An epidemic of acute hemorrhagic conjunctivitis in Sendai area, 1973-1974.

In 1973 and 1974, an epidemic of acute hemorrhagic conjunctivitis (AHC) with a tendency of less frequent conjunctival hemorrhage occurred among the staff of the National Railways and their family in Sendai area. Four strains of AHC virus and 4 strains, 1 of type 7 and 3 of type 8, of adenoviruses were isolated from 22 conjunctival swabs of the patients. Thirty-six (66%) out of 55 cases examined were proved serologically to be of AHC virus infection, and 7 cases (13%) were of adenovirus infection. Clinically, infrequent association of hemorrhagic conjunctivitis was most remarkable. Only 10 cases (28%) had detectable signs of hemorrhagic conjunctivitis. There were no substantial changes in antigenicity and optimum temperature for virus multiplication between prototype and isolated strains. The isolated strains, however, seemed to be less neutralizable and less producible at 29 degrees C than prototype strain.