Tick Fever in Dogs: Causes, Signs, Diagnosis and Treatment

Tick fever in dogs, also known as canine ehrlichiosis or canine anaplasmosis, is a tick-borne disease caused by various species of bacteria called Ehrlichia and Anaplasma. These bacteria are transmitted to dogs through the bite of infected ticks, such as the brown dog tick, the American dog tick, and the deer tick.

Causes of Tick Fever in Dogs

Tick fever in dogs is caused by various species of bacteria from the genera Ehrlichia and Anaplasma, which are transmitted to dogs through the bite of infected ticks. Here are the primary causes of tick fever in dogs:

• Ehrlichia canis: This bacterium is responsible for causing canine ehrlichiosis, one of the most common forms of tick fever in dogs. It is transmitted mainly by the brown dog tick (Rhipicephalus sanguineus). Ehrlichia canis infects and replicates within white blood cells, leading to various symptoms and potential complications.
• Anaplasma phagocytophilum: This bacterium causes canine anaplasmosis and is transmitted by the black-legged deer tick (Ixodes scapularis) and the western black-legged tick (Ixodes pacificus). Anaplasma phagocytophilum primarily infects neutrophils, a type of white blood cell, and can lead to symptoms like fever, joint pain, and lethargy.
• Other Ehrlichia and Anaplasma species: Besides Ehrlichia canis and Anaplasma phagocytophilum, other species of these bacteria can cause tick fever in dogs. For example, Ehrlichia ewingii and Anaplasma platys can infect dogs, resulting in similar clinical signs.

Risk Factors of Rocky Mountain Spotted Fever in Dogs

Rocky Mountain spotted fever (RMSF) is a tick-borne disease that can affect dogs. Several risk factors can increase a dog’s susceptibility to this potentially serious condition:

• Geographic Location: RMSF is more commonly reported in some areas of the United States, including the Rocky Mountain region, the southeastern states, and parts of the Midwest. Dogs living or spending time in these areas are at a higher risk of exposure to the disease.
• Tick Vectors: RMSF is primarily transmitted to dogs through the bite of infected ticks. The American dog tick (Dermacentor variabilis) and the Rocky Mountain wood tick (Dermacentor andersoni) are two common tick species that can carry and transmit the causative agent, Rickettsia rickettsii, to dogs. Dogs that come into contact with these ticks are at risk.
• Tick Season: The risk of RMSF is generally higher during the warmer months when ticks are more active. Spring and summer are peak tick seasons in many regions, increasing the likelihood of tick exposure.
• Outdoor Activities: Dogs that spend much time outdoors, especially in wooded or grassy areas with prevalent ticks, are likelier to encounter infected ticks. Hunting dogs, hiking companions, and dogs in rural areas are often at increased risk.
• Lack of Tick Prevention: Failing to use tick prevention methods, such as tick collars, topical treatments, or oral medications, can leave dogs vulnerable to tick bites and infection with RMSF.
• Tick Checks: Owners who do not regularly check their dogs for ticks after outdoor activities may miss the opportunity to remove ticks before they transmit the disease-causing bacteria.
• Previous Tick-Borne Infections: Dogs previously exposed to tick-borne diseases may be more susceptible to RMSF because their immune systems may be compromised.
• Age and Health Status: Young puppies, elderly dogs, and dogs with weakened immune systems are generally more vulnerable to tick-borne diseases, including RMSF. Their ability to fight off infections may be reduced.
• Long Hair and Thick Fur: Dogs with long hair or dense fur may make it more challenging to spot ticks on their bodies, increasing the time ticks have to attach and transmit the bacteria.
• Lack of Vaccination: Unlike other tick-borne diseases, dogs have no specific vaccine available for RMSF. Vaccination against other diseases, such as Lyme disease, is unrelated to RMSF protection.

Clinical Signs of Tick Fever in Dogs

Tick fever in dogs, caused by bacteria like Ehrlichia and Anaplasma, can result in various clinical signs and symptoms. These signs can differ in severity depending on the specific bacterium involved, the dog’s overall health, and the stage of the disease. Here are some common clinical signs of tick fever in dogs:

