Fractional-Order Dengue Disease Epidemic Model in Nepal

The dengue disease epidemiological patterns of Nepal have become a geographical challenge. It is one of the emerging public health issues in the country. In Nepal, the disease has been reported since 2004 in both tropical and sub-tropical regions. In this work, the dengue disease epidemic model is formulated by using fractional-order derivatives. The least-squares method is used for estimation of the parameters with the help of the classical compartmental model of the dengue infections recorded in the year 2019, which is the largest-ever outbreak to occur in Nepal. The existence and uniqueness of a non-negative solution are discussed for the fractional-order model. An epidemiologically important dimensionless number, R 0 is obtained using the next-generation method. Two equilibriums disease free and endemic points are obtained and their stability is studied. The Euler’s method is implemented to solve the fractional-order model numerically. The numerical results suggest that the fractional model fits better with an appropriate choice of the memory level, α than the classical model based on the real data of Nepal.