The dairy industry organisation Dairy NZ is warning South Island farmers to be on the lookout for the cattle disease Theileria Ikeda because it has now become established there.
The Ministry for Primary Industries says the blood-borne parasite, spread by ticks, has been confirmed in a dairy herd on the West Coast.
The disease has already infected about 1000 herds in the North Island.
Dairy NZ technical veterinary advisor Dr Nita Harding said the only South Island case seen previously was linked to cattle that had come from the North Island.
"This particular infection has almost certainly been picked up in the South Island, rather than being North Island cattle that have come to the South Island, so Theileria is no longer a North Island only disease," she said.
Dr Harding said the particular animals that were diagnosed with Theileria had also grazed in Canterbury.
"MPI think the disease may have been picked up in Canterbury rather than on the West Coast. There's still a bit more work to do to get to the bottom of this, but it does show that Theileria is a possibility in those areas."
Theileria Ikeda makes cattle anaemic and lethargic and kills about one percent of the animals it infects.
