Hepatitis Ain Greenland: importance of specific antibody testing in epidemiologic surveillance.

An epidemic of viral hepatitis type A in an arctic area is described. From 1970-1974, 4961 clinical cases of hepatitis were reported in Greenland, corresponding to 11 per cent of the total population. Epidemiologic surveillance indicated person-to-person transmission of the disease, apparently by the oralfecal route. The course of the disease was mild, and complications were rare with a case fatality rate of 0.3%. Ninety-three per cent of the cases occurred in individuals 1-25 years of age, suggesting widespread immunity in the adult population presumably due to infection with hepatitis A during a similar epidemic in 1947-1948. The occurrence of antibody to hepatitis A antigen (anti-HA) in healthy Greenlanders, as detected by radioimmunoassay, closely paralleled this observation. Anti-HA was present in 38 (93%) of 41 individuals born before 1948 and in one (3%) of 29 younger persons. Anti-HA also was detected during the epidemic in the sera of 25 randomly selected hepatitis cases. Immunoglobin analysis in three acute-phase sera showed anti-HA reactivity predominantly in the IgM fraction. The epidemic showed no relation to the hepatitis episodes occurring annually in the area, and seroepidemiologic data indicated that the endemic hepatitis may be caused by hepatitis B virus only.