Mycoplasma bovis could have serious effects on cattle, including mastitis, abortion, pneumonia and arthritis. It was difficult to diagnose and control.
Since first confirmed on a South Canterbury dairy farming operation in July 2017, the disease has caused enormous heartache and stress for those caught up in its spread.
Make no mistake, the human toll of this biosecurity incursion has been massive for those affected farmers, whether under surveillance or restriction, or if they had the misfortune to have the disease confirmed on their property.
Coupled with the slaughter required of more than 150,000 cattle - and the staggering financial cost - this disease has been an unmitigated disaster for New Zealand's primary sector.
The response has highlighted many shortcomings, including the well-documented failure of the National Animal Identification and Tracing (Nait) scheme which has since been reviewed.
But one of the biggest concerns to come out of this debacle has been the response by the Ministry for Primary Industries.
Repeatedly, the attitude of senior management has been labelled by farmers as arrogant, while many staff have been found without a clue how to relate to farmers, and with a reluctance to listen to those who have practical knowledge or could offer assistance.
It is pleasing to hear that improvements have been made to dealing with compensation which has been a challenge.
Since the M. bovis recovery package was announced two months ago, the welfare and recovery team had been boosted to 36 people.
There were now 22 people working on the DairyNZ and Beef + Lamb New Zealand compensation assistance team.
So far, they have helped at least 180 farmers with their compensation needs, with almost $37 million in compensation paid to farmers to date.
While no one will argue with the need to ensure a robust system when public money is at stake, some of the previous delays have been ridiculous.
Farmers need to get back on their feet as quickly as possible. And compensation will never cover the disruptions to many of those businesses which will take years to rebuild, along with those business and personal relationships that have been damaged, and the subsequent mental and physical health effects on some of those involved. None of those qualify as verifiable losses under the Biosecurity Act.
MPI's new director-general Ray Smith recently acknowledged "things haven't always gone smoothly" and he was committed to working with the response head Geoff Gwyn and the rest of the staff in the Mycoplasma bovis directorate to "work on solutions going forward'.
Let's hope for everyone's sake that is the case. Because this response is far from over.
