Evaluation of serological responses in horses challenged with Burkholderia pseudomallei using current diagnostic tests for glanders.

This study examines the responses of six horses infected with a specific strain of Burkholderia pseudomallei, the bacterium that causes glanders disease. The results revealed the limitations of current diagnostic tests in distinguishing between glanders and a similar disease, melioidosis.

Study Design

• The research involved an experiment with six horses that were intentionally infected with Burkholderia pseudomallei. This bacterium was derived from a previous lethal infection case in a dromedary camel in Dubai.
• The modes of administration varied, with half of the horses receiving the bacterium through subcutaneous injection, while the rest were orally administered.

Results and Observations

• Outcome of the experiment showed that four out of the six horses had a positive serological response. This was determined by their reaction to one or more tests recognized by the World Organisation for Animal Health (OIE) for glanders.
• The same bacteria were re-isolated from these four serologically positive horses, providing confirmation of infection.
• However, interestingly, only a single horse- the one that was infected subcutaneously- developed a fever for a period of 3 days. This horse also exhibited elevated levels of white blood cells and neutrophils, indicative of an immune response to infection.

Study findings

• The primary conclusion of the study was the confirmation of the limitations of current diagnostic tests for glanders in horses. Notably, these tests could not differentiate between glanders and melioidosis – a similar disease also caused by a strain of Burkholderia.
• This observation underlines a significant challenge in equine health, highlighting the need for improved diagnostic methods that can accurately distinguish between the two diseases. Both diseases pose serious health risk to horses and other animals, and can even be transmitted to humans, causing severe infection.