Canine Babesiosis

What is Canine Babesiosis?

Canine babesiosis is a serious, potentially fatal disease in dogs caused by the parasite Babesia canis, which infects and destroys red blood cells. It is transmitted by the tick Dermacentor reticulatus.

The disease was long considered absent from the UK, but locally acquired cases were confirmed in Essex in 2015–2016. Since then, further cases have been reported, and the tick vector has been found in several parts of England and Wales.

How Dogs Get It

Through the bite of an infected Dermacentor reticulatus tick. This tick is found in grassland, marshes, sand dunes, and coastal pasture in parts of the UK (see species page). Dogs can also become infected abroad and show symptoms after returning to the UK.

Canine babesiosis is not contagious between dogs (except theoretically through blood contact, e.g. fighting) and it does not affect humans.

Signs to Watch For

Symptoms can appear a few days to several weeks after a tick bite:

• Lethargy and weakness — your dog seems unusually tired
• Loss of appetite
• Fever
• Pale gums (a sign of anaemia)
• Dark or red-brown urine (from red blood cell destruction)
• Jaundice (yellowing of the gums or whites of the eyes)

Diagnosis & Treatment

Your vet can diagnose babesiosis with a blood test (blood smear or PCR). Treatment involves anti-parasitic drugs (typically imidocarb) and supportive care. Severe cases may require blood transfusions. With early treatment, many dogs recover fully.

How to Protect Your Dog

• Use tick prevention products — ask your vet about spot-on treatments, tick collars (e.g. Seresto), or oral tablets (e.g. Bravecto, NexGard). These are especially important if you walk in areas where D. reticulatus has been recorded.
• Check your dog after every walk — feel for small bumps, paying attention to ears, head, legs, belly, and between toes.
• Remove ticks promptly using a tick removal tool (see our guide). Don’t squeeze the tick’s body.
• Be extra vigilant in autumn and late winter/early spring — adult D. reticulatus are active in cooler months, unlike most other UK ticks.

References & Further Reading

• GOV.UK — Tick Surveillance Scheme
• British Veterinary Association
• Blue Cross — Ticks on Dogs
• RSPCA — Ticks
• Royal Veterinary College