Questions are now being asked about how Mycoplasma bovis managed to spread such a long way from Southland to South Canterbury and all the way up to Waikato.
The Ministry for Primary Industries (MPI) found the original infected farm five months after the disease was first detected in the country.
What you need to know about the cow disease, and a timeline of its spread.
M Bovis was first discovered in July last year on the South Canterbury farm owned by the Van Leeuwen Dairy Group.
Attempts to control its spread were focused on this farm and all of the properties who had received cows and calves from it.
MPI has confirmed the infection is linked to another farm in another part of the country - one owned by Alfons Zeestraten in Southland.
The problem is this farm was not declared to be an infected property until December last year.
This allowed cows and calves to be traded from the Zeestraten property to farmers around the country who had no idea they were taking in infected cattle.
MPI director of response Geoff Gwyn said the reason it took five months to establish a connection between the South Canterbury farm and the one in Southland was that the infected livestock went through two or three intermediaries, none of which used the animal tracing scheme known as Nait.
Asked if MPI had apologised to the van Leeuwen's for naming them as the original farm, he said it was the van Leeuwen's and not MPI who first identified them.
He said he was working with the best information he had at the time when he talked about the van Leeuwen's being the original farm.
"It is a fair comment to say we probably did say ... or I would have said that they were the first farm and at that point in time that would have been an accurate statement, until such time as we found the Zeestraten's, which indicates, or the genetic information we have indicates that the point of introduction on their farm was earlier or predates the van Leeuwen's."
Agriculture Minister Damien O'Connor said a decision would be made on Monday about whether M Bovis could be managed or whether an attempt would be made to eradicate it completely.
He said both options were put to industry leaders on Tuesday.
Mr O'Connor said he was expecting a briefing within the next month on how the joint police and MPI investigation in to how the disease entered the country was going.
