disease, a rapidly growing global issue. The tick must feed for before 24 to 48 hours before infecting a host.
This illness can result in symptoms ranging from joint pain or swelling, limping and enlarged lymph nodes to lethargy, lameness and fever. These symptoms can progress to kidney failure, which may be fatal, as well as serious cardiac and neurological effects.
One of the less common blood-borne diseases in dogs is transmitted by the brown dog tick. Canine bartonellosis can cause disturbing symptoms, from fever and lameness to altered brain function, seizures, loss of appetite and irregular heartbeat. People can also contract the condition.
Rickettsia is a bacteria that causes widely recognized tick diseases such as canine anaplasmosis, ehrlichiosis and Rocky Mountain Spotted Fever. Rickettsial organisms are comprised of small, intracellular bacteria.
Since it can be challenging to interpret diagnostic test results, if your dog has a severe case it may be necessary for your vet to conduct several rounds of treatment and tests to make a definitive diagnosis.
Also referred to as dog tick fever or dog fever, the deer tick carries this disease. Infected hosts can experience symptoms similar to other tick-borne diseases, from lethargy, fever, stiff joints and loss of appetite to diarrhea and vomiting. Extreme cases may lead to seizures.
The brown dog tick, lone star tick, American dog tick and others can carry and transmit canine ehrlichiosis – a disease that’s found throughout the world.
Between 1 and 3 weeks after your dog is bitten by an infected tick, symptoms will begin to appear. Watch for symptoms including fever, bruising or nose bleeds, and poor appetite. Testing may reveal low blood platelets (cells that help with blood clotting).
While canine ehrlichiosis can have better outcomes for treatment, this disease may be more difficult for your dog to recover from if chronic symptoms have developed.
The Rocky Mountain wood tick, American dog tick and brown deer tick carry RMSF, one of the more commonly recognized tick-borne diseases that’s found throughout North, South and Central America. Both dogs and people can be infected.
Symptoms may include swollen lymph nodes, low platelet levels, fever, poor appetite and joint pain. Some dogs may experience neurological challenges, including weak limbs or wobbly stature.
With both canine ehrlichiosis and RMSF, bacteria can be transmitted within 3 to 6 hours of a tick attaching to your dog.
A protozoal intracellular parasite that resides in your dog’s red blood cells can cause these diseases, which include:
While tick bites (from the brown dog tick and/or American dog tick) are the most common causes for this disease, it can also be transmitted by transplacental transmission and contamination of IV blood.
Red blood cells can break down, leading to symptoms such as jaundice (orange or yellow-colored skin or whites of eyes), dark-colored urine, pale gums and lethargy. Other symptoms may include vomiting and weakness.
If your dog ingests protozoa by eating infected animals such as rodents or birds, he or she can contract this tick-borne disease, which distinguishes it from other tick-borne illnesses.
What other symptoms should I look for?
Hallmark signs of tick-borne diseases in dogs include vomiting fever, swelling around joints, lameness and lethargy. Other symptoms may include:
Treatment for anaplasma is similar for that for the other two tick-borne diseases mentioned. Many pets clear the infection without treatment and with no prolonged effects. However, subsequent annual 4dx tests may continue to be positive, which indicates exposure, but not necessarily active disease.
Lyme disease is not considered a zoonotic disease, meaning it cannot be spread directly from pet to human, but pets may bring unknown attached ticks into your household. This allows the tick to have the opportunity to crawl off your pet and onto you, putting you at risk for contracting lyme disease from the tick.
The most common symptom of lyme disease in dogs is lameness. In some cases the infection may cause a fever, joint swelling, kidney damage and neurological issues. Your pet may have an increase in thirst, an increase in urination, lethargy, and stiffness.
Here at Prairie View Animal Hospital we use the 4dx test to screen our dogs annually for an immune respose to three common tick-bourne diseases, lyme, ehrlichia, and anaplasma. Unfortunately, all three diseases have been diagnosed in patients in our hospital just this year.
Lyme disease is a bacterial infection that can affect humans, mammals, and birds. It is spread mainly through the bite of a deer tick.
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Tick-borne disease occurs when ticks infected with a pathogen bite a dog and transmit the pathogen into the dogs body. Many of these pathogens are zoonotic, meaning they can also infect humans. Disease is not spread between dogs and humans directly because these pathogens must complete their lifecycle phase within the tick to become infectious. Therefore, while humans and other non-canine family members can also become infected, a direct tick bite is required to transmit disease. The most common tick-borne diseases are Ehrlichiosis, Anaplasmosis, Rocky Mountain spotted fever, Hepatozoonosis, Babesiosis, and Lyme disease. The feeding time required to allow disease transmission from a tick to a dog or person varies between ticks and disease agents. Ehrlichiosis and Rocky Mountain Spotted Fever-causing bacteria can be transmitted within 3-6 hours of tick attachment, while Lyme Disease-causing bacterial transmission can require 24-48 hours of feeding before a host is infected.
Distribution of tick-borne disease is associated with the species of tick endemic to a given region. Distribution of tick species, prevalence of ticks within a region and the prevalence of infectious pathogens they carry is not stable and fluctuates on a seasonal basis depending on weather, rainfall and climate. For this reason monitoring of tick-borne disease is a dynamic, ongoing process.
This interactive map shows the number of reported positive cases of Ehrlichiosis, Lyme disease, Anaplasmosis and heartworm disease in dogs. Maps are available for all regions of the United States and Canada. Because so many dogs go untested for tick-borne diseases, the actual number of dogs infected by ticks is likely many times higher than reported figures.