Towards an eradication strategy for Mycoplasma hyopneumoniae from the UK pig herd
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Research partners: The Royal Veterinary College, Veterinary Laboratories Agency
Sponsors: BBSRC, BPEX
Duration: July 2009 – June 2013
Mycoplasma hyopneumoniae is the causative agent of enzootic pneumonia (EP) and is also considered to be one of the main causes of porcine respiratory disease complex (PRDC). Correct diagnosis of M. hyopneumoniae is essential for treatment and control of the disease; however, currently there is no single ‘gold standard’ diagnostic test available in the UK.
The aims of this project are to develop and validate a diagnostic tool for the detection of Mycoplasma hyopneumoniae and to propose a protocol on how EP can be eradicated from the UK pig herd.
The tool being developed is known as immunohistochemistry (IHC) and allows the visualisation of pathogens within tissues under the microscope, this makes it ideal for use with M. hyopneumoniae which cannot be identified in lung lesions using other diagnostic tests.
Preliminary studies were conducted to develop a working IHC protocol for the identification of M. hyopneumoniae. Further studies focussed on developing the test and once it had been fully optimised archived lung sections were tested and specific staining was achieved. To ensure the antibody did not cross react with M. hyorhinis, another pathogenic mycoplasma found in the lung, tissue sections known to contain M. hyorhinis were tested and no specific staining was achieved. A working immunohistochemical protocol has been developed and optimised for the identification of M. hyopneumoniae within lung tissue sections indicating significant progress in the diagnosis of enzootic pneumonia.
Work is now underway to validate the technique using a tissue bank containing 50 lung samples. Each sample was scored for enzootic pneumonia like lesions, photographed and samples were taken for histology and IHC. Samples were also taken for polymerase chain reaction (PCR), which is the routinely used diagnostic test, although it detects both live and dead organisms. All lung samples have also been cultured following the normal protocol as culture is considered to be the definitive test, although it is time consuming and often unreliable. The PCR and culture results will be compared against those of the IHC.
Preliminary work has been undertaken to identify the costs of enzootic pneumonia to the pig industry and the costs associated with its control and eradication.
Currently IHC is not offered as a diagnostic test for M. hyopneumoniae in the UK. This project will ensure that the test becomes available to the industry. The feasibility of eradication of M. hyopneumoniae will have been fully researched, taking into consideration the cost-benefit. This will provide a solid foundation upon which the industry will be able to make an informed decision on whether to eradicate M. hyopneumoniae at pig level, herd level, regionally, or nationally.
Page last updated
11 April 2011