摘要
There are 6 epidemic models of hepatitis A in the world.In China,there are 3 mod-els,namely,Beijing,Shanghai and Guangzhou models.In 1979,Schenzle proposed a modifiedsimple catalytic model whose force of infectivity is a logistic function.We made a modifiedmodel with the infectivity force of a linear or conic function.According to the actual data,theauthors have fitted 3 epidemic models.The results are satifactory as proved by the x^2-test ofgoodness of fit.The analysis of the models indicates that the force of infectivity has been lower inShanghai than in Beijing and Guangzhou since·1970.An interesting finding is that the differencebetween the 3 epidemic models is due to the function of infectivity force of hepatitis A.
There are 6 epidemic models of hepatitis A in the world.In China,there are 3 mod- els,namely,Beijing,Shanghai and Guangzhou models.In 1979,Schenzle proposed a modified simple catalytic model whose force of infectivity is a logistic function.We made a modified model with the infectivity force of a linear or conic function.According to the actual data,the authors have fitted 3 epidemic models.The results are satifactory as proved by the x^2-test of goodness of fit.The analysis of the models indicates that the force of infectivity has been lower in Shanghai than in Beijing and Guangzhou since·1970.An interesting finding is that the difference between the 3 epidemic models is due to the function of infectivity force of hepatitis A.