• Fever: An elevated body temperature is often one of the first signs of tick fever. A dog with tick fever may have a persistent fever that doesn’t resolve independently.
• Lethargy: Affected dogs tend to become lethargic and may lack energy or enthusiasm for their usual activities.
• Loss of Appetite: Tick fever can cause a decreased appetite, leading to a dog not eating as much as usual or refusing food altogether.
• Joint Pain: Some dogs with tick fever may experience joint pain, manifesting as lameness, stiffness, or reluctance to move.
• Swollen Lymph Nodes: Swollen lymph nodes may be observed in dogs with tick fever, particularly in the neck and under the jaw.
• Bleeding Disorders: In severe cases, tick fever can lead to bleeding disorders, resulting in symptoms such as nosebleeds, bruising, or blood in the urine or stool.
• Respiratory Signs: Coughing or labored breathing may occur in dogs with advanced cases of tick fever.
• Gastrointestinal Symptoms: Dogs with tick fever may experience vomiting and diarrhea, which can contribute to dehydration.
• Weight Loss: Dogs with tick fever may lose weight due to reduced appetite and metabolic changes.
• Eye and Nasal Discharge: Some dogs may develop eye discharge or a runny nose as part of their clinical signs.
• Neurological Symptoms: In rare cases, tick fever can affect the nervous system, leading to seizures, ataxia (lack of coordination), or other neurological abnormalities.

Diagnosis of Tick Fever in Dogs

Detecting tick fever in dogs typically involves a combination of clinical evaluation, laboratory tests, and a thorough medical history. Here are the critical steps involved in diagnosing tick fever in dogs:

• Clinical Evaluation: The veterinarian will begin by physically examining the dog. During this examination, they will look for signs and symptoms suggesting tick fever, such as lethargy, joint pain, swollen lymph nodes, and evidence of tick exposure. They will also inquire about the dog’s recent activities, including any potential tick exposure.
• Blood Tests: Blood tests are crucial to diagnosing tick fever in dogs. Several blood tests can be used:
  • Complete Blood Count (CBC): A CBC provides information about the dog’s red blood cells, white blood cells, and platelets. Tick fever can cause changes in these blood cell counts.
  • Serology: Serological tests can detect antibodies produced by the dog’s immune system in response to the infection. These antibodies can help confirm exposure to the tick-borne pathogen. Tests may include the indirect immunofluorescence assay (IFA), enzyme-linked immunosorbent assay (ELISA), or others specific to the pathogen.
  • PCR (Polymerase Chain Reaction): PCR tests can detect the DNA of the tick-borne pathogen in the dog’s blood. This is a more direct method of identifying the pathogen.
• Other Diagnostic Tests: In some cases, additional tests may be necessary to evaluate the dog’s overall health and assess for complications related to tick fever. These tests may include urinalysis, X-rays, or ultrasound.
• History and Tick Exposure: The veterinarian will inquire about the dog’s history of tick exposure, travel history, and any recent tick removals. Knowing the type of tick and its geographic prevalence can provide valuable information for diagnosis.
• Response to Treatment: If there is a strong clinical suspicion of tick fever and diagnostic test results are pending, the veterinarian may initiate treatment with appropriate antibiotics. The dog’s response to treatment can further support the diagnosis. However, this should not replace definitive diagnostic testing.

Differential Diagnosis of Tick Fever in Dogs

The clinical signs of tick fever in dogs can overlap with those of other diseases. Therefore, veterinarians must consider a range of potential differential diagnoses to determine the underlying cause of a dog’s symptoms. Here are some common conditions and diseases that may need to be ruled out when evaluating a dog with suspected tick fever:

• Other Tick-Borne Diseases: Tick-borne diseases like Lyme disease, anaplasmosis, and babesiosis can present symptoms similar to tick fever. Different pathogens cause each disease, so diagnostic tests are essential to differentiate them.
• Other Infectious Diseases: Dogs can contract bacterial, viral, and parasitic infections that may mimic tick fever symptoms. Some examples include leptospirosis, canine distemper, parvovirus, and fungal infections.
• Immune-Mediated Disorders: Autoimmune diseases, such as immune-mediated thrombocytopenia (IMT) or immune-mediated hemolytic anemia (IMHA), can cause similar symptoms, including fever, lethargy, and abnormal blood cell counts.
• Orthopedic Conditions: Joint pain and lameness may be attributed to orthopedic issues like arthritis, joint injuries, or developmental disorders.
• Gastrointestinal Conditions: Vomiting, diarrhea, and weight loss can be symptoms of various gastrointestinal disorders, including inflammatory bowel disease, gastritis, or intestinal parasites.
• Endocrine Disorders: Conditions like hypothyroidism or hyperadrenocorticism (Cushing’s disease) can cause generalized symptoms such as lethargy and changes in appetite.
• Neoplastic Diseases: Certain cancers can lead to non-specific clinical signs, including weight loss, fatigue, and swollen lymph nodes.
• Toxicities: Ingestion of toxic substances can result in symptoms such as vomiting, diarrhea, and neurological signs.
• Cardiovascular Diseases: Heart disease or heartworm infection can cause coughing, labored breathing, and exercise intolerance.
• Heatstroke: In hot weather, dogs can suffer from heatstroke, manifesting as lethargy, vomiting, and elevated body temperature.
• Neurological Disorders: Neurological conditions, such as epilepsy or meningitis, can lead to seizures and other neurological abnormalities.
• Allergies and Skin Conditions: Itching, skin rashes, and hair loss can be symptoms of allergies, dermatitis, or parasitic infestations.

