May 27, 2024

As Lyme disease cases rise in the United States, not only humans are at risk; dogs are increasingly vulnerable to this tick-borne illness. The disease’s spread is facilitated by ticks, which thrive in tall grasses and wooded areas and symptoms in dogs can range from fever and joint pain to more serious conditions like kidney damage if left untreated. This article dives into what dog owners should know about Lyme disease, from its transmission and symptoms to diagnosis, treatment, and practical prevention strategies.

The number of human Lyme disease cases in the United States has climbed in recent decades, but Lyme disease affects more than just humans. Wild and domestic animals, including dogs, can also contract the disease.  

Lyme disease is caused by bacteria from the genus Borrelia, with Borrelia burgdorferi being the most common species responsible for the disease in North America. These bacteria are transmitted to humans and animals through the bite of infected ticks, specifically the black-legged tick (Ixodes scapularis) in the northeastern and north-central United States and the western black-legged tick (Ixodes pacificus) on the Pacific Coast. 

Also called the deer tick, the black-legged tick picks up B. burgdorferi when it bites an infected animal (usually a rodent), and when it feeds on another animal, it transmits the bacteria.  

Blacklegged ticks are small, ranging from about the size of a poppy seed to a sesame seed.  

The Transmission Mechanism 

Understanding the transmission mechanism of Lyme disease is helpful for prevention. The black-legged tick undergoes three life stages: larva, nymph, and adult. Each stage requires a blood meal to progress to the next; during these meals, the tick can acquire or transmit B. burgdorferi. Larvae and nymphs often feed on small rodents, which are reservoirs for the bacteria. Nymphs and adults can transmit the bacteria to dogs and humans. Awareness of this cycle is helpful to understand the risks at different times of the year and the importance of tick control measures. 

Where is Lyme disease transmitted?  

Black-legged ticks thrive in tall grasses and in the woods. Ticks hang out on the tips of leaves and other vegetation, waiting for an animal or person to walk by so they can grab on and crawl until they find a place to bite.  

While Lyme disease was traditionally thought to be limited primarily to the Northeastern United States (the disease is named after the town of Lyme, Connecticut, where it was first described in 1976), positive cases of canine Lyme disease have now been reported across the U.S., with 39 states reporting high and moderate prevalence.  

The black-legged tick’s range has expanded significantly over the past few decades, which means the tick and the Lyme-causing bacteria are present in Virginia.  Climate change is significantly impacting the distribution of the black-legged tick, leading to an increase in Lyme disease cases in areas once considered low-risk. Warmer temperatures and milder winters allow ticks to remain active longer and expand into new territories. 

In 2015, Professor Emerita Anne Zajac co-authored a paper on vector-borne and zoonotic diseases in which researchers collected hundreds of ticks from Giles and Pulaski counties. They found that one-third of those ticks carried B. burgdorferi!  

Dogs tend to be bitten by infected ticks in the early spring and late fall when adult ticks are most active, but animals and humans can contract Lyme disease any time of year.  

Lyme disease in dogs 

Black-legged ticks and B. burgdorferi may be uncomfortably common, but the good news is that most animals with Lyme disease show no signs of illness. Symptoms of Lyme disease in dogs can vary widely and may not appear for months after infection.  

Some dogs may exhibit more subtle signs or more severe reactions. Those symptoms might only appear months after infection for dogs who show symptoms. Those symptoms include: 

  • Fever 
  • Joint pain or swelling 
  • Swollen lymph nodes 
  • Lethargy  
  • Appetite loss  
  • Increased thirst and urination 

If left untreated, the disease can damage the kidneys, nervous system, and heart and cause chronic joint pain. Kidney damage from Lyme disease is typically fatal, and damage to the nervous system can lead to seizure disorders. Heart damage due to Lyme disease is rare.  

Diagnosis, treatment, and prevention 

To diagnose Lyme disease, your dog’s veterinarian will examine its clinical signs, exposure to black-legged ticks, and test results. Dogs produce antibodies 4-6 weeks after infection, which can be detected through testing.  

Lyme disease is treated with antibiotics, typically for around a month. Most symptoms clear up quickly with antibiotic treatment. The choice of antibiotic and the duration of treatment can depend on the severity of the symptoms, the stage of the disease, and the dog’s overall health. While antibiotics are effective in most cases, it’s critical to complete the entire course of treatment, even if symptoms improve, to prevent the recurrence of the disease and reduce the risk of complications. 

Like so many diseases, the best treatment is prevention. Consistent usage of tick-preventative products can help your pet stay tick-free, and it’s important to avoid tick hotspots like fields with long grass.  

Your veterinarian might suggest vaccinating your dog against Lyme disease, depending on its needs and exposure to ticks.  

When would it be appropriate to get your dog vaccinated for Lyme?  

Jenny Marin, clinical assistant professor in Community Practice at the Veterinary Teaching Hospital, said, “We recommend vaccinating all dogs for Lyme in this area (SW Virginia) starting when they are puppies.”

Beyond vaccination and tick-preventive products, reducing exposure to ticks through environmental management is a critical strategy in Lyme disease prevention. This includes maintaining lawns, clearing brush and leaf litter, and creating tick-safe zones using wood chips or gravel barriers. Personal protective measures, such as checking dogs for ticks after outdoor activities and promptly removing ticks, are also good steps. Prompt tick removal is important — it typically can take 1-2 days for the bacteria to transmit from the tick to the animal. 

One last reminder: Remember that your dog can’t directly spread Lyme disease to you or your other pets; the disease-causing bacteria can only be spread through tick bites!


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