INTRODUCTION

Canine ehrlichiosis is a disease of dogs caused by bacteria of the genus Ehrlichia called Ehrlichia canis. It is transmitted by tick bites.

WHAT IS CANINE EHRLICHIOSIS?

Canine Ehrlichiosis is a disease caused by a parasite of the rickettsiae family called Ehrlichia and is transmitted to humans and animals mainly by the bite of ticks. This disease is very serious and almost always leads to death if not detected and treated in time.

All ticks do not transmit the disease, a tick becomes a vector of Ehrlichia canis when it ingests blood from an infected dog, acquiring the parasite in larval form and transmitting it as an adult nymph to a healthy dog.

When a tick carrying Ehrlichia canis comes into contact with a new host animal, it transmits the parasite via saliva when feeding. Infection also occurs through blood transfusions in which the donor animal is rickketsiemic.

Dogs can be affected by two types of Ehrlichia: Ehrlichia canis, which affects white blood cells and results in Ehrlichiosis, and Ehrlichia platys, which affects platelets and results in infectious cyclic thrombocytopenia.

The time from tick bite to onset of symptoms, called the incubation period, is approximately 8 to 21 days.

SYMPTOMS OF CANINE EHRLICHIOSIS

The most common symptoms of canine ehrlichiosis are:

• Changes in behaviour and mood.
• Lethargy and lack of coordination.
• Weight loss due to lack of appetite.
• Spontaneous haemorrhages and seizures.
• Inflammation of joints, brain or lymph nodes.
• Respiratory problems.
• Uveitis.
• pale mucous membranes
• Fever.
• epistaxis
• darkening of the teeth

Some rare symptoms:

• Nasal discharge and cough, due to pneumonia.
• Intermittent lameness, caused by polyarthritis due to deposition of immunocomplexes at joint level.
• Meningitis due to inflammation or haemorrhages in the nervous system.
• renal failure due to immune-mediated glomerulonephritis.

HOW IS CANINE EHRLICHIOSIS TRANSMITTED?

Like anaplasmosis, canine ehrlichiosis is caused by rickettsiae. These are single-celled bacteria that enter the dog's body during tick-sucking.

The brown dog tick (Rhipicephalus sanguineus) is the main transmitter and is widespread in the Mediterranean region. In addition, this tick has already been introduced into other countries, such as Germany, so that dogs become ill there as well.

It is also possible that the disease is transmitted by the veterinarian from one dog to another via contaminated needles and blood transfusions (iatrogenic). Theoretically, it would also be possible for a person to transmit it to a dog.

Ehrlichia canis is an intracellular bacterium that infests the dog's blood cells, thus spreading throughout the body. As the infected blood cells adhere to the vascular walls of various organs, damage occurs.

The acute phase is followed by the subclinical phase. The dog shows no symptoms and the immune system is working flat out to eliminate the pathogen. If this is not completely successful, the disease becomes chronic.

Diagnosis is made by clinical signs and blood tests. A haemogram, where anaemia, decreased white blood cells and/or platelets may be detected, and serology, which detects the presence of antibodies against Ehrlichia in the blood, may be performed. Bone marrow aspiration may sometimes be necessary.

Ehrlichiosis is prevented by strict control of tick infestations, as a single infected tick can develop the disease; your veterinarian will recommend the most appropriate product depending on your pet's lifestyle. There is no vaccine against the disease.

HOW TO PREVENT CANINE EHRLICHIOSIS?

There are many methods of controlling ticks, the main ones being the use of flea collars and flea pills.

Tick infested areas should also be avoided and in case of tick infestations indoors, spraying with amitraz and/or cypermethrin is recommended.

CONCLUSION

Ehrlichiosis is transmitted by tick bites. Avoiding tick bites prevents this and other tick-borne diseases.

Ticks have a structure in their mouths that allows them to attach themselves firmly to the site from which they are sucking blood and only manage to detach themselves from the host when they are full, but this can take several days.

Studies suggest that a tick has to remain attached to the body for at least 24 hours to cause disease; hence early removal prevents infection.