To the problem of toxoplasmosis in Vietnam.

The number of 259 human seria was examined for Toxoplasma gondii antibodies in 1984. Under survey were 140 persons from Duyen Thai village situated in a suburban agricultural area of Hanoi, and 119 persons from the villages of Mai Chau district in a mountainous valley near Laos border. A microreaction of complement fixation had shown higher titres in Mai Chau (24.3%) in comparison with 15.7% in Duyen Thai, using 1:16 and higher titres as significant reaction. Age distribution of antibodies revealed early infection in the childhood, as 50% of children had significant reactions in Mai Chau and 27.6% in Duyen Thai. Lately the level of antibodies was decreasing to a minimum (8%) in Duyen Thai in the age group of 30-49 years.