There are many diseases carried by ticks. One of them, Ehrlichiosis (pronounced “err-lick-iosis”) goes by many names, but no matter what you call it, this devastating dog disease can wreak havoc on your pet.

In April 2026, the Centers for Disease Control and Prevention (CDC) reported that emergency department visits for tick bites were higher than usual in most U.S. regions and the highest reported for that time of year since tracking began in 2017. These data underscore an important message: people and pets may be encountering ticks more frequently. Ticks can transmit diseases that affect both animals and humans, reinforcing the need for awareness and preventive action. (CDC.gov) 

“The good news is that pet owners have effective tools available to help reduce parasite risks,” said Dr. Susanne Heartsill. “The most successful prevention plans are proactive, consistent, and tailored to each pet’s individual lifestyle and exposure risk.” Dr. Susanne Heartsill, DVM, DABVP (Canine and Feline Practice), is the U.S. Companion Animal Chief Veterinary Officer at Ceva Animal Health

Ticks Change With the Weather

The CDC recommends repellents for people because preventing tick attachment helps reduce opportunities for disease transmission. A similar principle applies to dogs. Some canine parasite preventive products both repel and kill ticks and fleas, helping reduce tick attachment and feeding as part of a comprehensive prevention program. Preventing Tick Bites | Ticks | CDC 

“From a One Health perspective, preventing tick attachment and feeding is an important objective for both people and pets,” said Dr. Heartsill. “Just as public health experts recommend repellents as part of personal protection, veterinarians may recommend products with repellent activity for dogs as one component of a broader parasite prevention strategy. The goal is to reduce parasite exposure whenever possible.” 

At our house, we provide our Shadow-Pup (and also Karma-Kat and Trinity-Kitty) with protection. Even pets that don’t step a paw outside may still have a tick come inside on a human’s shoes or a canine friend’s fur. We also keep the yard manicured and short, since ticks don’t like that. By combining preventive products, routine tick checks, environmental awareness, and responsible pet care, pet owners can help protect their pets while supporting healthier families and communities.

To learn more about one of the nastiest tick-borne diseases, read on.

WHAT IS CANINE EHRLICHIOSIS?

Canine ehrlichiosis is caused by one or several species of Ehrlichia bacteria, most commonly Ehrlichia canis (E. canis) or Ehrlichia lewinii (E. lewinii). This specialized bacteria requires an intermediate host, or vector, to infect its victim. The brown dog tick and the Lone Star tick are the primary vectors.

The disease has been reported worldwide wherever these ticks are found. Most cases in the United States occur in dogs living in the Texas Gulf coast regions and other southern states. All dogs are susceptible, but those with greater exposure to ticks. Outdoor dogs, working dogs and hunting dogs are at highest risk. Doberman Pinschers and German Shepherds seem to be more severely affected. Ehrlichiosis is diagnosed most often during the warm months of tick season.

HOW DO DOGS GET IT?

The tick becomes infected when it bites an exposed dog and ingests infected blood. The tick may transmit the disease for up to five months after engorgement with infected blood. Once infected, transmission of the disease to dogs can occur in any stage (by larva, nymph, or adult tick). It is even possible for ticks to survive winter months and infect susceptible dogs in the spring.

The organism is passed to dogs in the tick saliva when the infected parasite takes a blood meal. Blood transfusion from an infected donor dog also has the potential to transmit the disease. E. canis initially invades and damages the white blood cells of the host dog. From there, the rickettsiae spread via the blood to lymphatic tissue including the liver, lymph nodes and spleen.

WHAT SYMPTOMS DOES EHRLICHIOSIS CAUSE?

Signs of the disease can vary greatly from case to case. That makes canine ehrlichiosis an extremely frustrating disease to diagnose. Dogs suffering stress are also more susceptible.

There are both acute and chronic stages of the disease. Dogs suffering from the acute phase exhibit sudden severe symptoms, or show few or no signs at all. Signs include:

• a week-long fever
• eye and nasal discharge
• loss of appetite, depression
• swollen legs
• stiffness and reluctance to walk
• weight loss
• neurologic symptoms such as muscle twitches

X-rays may reveal signs of pneumonia. The acute stage lasts two to four weeks; dogs either recover, or proceed to the chronic phase of disease.

The chronic stage of the disease can last for several months, and appears to affect dogs with suppressed immune systems. The bone marrow is compromised, resulting in a reduction in the production of blood cells. Often, the dog will develop kidney disease. Low platelet counts may cause bleeding tendencies, and long nosed breeds like shepherds may suffer nose bleeds. Fatigue, bloody urine, discoloration and bruising of the skin occur in all breeds.

HOW IS IT DIAGNOSED?

Diagnosis is based on signs of disease along with history of tick exposure. Polymerase chain reaction (PCR) testing, which isolates the DNA of the causative agent, is now commonly employed for confirmation. The PCR test, in combination with a test for antibodies to the Ehrlichia infection, is typically the best way to make a concrete diagnosis.

WHAT TREATMENT IS RECOMMENDED?

The antibiotic doxycycline is effective against E. canis when administered early in the course of the disease. Dogs may require six weeks or more of treatment before being cured, and some may benefit from fluid therapy or blood transfusions. Infection does not impart immunity and dogs can be reinfected. Dogs with chronic disease in which bone marrow is irreparably damaged may require months of therapy before any improvement is apparent, but prognosis is not good and often th
e dog dies despite treatment.

CAN YOU PREVENT EHRLICHIOSIS?

There is no vaccination available to prevent canine ehrlichiosis. The best way to protect dogs is to reduce or prevent exposure to ticks. In high-risk environments (i.e., kennel situations where the disease has been diagnosed), your vet may recommend a daily low-dose of antibiotic used as a preventative.

Ticks hate bright sunlight so keeping yards and fields mowed short, and limiting your dog’s ranging can help. Ticks carry many other kinds of “nasties” so using a vet-approved tick preventive in endemic areas may be recommended.

Learn about tick prevention in this post about Rocky Mountain Spotted Fever.

Does your dog get ticks? Are you using tick treatment to protect him? Has your dog ever suffered from a tick-borne disease? Please share your tips and tricks so others can help keep their dogs safe.