At the end of March 2024 a dog in Christchurch was found to be infected with Babesia gibsonii, a parasite which mainly affects dogs and has not previously been detected in New Zealand. This dog was extremely sick and was euthanased.
A second infected dog has subsequently been found, through testing of close contacts of the first dog by MPI. This dog had been ‘in a tussle’ with the first dog and is currently asymptomatic. This dog was imported into New Zealand 2 years ago, but was negative on testing for Babesia gibsonii prior to entry.
Should you be worried about your dog being infected with Babesia gibsonii?
In short, not at this stage. The risk to the general dog population at this point is extremely low. However, MPI are recommending that you ensure that your dog is up to date with flea and tick treatments.
As this is a new disease to New Zealand and we are not sure how widespread it may be, it is worth all dog owners having a basic understanding of the disease, how it is spread and how it presents in dogs.
What is Babesia gibsonii?
Babesia gibsonii is a protozoal parasite that causes a dog's red blood cells to rupture. It is common throughout the World, including in Australia.
How it Babesia gibsonii spread?
Babesia gibsonii is spread by the transfer of blood between dogs. Most commonly this is is via ticks and the New Zealand cattle tick is capable of spreading this parasite. It can also be spread by dog bites and there have been cases of it being spread by normal dog play. Blood transfusions and transplacental infection from a bitch to her puppies are also possible routes of infection.
What are the symptoms of Babesia gibsonii infection?
Once infected many dogs have only subclinical infections. They are asymptomatic and their immune system suppresses the disease, but they remain able to transmit the parasite and if their immune system is compromised in the future, they may then develop clinical disease.
Severe disease, known as babesiosis, is more commonly seen in young dogs and dogs whose immune systems are compromised. Common signs include:
- Fever
- Lethargy
- Inappetence
- Pale gums and other mucous membranes (anaemia)
- Elevated heart and respiratory rates
- Vomiting
These are symptoms which are common to a range of other diseases, including rat bait poisoning and immune mediated haemolytic anaemia.
How is Babesiosis diagnosed?
The parasite can be seen on blood smears on general screening, but it is not always present, especially in dogs that are sub clinically affected. For the specific blood tests needed to diagnose it with more accuracy blood samples must be sent to New Zealand’s exotic disease laboratory.
How is Babesiosis treated?
Treatment involves supportive care, including fluid therapy and possibly blood transfusions, as well as combination antibiotic therapy. Treatment is not always successful and severely infected dogs may die or require euthanasia, as in the first case found in New Zealand.
How to prevent your dog being infected with Babesia gibsonii
MPI is recommending that you keep your dog’s flea and tick treatments up to date.
What happens next?
MPI are investigating how these dogs were infected and continuing forward and back tracing on dogs which have been in close contact with them to work out how widespread the disease may be. Veterinary clinical pathologists, who work in laboratories across the country, are on high alert for the parasite and clinical practice veterinarians, especially those in Canterbury, will have raised this up the list of possible differential diagnoses for dogs with the clinical signs listed above.
Take home message
The risk of your dog being infected with this parasite is extremely low, especially if you live outside of Canterbury, but it is well worth ensuring their flea and tick control is up to date, being aware of the symptoms and keeping a watching brief on what is happening.
