Descriptive epidemiologic study of disease associated with influenza virus infections during three epidemics in horses.
Abstract: To describe 3 epidemics of respiratory tract disease caused by influenza virus infections in a large population of horses. Methods: Cross-sectional and prospective longitudinal observational studies. Methods: All horses stabled at a Thoroughbred racetrack. Methods: During a 3-year period, descriptive information was collected as horses arrived at the racetrack and throughout race meetings. Routine observations and physical examinations were used to classify horses' disease status. Cause of epidemics was established by use of serologic testing and identification of influenza virus in nasal secretions. Results: An epidemic of respiratory tract disease caused by influenza virus infections was identified during each year of the study. Attack rates of infectious upper respiratory tract disease (IURD) ranged from 16 to 28%. Incidence of disease caused by influenza virus infections during racing seasons in the second and third years was 27 and 37 cases/1,000 horses/mo, respectively. Physical distributions of stall locations revealed that affected horses were stabled throughout the population; horses affected later in epidemics were often clustered around horses affected earlier. Mucopurulent nasal discharge and coughing were observed in 83 and 62% of horses with IURD, respectively. Median duration of clinical disease was 11 days. Serologic testing was the most sensitive method used to detect influenza virus infections; 76% of affected horses seroconverted to influenza virus. Conclusions: Epidemics of IURD were observed annually in association with influenza virus infections. Few precautions were taken to limit spread of infection. Preventing or decreasing the likelihood of exposure and improving immunity in the population could substantially decrease risk of disease in similar populations.
Publication Date: 2000-02-25 PubMed ID: 10687009DOI: 10.2460/javma.2000.216.535Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Diagnosis
- Disease control
- Disease Diagnosis
- Disease Etiology
- Disease Management
- Disease Outbreaks
- Disease Prevalence
- Disease Surveillance
- Disease Transmission
- Disease Treatment
- Epidemiology
- Equine Health
- Horses
- Infectious Disease
- Influenza
- Longitudinal Study
- Observational Study
- Respiratory Disease
- Thoroughbreds
- Veterinary Medicine
- Virus
Summary
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The research study documents three respiratory disease epidemics, caused by influenza virus infections, among a large horse population at a Thoroughbred racetrack across three years. It suggests that improving immunity and reducing exposure can significantly lower disease risk in similar groups.
Studies and Methods
- The researchers conducted both cross-sectional and longitudinal observational studies over a three-year period.
- Data on horses was collected as they arrived at the racetrack and throughout race meets.
- Regular physical examinations and observations were performed to determine the horses’ disease status.
- They utilized serologic testing and the identification of the influenza virus in nasal secretions to establish the cause of the epidemics.
Results of the Study
- The study identified an epidemic of respiratory tract disease each year caused by the influenza virus infection.
- The rate at which infectious upper respiratory tract disease (IURD) occurred ranged from 16% to 28%.
- The occurrence rate of the disease during racing seasons in the second and third years reached 27 and 37 cases per 1,000 horses per month, respectively.
- The study also reveals that horses affected later in the epidemics were often in close proximity to horses affected earlier.
- Of the horses with IURD, mucopurulent nasal discharge was observed in 83% and coughing in 62%.
- The median duration of clinical disease was 11 days.
- Serologic testing was found to be the most sensitive method for detecting influenza virus infections, with 76% of affected horses seroconverting to the influenza virus.
Conclusion
- The study observed annual IURD epidemics linked with influenza virus infections.
- The researchers noted that few precautions were taken to limit the spread of infection.
- The team concluded that implementing measures to improve immunity and decrease exposure could significantly reduce the risk of similar diseases among horse populations.
Cite This Article
APA
Morley PS, Townsend HG, Bogdan JR, Haines DM.
(2000).
Descriptive epidemiologic study of disease associated with influenza virus infections during three epidemics in horses.
J Am Vet Med Assoc, 216(4), 535-544.
https://doi.org/10.2460/javma.2000.216.535 Publication
Researcher Affiliations
- Department of Veterinary Internal Medicine, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.
MeSH Terms
- Animals
- Antibodies, Viral / blood
- Cross-Sectional Studies
- Disease Outbreaks / veterinary
- Female
- Horse Diseases / epidemiology
- Horse Diseases / transmission
- Horses
- Incidence
- Longitudinal Studies
- Male
- Orthomyxoviridae Infections / epidemiology
- Orthomyxoviridae Infections / transmission
- Orthomyxoviridae Infections / veterinary
- Physical Conditioning, Animal
- Prospective Studies
- Saskatchewan / epidemiology
- Sports
Citations
This article has been cited 7 times.- Gonzalez-Obando J, Forero JE, Zuluaga-Cabrera AM, Ruiz-Saenz J. Equine Influenza Virus: An Old Known Enemy in the Americas. Vaccines (Basel) 2022 Oct 14;10(10).
- Pusterla N, James K, Barnum S, Bain F, Barnett DC, Chappell D, Gaughan E, Craig B, Schneider C, Vaala W. Frequency of Detection and Prevalence Factors Associated with Common Respiratory Pathogens in Equids with Acute Onset of Fever and/or Respiratory Signs (2008-2021). Pathogens 2022 Jul 2;11(7).
- Singh RK, Dhama K, Karthik K, Khandia R, Munjal A, Khurana SK, Chakraborty S, Malik YS, Virmani N, Singh R, Tripathi BN, Munir M, van der Kolk JH. A Comprehensive Review on Equine Influenza Virus: Etiology, Epidemiology, Pathobiology, Advances in Developing Diagnostics, Vaccines, and Control Strategies. Front Microbiol 2018;9:1941.
- Pusterla N, Kass PH, Mapes S, Wademan C, Akana N, Barnett C, MacKenzie C, Vaala W. Voluntary surveillance program for equine influenza virus in the United States from 2010 to 2013. J Vet Intern Med 2015 Jan;29(1):417-22.
- Daly JM, Newton JR, Wood JL, Park AW. What can mathematical models bring to the control of equine influenza?. Equine Vet J 2013 Nov;45(6):784-8.
- Wood JL, Newton JR, Chanter N, Mumford JA. Association between respiratory disease and bacterial and viral infections in British racehorses. J Clin Microbiol 2005 Jan;43(1):120-6.
- Chambers TM. Equine Influenza. Cold Spring Harb Perspect Med 2022 Jan 4;12(1).
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