Treatment of Canine Rocky Mountain Spotted Fever 

Treating tick fever in dogs typically involves a course of antibiotics to kill the specific bacteria responsible for the infection. Early detection and treatment are essential to improve the prognosis and prevent disease progression. Here’s an overview of the treatment process for tick fever in dogs:

• Antibiotic Therapy: The primary treatment for tick fever in dogs is the administration of antibiotics. The antibiotic choice and treatment duration may depend on the specific bacterium involved. Commonly used antibiotics for tick fever include doxycycline and tetracycline for infections caused by Ehrlichia and Anaplasma species. Your vet will determine the appropriate antibiotic and dosage based on the dog’s condition and diagnostic results.
• Supportive Care: Depending on the infection’s severity and complications, supportive care may be necessary. Supportive care can include:
  • Fluid Therapy: Intravenous (IV) fluids may be administered to dehydrated dogs due to vomiting, diarrhea, or reduced fluid intake.
  • Pain Management: Dogs experiencing joint pain or discomfort may be given pain medications to alleviate their symptoms.
  • Treatment of Complications: If the dog has developed complications such as bleeding disorders, treatment may be directed at managing those issues.

Prevention of Canine Tick Fever

Preventing tick fever in dogs involves a combination of strategies to reduce tick exposure and manage the risk of infection. Here are some effective preventive measures:

• Use Tick Preventatives:
  • Consult your veterinarian to choose an appropriate tick-preventative product for your dog. These may include topical treatments, oral medications, or tick collars.
  • Administer tick preventatives according to the manufacturer’s instructions and your veterinarian’s recommendations.
  • Ensure that the chosen product is effective against the tick species prevalent in your area.
• Regular Tick Checks:
  • After your dog has been outdoors, especially in areas with tall grass or wooded environments, thoroughly check your dog for ticks. Pay close attention to the ears, neck, armpits, and between toes.
  • Promptly remove any ticks using fine-tipped tweezers or a tick removal tool. Hold the tick as close to the skin’s surface as possible and pull upward with steady, even pressure.
• Tick Control in Your Yard:
  • Reduce tick habitat in your yard by trimming grass and clearing leaf litter or brush that may harbor ticks.
  • Use tick control products or professional pest control services to manage tick populations in outdoor spaces.
• Avoid Tick-Prone Areas:
  • Be aware of where ticks are commonly found, and avoid them when walking or playing with your dog.
  • If you’re in a high-risk area, keep your dog on a leash to restrict them from wandering into tall grass or wooded areas.
• Tick-Repellent Clothing:
  • In tick-prone regions, you can dress your dog in tick-repellent clothing designed for dogs. These medicines can help reduce the risk of ticks attaching to your pet.
• Vaccination:
  • Vaccines may be available in some areas to protect dogs against specific tick-borne diseases. Consult your vet to determine if vaccination is recommended in your region.
  • Regular Vet Check-Ups: Schedule regular check-ups with your vet to monitor your dog’s health and discuss tick prevention strategies.
• Environmental Control:
  • Consider implementing environmental control methods, such as using tick-killing sprays in your home or your dog’s bedding, to reduce the risk of ticks infesting your living spaces.
• Tick Awareness and Education:
  • Stay informed about the types of ticks in your area and the diseases they carry.
  • Educate yourself about tick removal techniques and the signs of tick fever in dogs so that you can take prompt action if your dog is exposed.
• Consult Your Veterinarian:
  • If you have concerns about tick exposure or tick-borne diseases in your region, consult your veterinarian for specific advice and recommendations tailored to your dog’s needs.

Conclusion on Tick Fever in Dogs

In conclusion, tick fever in dogs, caused by bacteria like Ehrlichia and Anaplasma, is a significant concern for dog owners, particularly in regions where ticks are prevalent. If left untreated, this tick-borne disease can lead to clinical signs and potentially severe complications.

The prognosis for dogs with tick fever can vary depending on factors such as the dog’s health, the severity of the disease, and the promptness of treatment. Early diagnosis and treatment are crucial for a better outcome.

Overall, vigilance, proactive tick prevention measures, and regular veterinary care significantly protect dogs from tick fever and other tick-borne diseases. Timely detection and intervention can help ensure the health and well-being of our canine companions in tick-prone areas.