Evaluation of the field application of PCR in the eradication of contagious equine metritis from Japan.

The research carried out an evaluation of how effective the polymerase chain reaction (PCR) test was in eradicating contagious equine metritis (CEM) among Thoroughbred horses in Japan. The findings suggested that the PCR testing, paired with subsequent treatment, was a useful method for the disease’s eradication as it was more sensitive than isolated tests.

Research Methods and Participant Selection

• The researchers collected a total of 7,534 genital swabs from 4,026 Thoroughbred broodmares and stallions in Japan between 1998-2001.
• This wide-path sampling was aimed at identifying “high-risk” horses while also facilitating comprehensive surveillance testing for CEM.

PCR and Bacterial Isolation Testing

• Two types of testing were employed for the detection of Taylorella equigenitalis (the bacterium responsible for CEM) from the genital swabs. These were bacterial isolation and PCR testing.
• PCR testing was also used on both original specimens and specimens bred in a culture laboratory to ensure accuracy in the results.
• As a result of the tests, T. equigenitalis was detected in 12 mares and 1 stallion by PCR. However, the bacteria were only successfully isolated from 2 of the PCR-positive mares.

Treatment and Eradication Attempts

• The horses which were identified as infected or carriers of CEM were treated using a combination of chemotherapy and surgery.
• After the initial treatment, follow-up testing over three years was undertaken to confirm the absence of T. equigenitalis.
• This series of testing did not find any traces of T. equigenitalis, indicating successful treatment.

Conclusion and Recommendations

• The study concluded that PCR testing was more sensitive than isolation in detecting T. equigenitalis from genital swabs of horses in the field.
• Hence, they proposed that PCR testing, coupled with treatment, can significantly help in the eradication of CEM from Japan.