The most well known Coxsackie A disease is Hand, foot and mouth disease (unrelated to hoof and mouth disease), a common childhood illness which affects mostly children aged 5 or under, often produced by Coxsackie A16.In most cases infection is asymptomatic or causes only mild symptoms.iseases [edit]. The most well known Coxsackie A disease is Hand, foot and mouth disease (unrelated to hoof and mouth disease), a common childhood illness which affects mostly children aged 5 or under, often produced by Coxsackie A16. In most cases infection is asymptomatic or causes only mild symptoms.