Tick-borne diseases

According to ESCCAP France (European Scientific Counsel Companion Animal Parasites), 30 to 50% of dogs in rural areas carry at least one tick at some point in the season. And behind a tick bite lie several serious vector-borne diseases: babesiosis (piroplasmosis), ehrlichiosis, anaplasmosis, Lyme disease, hepatozoonosis. Some kill within 48 hours; others cause chronic problems diagnosed months later. This guide reviews each disease, its symptoms, vectors and treatment and, above all, effective prevention.

Know your enemy: ticks in France

Three tick species dominate in France and account for most of the risk to dogs:

• Ixodes ricinus (sheep tick, castor bean tick or European tick): the most widespread across the whole northern half of the country. The main vector of Lyme disease and anaplasmosis. Found in damp forests, undergrowth and long grass.
• Dermacentor reticulatus (ornate dog tick, or marsh tick): the main vector of babesiosis. Found in northern and central France, and spreading. Prefers woodland and meadows.
• Rhipicephalus sanguineus (brown dog tick): found mainly in the south, in the Mediterranean area. Can infest homes and kennels. A vector of ehrlichiosis and hepatozoonosis.

Risk season: peaks in spring (April–June) and autumn (September–November). With climate change, ticks are now active almost all year round in temperate areas.

1. Babesiosis (piroplasmosis) — emergency no. 1

Canine babesiosis is caused by a protozoan parasite, Babesia canis or B. vogeli, which destroys red blood cells. It is the most common and most serious vector-borne disease in France.

Vector: the Dermacentor reticulatus tick. The parasite is transmitted after the tick has been attached to the dog for 24–48 hours.

Incubation: 7 to 14 days after the bite.

Symptoms (sudden onset):

• High fever (40–41 °C) and marked lethargy.
• Complete loss of appetite.
• Very dark urine (cola-coloured) — massive destruction of red blood cells.
• Pale or yellowish gums (anaemia + jaundice).
• Vomiting, sometimes acute kidney failure.

Mortality: 10–15% without treatment, up to 50% in the peracute form. Excellent prognosis if caught in time.

Treatment: imidocarb injection (Carbesia®), IV fluids, blood transfusion if anaemia is severe. An absolute emergency — see a vet within hours of the first symptoms.

2. Lyme disease (borreliosis)

Caused by the spirochaete bacterium Borrelia burgdorferi sensu lato, transmitted by Ixodes ricinus.

Distinctive feature: only 5 to 10% of infected dogs develop clinical signs. Many remain symptom-free carriers.

Incubation: 2 to 5 months after the bite (a long time!).

Symptoms:

• Sudden-onset lameness, often shifting (affects one leg, then another).
• Moderate, intermittent fever.
• Polyarthritis, swollen joints.
• Tiredness, loss of appetite.
• In 1–2% of cases: glomerulonephritis (serious kidney damage, potentially fatal).

Treatment: doxycycline for 4 weeks. The outcome is usually good, but relapses do happen.

Note: Lyme disease is a zoonosis — humans can be infected too (by the same kind of tick bite, not by the dog).

3. Canine ehrlichiosis

Caused by Ehrlichia canis, an intracellular bacterium transmitted by Rhipicephalus sanguineus. Mainly affects dogs in the south of France and around the Mediterranean.

Clinical phases:

• Acute phase (1–3 weeks after the bite): fever, lethargy, weight loss, bleeding (nosebleeds, pinpoint skin haemorrhages called petechiae).
• Subclinical phase (months to years): the dog shows no symptoms but is a carrier; blood abnormalities can be detected.
• Chronic phase: pancytopenia (collapse of red cells, white cells and platelets), severe bleeding, opportunistic infections. Guarded prognosis.

Treatment: doxycycline for 4 weeks (acute form), sometimes longer. The chronic form is hard to eradicate.

4. Granulocytic anaplasmosis

Caused by Anaplasma phagocytophilum, transmitted by Ixodes ricinus. Emerging in France, particularly in the north-east and Brittany.

Symptoms:

• Fever, lethargy, loss of appetite.
• Sudden-onset lameness.
• Bleeding (thrombocytopenia).
• Neurological signs are rare but possible.

Treatment: doxycycline for 14–28 days. Good prognosis with early treatment.

5. Hepatozoonosis

Rarer, caused by Hepatozoon canis and transmitted by swallowing the tick (not by its bite) — typically when the dog catches the tick in its teeth while scratching. Found in the Mediterranean area.

Symptoms: recurring fever, muscle pain, weakness, anaemia, sometimes eye problems.

Treatment: a combination of imidocarb and toltrazuril. Variable prognosis.

Removing a tick correctly

The removal technique is crucial to limit the risk of disease transmission:

• Use a tick hook (O'Tom Tick Twister, Trixie) — it's the go-to tool.
• Slide the hook under the tick as close to the skin as possible.
• Twist gently (either direction) until the tick comes away.
• Never pull with ordinary tweezers: you risk crushing the tick (releasing contaminated saliva) or tearing it off and leaving the mouthparts in the skin.
• NEVER use ether, alcohol, petroleum jelly or paraffin: a stressed tick regurgitates heavily, which increases the risk of transmission.
• Disinfect the area after removal.
• Keep an eye on your dog for 3 to 4 weeks to spot any symptoms (fever, lethargy, dark urine, lameness).

Prevention: parasite treatments and checks

Prevention combines continuous chemical protection with systematic checks after every walk.

Tick treatments (acaricides) (on veterinary prescription):

• Monthly or three-monthly tablets (isoxazolines: Bravecto®, NexGard®, Simparica®) — very effective, fast-acting (4–12 hours after the bite).
• Monthly spot-on pipettes (Frontline®, Advantix®, Effitix®).
• Long-lasting collars (Seresto®, Scalibor®) — 6 to 8 months of protection.
• The choice depends on lifestyle (hunting dog, swimmer, etc.): discuss it with your vet.

Systematic checks after every walk:

• Run your hands against the lie of the coat over the whole body.
• Ticks' favourite spots: neck, ears (inside and out), armpits, groin, between the toes, muzzle.
• Remove any tick you find straight away.

Vaccinations: a vaccine against Babesia canis exists (Pirodog®) — moderately effective (≈ 80%), recommended in areas of very high prevalence. A Lyme disease vaccine also exists (Merilym®) but remains debated.

Tick-borne diseases at a glance

Conclusion

A tick is not just an unpleasant parasite: it transmits some of the most dangerous dog diseases in France. Babesiosis can kill within 48–72 hours; Lyme disease is diagnosed months after the bite. Prevention combines a monthly (or three-monthly) parasite treatment, systematic checks after walks and immediate removal with a proper tick hook. If you notice fever, lethargy, dark urine or unexplained lameness in the weeks after a walk, see your vet without delay.