Equus caballus.
D000059:Accidents; D000293:Adolescent; D000818:Animals; D000829:Animals, Domestic; D004683:Encephalomyelitis, Equine / Q000635:transmission; D005260:Female; D006734:Horse Diseases / Q000635:transmission; D006736:Horses; D006801:Humans; D008404:Massachusetts; D011634:Public Health; D014947:Wounds and Injuries; D015047:Zoonoses