GLOBAL CLIMATE-CHANGE AND EMERGING INFECTIOUS-DISEASES

Climatic factors influence the emergence and reemergence of infectious diseases, in addition to multiple human, biological, and ecological d eterminants. Climatologists have identified upward trends in global te mperatures and now estimate an unprecedented rise of 2.0 degrees C by the year 2100. Of major concern is that these changes can affect the i ntroduction and dissemination of many serious infectious diseases. The incidence of mosquito-borne diseases, including malaria, dengue, and viral encephalitides, are among those diseases most sensitive to clima te. Climate change would directly affect disease transmission by shift ing the vector's geographic range and increasing reproductive and biti ng rates and by shortening the pathogen incubation period. Climate-rel ated increases in sea surface temperature and sea level can lead to hi gher incidence of water-borne infectious and toxin-related illnesses, such as cholera and shellfish poisoning. Human migration and damage to health infrastructures from the projected increase in climate variabi lity could indirectly contribute to disease transmission. Human suscep tibility to infections might be further compounded by malnutrition due to climate stress on agriculture and potential alterations in the hum an immune system caused by increased flux of ultraviolet radiation. An alyzing the role of climate in the emergence of human infectious disea ses will require interdisciplinary cooperation among physicians, clima tologists, biologists, and social scientists. Increased disease survei llance; integrated modeling, and use of geographically based data syst ems wilt afford more anticipatory measures by the medical community. U nderstanding the linkages between climatological and ecological change as determinants of disease emergence and redistribution will ultimate ly help optimize preventive strategies.