Acute phase proteins in Andalusian horses infected with Theileria equi.
Authors: Rodríguez Rocío, Cerón José J, Riber Cristina, Castejón Francisco, Gómez-Díez Manuel, Serrano-Rodríguez Juan M, Muñoz Ana
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Acute Phase Proteins in Andalusian Horses with Theileria equi Equine piroplasmosis caused by *Theileria equi* presents clinically with non-specific signs—anorexia, anaemia and depression being most common in pastured mares, whilst performance loss and depression predominate in stabled stallions—yet the systemic inflammatory response appears surprisingly subdued. This PCR-confirmed infection study of 23 Andalusian horses compared with 10 healthy controls revealed that acute phase protein (APP) concentrations remained within normal reference ranges in all but a handful of cases, with elevated serum amyloid A detected in only 3 of 23 infected horses, haptoglobin in 5, and fibrinogen in just 1. Notably, thrombocytopoenia was evident in 5 of 7 stabled stallions, and serum iron concentrations were consistently depressed across both infected groups regardless of management system. The muted APP response despite clinical disease suggests practitioners should not rely on systemic inflammatory markers to rule out theileriosis, particularly when horses present with compatible clinical signs and anaemia; PCR confirmation remains the diagnostic gold standard for this condition. The iron depletion observed in infected animals warrants consideration of supplementation as an adjunctive management strategy, though the relationship between management type (pasture versus stabled) and clinical severity merits further investigation in larger cohorts.
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Practical Takeaways
- •Theileria equi infection may present with clinical signs (anaemia, depression, poor performance) but acute phase proteins often remain within reference limits, so negative APP results should not rule out theileriosis
- •Serum iron concentration measurement may be a useful supplementary diagnostic indicator when T. equi infection is suspected
- •Thrombocytopoenia occurred in a significant proportion of stabled stallions (5/7) and should prompt consideration of T. equi testing in at-risk populations
Key Findings
- •Andalusian horses infected with T. equi exhibited only mild systemic inflammatory response despite clinical signs of disease
- •Serum haptoglobin was elevated above reference limits in only 5/23 diseased horses, serum amyloid A in 3/23, and fibrinogen in 1/23
- •Lower serum iron concentrations were observed in infected horses compared to controls
- •Anorexia, anaemia, depression and icterus were most frequent clinical signs in pastured mares, while stallions showed loss of performance and depression