The Ministry for Primary Industries continues to be confident mycoplasma bovis has not "jumped the fence" from infected farms.
MPI says more than 15,000 tests are now completed and the only positive results are on six known infected properties.
The majority of tests have come back negative. Testingis carried out up to three times at three to four week intervals before there is a definite result for each farm.
It's encouraging that no neighbouring properties have as yet been identified as infected, MPI says.
All the current infected properties have direct links to each other through animals moving from one farm to another and disease passing between animals in close, repeated and prolonged contact.
