For a discussion of global climate change and its possible effect on infectious diseases, I shall deal necessarily in hypothetical terms. There is no way of knowing for certain what effect, if any, a rise in temperature and a change in rainfall patterns will have. He considers each transmissible disease a complex. The ambient temperature will have an influence on each of the factors in the complex. Many of the two-factor complexes are not limited by temperature and therefore are distributed anywhere in the world that the agent is introduced and that is inhabited by people.
Examples are poliomyelitis and measles.
The distribution, prevalence, and severity of these diseases are not expected to be modified by global climate change. One could argue that mortality rates of measles and poliomyelitis are higher in the tropics than in the temperate zones, and therefore these diseases will become more severe. The increased severity in the tropics is probably related to poorer socioeconomic conditions. To the extent that global warming increases poverty and its associated ills, the two-factor complexes will also be affected. Only rarely is a given vector-borne disease distributed everywhere people live.