Who is afraid of tick fever

When a tick bites a dog a blood parasite from the “rickettsiosis” group (Ehrlichia canis) is transmitted to the bloodstream. The parasites are microorganisms that can cause blood infection in various animals. They are transmitted to dogs through the “brown dog tick”. It is currently assumed that in order to transmit the bacteria the tick must be attached to the dog at least 24 hours (in the case of a shorter attachment period apparently the bacteria will not be transmitted and Tick Fever will not develop). Not all ticks carry the disease pathogen in their body, however one infected tick is sufficient to infect a dog. A blood parasite that harms dogs is not contagious to humans and is not dangerous, however it should be noted that the ticks that transmit the disease and are on the dog can be carriers of other diseases that can harm humans.

The Tick Lifecycle:
Adult ticks lay thousands of eggs and have four development stages: egg, larva, young tick and adult tick. They all feed on blood and lymph liquid.

There are 2 types of ticks in dogs:

• “The American Dog Tick” (not common in Israel) in the larva and the young tick stage it feeds on small mammals and falls from them in the development stages. Adult ticks feed on pets
• “Brown Dog Tick” (common in Israel) –feeds on pets in all stages of development

Disease Stages in Dogs:

• Incubation period – the incubation period of the disease – from infection to the eruption of the clinical disease is 7-21 days. Signs of the disease will not be evident during this period
• Acute stage –initial disease signs will be seen
• Sub-clinical stage – the stage in which the dog is a carrier of the bacteria, but there are no disease signs
• Chronic stage – the stage at which it is already difficult to treat the disease and the dog is very sick

It is important to understand that not all dogs reach the chronic stage and some overcome the disease (on their own or with the help of medication).

The acute stage – this stage spans 14 – 30 days. At this stage the bacteria spread in the body organs. In Israel, the disease at this stage is usually diagnosed in the summer, because that is when ticks are more prevalent. Tick fever signs in the acute stage are: high temperature, enlarged lymph nodes, small subcutaneous bleeding, nose bleeding (a very common sign), red eyes/expanded blood vessels in the eye, weakness and lack of appetite. Blood tests at this stage will mainly show a low blood platelet count. It is very important to remember that proper and rapid treatment at this stage will bring rapid recovery; dogs that are not treated properly will remain carriers of the parasite and will move to the sub-clinical stage, and even the chronic stage.
The sub-clinical stage – at this stage the dog is a carrier of the bacteria that causes tick fever but does not show signs of the disease! The dog looks completely healthy however the disease continues to develop. This stage can continue for months and even years. At times perhaps the dog will even recover spontaneously and will not reach the chronic stage in which disease signs become evident.
The chronic stage – this stage is characterized by significant weight loss, weakness, depression, pale mucus, severe anemia, high temperature, peripheral edema, diarrhea/bloody urine, bleeding on the skin, in mucus and from the nose (as a result of damage to bone marrow), damage to eyes – infections and sometimes blindness (due to bleeding behind the retina). At this stage, unfortunately, dogs do not always react to treatment and cannot in all cases be saved.
Diagnosis – diagnosis of tick fever is based on a combination of clinical signs and blood test findings: PCR test for genetic material of the bacteria in the blood (very reliable test); blood count that shows decreased blood platelet count/ white blood cells/ red blood cells.
Treatment of tick fever - the preferred and most effective treatment is the antibiotic Doxycycline (doxycyline). In severe or chronic cases it is sometimes necessary to give steroids to try to suppress over-reaction of the immune system that destroys blood cells and blood platelets.
At this stage of severe anemia blood transfusions or hormones (for example erythropoietin) are sometimes needed to support the creation of red blood cells. If a very low level of white blood cells is found, hormones that support their production can also be tried. In some cases hospitalization is required along with giving fluids, medication to reduce temperature or iron and vitamin supplements. Treatment at the chronic stage is long, complicated and costly due to the price of medication and hospitalization. Therefore, preventive anti-tick treatment has been proven to be the most effective way to prevent the disease, and its importance should not be underestimated.

Chances of Recovery
If tick fever is diagnosed in its early stages, and the disease is treated with antibiotics, the prognosis of recovery is good. Unfortunately, if diagnosis is made at the chronic stage, then recovery chances are small. How can we prevent dogs from contracting tick fever?

Unfortunately, at this time there is no vaccine for tick fever, and even a dog that was sick in the past is not immune from contracting the disease again. The most effective way to prevent the disease is to avoid exposure of dogs to ticks. This should be done by regularly using anti-tick pesticides, in collar, spray or drops – according to the recommendation of a veterinarian. You should remember that despite the fact that ticks and tick fever are more common in summer, infection can also take place in the winter if the temperature is warm enough. Therefore it is recommended to administer anti-tick preventive treatment throughout the year. In cases of a large quantity of ticks in the surroundings, an exterminator should be consulted in order to disinfect the dog’s surroundings from ticks.