n pl but sing or pl in constr :  an infectious febrile disease of horses and other equines that is caused by a bacterium of the genus Streptococcus (S. equi), is characterized by inflammation and congestion of mucous membranes and a tendency to swelling and suppuration of the intermaxillary and cervical lymph nodes, usu. affects young animals, has a low mortality rate, and confers subsequent immunity after one attack .
 
 
 
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