The incidence and risk factors for shipping fever in horses transported by air to Hong Kong: Results from a 2-year prospective study

M.J Hurley,C.M Riggs,N Cogger,S.M Rosanowski

doi:10.1016/j.tvjl.2016.01.006

M.J Hurley, C.M Riggs + Show 2 more

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https://doi.org/10.1016/j.tvjl.2016.01.006

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Abstract

A 2 year prospective study was performed between February 2011 and January 2013 to determine the incidence and risk factors for shipping fever (SF) in horses transported by air to Hong Kong (HK). Using a questionnaire, data were collected from professional flying grooms regarding the journey to HK and horses in the shipment. Horses were monitored in quarantine for 2 weeks after arrival in HK, and clinical signs of SF recorded. Poisson and logistic regression models were used to identify risk factors for SF at the horse and shipment levels.The study analysed data from 869 horses on 81 flights arriving from Australia (n = 24), New Zealand (NZ; n = 18), the United Kingdom (UK; n = 33) and the United States of America (USA; n = 6). The incidence risk of SF was 10.8 per 100 horses and the proportion of shipments with at least one horse that developed SF was 49/81 (60%). The study identified that the rate per shipment of SF in shipments of horses originating from NZ, the USA and the UK was 2.40 (95% confidence interval [CI] 1.22–4.71), 2.43 (95% CI 0.66–8.89) and 3.08 (95% CI 1.60–5.93) times the rate of SF compared to Australia. Shipments arriving in HK during March and May were 5.61 (95% CI 1.55–20.31) and 4.51 (95% CI 1.43–14.26) times more likely to contain horses that developed SF compared to shipments arriving in January. The identification of these risk factors and the recognition of at-risk shipments will help focus attention on preventative strategies.

Highlights

Shipping fever (SF) is a common respiratory disease of horses associated with transport over long distances by road, rail, sea, or air (Racklyeft et al, 2000)
Of the horses that were imported, 840/869 (96.7%) were Thoroughbreds destined for racing in Hong Kong (HK) and the remaining were a variety of horse breeds destined for riding schools
As the majority of horses imported to HK are destined for the racing industry, any conditions that could have a detrimental effect on future performance are of concern

Summary

Introduction

Shipping fever (SF) is a common respiratory disease of horses associated with transport over long distances by road, rail, sea, or air (Racklyeft et al, 2000). Horses affected by this condition typically first develop a fever, followed by other clinical signs as the condition progresses. These clinical signs may include inappetance, lethargy, coughing, nasal discharge, dyspnoea, tachycardia, abducted elbows, reluctance to move and a stiff gait (Mair and Lane, 1989; Wilkins, 2003; Davis et al, 2014). The stress associated with long distance travel, confinement in adverse environmental conditions, an elevated head position, and pre-existing lower respiratory disease, are well-known risk factors that contribute to the development of SF in horses (Rackyleft and Love, 1990; Leadon, 1995;1 ; Rackyleft et al, 2000; Davis et al., 2014)

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