Tick fever (Babesiosis; Piroplasmosis)

Updated: May 5


Babesia
Babesia: Illustration 162072077 © Katerynakon

What is babesiosis?

Babesiosis is a serious and fatal disease of dogs caused by microscopic parasites called babesia. There are two species of Babesia involved:

  1. Babesia canis

  2. Babesia gibsoni

Babesia canis has three subtypes or strains:-

  1. Babesia canis canis, (causes moderately severe disease).

  2. Babesia canis vogeli, (causes mild disease).

  3. Babesia canis rossi, (causes severe disease).

Babesia gibsoni causes a more chronic form of the disease.

These parasites are transmitted by infected ticks, dog bites and blood transfusion. The disease is commonly found in warm, temperate and tropical climates and it is spreading fast due to a combination of factors that include increased movements of both pets and people carrying ticks.

It is likely that Warming global temperatures are also allowing ticks carrying the parasite to get established in new areas.





How do dogs get infected with Babesiosis?

Dog tick | Photo 148977765 © Todorean Gabriel

Babesiosis is a parasitic disease that is carried and transmitted by ticks. The parasite is carried into the dog through a tick’s saliva when the tick attaches to a dog and begins to feed and the parasite enters the dog’s bloodstream. This transmission occurs 24-48 hours after the tick has attached to the dog. Once in the body, the parasites enter the red blood cells where they hide from attack by the dog's immune system.

Babesia in red blood cells : Illustration 165023378 © Katerynakon

They then divide rapidly, rupturing the red blood cells, freeing more parasites that invade other red blood cells.

Concurrently, dogs infected with babesia may be infected with two other parasites: Ehrlichia and Leishmania. Babesiosis can also be transmitted through blood transfusion - and all blood donors should be screened before donation. In the case of one species of babesia, B. gibsoni, the transmission may occur through infected dog bites.


What predisposes dogs to babesiosis?

  • Residence in an endemic area.

  • Exposure to ticks.

  • Dog imported into the endemic area.

  • Age and immune status of the dog.

  • Virulence of the strain of the parasite - B. canis rossi causes a more severe disease than B. canis vogeli.

  • Stress.

  • Concurrent disease.

  • Spleen surgery (Splenectomy).


What are the clinical signs of Babesiosis?

Common clinical 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

  • Presence of ticks.

  • Shock.

  • Depression

  • Weight loss

  • Nervous signs

  • Lameness or stiffness

  • Exercise intolerance


What are the complications associated with Babesiosis?

  • Oral ulcers (Stomatitis)

  • Stomach ulcers (Gastritis)

  • Nose bleeding (Epistaxis)

  • Diarrhoea (Enteritis)

  • Respiratory distress, moist cough and blood-tinged frothy nasal discharge.

  • Cerebral babesiosis (incoordination, collapse, seizures, coma).

  • Oedema.

  • Keratitis (inflammation of the cornea)

  • Iritis (inflammation of the iris).


How is babesiosis diagnosed?

Babesiosis is confirmed by examining the blood of the dog to look for signs of anaemia, 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).


How is Babesiosis treated?

The parasite can be killed by a variety of antibiotics and injections of a drug called imidocarb dipriopionate.

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

Early diagnosis and treatment in the early stages give a good outcome. Where treatment is delayed, life-threatening anaemia can occur. However even if dogs are treated and appear to recover, the infection does seem to be lifelong and relapses of disease can occur if infected dogs are stressed, suffer from other diseases or become pregnant.


The drugs used in the treatment of babesiosis include one, or a combination of the drugs below.

  • Imidocarb dipropionate Imidocarb, 5 mg/kg IM

  • Trypan blue, 10 mg/kg as a 1% solution given IV.

  • Blood transfusions

  • Diminazene aceturate, 3.5 mg/kg IM. Drug of choice in uncomplicated babesiosis

  • Pentamidine isethionate, 1.5 mg/kg SC on 2 consecutive days

  • High dose Clindamycin (12.5 mg/kg per os BID) or Doxycycline (10mg/kg).

  • Fluid therapy

  • Immunosuppressive doses of prednisolone


How is Babesiosis prevented?

Controlling ticks helps to prevent transmission of the disease. Various veterinary products are available to rapidly kill ticks before transmission takes place or expel/repel ticks. No product is 100% effective. However, if the dog is in an area where there is a high tick population carrying the babesia parasite, or the dog is travelling to these areas, the pet should be checked at least every 24 hours and the ticks carefully removed if found. This is achieved with a simple ‘twist and pull’ action using a specialised tick remover. Otherwise, the pet is immediately taken to a Veterinary clinic to have the tick removed. Products used to control ticks on dogs include Bravecto, Frontline, Nexgard, Simparica, Triatix, Advantix and Advocate.


Conclusion

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 dogs to remove ticks. If a tick can be removed within 24 hours of it attaching to a dog, it is unlikely that the parasite will have been transmitted.



References

Swainsbury C, Bengtson G & Hill P (2016) Babesiosis in dogs. Vet Rec 178, 172 PubMed.


Holm L P, Kerr M G, Trees A J, McGarry J W, Munro E R & Shaw S E (2006) Fatal babesiosis in an untravelled British dog. Vet Rec 159, 179-180 PubMed.


Matjila P T, Penzhorn B L, Bekker C P, Nijhof A M & Jongejan F (2004) Confirmation of occurrence of Babesia canis vogeli in domestic dogs in South Africa. Vet Parasitol 122, 119-125 PubMed.


Lobetti R G (1998) Canine Babesiosis. Comp Cont Educ Pract Vet 20 (4), 418-431 VetMedResource.

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