Infectious disease and migration

This paper constructs a simple-urban migration model that explicitly incorporates the interaction between individual migration decisions and the risk of incurring infectious diseases in the urban region. We show that excess migration to urban areas occurs despite the existence of the externality effect, which makes the risk of infection extremely high in the urban region. The larger the wage gap between rural and urban workers the greater the size of the urban population. We also show that foreign medical aid that aims at improving urban health infrastructure may worsen the morbidity rate in the urban region, because it induces further excess migration