Can cows get Lyme disease? They can be infected, but they rarely get sick from it, and most reported cattle cases are presumed rather than proven. Dogs are the animals that most often get ill, and even then only a small minority of infected dogs ever show signs. Horses sometimes do. Cats almost never seem to. People do, from tick bites, not from their pets.
That gap between infection and illness runs through everything below. Ticks are most active from April to September, so spring is the time to get ahead of them. Here is what Lyme disease means for each animal, what your vet will check, and how to keep ticks off the whole household.
Which animals get Lyme disease?
Lyme disease is caused by Borrelia burgdorferi, a spiral-shaped bacterium (a spirochete) spread by blacklegged ticks. Many mammals and birds pick up the infection without ever looking sick, according to the Merck Veterinary Manual. Clinical cases are reported mainly in dogs and horses.
Animal | Gets infected? | Gets sick? | What illness looks like |
|---|---|---|---|
Dogs | Often, in tick areas | A small minority | Shifting-leg lameness, fever, tiredness; rarely a serious kidney disease |
Horses | Often, in tick areas | Sometimes; may be overdiagnosed | Eye inflammation (uveitis), nervous system signs, skin nodules at bite sites |
Cows | Yes | Rarely; mostly presumed cases | Fever, stiffness, swollen joints, less milk |
Cats | Sometimes test positive | Not proven in natural cases | No clear disease pattern |
People | Yes | Yes | Rash, flu-like illness, later joint, nerve or heart problems |
A positive blood test in any of these animals usually means "this animal met the bacteria," not "this animal has Lyme disease." In tick areas, 5 to 50 percent or more of healthy dogs, cats, horses and some cattle have antibodies, according to Iowa State's Center for Food Security and Public Health.
How animals and people catch it
Lyme disease spreads through the bite of an infected blacklegged tick (Ixodes), sometimes called the deer tick. In the US that means the blacklegged tick in the Northeast, mid-Atlantic and upper Midwest, and the western blacklegged tick along the Pacific coast. Ticks in most of the Southeast are rarely infected, says the CDC.
- Ticks pick it up from wildlife. Young ticks get infected feeding on small animals, mostly rodents. Deer feed adult ticks but don't carry or spread the bacteria themselves.
- Ticks don't pass it to their eggs. A newly hatched tick isn't infected yet.
- The tick has to stay on. It usually needs to be attached for more than 24 hours to pass the bacteria, so finding and removing ticks early matters.
- Nymphs are the sneaky stage. Young ticks are about the size of a poppy seed and easy to miss in fur or on skin.
- It isn't contagious. Animals and people don't catch Lyme disease from each other by touch, and mosquitoes, fleas, food and water don't spread it.
Dogs, horses and farm animals are not a reservoir for the bacteria. Their risk is the tick, not each other.
Can cows get Lyme disease?
Yes, cattle can be infected, but illness is rare and hard to prove. Iowa State's factsheet describes only "a few putative cases" in ruminants, and calves deliberately infected with European strains in one study stayed healthy.
Signs that have been attributed to Lyme disease in cattle include:
- fever
- stiffness or lameness, with or without swollen joints
- lower milk yield
- chronic weight loss
- abortion
- red, warm, swollen skin on the lower udder
An older review in the Cornell Veterinarian described it as usually a herd problem. Each of these signs has many other, more common causes in cattle, and plenty of healthy cows in tick country carry antibodies. So a positive blood test alone doesn't explain a lame cow. Your herd veterinarian will look for those other causes first.
The bigger practical point for farms: cattle host ticks, and people who work with them are exposed. The New York State Department of Agriculture and Markets urges farmers to check themselves, their pets and their gear after work outdoors.
Lyme disease in dogs
Most people asking about Lyme disease are asking about their dog, and the news there is mostly good: most dogs that test positive never get sick. The ACVIM consensus statement on Lyme disease in dogs and cats says most seropositive (antibody-positive) dogs show no signs, and Iowa State estimates 5 percent or less of infected dogs in endemic areas develop disease. Cornell's diagnostic lab puts it at 5 to 10 percent of infected animals.
Signs of Lyme disease in dogs
When signs do appear, it's usually 2 to 5 months after the tick bite, sometimes later. Watch for:
- lameness that shifts from leg to leg or comes and goes
- swollen, painful joints
- fever
- tiredness and low energy
- poor appetite
- swollen lymph nodes
The classic patient is a young, often large, active outdoor dog. These signs overlap with injuries, other joint disease and other tick infections, so a limp alone doesn't mean Lyme disease. The same tick can carry Anaplasma, which causes anaplasmosis in dogs, and dogs can have both.
