1 July 2010

4 minute read

Paratuberculosis or Johne’s disease is a progressive regional intestinal inflammatory pathology caused by the Mycobacterium avium subspecies paratuberculosis bacteria. Paratuberculosis is passed from cows, ewes and goats to their offspring, which remain heavily infected and later can transmit it to other herds through their contaminated faeces. It is insistently linked to Crohn’s disease, a serious regional intestinal inflammatory pathology of humans. However, the gastroenterological community does not consider that the link is a causal one.

The possible similarity with Crohn’s disease, together with the production losses in the ruminant industry, has prompted the European Commission to take preventive measures and to finance the ParaTBTools project. The initiative involves 200 scientists working in teams in Europe, the United States, Canada, Argentina and New Zealand. The contribution from Spain is through researchers Dr Ramón A. Juste (President of the International Association for Paratuberculosis) and Dr Joseba Garrido, both scientists at NEIKER-Tecnalia as well as Dr Alicia Aranaz and Miss Beatriz Romero from the Complutense University of Madrid and Dr Valentin Perez and Miss Laetitia Delgado from the University of Leon.

The harmonisation of diagnostic test systems, control programmes and, in general, paratuberculosis control approach strategies, could be the first step in helping the livestock industry to eradicate Johne’s disease, according to the conclusions of the experts.

The director of ParaTBTools, the Dutch scientist Dr Douwe Bakker (of the Netherlands Central Veterinary Institute), has proposed the slaughter of infected animals as a principal measure to control the infection, although he recognises that this action would be very costly for farmers.

The NEIKER-Tecnalia specialists explained that there was already a vaccine in Spain, for whose evaluation and improvement the Basque technological centre is currently working, which will allow to avoid the killing of the infected animals and the subsequent financial loss to the ruminant production sector.

Cases in Denmark, the Netherlands and Spain

Dr Bakker gave the example of the initiative taken by Danish dairy farmers – applying a selective killing of infected animals.

“Their financial results are improving because they end up with greater yields”, stated the expert.

Dr Bakker pointed out that this measure is being well accepted by farmers in Denmark, where it is admitted that there is an infection prevalence of 80 per cent of farms. In reality this success is not only due to the culling of infected animals, but also to an increase in the rate of renovation of the animals, resulting in a substantial shortening of their productive life, but an even more rapid incorporation of improved genetic traits.

The Netherlands is also obliging their farmers to take action. From next year on, dairy cattle farms will only be able to sell their production if they are integrated into some control programme for paratuberculosis, and if they take care of the infected animals. This initiative has the support of the country’s producers, Dr Bakker emphasises. The programme also include penalties for non-complying producers.

In France, however, the preferred strategy seems to be that of vaccination, thus prolonging the productive life of the animals and, thereby, making the system more sustainable.

In the Spanish case, the latest figures point to 30 per cent of Friesian dairy milk cattle being infected. In this sense, Euskadi (the Basque Country Autonomous Community) is playing a leading role in being the only Autonomous Community within Spain with a developed programme for the control of paratuberculosis. This programme, based on vaccination, has been carried out for over five years under the auspices of the Livestock Services of the Gipuzkoa Provincial Government, and to the great satisfaction of the farmers. In fact, currently, both the Provincial Government of Bizkaia and that of Araba (the other two provinces within Euskadi) have been integrated into the programme to a greater or lesser degree.

Dr Bakker hopes that the team of experts will come to an agreement on a strategy for control, to be submitted to the European Commission within a matter of months. In his view, there is a need for a control programme common to all member states participating in ParaTBTools, given that to date each country has had different ways of approaching the disease, a fact that has made it more difficult to obtain overall conclusions about the incidence of the illness and about its treatment.