Why NZ must try to eradicate M. bovis despite the cost

Richard Laven, an associate professor at Massey University and veterinarian with an interest in production animal health and welfare,  has expressed support for the Government’s decision to attempt to eradicate Mycoplasma bovis.  

A phased eradication means that an additional 126,000 livestock will need to be culled, at an estimated cost of NZ$886 million.

Eradication may prove to be impossible, Dr Laven writes in a post featured on Sciblogs – but the attempt should be made.

His article, originally published on The Conversation, discusses what we know, what we don’t know and what’s at stake.

How do we know this is a new incursion?

M. bovis causes mastitis and arthritis in adult cattle and pneumonia in calves. It is found around the world, but New Zealand was one of the last disease-free countries until the detection of infected cows on a dairy farm in July 2017.

We can’t be sure that M. bovis didn’t arrive in New Zealand before the current outbreak, but the Ministry of Primary Industries has tested for the disease over the years and not found it. This has involved checking animals with symptoms similar to those caused by M. bovis as well as large-scale testing of bulk tank milk in 2007.

In addition, all countries with M. bovis – including Australia, where less than 4% of dairy herds are affected – have had outbreaks of untreatable mastitis and arthritis due to M. bovis. No such outbreaks were recorded in New Zealand until July 2017.

In Australia, the disease was first reported in the 1970s, but it was not until 2006 that it was seen in the main dairying areas of New South Wales and Victoria where it caused outbreaks of mastitis. It is difficult to prove a negative and we certainly don’t have enough data to show it was definitively not in New Zealand before 2015. But the history of the disease in Australia shows that it can be detected even if it is rare.

Furthermore, the evidence so far from the investigation of the outbreak has been that all the infected farms can be traced back to cattle movements. If the disease had been here before, then tracing would likely have identified clusters of farms with no connections.

Is eradication feasible?

We do not currently know how the disease came into New Zealand. The only likely route, via imports of infected cattle, has been ruled out because live cattle imports ceased before 2015. In any case, live cattle imports have only come from Australia and the strain of bacteria in New Zealand is not the Australian one. Semen, embryos and illegal imports of veterinary products such as vaccines remain the most likely source, but all of these are very low risk. Although M. bovis can survive in these products, the chance of them being infected and that infection spreading to cattle is very low.

Without knowing where the disease came from, we cannot prevent it happening again. However, the risk of semen or embryos bringing in disease hasn’t changed in the last 20 years, so if it did indeed arrive via this route, it was simply bad luck.

So even if – after eradication – we did nothing to change the way semen, embryos or vaccine imports are regulated, it is possible that New Zealand would still remain free of M. bovis.

How can we get rid of M. bovis?

Authorities will use a systematic process of testing to identify infected herds. The biggest component will be testing the bulk tank milk of all dairy herds in the country. Tracing from infected herds will help to identify more infected herds and more traces. This is effectively a continuation of the current process with the aim of eliminating the disease.

The key problem with eradication is that currently the whole herd needs to be culled if one animal is infected because infection can only be detected at the herd level. This comes with significant cost and negative impact on affected farmers.

However, culling entire herds doesn’t necessarily influence the chances of a successful eradication process. The main issue is that we currently do not know exactly how many infected cattle or infected farms there are. It is going to take time to identify all the infected farms and it is possible that the number is much higher than the models suggest. This could make eradication impossible.

Tracing animal movements between farms is another key issue, and the lack of accurate recording is hindering our response to the outbreak. For an eradication to be successful, farmers have to get better at keeping track of where animals are moved.

The ConversationThe decision to eradicate the disease is based on science, but it is not a scientific decision alone. Rightly, it is a political call, with the decisions being taken by the government with support from the industry. Eradication may prove to be impossible, but that does not mean we shouldn’t try. It just means that, unfortunately, the disease had spread far more widely than our current models suggest.

The original article can be read  HERE. 

Source: Sciblogs


New round of Mycoplasma bovis milk testing to start

The Ministry for Primary Industries (MPI) is about to carry out a second round of nationwide milk testing, checking the country’s dairy herd for the presence of Mycoplasma bovis.

Under the programme, milk samples from every New Zealand dairy farm will be taken shortly after the start of calving, when cows are most likely to be shedding the bacterium. Samples will be collected from each farm approximately 4 weeks following the start of supply, with the first samples expected to be collected in the North Island in late July.

