The data presented remains consistent with a single source of introduction in the last four years, it said.
The small number of herds detected following six months of bulk milk testing by PCR and three rounds of testing by ELSDA support the assumption there is no widespread, unlinked disease in the dairy herd population, TAG chairman Scott McDougall said.
“Given the data provided the TAG is more confident now than in mid 2018 that eradication is achievable.”
But there is urgent need to design and implement an effective surveillance strategy for the beef industry and for a risk analysis of transmission between the dairy and beef sectors.
Successful eradication remains critically dependent on a clear definition of the expected outcomes, a functional Nait system, ongoing support from the farming community and other stakeholders, clarity around prevalence and incidence of M bovis in the beef industry and ongoing availability and retention of appropriately skilled people to ensure operational success.
Reassurance that eradication remains feasible despite the imperfect tests and tracing data alongside the complexity of decision-making about the status of individual farms given the limitations of available tests needs better communication in future, McDougall said.
Tag said the epidemiological and phylogenetic data presented support the conclusion the incursion is of relatively recent origin – likely sometime in late 2015 or early 2016 and that there was one source.
Despite extensive testing in the dairy industry there is no evidence of the presence of unrelated M bovis cases though a small number of infected herds are yet to be connected to the network. Those herds might be linked by unrecorded movements.
More infected dairy herds are very likely to surface after the introduction of service bulls in spring and summer 2018 and the return of 2017-born dairy animals from grazing to dairy herds in spring 2019.
These herds will, hopefully, be found by ongoing tracing and bulk milk surveillance, he said.
The prevalence and incidence in the beef industry remains unknown and there’s urgent need to implement an effective surveillance strategy while beef cattle potentially remain a source of infection.
It’s assumed most infected dairy herds will have been detected by June 2020 and more than five years of ongoing surveillance testing will be required to demonstrate freedom from disease.
TAG said tests to detect infection with M bovis are imperfect.
Serological tests based on the presence of antibodies will provide greater sensitivity than tests to detect the presence of the bacteria (PCR.
Some herds will probably need to be declared as restricted places and depopulated based on serological results alone because of the low sensitivity of thre PCR test.
TAG said that needs to be clearly communicated.
Clear and timely communication with herd owners and other stakeholders is of critical importance to the eradication campaign, TAG said.
“It needs to be communicated that eradication remains feasible despite imperfect tracing and tests.”
M bovis programme director Geoff Gwyn said there’s no surprises in the report that gives an independent validation the programme is on track.
“It clearly states that the data presented shows we are looking at a relatively recent incursion that is not widespread in our dairy herd.
“The report helps guide our direction, highlighting what is working well as well as some potential risks to the eradication programme,” Gwyn said.
“It is important the public understands that while some systems and processes are imperfect, eradication is still possible.
“These are all valid points and we are continuously improving our approach where necessary and based on the evidence available.
“We have already begun making improvements in many of the areas the TAG highlighted.
“Work is under way to develop a new surveillance approach for the beef industry and we are increasing our focus on improving communications to affected farmers, the public and staff working on the M bovis programme.”
Gwyn said some of the recommendations made are relatively simple to implement or are already in train but others will need careful consideration decisions are made.
