[Calculation of trends in typhoid morbidity in different regions of the country].

The relationship linearity criterion and its derivatives were used in processing the mass of official statistical data on typhoid morbidity throughout the whole territory of the USSR and in the union republics during the period 1950-1976. In the majority of the union republics (the RSFSR, the Ukrainian, Byelorussian, Georgian, Armenian, Moldavian, Lithuanian, Latvian and Estonian SSR) the time course of typhoid morbidity was found to have a linear character and could be adequately described by the exponential function. The calculation of the average rate of annual decrease in typhoid morbidity in the above-mentioned union republics and the extrapolation of the tendencies of morbidity decrease for the last 20 years indicated that the morbidity level in the USSR would decrease by 6.14%, varying from 3.09% to 9.89% in individual union republics. The authors believe that similar rates of decrease in typhoid morbidity in different regions of the country can be attributed to reduced circulation of the causative agent of this infection and to the constant radical improvement of the sanitary and hygienic conditions of the Soviet people.