The kidney form: rare but serious
A small number of dogs develop Lyme nephritis, an immune reaction that damages the kidney's filters (glomerulonephritis) and makes the kidneys leak protein into the urine. ACVIM notes retriever breeds are over-represented, and protein loss in the urine is seen in fewer than 2 percent of antibody-positive dogs. Iowa State describes the disease as often progressing quickly. Merck adds that a direct cause-and-effect link with Borrelia hasn't been proven, which is why vets rule out other kidney diseases first.
By the time most affected dogs look sick, they show the usual signs of kidney failure in dogs. Catching protein in the urine earlier is the point, which is why ACVIM recommends a urine protein check for every dog that tests positive, even one that seems perfectly well.
How vets test for Lyme disease
- Screening test: a quick in-clinic or lab blood test looks for antibodies to a Lyme protein called C6. It's often part of a combined screen for heartworm and other tick diseases. ACVIM recommends screening healthy dogs that live in, live near or travel to Lyme areas.
- What a positive means: exposure. Merck is blunt that a positive result predicts disease poorly, because most positive dogs stay healthy.
- Follow-up tests: urine protein testing, bloodwork, and sometimes a quantitative antibody test (such as Quant C6 or Cornell's Lyme Multiplex) to gauge the stage of infection or track treatment. ACVIM notes the Quant C6 number by itself doesn't predict who will get sick.
Treatment
Dogs with signs are treated with antibiotics, usually from the tetracycline family, and joint signs often improve quickly. Your veterinarian chooses the drug, the dose and how long to give it. Dogs with kidney involvement need more: kidney-protective treatment and sometimes medicine to calm the immune reaction.
What about a healthy dog that tests positive with normal urine? The ACVIM panel did not reach full agreement, and most panelists do not routinely recommend antibiotics for these dogs. Many vets monitor instead, rechecking urine protein over time. It's a decision to make with your vet.
The Lyme vaccine for dogs
Several Lyme vaccines are licensed for dogs, and immunity lasts about a year, according to Merck. A few things to know:
- Vets often test for exposure first, since the vaccine doesn't treat an existing infection.
- Expert opinion is split. Half of the ACVIM panel recommends vaccinating healthy, antibody-negative dogs in Lyme areas; CAPC says to base the decision on each dog's risk.
- Sick dogs and dogs losing protein in their urine should not be vaccinated.
- A vaccine never replaces tick control.
Ask your vet whether your dog's lifestyle and location make it worth it.
Lyme disease in horses
Horses in Lyme areas are exposed often, but proven disease is less common than many owners assume. The ACVIM consensus statement on horses names three syndromes as the best documented:
- Neuroborreliosis (infection of the brain, spinal cord or nerves): stiffness, weakness, wobbliness, trouble swallowing
- Uveitis: painful eye inflammation that can threaten vision
- Cutaneous pseudolymphoma: lumps in the skin at the site of a tick bite
Shifting lameness, vague stiffness, sensitivity to touch and poor performance are often blamed on Lyme disease. Merck notes that lameness hasn't been conclusively linked to the infection, and the ACVIM panel warns that Lyme disease may be overdiagnosed in areas where many horses test positive. Neurologic cases tend to carry a poor outlook, according to Iowa State.
There is no Lyme vaccine labeled for horses. Some vets use dog vaccines off-label, so talk to your equine vet about tick control and whether vaccination fits your horse.
Can cats get Lyme disease?
Cats can test positive, but naturally infected cats with clear Lyme disease have not been documented, according to CAPC. In experiments, cats infected through tick bites didn't get sick, and ACVIM says there's no reason to screen healthy cats. Merck calls illness in positive cats rare.
Ticks still matter for cats. In Lyme areas, the tick-borne illness documented in cats is anaplasmosis, so a cat that roams outdoors still needs tick protection your vet recommends.
Lyme disease in people
People get Lyme disease from tick bites. Your dog or cat can't give it to you directly, but pets can carry ticks into the house, says the CDC. An unattached tick can walk off the dog and onto you.
Symptoms start 3 to 30 days after the bite:
- Erythema migrans rash in about 70 to 80 percent of people. It usually appears around 7 days after the bite, spreads slowly, and may or may not look like a bull's-eye.
- Fever, chills, headache, tiredness, muscle and joint aches, swollen lymph nodes.
