Tick-Borne Diseases in Dogs

Tick-Borne Diseases at a Glance

Dogs can carry more than one infection at once, which can make signs more severe.^8,6 Parasite experts publish county-level maps of positive tests across the US; a low-risk area is not a no-risk area.¹⁷

Lyme Disease

Lyme disease is caused by bacteria carried only by Ixodes ticks, the black-legged or deer tick.¹ Up to half of ticks are infected in some areas.⁷ Most exposed dogs never get sick.^8,18 Dogs that do usually develop:

• Lameness that may shift from leg to leg, with swollen, painful joints^7,14
• Fever, low energy, poor appetite and swollen lymph nodes^8,7

Lyme arthritis is most common in young, often large, outdoor dogs.⁸ Read more on our pages about canine Lyme disease symptoms, Lyme disease signs in dogs and Lyme disease in dogs.

Lyme kidney disease (Lyme nephritis)

Lyme kidney disease is rare, but it is serious and can be fatal.^18,7,19 Retriever breeds seem to be over-represented.⁸ That's why vets check the urine for protein in dogs that test positive.⁸ See kidney disease in dogs.

Are there stages of Lyme disease in dogs?

Dogs don't follow the staged pattern described in people. Most infected dogs have no signs, a smaller group get arthritis, and a rare few develop kidney disease.^8,18

Anaplasmosis

One form of anaplasmosis infects white blood cells and is spread by black-legged ticks, the same ticks that carry Lyme. Another form infects platelets and is spread by the brown dog tick.⁶ Most infections cause no signs.⁶ When dogs do get sick, about 1 to 2 weeks after a bite, they may have fever, poor appetite, lethargy, lameness, swollen lymph nodes, and bruising or pinpoint bleeding from low platelets.^6,15 Signs usually clear within about a week of starting antibiotics.⁶

Ehrlichiosis

Ehrlichiosis is spread by tick bites, mainly the brown dog tick and the lone star tick.^16,2 The acute stage starts 1 to 3 weeks after infection, with fever, bleeding tendencies, an enlarged spleen and swollen lymph nodes, and sometimes nerve signs.² Most dogs clear the infection within 2 to 4 weeks.² A rare chronic form can damage the bone marrow, eyes, joints and kidneys, and it's more common in German Shepherd Dogs.² Recovery doesn't give lasting immunity, so dogs can be reinfected.⁹

Rocky Mountain Spotted Fever

Rocky Mountain spotted fever (RMSF) is spread by the American dog tick and the Rocky Mountain wood tick, and by the brown dog tick in parts of Arizona and Mexico. Most US cases are in the southeastern and south-central states.¹⁰ Signs include fever up to 105°F, pinpoint bleeding, swollen lymph nodes, joint pain, swelling, and breathing, eye or nerve signs. Severe cases can lead to tissue death (gangrene) in the extremities and a body-wide clotting disorder.¹⁰ Response to treatment is usually dramatic, but dogs with nerve damage may keep some deficits.¹⁰

Babesiosis

Babesiosis is caused by parasites that destroy red blood cells. It spreads through tick bites, and also through dog fights and bites, blood transfusions and from mother to puppies.¹¹ In North America most cases are in the southern US. One species is most common in Pit Bull-type dogs, and Greyhounds are also at higher risk.¹¹ Signs include lethargy, pale gums, fever, dark urine, jaundice and weight loss, ranging from mild to rapidly fatal.^11,3 Treatment uses antiprotozoal drugs plus supportive care such as transfusions. Survivors may stay infected and relapse, and they should never be blood donors.¹¹ One species is not readily cleared by standard medicines.³

Hepatozoonosis

American canine hepatozoonosis is unusual: dogs catch it by swallowing an infected Gulf Coast tick, or by eating infected rodents or rabbits, not from a bite. It was first found on the Texas Gulf Coast and has spread north and east with the tick.⁴ Signs include a high fever that doesn't respond to antibiotics, severe muscle pain, stiffness, weakness, eye discharge and weight loss.⁴ Treatment is a short course of combined medicines followed by long-term antiprotozoal medicine for at least 2 years. It isn't curative, and many dogs relapse, but quality of life can be good with care.⁴

How Soon After a Tick Bite Do Dogs Get Sick?

Signs of tick-borne disease may not appear for 7 to 21 days or longer after a bite.⁵ Ehrlichiosis usually shows up in 1 to 3 weeks and anaplasmosis in 1 to 2 weeks.^2,15 Lyme signs, if any, appear weeks to a few months after the bite.^18,19

How fast ticks pass on infection

Lyme bacteria usually need a tick attached for a day or two, so quick removal helps.^1,8,7 Anaplasma also needs about 24 to 48 hours.^15,13 Some other tick germs, such as Ehrlichia and the RMSF bacterium, can pass in just a few hours, which is why prevention products matter more than tick checks alone.^1,10 Learn how to safely do tick removal from dogs, and see tick bite pictures. Some infections can enter through broken skin, so take care when handling ticks.²⁰

Testing for Tick-Borne Diseases

Many vets use an in-clinic screening blood test for tick diseases and heartworm.^8,2

• A positive screening test means exposure, not illness. It doesn't prove a tick disease is causing your dog's signs or predict that your dog will get sick.⁸
• Early tests can be negative. Lyme antibodies take about 4 to 6 weeks to appear, and anaplasmosis tests can be negative in the first week.^14,7,6 Vets shouldn't stop treating ehrlichiosis just because an early test is negative.²
• Follow-up tests include a blood count (low platelets are common), repeat antibody tests a few weeks apart, PCR tests that detect the germ itself, and a urine protein check for Lyme-positive dogs.^2,10,3,8

Does a healthy dog that tests positive need treatment?