Mycoplasma bovis is difficult to test for because animals can be carrying the bacteria but not appear ill or show evidence of it in their blood or milk.

Testing at this time of year, when cows are in the early weeks of lactation and under some physical stress (and therefore more likely to be shedding), will yield the most accurate results and provide further information and assurance about the location of the disease in New Zealand.

MPI’s director of response Geoff Gwyn says farmers won’t have to do anything because all test samples will be collected as part of the standard on-tanker test process.

“Samples will be collected from each farm every 2 weeks up to a total of 6 samples over 12 weeks and tested by Milk TestNZ. Tests will look for both the presence of antibodies to Mycoplasma bovis and also the DNA of the bacterium.”

Mr Gwyn says the bacterium itself presents no food safety concern. Most dairying countries live with Mycoplasma bovis and safely consume milk products.

Farmers can expect to receive more information about the testing programme from their dairy companies this week.  Dairy companies are working with MPI to support the delivery of the programme, and the wider Mycoplasma bovis eradication plan.

Once the programme is completed, farmers with “not-detected” results will receive an email from their dairy company confirming the disease has not been found in their samples. Those in the North Island will receive their results on or before 1 November and those in the South Island will hear on or before 15 November.

Any farm that has a sample where Mycoplasma bovis is detected will be contacted immediately by MPI and given details of the next steps.

Mr Gwyn says farms that receive a not-detected result can take some assurance that the bacterium was not in the samples provided.

“Unfortunately, however, the complex nature of Mycoplasma bovis means results cannot be taken as a guarantee the farm is free of the infection.”

As the eradication programme continues, it’s likely that more rounds of this testing will take place to ultimately confirm that the disease is gone and eradication has been successful.

Find out more HERE. 

Source:  Ministry for Primary Industries  

New initiatives to support M.bovis response

Minister for Biosecurity Damien O’Connor has unveiled a set of initiatives to support the Mycoplasma bovis response and improve farm biosecurity practices based on feedback from farmers and rural communities.

Big numbers of farmers have been attending the Mycoplasma bovis roadshow meetings, Mr O’Connor said.  They have been interested in the response and in the changes that could be made to help them manage their on-farm biosecurity.

“We have been listening to them and the Ministry for Primary Industries is making a number of changes that can be implemented quickly, without legislation,” he said.

Some farmers have expressed frustration at not being formally told when a neighbour’s farm is identified as an Infected Property.

The Ministry for Primary Industries will start directly informing neighbouring farms of Infected Properties or high-risk properties, enabling farmers to take appropriate steps to improve their on-farm biosecurity and reduce the risk to their own stock.

The aim has been to take a measured step that balances individual privacy concerns with the need for farmers to protect their own farms.

The ministry will also publish a list of the NAIT numbers of all affected animals on its website. This includes all animals associated with or traced from an Infected Property.

 “This will give farmers better information to make informed decisions when purchasing new stock,” Mr O’Connor said.

The ministry will do more, too, to ensure enforcement of the Animal Status Declaration (ASD) form. It is a legal requirement that this form must accompany a consignment of cattle when a stock sale takes place.

Regulatory and legislative changes being considered include:

  • Amending the Animal Products Act to add a new infringement offence for failing to use the ASD form correctly
  • Amending the NAIT Act to bring its search powers in line with the Search and Surveillance Act
  • New regulation to control the use of discarded milk

Mr O’Connor said he was continuing to listen to feedback from farmers and will work with the ministry and industry groups to consider further changes to support strengthened biosecurity practices and compliance in  rural communities.

Source: Minister for Biosecurity

Science investment to support Mycoplasma bovis fight

The Coalition Government is investing $30 million over two years in scientific research to support the fight against Mycoplasma bovis, says Agriculture and Biosecurity Minister Damien O’Connor.

The Government would continue to call on all the available domestic and international scientific expertise to track and eradicate the disease. he said.

“This investment will enable us to address the bigger picture scientific challenge and research new tools in the fight against the disease.

“No other country has attempted eradication, and our farming systems are unique, so there are questions that have never been adequately explored by scientists.

“At the top of the list of priorities will be developing a single animal test. This will help us to provide greater clarity to affected farmers, and help us to understand the spread of the disease and to focus our efforts where they are most needed.”

