Inflammatory airway disease, nasal discharge and respiratory infections in young British racehorses

Abstract

Summary Reasons for performing study: Respiratory disease is important in young Thoroughbred racehorses, but the variation in the rates of occurrence between different ages and training groups has not been characterised. Objectives: To determine the rates of respiratory disease, particularly inflammatory airway disease (IAD), as well as evidence of infection, and their variation between age and group. Methods: Horses were examined monthly in 7 British flat training yards over a 3 year period. IAD was defined as increased mucus in the trachea with increased proportions of neutrophils in tracheal wash samples. Frequencies of disease outcomes were estimated from the data. Results: The prevalence of IAD was 13.8% and the incidence was 8.9 cases/100 horses/month. Rates varied with training and age groups, decreasing in older animals. The prevalence of nasal discharge (ND) was 4.1%. Rates of bacterial isolation were more common than viral infections. The incidence and prevalence of several bacterial species decreased with age. Conclusions: IAD and ND were common in young racehorses, varying significantly between training groups and decreasing with age, consistent with infection playing a role in aetiology. Potential relevance: The high prevalence of IAD in 2‐year‐old horses in Britain suggests that routine endoscopic examination may be helpful in providing early diagnosis and appropriate therapy. The transmission of bacteria and viruses within and between groups of young animals and the role of infection, stable environment and factors inherent to each horse, including their genetic make‐up, in the multifactorial aetiology of the disease all merit further study.

Control of equine influenza: scenario testing using a realistic metapopulation model of spread

“…Unsurprisingly, the strength of this effect was sensitive to the level of influenza surveillance. Respiratory disease is common in young racehorses (Burrell et al 1996;Wood et al 2005) and trainers will often ignore the first few cases of disease in their yard before investigating it. This study demonstrates how important it can be to differentiate low-level endemic disease from an incursion of epidemic disease, as is also the case when considering control of avian influenza (Savill et al 2006).…”

“…A. Mumford 1990Mumford -2005, but further efforts to diminish this subset of the population further are justified. It has been known for some time that individual trainers can diminish the likely impact of epidemics by their general management (Newton et al 2000b).…”

Investigation of the presence of Mycoplasma as an etiologic agent of inflammatory airway diseases in thoroughbred racehorses in İstanbul Province

“…The culture method has been used in many retrospective studies (3)(4)(5)7,10,12,24). In our study, both culture and PCR methods were used in order to detect M. felis and M. equirhinis, which were thought to be associated with IAD in horses.…”

“…The samples were submitted to the İstanbul Race Horse Hospital along with complaints of poor performance and/ or abnormal respiratory sounds at rest or while training. The same clinician evaluated the clinical signs of the horses, and the amount of tracheal mucus accumulation (classified as none, little, intermediate, or high), poor performance, coughing at rest or during exercise, and nasal discharge were recorded while collecting samples from the horses (2,5,(16)(17)(18). The sex, age, and strain (English or Arabian thoroughbred) of the horses were also recorded.…”

“…A variety of etiological agents may be involved in IAD, and their relative contribution in the development of the disease varies within different populations according to many factors such as the genetic makeup of the animal and the type of infectious agent but also environmental conditions, feeding, housing season, and preventive medicine practices. Beta-hemolytic streptococci, Actinobacillus/Pasteurella spp., Klebsiella pneumoniae, Bordetella bronchiseptica, and Streptococcus pneumoniae are isolated from IAD cases as bacterial pathogens (1,4,5). In addition to these agents, Mycoplasma equirhinis and Mycoplasma felis can also be isolated from the lower respiratory tract of horses and are determined to be the etiologic agents of IAD (1,3,4,(6)(7)(8).…”