Piroplasmosis in Italian Standardbred Horses: 15 Years of Surveillance Data.
Authors: Padalino Barbara, Rosanowski Sarah M, Di Bella Caterina, Lacinio Rosanna, Rubino Giuseppe T R
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Piroplasmosis in Italian Standardbred Horses Over fifteen years of surveillance data from Italian Standardbred racehorses reveals that chronic equine piroplasmosis affects 9.3% of poorly performing animals, with no predisposition based on sex or age, suggesting this is an opportunistic infection affecting the broader racing population rather than specific demographic groups. Using blood smear cytology combined with haematological and biochemical analysis on 520 horses (median age 4 years), researchers identified characteristic but inconsistent disease markers: mild normocytic normochromic anaemia, hyperbilirubinemia, thrombocytopenia, and hypergammaglobulinemia. Critically, significant overlap existed between infected and uninfected horses' blood parameters and normal reference ranges, meaning that routine haematology alone cannot reliably confirm or exclude the disease. For equine practitioners managing underperforming racehorses in endemic regions, blood cytology should form the initial diagnostic step in differential diagnosis protocols, ideally supported by PCR or ELISA confirmation, since chronic piroplasmosis remains a treatable condition and accurate diagnosis is essential for both animal welfare and regulatory compliance regarding health status certification.
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Practical Takeaways
- •In Italian Standardbreds with poor racing performance, include chronic piroplasmosis in your differential diagnosis list—9% prevalence justifies testing in endemic areas
- •Don't rely solely on hematological and biochemical parameters to diagnose piroplasmosis; request blood smear cytology and molecular tests (PCR/ELISA) for definitive diagnosis since results overlap significantly with normal horses
- •Know that piroplasmosis-positive horses may appear only mildly anemic and have subtle blood abnormalities, so clinical suspicion based on performance and geographic history is important
Key Findings
- •Prevalence of chronic equine piroplasmosis in poorly performing Italian Standardbred racehorses was 9.3% (95% CI: 6.9%-12.1%) over 15 years of surveillance (2004-2018)
- •No significant association was found between piroplasmosis infection status and horse sex or age
- •Chronic piroplasmosis was associated with mild normocytic normochromic anemia, hyperbilirubinemia, thrombocytopenia, and hypergammaglobulinemia, but substantial overlap existed with uninfected horses
- •Blood cytology should be performed as a first-line diagnostic test in poorly performing Standardbreds in endemic regions, with confirmation by PCR or ELISA recommended