Use of ELISAs for Monitoring Exposure of Pig Herds to <em>Brachyspira hyodysenteriae</em>

Based on the three independent studies, researchers in Australia found IgG ELISAs using either WC or Bhlp29.7 as plate-coating antigens to be useful for monitoring the dynamics of B. hyodysenteriae infection in grower pigs, with certain advantages favouring the WC preparation. Meat juice samples collected from pigs on infected farms contained specific antibodies to B. hyodysenteriae and so they suggested that analysis of this material could be incorporated into routine health surveillance.

15 February 2012

3 minute read

By: Jackie Linden

In the introduction to their paper published recently in BMC Veterinary Research, Yong Song of Murdoch University in Western Australia and co-authors with Consistent Pork and the University of Western Australia explain that swine dysentery (SD) is a mucohaemorrhagic diarrhoeal disease of pigs, which results from infection of the large intestine with the spirochaete, Brachyspira hyodysenteriae.

They continue that ELISA systems using whole spirochaete cells (WC) and the B. hyodysenteriae outer membrane lipoprotein Bhlp29.7 have previously been established as potential diagnostic tools for SD. However, their true value in identifying infected herds remains unclear. Their present study aimed to compare the performance of whole-cell and Bhlp29.7 based ELISAs in detecting specific immunoglobulin class IgG and IgM to B. hyodysenteriae in growing pigs, and additionally evaluated whether meat juice could serve as a source of specific antibodies.

The researchers found that levels of circulating IgG and IgM reacting with WC spirochaete preparations and recombinant Bhlp29.7 peaked four to six weeks post-infection in the experimentally challenged pigs, and remained elevated in the study. In a cohort of pigs on an infected farm, levels of antibody directed against both antigens showed a progressive increase with time. However, other than for the level of IgG against WC antigen, a significant increase in antibody levels also was observed in a cohort of pigs on a non-infected farm.

In addition, assays using meat juice had 100 per cent specificity and equivalent sensitivity to those based on serum, and likewise, the best performance was achieved using the WC IgG ELISA.

IgG ELISAs using either WC or Bhlp29.7 as plate-coating antigens were shown to be useful for monitoring the dynamics of B. hyodysenteriae infection in grower pigs, concluded Song and co-authors. Of the two antigens, the WC preparation tended to give better discrimination between pigs from infected and non-infected farms. Testing of meat juice was shown to have potential for identifying infected herds.

Reference

Song Y., B. Frey and D.J. Hampson. 2012. The use of ELISAs for monitoring exposure of pig herds to Brachyspira hyodysenteriae. BMC Veterinary Research, 8:6. doi:10.1186/1746-6148-8-6