Picture of the coxsackie virus; SOURCE: CDC. Type A viruses cause herpangina (painful blisters in the mouth, throat, hands, feet, or in all these areas). Hand, foot, and mouth disease (HFMD) is the common name of this viral infection.Coxsackie A 16 (CVA16) causes the majority of HFMD infections in the U.S. It usually occurs in children (age 10 and under), but adults can also develop the condition.icture of the coxsackie virus; SOURCE: CDC. Type A viruses cause herpangina (painful blisters in the mouth, throat, hands, feet, or in all these areas). Hand, foot, and mouth disease (HFMD) is the common name of this viral infection.