If confirmation of the frustration over the longevity of the Irish efforts to eradicate Bovine TB were needed, I got it following a recent article on the topic.
Responses came from:
nHerdowners in Wicklow, Laois and Kilkenny who suffered major TB breakdown after being TB clear for decades;
nA Donegal herdowner, also TB clear for decades, was convinced that a carcase identification mistake was made when lesions were found in his factory bullock.
Yet he and his neighbours suffered the hassle of being locked up;
nHerdowners who were surprised that badgers caught after a TB breakdown were not tested for TB.
One caller even questioned the validity of a TB eradication scheme. "M Bovis is not causing economic loss in cattle.
There is no evidence of transfer of M Bovis from cattle to humans. (A recent human infection was traced to goats) So why spend €70m plus every year on a scheme that is going nowhere?"
At one stage, Ireland had compulsory dipping to control sheep scab. The sky didn't fall when it was dropped.
However, a decision to cease TB testing would have to come from the EU.
The issue of jobs for vet graduates arose. I was told that openings are scarce for recently qualified Irish vets.
accuracy
My reference to a delay in finding a blood test for TB drew a response from Enfer Scientific in Co Kildare.
This is the company which pioneered the lab tests for BSE and for hormone residues in cattle.
Over the past seven years, Enfer has invested almost €4m in developing their "Enferplex" blood test for TB. It has been trialed on more than 100,000 cattle.
The results in the scientific literature suggest that it is more accurate than the current skin test in finding TB reactors but that it will result in marginally higher false positives.
Dr Martin Vordermier of the UK State Veterinary Laboratory Agency concluded that "Enferplex is the best serological assay that I have seen."
To be acceptable for the TB round tests, Enferplex would need EU approval and this application has been made by Enfer Scientific.
However, it could be used immediately as a back up to support the current round test in Ireland.
Any blood test confers huge benefits. It's fast, (three-hour turnaround). It's independent.
Only one cattle assembly is needed. Animals can be retested immediately.
Enfer say it would be price competitive. Could it be the shot in the arm to crack Ireland's bovine TB?
Aware that at EU and national level bovine TB issues move slowly, I submitted a number of queries to the Department of Agriculture. See the replies below.
Has the Minister and the Department got a target date for the eradication of TB in the Republic of Ireland?
The ultimate objective of the Minister and the Department is to eradicate this disease as quickly as possible.
It is unlikely the disease can be eradicated from the cattle population in either Ireland or Britain without the entire reservoir of M Bovis infection being adequately addressed.
While the levels of TB in cattle can be reduced below the current incidence, final eradication will not be achievable until the transmission of TB from badgers has been halted either by population control or by vaccination.
In this context, it is not possible to set a precise time-frame for the eradication of the disease.
It should be noted, however, that countries with no wildlife maintenance hosts took up to 20 years to become OTF [
disease free].
It is not expected to take Ireland that length of time because we will already have the disease largely controlled in cattle.
Has the Minister and the Department got a target for reducing TB level in 2012? What is this target in herd incidence or in animal incidence?
The Minister is obliged to set a target for reducing TB levels to be eligible to apply for EU co-financing of the programme.
The target for herd incidence in the 2012 programme is 4.36pc.
This compares with actual herd incidence of 4.65pc in 2011. Once submitted for co-funding, the TB eradication programme is extensively evaluated at EU level before being approved for co-financing.
In the Department's opinion, what is the prime cause of the residual incidence of TB?
Infected wildlife is the main cause of continuing infection in Ireland.
There is now little doubt the primary driver of TB infection seeding into the cattle population is the badger.
Badger density in Ireland is currently estimated at 0.71-1.15 badgers per square kilometre.
Excluding Ireland and England, mean badger density across 27 European countries appears to be rising and is estimated to be 0.41 to 0.9 per square kilometre.
The relatively high badger density and the fact that, in Ireland, the vast majority of badger setts are in hedgerows adjacent to cattle pasture contributes to why, in Ireland, badger TB is a problem.
In Ireland, as the population control measures on badgers initiated in 2002 have taken effect, the importance of cattle as a factor in the spread of TB has again risen in importance.
I understand that there has been extensive evaluation of a blood test (Enferplex TB ELIZA test) as an alternative to the standard skin test.
This is true and the assay looked very promising in the initial limited scale investigations but, when more extensive trials were conducted, it failed to live up to that promise, being at the same time less sensitive and less specific than the SICTT skin test.
What is the Department's assessment of this Enferplex Eliza test. Does the Department regard this test as;
1. An alternative to the SICCP skin test? Not at this time
2. Complementary to the skin test? Not at this time
3. A replacement for the Gamma Interferon check test? Not at this time
What are the sensitivity and specificity percentages of the current standard skin comparative test
1 Under standard interpretation?
2 Under severe interpretation?
The SICTT (skin test) has 91pc and 98pc sensitivity (standard and severe interpretations, respectively) and 99.8-99.95pc specificity.
I understand that a TB vaccine for badgers is under trial.
Ireland is committed to the development of an effective badger vaccine and the implementation of a strategic programme of badger vaccination, with the aim to reduce the transmission of M Bovis between infected badgers and susceptible animals. This is a long-term project.
Are there any results from this trial?
Significant progress has been made in demonstrating that, in laboratory conditions, badgers can mount a protective immune response against tuberculosis and that BCG vaccine, when delivered by a variety of routes, including parenteral subcutaneous (s/c) and intramuscular (i/m) or mucosal (conjunctival and oral) routes, is effective in generating such a response in captive badgers (Corner et al., 2008; Corner et al., 2010).
A three-year long oral vaccine field trial in badgers is currently under way in Ireland with the aim of demonstrating that the protection observed in captive badger studies also occurs in wild badgers under conditions of natural M Bovis transmission, and to measure vaccine efficacy.
If so, is it showing promise?
It will be a further year before results from this trial are available. Research into an oral delivery strategy -- the optimal method -- is ongoing.
A further vaccine project has commenced in Ireland to "grow" and establish a BCG vaccinated population by a strategy of capture/vaccinate/release of badgers caught in previously culled, low density badger population localities that were burdened with high levels of TB in cattle and badgers.
This study will comprise a vaccinated area and a control area where culling will be maintained. Levels of TB in cattle will be monitored and compared and will last a minimum of six years.
- John Shirley
Source: irishindependent.
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