Update on Biosecurity New Zealand Babesia gibsoni investigation 

Published on 5 August 2024.

The Ministry for Primary Industries (MPI) has shared the following update on Biosecurity New Zealand's Babesia gibsoni investigation.

You will likely be aware that the exotic blood parasite Babesia gibsoni was detected in a dog in the Canterbury region at the end of March this year.

This organism is a protozoal parasite that causes the rupture of red blood cells in dogs. It is widespread around the rest of the world, including Australia. While most infections with B. gibsoni are mild or subclinical, some can be severe.

The infected dog was badly affected and euthanised at the owners’ request.  

Our investigation since then has focused on how the dog became infected with this parasite not previously found in New Zealand and determine if there are other cases.

Contacts from the first dog were tested and two further dogs tested positive. Neither are displaying clinical signs.  A decision has been made to manage the two positive cases to prevent further spread. This decision was informed by advice from a Technical Advisory Group which provided international expertise. The approach is to mitigate the spread of disease through a couple of measures, the first being legal instructions to the owners of both dogs to carry out regular tick control, manage interactions with other dogs to prevent fighting, and not bring other dogs into the household for the life of the affected dogs. In addition, the two animals will receive treatment with the recommended regime - Malarone and Azithromycin (+/- ondansetron) which are known to decrease or eliminate circulating parasites. There will also be post-treatment PCR testing at recommended intervals.  This will further reduce the likelihood of onward transmission of the parasite to other dogs. 

The detection of these two dogs has seen our investigation extend to a further 23 close contacts who are all going through a series of testing. The dogs have all had a first round of PCR and IFAT testing and all returned negative results. However, the technical advice is that multiple rounds of testing over time are necessary for confirmation of true-negative status, so the contact dogs are this week undergoing a second round of tests.

The response team believes that the situation in Canterbury is restricted to a known group of associated dogs and the risk of there being further undetected infected dogs in the area is low.

We may not be able to definitively identify how the dogs came into contact with this organism that has not been previously found in New Zealand. One of the three affected animals had been imported two years ago but met all import requirements and had tested negative for the parasite.  You can help us in this investigation by contacting us if you have any suspected cases by calling the exotic pest and disease hotline - 0800 80 99 66. 

Download Biosecurity New Zealand's information sheet for veterinarians.

We are also asking veterinary clinical pathologists who examine blood smears from dogs across New Zealand to be on the alert for the parasite.

Biosecurity New Zealand will provide further updates when there is new information.