The work will be overseen by a Ministry for Primary Industries’ led Strategic Science Advisory Group.

“The group will work on ensuring we have the tools we need to better manage and understand the disease, so we can be faster, more efficient and more effective in our response to it,” Mr O’Connor said.

The newly-appointed MPI Departmental Science Adviser, Dr John Roche, will assemble and lead the group, which will include both international and domestic scientific expertise.

Dr Roche has a PhD in ruminant nutrition from the National University of Ireland and has most recently worked as a principal scientist at DairyNZ and adjunct professor in the School of Biological Sciences at the University of Auckland.

Source: Minister of Agriculture and Biosecurity


Minister says M.bovis eradication is progressing well

Nearly two weeks after the decision to take our one shot to eradicate Mycoplasma bovis, the programme is making good progress, Agriculture and Biosecurity Minister Damien O’Connor says.

The number of farms under regulatory control has been reduced from 300 to about 200, although this is likely to change as the response progresses.

Mr O’Connor says:

“The reduction is mainly due to farms under Notice of Direction being tested, cleared and allowed to get on with business as usual.

“The number of properties with confirmed infections has recently reduced from 39 to 36 as a result of several properties completing the culling and disinfection process.

“The culling of some 24,500 animals on 28 of those infected properties (IP) has been completed, allowing them to go into the disinfection stage.

“In total 44 farms have been identified since July 2017, with eight now cleaned and cleared of Mycoplasma bovis.

“This is clearly an improving situation for those farmers under the strain of an IP, who can now get back to business.

Phased eradication was in its early stages and his officials  expect to uncover more suspicious or infected properties over coming months.

Mr O’Connor was disappointed by the first confirmed detection in the Wairarapa this week.

He acknowledged there’s a long way to go and thanked everyone for contributing to a significant step forward in our Mycoplasma bovis eradication programme.

 Source: Minister of Agriculture and Biosecurity

Mycoplasma bovis confirmed in the Wairarapa

Biosecurity New Zealand today confirmed positive test results for Mycoplasma bovis from a property in the Wairarapa.

The farm concerned is a sheep and beef farm near Masterton and was located through the tracing of animal movements from other affected farms.

The property is under legal controls restricting the movement of animals and other risk goods off the farm.

As part of the Government and sector group programme to eradicate the disease, all cattle on the farm will ultimately be culled, in agreement with the farmer concerned around timing.

This new property brings the total number of infected properties nationwide to 36. Biosecurity New Zealand expects to find further infected properties as the extensive tracing of animal movements continues.

Source: Biosecurity NZ


The social science of Mycoplasma

Usually when animal disease strikes, the advice and expertise of the veterinary sciences is sought. But recent outbreaks such as Foot and Mouth in the UK in 2001 have led to the recognition that the social sciences should also play an important role in the management of animal disease, a guest article on Sciblogs points out.

They should also be important to help understand and manage the impacts of Mycoplasma in New Zealand.

Dr Gareth Enticott, Cardiff University, UK, Dr Anne Galloway, Victoria University of Wellington, NZ, the authors of the article, acknowledge there are some important differences between Mycoplasma and the UK’s FMD outbreak.  They also say there is a remarkable similarity between the two events.

Taking lessons from social studies of animal disease, they write, the following issues should be of concern for all involved in the management of Mycoplasma:

1. Trust

In 2001, the outbreak of FMD in the UK was accompanied by a complete breakdown in trust between farmers, vets and the Government (Poortinga et al., 2004). Why was this? Partly because of organisational inefficiencies and a perceived cultural distance between London (where policy was made) and the countryside (where policy was delivered). The impact was to make eradication harder as decisions were challenged.

To be sure, the importance of trust in disease eradication is not unknown to New Zealand: in the early days of the bovine Tuberculosis eradication programme, farmers and vets were distrustful of officials from Wellington, refusing to test their cattle and even going on strike (Enticott, 2017). Distrust of government advice has affected other disease programmes in the UK (Enticott, 2008) and Australia (Palmer et al., 2009).

The lesson for policymakers is to engage rather than lecture, and to work in—and with—the communities that they are serving rather than from a distance. Trust is also maintained through transparency of decisions made, activities to be undertaken, and in the clarity and consistency of information provided.