Weeks to months later, untreated infection can cause joint pain and swelling (often the knees), facial drooping, nerve pain, and heart rhythm problems, per the CDC's symptom page. More than 80,000 cases are reported to the CDC each year. If you develop a rash or fever after a tick bite, see your doctor.
Spring tick season: how to protect pets and family
Ticks are most active from April through September, and adult blacklegged ticks can be out on any day above freezing. Prevention is the same idea for every species: stop the bite, and find ticks before they've been on for a day.
Check daily, remove ticks fast
After time outdoors, run your hands over your pet: ears, around the eyes, under the collar, armpits, between the toes and around the tail. Merck points out that small Ixodes ticks are easy to miss in thick fur, which is why checks work best alongside a preventive.
Found one? Grasp it as close to the skin as you can with fine-tipped tweezers or a tick tool, pull straight out with steady pressure, and clean the bite. Skip petroleum jelly, nail polish and heat, which the CDC warns against. Our dog ticks guide walks through every step and the spots ticks like to hide.
Use a tick preventive your vet recommends
Both CAPC and the ACVIM panel recommend year-round tick control for dogs at risk, using products that kill ticks quickly or stop them attaching. They come as chewables, spot-on liquids and collars, and your vet will match the product to your pet's species, size, health and local ticks.
Never use a dog tick product on a cat. Some dog spot-ons contain concentrated permethrin, which can cause tremors and seizures in cats, according to the ASPCA Animal Poison Control Center.
Make the yard less tick-friendly
Ticks like leaf litter, tall grass and brushy edges where lawns meet woods. Keeping grass short and walking pets on cleared paths reduces contact. For horses and cattle, ask your vet about tick control that suits your pasture.
Protect yourself
- Use an EPA-registered insect repellent, following the label.
- Treat boots and outdoor clothing with permethrin, or buy pre-treated gear.
- Shower within two hours of coming inside and check your hairline, armpits and behind your knees.
- Put outdoor clothes in a hot dryer for about 10 minutes to kill hitchhiking ticks.
When to call the vet
Call now or go in today
- Your dog suddenly can't bear weight, has hot, swollen joints, or a fever and won't eat.
- Your dog is vomiting, not eating or seems very weak, especially if it has tested positive for Lyme.
- Your horse has a painful, cloudy or squinting eye, or is suddenly wobbly or weak.
See your vet soon
- Lameness that shifts between legs or keeps coming back.
- Your dog tested positive and hasn't had a urine protein check.
- A tick bite site stays red, swollen or sore.
Mention at your next visit
- Planning a trip to a Lyme area, or you've moved to one.
- Whether your dog needs yearly screening or the vaccine.
- Which tick preventive fits each pet in the house.
Quick answers
Can my dog give me Lyme disease? No. Lyme disease isn't spread from pets to people. A dog can bring an unattached tick indoors, and that tick could bite you.
My dog tested positive but seems fine. Does it need antibiotics? Not always. Most positive dogs never get sick. Your vet will usually check urine protein and may recommend monitoring rather than treatment.
Do deer give animals Lyme disease? No. Deer feed ticks, but the bacteria come mainly from small wild animals such as mice.
Can Lyme disease come back? A dog can be reinfected by another tick bite, which is one reason vets pair treatment with ongoing tick control.
Sources
- Merck Veterinary Manual: Lyme Borreliosis in Animals
- ACVIM consensus update on Lyme borreliosis in dogs and cats (Littman et al., J Vet Intern Med, 2018)
- Borrelia burgdorferi infection and Lyme disease in North American horses: a consensus statement (Divers et al., J Vet Intern Med, 2018)
- Iowa State University CFSPH: Lyme Disease factsheet
- Parker and White: Lyme borreliosis in cattle and horses, a review of the literature (Cornell Veterinarian, 1992)
- CAPC: Lyme Disease guideline
- Cornell University Animal Health Diagnostic Center: Lyme Disease
- CDC: How Lyme Disease Spreads
- CDC: Signs and Symptoms of Lyme Disease
- CDC: Lyme Disease Facts and Stats
- CDC: Preventing Tick Bites
- CDC: Preventing Ticks on Pets
- CDC: What to Do After a Tick Bite
- New York State Department of Agriculture and Markets: Protection Against Lyme Disease and Other Tick-Borne Diseases
- ASPCA Animal Poison Control Center: Permethrin toxicosis in cats
This article is for general information and is not a substitute for advice from your veterinarian.
