Respiratory disease and sero-epidemiology of respiratory pathogens in the working horses of Ethiopia.
Authors: Laing G, Christley R, Stringer A, Aklilu N, Ashine T, Newton R, Radford A, Pinchbeck G
Journal: Equine veterinary journal
Summary
# Respiratory Disease and Sero-epidemiology of Respiratory Pathogens in Working Horses of Ethiopia Respiratory disease ranks among the most common presentations at veterinary clinics in Ethiopia, yet little was known about which pathogens contribute to disease in the country's working horse population. Laing and colleagues conducted a cross-sectional serological survey of 350 horses across 19 sites in central Ethiopia between August and December 2013, combining clinical examination with serum antibody testing for equine influenza virus, equine herpesviruses 1 and 4, equine rhinitis viruses A and B, equine arteritis virus, and Streptococcus equi subspecies equi, alongside detailed management data collected via owner interview. Owner-reported respiratory signs were common—38% of horses had recently coughed and 7% displayed nasal discharge—yet clinical signs during examination were minimal, suggesting either disease resolution or over-reporting of mild signs. Antibodies to S. equi emerged as the most prevalent finding (8%), with younger animals and those worked less frequently showing higher seropositivity; by contrast, viral antibodies were sparse, with the notable exception of universal prior exposure to EHV-1/4 and ERA/BV, whilst EIV antibodies were completely absent. These results indicate that S. equi may be endemic within this population and partially responsible for respiratory signs, whilst the absence of EIV serology despite clinical disease signals both that non-infectious causes warrant investigation and that the working horse population remains immunologically naive and highly vulnerable to equine influenza incursion—a significant biosecurity concern for the region.
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Practical Takeaways
- •S. equi appears to be endemic in Ethiopian working horse populations and may be a primary driver of respiratory disease in this region—biosecurity and vaccination strategies should be prioritized
- •Working horses in Ethiopia lack immunity to equine influenza and would be highly vulnerable to an outbreak; vaccination protocols should be considered if trade or movement increases
- •Respiratory signs in working horses cannot be attributed primarily to viral causes in this population; investigate non-infectious causes (dust, poor ventilation, work intensity) and management factors
Key Findings
- •38% of working horses had owner-reported recent coughing history, but only 6% showed nasal discharge on clinical examination
- •Streptococcus equi antibodies were most prevalent at 8% (33/350), suggesting endemic presence in the population
- •No horses had detectable antibodies to equine influenza virus despite viral presence indicated by low EHV-1/4 and ERAV/ERBV titres
- •Younger horses and those working less frequently had significantly higher odds of S. equi seropositivity