2. Education and Awareness

Improving awareness and education of a problem like Mycoplasma and its consequences is often assumed to be the best way to get people to ‘do the right thing’. In fact, this style of communication is often shown to have little or the opposite effect – and is magnified where trust is in short supply.

In animal disease control the same is true. Studies have shown that farmers develop and rely on their own understandings of disease processes. They share stories and accounts of expected and unexpected incidents and these can drive decisions whether to implement biosecurity advice (Enticott, 2008).

Cattle movement restrictions may be something that New Zealand farmers will need to get used to, and will bring pre-existing NAIT compliance issues into high relief. But for other diseases, analysis of the regulations and communication of risk advice shows that many farmers make ‘risky’ cattle purchases (Hidano et al., 2016) or ignore risk assessments in favour of their own explanations of disease susceptibility (Enticott, 2016).

In fact other studies have shown how animal disease regulations may promote ‘risk compensation’ – the protection provided by biosecurity measures and financial compensation may be compensated for by other risky behaviours (Wiethoelter et al., 2017). As Mycoplasma eradication unfolds, it will be important to look for and monitor these effects. Acknowledging, and working with, farmer expertise will help mitigate some of these risks and their effects.

3. The Politics of Expertise

Diseases are political: whether a disease deserves to be eradicated depends on social and economic processes, and the power of vested interests to turn a disease into a problem (Woods, 2004). What this means is that disease outbreaks inevitably become the focus of dispute and contestation because there is no certainty around why some diseases should be eradicated whilst others are left to farmers to deal with.

Consider, for instance, differences between the management of Mycoplasma, bovine TB, BVD and Johnes disease. At the same time, the forms of expertise used to justify disease controls, such as the contiguous slaughter policy used during FMD, reflect political choices (Bickerstaff and Simmons, 2004). In this case, it was a preference for a command and control style of epidemiological modelling versus the more nuanced but uncertain field knowledge of local vets. These political choices can therefore usher in new styles of disease control.

As the eradication of Mycoplasma unfolds, particularly if it is unsuccessful, watch for these disputes between different disease control experts and how they are adopted by different political groups. Of particular interest will be how long the authority and expertise of MPI holds, how local veterinary advice will be received, and what these disputes will indicate about the governance of agriculture in the long term.

4. Social Impacts

Finally, media reports have rightly featured the social impacts of Mycoplasma suffered by those farmers, for example, who have been made to send heavily pregnant cows to slaughter and others who will lose a half-century of selective breeding, Recognising and understanding these impacts is an important part of managing animal disease outbreaks.

As previous research of events like FMD in the UK have shown, the effects of losing cattle in whole-herd slaughter policies can result in severe emotional trauma leading to new recommendations for the National Health Service on the best ways to cope with the increased stress felt by farmers and their families (Mort et al., 2005; Nerlich et al., 2005). It is not just the untimely loss of cattle that causes emotional trauma, but the stress of navigating bureaucratic procedures and regulations (Hood and Seedsman, 2004). Maintaining consistency in the rationale for movement restrictions, and the culling of some animals but not others, will not only foster trust between farmers and government, but help maintain social ties between farmers.

How MPI publicly justifies its actions and demonstrates support for farmers will also impact broader social responses and public sentiment. Vets and other rural professionals involved in the management of disease may also suffer, and providing time and places to talk through and share the experiences of their work is a key recommendation from this research (Convery et al., 2008; Hood and Seedsman, 2004). If not, as others have shown, the mental health consequences of managing disease outbreaks may ultimately lead them to abandon farming (Lehane, 1996) or their careers (Enticott, 2018).

For the eradication of Mycoplasma what is important is not just to fully resource rural mental health services, but to recognise that it is human behaviour that drives these social impacts. If Mycoplasma needs eradicating, then developing a caring, compassionate response that answers to the consequences of killing 126,000 cattle should be a priority. This response will also need to be flexible and adaptable, as the impacts will vary amongst decision-makers, farmers, vets, livestock transporters, meat processors, and future consumers of animal products.

And finally, the social relationship between people and animals will, and should, be put under ethical scrutiny. What will be used to justify the untimely slaughter of that many animals—and will that lead to a public backlash against livestock farming in general?


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Convery I, Mort M, Baxter J, et al. (2008) Animal Disease and Human Trauma: Emotional Geographies of Disaster, London: Palgrave Macmillan.

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Source: Sciblogs