Etiologic and immunologic characteristics of thoroughbred horses with bacterial infectious upper respiratory disease at the Seoul Race Park.
Equine respiratory disease is a common cause of poor performance and training interruptions. The higher incidence rate of infectious upper respiratory disease (IURD) in thoroughbred racehorses at the Seoul Race Park coincided with the frequent stabling season, shorter stabling periods, and younger ages in this study. Incidence rates were also correlated with significantly lower proportions of cells expressing MHC class II-, CD2 antigen-, CD4+- or CD8+-T lymphocyte-, and B lymphocyte in IURD patients compared with healthy control groups in the summer and fall and in 2-and-3-year-old groups. The data suggested that movement and new environments may have resulted in immunosuppression and inappropriate responses to respiratory pathogens in IURD patients. The IURD incidence decreased with age, perhaps by the acquisition of immunity, and study results suggested that immunologic protection was associated with IURD, particularly in young thoroughbred racehorses. Streptococci isolates were identified in 11 of 72 IURD horses, and 3 of these isolates were identified as Streptococcus. equi subsp. equi. S. equi subsp. zooepidemicus was isolated from 2 of 23 IURD horses in the spring (8.7%), 5 of 23 in the summer (21.7%), and 1 of 6 in winter (16.7%). S. equi subsp. zooepidemicus (5%) was also identified in 3 of 61 isolates from clinically normal horses. Racetracks should implement anti-IURD protective measures by assessing the capacity of equine immunologic protection at the Park and by limiting the introduction of specific respiratory pathogens (such as S. equi subsp. equi) by preventing the access of infected horses with a respiratory pathogen-free certification system prior to Park entry.
Ryu
Seung-Ho
SH
Korea Racing Authority, Gwacheon, Gyeonggi 427-711, Korea.
Koo
Hye Cheong
HC
Park
Young Kyung
YK
Kim
Jun Man
JM
Jung
Woo Kyung
WK
Davis
William C
WC
Park
Yong Ho
YH
Lee
Chang-Woo
CW
D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D017931:DNA Primers; D004777:Environment; D020022:Genetic Predisposition to Disease; D006734:Horse Diseases / Q000188:drug therapy / Q000209:etiology* / Q000276:immunology / Q000382:microbiology*; D006736:Horses; D007723:Korea; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction / Q000379:methods; D012016:Reference Values; D012141:Respiratory Tract Infections / Q000188:drug therapy / Q000209:etiology / Q000276:immunology / Q000662:veterinary*; D013290:Streptococcal Infections / Q000188:drug therapy / Q000209:etiology / Q000276:immunology / Q000662:veterinary*; D018502:Streptococcus equi / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*
D000900:Anti-Bacterial Agents; D017931:DNA Primers