SAC Research

Paratuberculosis is a chronic, infectious disease of ruminants that results in chronic weight loss and particularly in cattle a profuse diarrhoea. The disease has a worldwide distribution and is of serious economic and possibly of public health importance. The cause of the disease is infection by a bacterium called Mycobacterium avium subspecies paratuberculosis (Map).

Control schemes for infected cattle herds are available (see SAC Consultancy Services link to PCHS) but our research work, carried out in collaboration with BioSS, has been to examine the impact of wildlife reservoirs of infection (see Animal Health publication lists link on the right) and to develop an epidemiological computer based model to optimise the disease control strategies.

The model includes the important epidemiological features of paratuberculosis infection and for further detail please see the attached pdf document.  By simulating infection a number of practical control options for cattle herds have been examined.  Our findings highlight some important features about disease control and include a number of important recommendations:

• that test and cull control policies based on blood testing were comparable to those based on testing of dung by culture
• that vaccination alone will reduce the occurrence of the disease but very importantly will not eliminate infection
• that management changes alone will cause the number of cases to fall in a herd but must be used in combination with other testing and culling to reduce the average prevalence to a low level
• a combination of test and cull with management changes is required to reduce the average prevalence to a negligible level

Our intention is in the next weeks to develop this site with further details of paratuberculosis research and also to provide a linkage to the Defra Johne’s initiative that SAC supports.

Project Number:  661601

The Scottish Government

BioSS