Pet Factsheets


Babesiosis is a serious parasitic infection of dogs that primarily affects the blood, leading to anaemia, jaundice and in some cases, death. The disease is caused by babesia parasites and infection is acquired through exposure to infected ticks, dog bites and blood transfusion.

What is babesiosis?

Babesiosis a serious disease of dogs caused by a group of microscopic parasites called babesia which are transmitted by ticks. The disease is seen mainly in the Americas, Asia, Africa and southern Europe, ie warm temperate and tropical climates (but not Australia) but is spreading North through Europe. This spread is thought to be due to a combination of factors including increased movements of both pets and people carrying ticks. It is likely that warming global temperatures are also allowing ticks carrying the parasite to establish in new areas. A recent outbreak occurred in Essex (South East England) in dogs that had never been abroad and the parasite was identified in the local tick population. This suggests that ticks in the local area are now infected and spreading the disease.

How can my dog catch Babesiosis?

The parasite is carried and transmitted by ticks. When a tick attaches to a dog and begins to feed the parasite is carried into the dog in the tick’s saliva and enters the dog’s bloodstream. This transmission is thought to occur 24-48 hours after attachment of the tick. Once in the body the parasites enter red blood cells where they can hide from attack by the immune system. They then rapidly divide, rupturing the red blood cells and freeing more parasites to invade other red blood cells.

Dogs may be simultaneously infected with babesia and two other parasites: Ehrlichia and Leishmania (see separate factsheets on these conditions). Although there are types of babesia that can infect people, the babesia parasites that infect dogs are not thought to be a significant risk to people.

Transmission can also occur through blood transfusion - and all blood donors should be screened before donation. In the case of one species of babesia, B.gibsoni, transmission may occur through infected dog bites.

How would I know if my dog had Babesiosis?

Common signs of babesia infection are:

  • Anaemia
  • Jaundice
  • Lack of energy
  • High temperature
  • Poor appetite
  • Red of dark brown urine (“coffee ground urine”)
  • Enlarged lymph nodes
  • Increased breathing rate

Disease most commonly occurs in young adult dogs as older animals can develop some immunity to the parasite.  Disease can be more severe in dogs travelling from areas free from the parasite to areas where ticks harbour the disease.

Infected dogs that develop clinical signs may recover without medical treatment but if allowed to progress, clinical signs can become severe and sometimes fatal. Some animals develop a more chronic form of the condition with low grade anaemia for weeks with relapses occurring.

What will my vet do to make a diagnosis?

In parts of the world where this disease is common, and in dogs having travelled to these regions, characteristic signs such as anaemia and jaundice often lead to a suspicion of babesiosis. This suspicion may be supported by ticks being present on the dog or there being a history of exposure to ticks.

Infection can be confirmed by examining the blood of the dog to look for signs of anaemia, an active immune response and the parasite itself inside red blood cells. Blood samples may also be taken to look for antibodies to the parasite (made by the dog’s immune system) or to amplify parts of the parasite for identification (PCR).

Can Babesiosis be treated?

The parasite can be killed by certain types of antibiotics or injections of a drug called imidocarb dipriopionate. This drug is highly efficient at treating the parasite but may be painful when injected and cause a reaction at the injection site. It can also lead to short term side effects such as increased salivation and gut problems. Your vet will discuss the most appropriate treatment with you if your pet is diagnosed with babesiosis.

Other treatments may be needed to support dogs suffering from severe anaemia such as oxygen and blood transfusion.

With appropriate treatment in the early stages, the outlook for the dog is good. In severe cases or cases where treatment is delayed, life threatening anaemia can occur. However even if dogs are treated and appear to recover, infection does seem to be lifelong and relapses of disease can occur if infected dogs are stressed, suffer from other diseases or become pregnant.

How can I prevent my dog getting Babesiosis?

Controlling ticks will help to prevent transmission of the disease. Various veterinary preparations are available to rapidly kill ticks before transmission takes place or expel/repel ticks. No product is 100% effective however so if you live in an area where the parasite is known to be present in the local tick population, or are travelling to these areas, you should check your pet at least every 24 hours and carefully remove any ticks found. This is achieved with a simple ‘twist and pull’ action using a specialised tick remover. If you feel unable to do this you should take your pet immediately to a Veterinary clinic to have the tick removed.


Babesiosis is an unpleasant and potentially fatal disease in dogs. However, risks of infection can be minimised by simple precautions such as attention to tick control using regular treatments to repel and kill ticks and with careful regular examination of your pet to remove ticks. Remember if you can remove a tick within 24 hours of it attaching to your pet it is unlikely that the parasite will have been transmitted.

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