Tick Fever and other Tick Borne Infections in Dogs

It can be tricky to deduce if a dog has spotted fever because the symptoms vary in severity and type. They include:

• Fever: The normal temperature of your dog is between 101 and 102.5 degrees Fahrenheit. If your dog’s temperature is consistently higher than this, you should visit the vet.
• Lethargy and loss of appetite (inappetence)
• Cough 
• Difficulty walking or lameness
• Enlarged lymph nodes
• Petechial haemorrhage: These are tiny red/purplish spots that occur all over the body. The condition is called spotted fever because of this.

In more severe cases, there are neurological symptoms as well. These include an altered mental state, balance and coordination problems and increased spinal sensitivity.

You will need to give your vet a detailed medical history of your dog, including deworming and vaccine details. Try your best to recall when symptoms first started and explain how your dog’s behaviour has changed (report if they have become inactive or refuse to eat, for example). This will help your vet figure out the extent of the infection and if any specific organs are affected.

A range of blood tests will help to make the diagnosis. These include:

• Complete blood count (CBC): A blood test, CBC gives information on antibody production. An increase will indicate infection.
• Platelet count and clotting test: Tests assessing the coagulation (clotting) levels of the blood and platelets will also be conducted.
• Titer test: To confirm the diagnosis, another blood test may be prescribed two weeks later, to check for the concentration of antibodies in the blood to assess the presence and levels of the parasite.

However, your vet is unlikely to wait for the latter and begin treatment anyway. The information from the titer will be used later to assist in tick management in the household and prophylactically treating any other pets you may have.

Antibiotics are the first line of treatment for tick fever. Doxycycline is the most commonly used one and your pet will likely be on it for up to a month. After this period, blood tests will be conducted again to check effectiveness. There may also be supplementary treatments such as blood transfusions if there are complications. 

Usually, dogs will respond well to timely treatment. In cases where there are no complications, the dog will develop lifelong immunity as well.

However, the situation can turn grim if there are complications. Kidney disease, liver problems and neurological problems may persist as the after-effects of infection.

Since the parasite attacks red blood cells, the body will mount an immune attack on red blood cells to combat the infestation. Unfortunately, healthy red blood cells are also killed in the process, leading to immune-mediated hemolytic anaemia (IMHA) in which the red blood count falls strongly. Symptoms occur largely as a result of:

• High fever, lethargy and weakness 
• Jaundice in dogs, a condition in which there is an excess of bilirubin (a byproduct of the breakdown of haemoglobin in red blood cells) in the body
• Dark-coloured urine and stool
• Bloated abdomen 

The high levels of inflammation can also lead to a decrease in blood platelets and coagulation issues (clotting problems). Further neurological symptoms such as altered states, issues with balance and seizures can also occur. 

Certain species of Babesia will show up on blood smears. A complete blood profile, antibody testing (such as Immunofluorescent antibody [IFA]) and PCR (Polymerase Chain Reaction) may be conducted as well, depending on the infrastructure available at your vet’s clinic. Often blood tests will be inconclusive, so PCR remains the strongest diagnostic tool. 

For thoroughness, the vet will also conduct a complete physical exam and ask for your dog’s medical history. 

If you are living in an area known to have Babesia, or your dog is prone to tick infection, your vet may take it as sufficient evidence that a form of tick fever is at play and initiate treatment.

The most commonly used drug for the treatment of Babesiosis in dogs is imidocarb. A shot of imidocarb is usually sufficient for certain strains of the parasite, whereas other strains will require another shot in the space of a couple of weeks. Note that the injection is painful and can cause side-effects such as drooling in dogs, facial swelling, agitation, tremors and elevated heart rate. 

Supplementary antibiotics such as azithromycin, quinine, may also be used. Since Babeosis can occur in humans as well, the drug used for treatment, clindamycin, is also used sometimes. Research suggests that other drugs may be more effective and cause fewer side effects, but these treatments are on the horizon. Your vet will suggest an antibiotic based on your dog’s current status as each drug has its own contraindications and side effects. 

Supplementary therapy such as blood transfusions will be required in some cases. If cases resolve without further complications, prognosis is good. However, in more severe cases, prognosis is guarded.

The disease evolves through different stages:

Acute phase

In the acute phase, the parasites will begin to make their presence felt by attaching to white blood cells and triggering a drop in platelets. There will be:

• Fever in dogs
• Lethargy in dogs
• Loss of appetite or inappetence in dogs
• There may also be swelling in the lymph nodes and spleen.

It’s important to remember that if the disease is caught at this stage, the prognosis is good and the dog won’t move to the next phase.

Subclinical phase

The subclinical phase occurs after two to four weeks of the acute phase. The outward symptoms diminish and the dog appears to operate largely normally. The infection has actually settled in the spleen and will remain there for months or years. This phase of the disease is dangerous because the owner will believe that the crisis has passed and not take the opinion of the vet. The only signs of disease at this point will be:

• Slightly abnormal blood reports suggesting an increase in white blood cells.
• Some dogs will stay in this stage indefinitely and may not face too many issues, however, some will graduate to the chronic stage.

Chronic stage

The chronic stage has a poorer prognosis and symptoms will reappear. A series of problems will occur, such as:

• Anaemia in dogs
• Chronic bleeding in dogs
• Difficulty with coordination, walking and lameness
• Eye problems in dogs such as uveitis
• Swollen limbs
• Neurological issues such as seizures and altered consciousness

The bone marrow can also be implicated, leading to disastrous outcomes. For dogs in the chronic stage, the mortality rate is higher as other complications arise and the dog’s immune system takes a beating.

As with other tick-borne infections, blood tests, and urinalysis are conducted to study changes in blood cell count. The medical history of the dog is also helpful in providing hints. Again, if PCR and antibody testing facilities are available at your local veterinarian’s office, these will be used to confirm suspicions. 

Rarely, evidence of the microorganism will be visible under a microscope.

The antibiotic doxycycline is usually prescribed to dogs with E. canis infection. For those dogs in the earlier stages, the response is usually good and quite rapid. The drug regimen will last around 28 days after which a diagnostic test will be conducted. If the test suggests that the infection isn't entirely gone, then the regimen will continue.

For more serious cases, supplementary treatment such as blood transfusions will also be required.

As mentioned above, the common symptoms of Lyme disease include:

• Stiffness in the joints: Your dog may develop a limp in one leg that will last a couple of days and disappear. It will then reappear in the same or different leg.
• Neurological and cardiac abnormalities such as altered state, depression, seizures in dogs and increased heart rate and shortness of breath.
• Fever and bruising in dogs.
• Inappetence or loss of appetite
• Swelling close to the site of the bite 
• Sensitivity to touch

While the procedure for diagnosing tick-borne infections remains largely the same, the joint issues presented in Lyme disease mean that vets usually conduct other tests to eliminate differential diagnoses. Underlying causes of arthritis in dogs can be trauma and degenerative joint disease, for example. 

The vet will look at the physical symptoms of the dog as well as the medical history you provide. Blood tests, antibody tests, and a urinalysis will also be used to confirm the diagnosis.

Doxycycline, which is used for most types of tick-borne infections in dogs, is used in treatment. The advantage of doxycycline is that if treatment is provided in time, the infected dogs usually respond rapidly and feel better within 24 hours. Further, the joint pains and aches of the disease are also alleviated by the drug. Again, your dog will be on the drug for up to a month following which there will be a diagnostic test. If that turns out negative, the dog is considered cured.

However, Lyme disease is insidious and can return even after tests turn negative. This form is usually more aggressive and kidney and systemic organ damage can occur.