The importance of scale in assessing the relationship between
climate variability and disease emergence potential

Korine N. Kolivras

Dept. of Geography, Virginia Tech, Blacksburg,VA

The potential for the emergence or re-emergence of infectious diseases is driven by factors including land use change, climate variability or change, human migration, and changing cultural or human behaviors.  In particular, environmental variability and change have been implicated as playing a crucial role in concert with other factors in both developed and developing locations.  One particular challenge in understanding the complex interaction between these factors, and in evaluating the relationship between disease outbreaks and environmental variability, is related to the involvement of multiple scales of action.  The movement of humans at the global scale can transport microbes and vectors around the world relatively quickly.  Once established in a location, disease vectors can operate at very fine scales and spread disease while acquiring a blood meal. Additionally, climate patterns at global, regional, and local scales affect vector habitat.  This research closely examines the interrelated role of these multiple scales of action through a case study of the relationship between climate variability and mosquito-borne disease.  In 2001-2002, Hawaii experienced its first outbreak of dengue, spread by Aedes albopictus in this instance, since World War II.  Hawaii’s average climate conditions are conducive to mosquito survival, but local climate variability played a role as well.  Mosquito habitat, based on climate conditions and stream/wetland location, are delineated using a geographic information system (GIS), and the potential expansion and contraction of habitat based on climate variability is considered.