Control of paratuberculosis and other diseases through new immunogens: protection, DIVA diagnosis and interference with tuberculosis
- Funding: INIA (National Institute for Agricultural and Food Research and Technology)
- Leader: Natalia Elguezabal
- Implementation: 2017-2020
There are several pathologies which, without being subject to official eradication programmes, cause serious financial losses on livestock farms. One of these is paratuberculosis, a chronic infectious disease of mycobacterial aetiology that causes granulomatous enteritis and is a major health and financial problem for ruminant farms worldwide. Although first described at the end of the 19th century, the mechanisms regulating host-pathogen interaction in this disease are not fully defined.
To date, vaccination has been the only effective method with an affordable cost for farmers to control the disease in both sheep and cattle on a large scale. However, it does not confer absolute protection and causes interference with serological tests, as a result of which a DIVA (Differentiating Infected from Vaccinated Animals) test would be necessary. Moreover, vaccination against paratuberculosis is restricted by possible interferences with the diagnosis of bovine tuberculosis, which means that the best tool for controlling paratuberculosis is used in a residual manner at a field level.
The overall objective of this project is to develop effective tools that make it possible to vaccinate against paratuberculosis by providing protection without interfering with the serological diagnostic techniques of paratuberculosis and official routine techniques for diagnosing bovine tuberculosis, in addition to studying the non-specific effects of vaccination against paratuberculosis.. To this end, new reagents will be created to develop a DIVA test aimed at inactivated vaccines against Mycobacterium avium subsp. paratuberculosis (MAP).
It will be checked whether vaccination with a vaccine against MAP, another mycobacterial vaccine against M. bovis (MBV) developed in previous projects and combined probiotics, all administered orally, do not interfere with the diagnosis of tuberculosis, opening a new way for their use. In addition, the protective effect of all of these immunogens against infection from MAP will be evaluated. In this way, the specific immune response against MAP can be evaluated, in addition to the possible “learned” immune response or cross-protection generated by the MBV vaccine and probiotics. A learned immune response is understood as one that confers an immunogen to the host that protects it against pathogens that differ from the one against which it is designed.
Lastly, the aim is to verify whether the administration of these immunogens is capable of inducing a learned immune response against other pathogens of interest of a non-mycobacterial origin in livestock by means of in vitro tests. If beneficial side effects occur after immunisations, these immunogens would be an alternative to the use of antibiotics against certain pathologies. The work proposed in this project will provide knowledge on the pathogenesis of paratuberculosis applicable to other inflammatory bowel diseases and also more advanced information on the beneficial side effects of vaccination against mycobacteriosis.
The results of this project will support the vaccination strategy and may lead to products and/or guidelines whose implementation will improve the profitability of farms and contribute to resolving a global economic problem.
Objectives:
General objective:
To develop effective tools that make it possible to vaccinate against paratuberculosis by providing protection without interfering with the serological diagnostic techniques of paratuberculosis and official routine techniques for diagnosing tuberculosis, in addition to studying the non-specific effects of vaccination against paratuberculosis..
Specific objectives:
- To analyse whether the effect of oral vaccination with inactivated MAP vaccine or other products interferes with the outcome of routine official tests in the diagnosis of bovine tuberculosis.
- To analyse the protective effect against MAP infection of different vaccines and probiotics in rabbits, taking into account bacteriological, immunological and histopathological parameters.
- To analyse the learned immune response in animals treated with different vaccines and probiotics in in vitro tests to evaluate their potential against other pathogens of interest in livestock.
- To evaluate the usefulness of MAP-specific recombinant proteins absent in the vaccine strain and recombinant proteins with proven immunogenicity as a DIVA test for bovine paratuberculosis