Dermacentor reticulatus causes canine babesiosis

Canine Babesiosis: An Emerging Threat to UK Dogs

Canine babesiosis is a parasitic disease caused by infection with Babesia spp. Ticks carrying the Babesia parasite transmit it to dogs when they fed on their blood. Babesia infection leads to babesiosis. Until recently, this disease was rare in the UK, although commonly found across Europe and Central America 1. The main species currently affecting dogs in the UK is Babesia Canis.

Babesia infects red blood cells, leading to anaemia. If left untreated, this can be fatal.

Cases of canine babesiosis had not been reported in the UK until this year. Four dogs in Harlow, Essex contracted the disease. These dogs had no history of travel outside of the UK, suggesting the parasite has migrated. Easier movement of pets throughout the EU could be a possible explanation for infected ticks reaching the UK. There is concern that ticks carrying Babesia could spread throughout the country.

“The problem in the future is that every female tick will lay a couple of thousand eggs and all those offspring will carry the disease. Even if you do all you can, you are not going to stop the spread of the disease.”
Clive Swainsbury, Forest Veterinary Centre

Map of Canine Babesiosis in Essex
A map of the area where the first UK Babesia infections are thought to have occurred

Public Health England are monitoring the spread of the tick responsible (Dermacentor reticulatus), which is extremely rare in the UK. Advice on participating in the tick surveillance scheme can be found here.

It is advised that dog owners regularly check for ticks after walks. This is important for all dog owners, not just those in the affected area. Ticks can spread other parasites such as the bacteria that causes lyme disease in dogs. Ticks are found more frequently in the warmer months. See below for more advice on keeping ticks at bay.

If a tick is found, it should be removed quickly using a tick removal tool like this one. It can take 24-48 hours for a tick to cause infection, so quick removal could prevent infection. However, dog owners should still seek veterinary advice even if the tick is removed within this timeframe. Symptoms may not develop for a couple of weeks.

Symptoms of Canine Babesiosis

Babesia reproduces in red blood cells. This can cause anaemia due to the breakdown of blood cells. Anaemia results in pale mucous membranes and an excess of bilirubin, which leads to yellowing of the skin (jaundice). The exact symptoms can vary depending on the species of Babesia. More symptoms of canine babesiosis are listed below:

  • Lethargy
  • Fever
  • Anorexia
  • Weight loss
  • Hyperthermia
  • Pale mucous membranes (e.g. gums)
  • Jaundice
  • Coloured urine (red/brown)
  • Splenomegaly (enlarged spleen)

Treatment Options

A treatment is required that can kill the parasite and stop the immune system causing damage to red blood cells. Currently, there are no effective vaccines available in the UK. Fortunately, there are medicines that can remove the Babesia parasite from the blood.

Imidocarb dipropionate is the recommended treatment for removing the parasite 2. It requires two doses, 14 days apart. Some species of Babesia are resistant to certain medications. Other treatments are available however, if the initial treatment isn’t effective.

Immunosuppressants may also be given. This is to stop the immune system attacking the body’s own red blood cells.

In cases where complications arise, the dog will need to be closely monitored. In some cases, blood transfusions have been necessary. Leaving canine babesiosis infections untreated could result in death.

Sometimes, the parasite may not be completely removed and it can lie dormant. This is unlikely to cause problems unless the dog becomes immuno-suppressed later in life. Although the infected dog will rarely display symptoms, they should be considered a carrier of the infection.

Tick Control and Removal

Using a tick removal tool to remove a tick from a dog
Using a tick removal tool to remove a tick from a dog

Tick control is important to limit the risk of disease. Quick removal is necessary to help prevent disease. If a tick is removed within 24 hours of attaching, infection can be prevented.

To limit the risk from ticks, try to avoid their habitats. Ticks are often found in leaf litter, vegetation, overhanging branches or overgrown lawns. Ticks are more active in the warmer spring/autumn months.

You should regularly check your pet for ticks. Especially if heading to areas where ticks thrive. See our guide on how to remove a tick from a dog.

Summary: Canine Babesiosis

  • Canine babesiosis is caused by the parasite Babesia. There are many species, but Babesia Canis is the species currently found in the UK.
  • Babesia causes the disease canine babesiosis. A malaria-like disease that attacks red blood cells causing anaemia. It can be fatal if not treated.
  • Symptoms can take weeks to develop, so if you find a tick on your dog you should remove it immediately and contact your vet.
  • Treatment with Imidocarb dipropionate and immunosuppressants can kill the parasite and stop the body attacking its own red blood cells.  
  • Tick control and removal is the best action to minimise the risk of canine babesiosis. Quick removal of a tick can prevent it from spreading infection to a dog.

Featured Image – I, Accipiter CC BY-SA 3.0, via Wikimedia Commons


  1. René-martellet M, Chêne J, Chabanne L, Chalvet-monfray K, Bourdoiseau G. Clinical signs, seasonal occurrence and causative agents of canine babesiosis in France: results of a multiregional study. Vet Parasitol. 2013;197(1-2):50-8.
  2. Nalubamba KS, Mudenda NB, Namwila MM, et al. A Study of Naturally Acquired Canine Babesiosis Caused by Single and Mixed Babesia Species in Zambia: Clinicopathological Findings and Case Management. J Parasitol Res. 2015;2015:985015.

About James Watts

BSc Bioveterinary Science. Editor of PetSci. When I'm not writing, learning, discussing, or reading about animals, you know it's the weekend! Currently developing PetSci HealthTrak, the fast and easy way to monitor your pet's weight and calorie intake. HealthTrak offers a simple way to track your pet's progress, helping them achieve a healthy weight and a long, happy life.

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