Not always. A positive screening test means exposure. Many healthy positive dogs are monitored, with a urine protein check for Lyme, rather than treated, and your vet will decide.^8,9

Treatment and Recovery

• Lyme disease: a tetracycline-class antibiotic for about 4 weeks. Dogs with Lyme arthritis should improve within 1 to 3 days. Some keep long-term joint pain, and infection can persist.^8,7
• Ehrlichiosis: a tetracycline-class antibiotic for about 4 weeks. Most dogs improve within 24 to 48 hours, and platelets usually return to normal within 2 weeks. Chronic cases recover more slowly.^9,2
• Anaplasmosis: a tetracycline-class antibiotic, often for at least 10 days; signs usually resolve within a week.^13,6
• RMSF: a tetracycline-class antibiotic, usually for about a week, longer if other infections are suspected, started before test results are back.¹⁰
• Babesiosis and hepatozoonosis: antiprotozoal medicines plus supportive care; outlook is more guarded.^11,4

Your vet will choose the medicine and amount for your dog.

Can a dog recover from a tick-borne disease?

Usually, yes, when treated early. Most dogs with Lyme arthritis, anaplasmosis or acute ehrlichiosis recover fully.^8,6,9 The outlook is worse for Lyme kidney disease, chronic ehrlichiosis, RMSF when treatment is delayed, hepatozoonosis and some forms of babesiosis.^7,2,10,4,3 Your vet can estimate your dog's outlook.

What if months have passed since the bite?

It isn't too late. Lyme signs may not start until 2 to 5 months after the bite, and vets treat sick dogs whenever signs appear.^19,8,9

Cost of Treatment

One US pet insurer reported average claims of about $600 for Lyme disease and $650 for anaplasmosis in 2017, up from about $350 in 2011.²¹ Serious cases cost far more. These are older figures from a single insurer, and prices vary by clinic and region.

Preventing Tick-Borne Diseases

• Use tick prevention all year. US parasite experts recommend year-round tick control, because ticks can be active on any day above about 40°F.^1,22,19 A specialist panel agreed unanimously for dogs in Lyme areas, vaccinated or not.⁸ See flea and tick prevention for dogs.
• Prefer fast-acting products. Specialists favor products that stop ticks attaching or kill them quickly.⁸
• Check for ticks daily after outdoor time, including the ears, eyelids, collar area, under the front legs, between the back legs and toes, and around the tail.⁵
• Keep dogs out of tick habitat where you can.²⁰
• Ask about the Lyme vaccine. Experts disagree on whether every dog in a Lyme area should be vaccinated. Talk to your vet. Either way, use tick prevention year-round.^8,14,19

Dogs don't pass these diseases directly to people, but they can bring infected ticks into the home, and dogs can act as early warnings of tick risk for families.^7,14,10

Frequently Asked Questions

Can a dog recover from a tick-borne disease?

Most dogs do, especially when treated early. Lyme arthritis, anaplasmosis and acute ehrlichiosis usually respond within days to a few weeks of antibiotics. Kidney-related Lyme disease and chronic infections are harder to treat.

How soon after a tick bite would a dog get sick?

Usually 1 to 3 weeks or longer. Lyme disease can take weeks to a few months to cause signs, and many infected dogs never get sick at all.

What are the stages of Lyme disease in dogs?

Dogs don't follow the stages seen in people. Most infected dogs have no signs, some develop lameness and swollen joints, and a rare few get a serious kidney disease.

What is Lyme nephritis?

It is a rare kidney disease linked to Lyme infection that causes protein loss in the urine. It is serious and can be fatal, so vets check urine protein in dogs that test positive.

What is the life expectancy of a dog with a tick-borne disease?

Most dogs that recover from Lyme arthritis, anaplasmosis or acute ehrlichiosis live normal lives. Lyme kidney disease and chronic ehrlichiosis can shorten life. Your vet can give you an outlook for your dog.

How much does it cost to treat a tick-borne disease?

One insurer reported average claims of about $600 to $650 in 2017 for Lyme disease and anaplasmosis. Severe cases cost much more, and prices vary by clinic and region.

Is 4 months after a tick bite too late to treat?

No. Lyme signs may not appear until 2 to 5 months after a bite, and vets treat sick dogs whenever signs show up.