Epidemiological investigations were carried out with 87 cases of epidemic nephritis, having prevailed in autumn, 1957 in Kanagase, Okawara-machi, Miyagi prefecture.
The results were as follows:
1. The peak of epidemy extended from late summer to autumn. The infection ratewas 2.2%.
2. There was no difference in susceptibility by sex.
3. The highest incidence was seen between 3 and 11 years of age, showing its maximum in 8 years.
4. The family infection rate was 17.2%.
5. Out-of-the-way-places were frequented by the infection.
6. Hemolytic streptococci were isolated from the pharyngeal mucus membrane in 14.2% of patients.
