Situation update: 07 July 2025
Babesia gibsoni is a parasite that primarily affects dogs. It can lead to the disease babesiosis which can cause anaemia, lethargy, and other symptoms. It was found in a dog in Christchurch at the end of March 2024 and investigations identified 2 other affected dogs from the same connected group.
Tracing and testing contacts from the first known case identified the other 2 dogs that tested positive for the parasite.
The first dog was severely affected and was euthanised at the owners’ request. The owners of the other 2 dogs were issued with legal directions to manage any risk of spread.
We carried out extensive testing of dogs that may have been in contact with the affected dogs. Results of those tests were negative, indicating there has been no further spread.
The 2 positive dogs have now completed treatment regimens for Babesia gibsoni, as well as post-treatment monitoring, which involved 3 lots of tests over a 6-month period. Both dogs achieved 3 negative results each. This gives us confidence that the risk of transmission of Babesia gibsoni has been reduced to negligible.
The dogs will be tested annually to check their Babesia gibsoni status.
What is Babesia gibsoni?
Babesia gibsoni is a parasite that mainly affects dogs. It is widespread around the rest of the world, including Australia, but until 2024, it was not present in New Zealand. Infection with the parasite can cause the disease babesiosis, which is mostly mild and without symptoms, but in some cases can be severe.
How is it spread?
Babesia gibsoni is blood-borne and spreads where there is transfer of blood between dogs. It can be transmitted by ticks from dog-to-dog through bites from the New Zealand cattle tick (Haemaphysalis longicornis). Ticks that are exotic to New Zealand, such as the brown dog tick (Rhipicephalus sanguineus) also spread this parasite.
Along with ticks, Babesia gibsoni can also be spread through dog bites, blood transfusion, and through the placenta from an infected mother to her pups.
There are veterinary treatments available for infected dogs that reduce the risk of transmission.
The disease Babesia gibsoni causes
Many dogs do not develop symptoms of disease but remain infected by the parasite. When disease does occur, it is referred to as babesiosis. The disease is often chronic and mild, but in some cases, it can be acute and severe.
Species that are prone to Babesia gibsoni
Dogs are the most affected species. Pit bull terriers, Staffordshire bull terriers, and greyhounds are the most commonly affected breeds.
Find out more
Babesia gibsoni information sheet for dog owners [PDF, 291 KB]
Information fact sheet for vets [PDF, 398 KB]
Media release: Dog owners reminded to treat their pets for ticks (5 April 2024)
