The American Association of Equine Practitioners (AAEP) has published Field Diagnostic Guidelines for Equine Infectious Respiratory Disease on its website tohelp veterinariansevaluate and diagnose equine respiratory disease of unknown etiologywhen the cause is unclear.Equine respiratory disease etiologies range fromviral and bacterial infections to environmental allergens or inflammatory factors. Diagnostic testing todetermineetiology is strongly recommended to provide targeted treatment strategies, implement biosecurity protocols ifnecessary, and support overall herd health.Multiple febrile animals or one or more horseswith acute respiratory abnormalities and feverare suggestive of underlying infectious disease and should prompt practitioners to implement biosecurity practices andestablishaquarantine on the premises.The diagnostic flowchart contained within the guidelines will help practitioners navigate their differential list (the list of possible diseases or conditions that could explain a horses clinical signs), samplecollection,and diagnostic test selection to achieve a definitive diagnosis.There are many considerationsinvolved in differentiating the causeof equine respiratory disease, so it is our hope that these field diagnostic guidelines willbe aconvenient andvaluableresource forequine practitionerswhen confronted with such cases, said Toby L. Pinn-Woodcock, DVM, Dipl. ACVIM, chair of the AAEPsField Guidelines Subcommittee andassociateclinical professor in the Department of Population Medicine and Diagnostic Sciences at Cornell University College of Veterinary Medicine, in Ithaca, New York.Authored collaboratively by members of theAAEPField Guidelines Subcommittee, the Field Diagnostic Guidelines for Equine AcuteRespiratory Diseasewere reviewed and approved by the AAEP Infectious Disease Committee and board of directors. View the guidelines or save them to your mobile device athttps://aaep.org/resource/equine-infectious-respiratory-disease-field-diagnostic-guidelines.This is thethirdset of Field Diagnostic Guidelines published by the AAEP and followspreviousissuance of similar step-by-step protocols for Infectious Neurologic DiseaseandforAcute Infectious Diarrhea. All AAEP Field Diagnostic Guidelines areaccessible athttps://aaep.org/guidelines-resources/field-diagnostic-guidelines.