A cross-sectional study on performance evaluation in Italian standardbred horses' real-time PCR-positive for Theileria equi.
Authors: Coluccia Pierpaolo, Gizzarelli Manuela, Scicluna Maria Teresa, Manna Giuseppe, Foglia Manzillo Valentina, Buono Francesco, Auletta Luigi, Palumbo Veronica, Pasolini Maria Pia
Journal: BMC veterinary research
Summary
# Editorial Summary Chronic equine piroplasmosis caused by *Theileria equi* can trigger inflammatory muscle and blood vessel changes that may compromise athletic performance, yet the clinical significance of subclinical infection in racing populations remains poorly understood. Researchers screened 258 Italian Standardbred racehorses using real-time PCR for *T. equi* and *B. caballi*, then compared haematological profiles, blood chemistry markers, muscle mass scoring and race performance data between infected and uninfected animals. Horses testing positive for *T. equi* demonstrated measurable performance deficits alongside altered inflammatory markers and reduced muscle mass, suggesting that even clinically silent infections warrant clinical consideration in underperforming individuals. These findings highlight the importance of serological screening protocols in racing yards, particularly where poor performance cannot be attributed to other orthopaedic or metabolic causes, as occult piroplasmosis may contribute to subclinical myopathy and reduced racing efficiency. For practitioners managing Standardbreds with unexplained performance plateaus, *T. equi* status should be incorporated into diagnostic protocols, with positive cases potentially benefiting from targeted anti-parasitic intervention and enhanced nutritional support for muscle recovery.
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Practical Takeaways
- •Clinically healthy racehorses may harbour T. equi or B. caballi infections that cause subclinical inflammatory changes and impact performance; consider PCR testing in underperforming horses
- •Blood work abnormalities and reduced muscle mass in apparent clinically sound horses warrants investigation for piroplasmosis as a potential underlying cause
- •T. equi and B. caballi infections should be considered in the differential diagnosis for standardbred racehorses with unexplained poor racing performance or training difficulties
Key Findings
- •Theileria equi and/or Babesia caballi PCR positivity was detected in Italian Standardbred racehorses presented as clinically healthy
- •Haematological and blood chemistry parameters differed between PCR-positive and PCR-negative horses
- •Chronic equine piroplasmosis infection was associated with altered muscle mass scores in positive horses
- •Performance metrics showed differences between infected and non-infected standardbred racehorses