Passive hemagglutination test for detection of antibodies against Taylorella (Haemophilus) equigenitalis in sera of mares.

This research article explores the improvement of the passive hemagglutination (PHA) test to detect antibodies for Taylorella equigenitalis in horse serum, which brilliantly performed superior to other animal’s red blood cells (RBCs).

Testing and Enhancement of the PHA Test

• The research focussed on enhancing the PHA test to accurately detect the antibodies for Taylorella equigenitalis in mare’s serum. Taylorella equigenitalis causes contagious equine metritis (CEM), a sexually transmitted infection in horses which can cause a temporary infertility in mares.
• The researchers tested RBCs from horses, cows, pigs, and sheep. They particularly improved the effectiveness of the PHA test with horse RBCs.
• The superiority of the horse RBCs was confirmed through their effectiveness in detecting CEM compared to the RBCs from other animals.

Procedure and Outcome of the PHA Test

• The PHA test used horse RBCs as an indicator and an antigen prepared from T. equigenitalis by sonication. This was after treating these cells with an enzyme called hyaluronidase.
• In terms of specificity and sensitivity, this set-up of the PHA test was the most satisfactory.
• 156 serum samples from healthy mares that had no history of contact with T. equigenitalis were tested. None of them showed PHA titers greater than 1:32, and only 7.1% of these samples showed PHA titers of 1:32.
• 50 serum samples from mares affected with CEM were tested. 4 of these samples showed PHA titers of 1:32, while 92.0% of the samples showed PHA titers higher than 1:32. These results signified the presence of T. equigenitalis in these mares.

Advantage of Using Glutaraldehyde-fixed Horse RBCs

• The advantage of using glutaraldehyde-fixed horse RBCs, sensitized with the antigen, was that they could be reproduced for a minimum of 7 months whilst being preserved at a low temperature of 4 degrees Celsius.
• This allowed for the long-term storage and usage of these cells, making them an ideal option for these kinds of tests.

Overall, this work displayed the improved detection of CEM in mares using an enhanced PHA test, with a high level of specificity and sensitivity. This advancement could be instrumental in swiftly diagnosing and managing CEM in the equine population.