[Study of coxsackievirus group A. II. Neutralization antibody positive against coxsackieviruses group A of sera of children in Gifu Prefecture].

One hundred forty seven sera of children in Gifu Prefecture, were tested for positive rate of neutralization antibody against Coxsackievirus group A (Cox. A). The results were as follows; 1. The positive rate of antibodies against Cox. A 4, Cox. A 10 and Cox. A 16 were detected in over 45%, but the positive rate of antibody against Cox. A 2 thought isolated rarely, was detected in the same rate. However, both the rate of isolation and positive rate of antibody against Cox. A 8 showed lower levels than other types. 2. The positive rate of antibodies against Coxsackievirus group A were different in every areas in the prefecture. In Seino area, the positive rate of antibodies of Cox. A 2, Cox. A 8 and Cox. A 10 were higher than in other areas. In Gifu area, the positive rate of antibodies against Cox. A 4 and Cox. A 16 were highest but the positive rate of antibody against Cox. A 8 was the lowest than other areas. In Hida(G) area, the positive rate of antibodies against Cox. A 2 and Cox. A 16 were the lowest levels than other areas. In Hide(T) area, the positive rate of antibodies against Cox. A 4 and Cox. A 10 of these viruses, were the lowest than other areas. 3. The positive rate of antibodies by age group, was showed the same pattern in Cox. A 2, Cox. A 4 and Cox. A 10, that is, there was a raise with age and reached to 80-90%. In Cox. A 8, the positive rate of antibody rose with age, but the highest positive rate of antibody reached only 35.5%. In Cox. A 16, the positive rate in 0-1 year olds showed a higher positive rate in 44%, which rose with age, but the rate dropped once at 6-7 age and again rose and reached to 86.7% in the 8-9 age group.