| Abstract: | Dynamic observation on 126 foci of infection formed by patients with manifest forms of chronic hepatitis B, 41 foci of chronic hepatitis of unknown etiology, and 37 foci formed by chronic "healthy" carriers was made. In the foci of type 1 the epidemic process developed intensively and was manifested mainly by HBsAg carriership in persons having had contacts with the patients. During the period of observation 43.0% of new cases of infection were detected. In the foci of types 2 and 3 the frequency of contacting infection was not different from that in the control group of the population. |
