carry the agent from a reservoir2 to a susceptible host. Vectors of human disease are typically species of mosquitoes and ticks that are able to transmit viruses, bacteria, or parasites to humans and other warm-blooded hosts. For the purposes of this discussion, a disease that is transmitted to humans, plants, or animals by any agent, arthropod, or fomite is a vector-borne disease.

Over the past 30 years—following decades during which many mosquito-borne human illnesses were controlled in many areas through the use of habitat modification and pesticides—malaria and dengue fever have reemerged in Asia and the Americas, West Nile virus (WNV) has spread rapidly throughout the United States3 following its 1999 introduction in New York City, and chikungunya fever has resurged in Asia and Africa and emerged in Europe (Gubler, 1998, 2007; Roos, 2007; Yergolkar et al., 2006). The world has also recently witnessed the emergence and spread of Lyme and other tick-borne diseases (Barbour and Fish, 1993), including bluetongue (a devastating viral disease, transmitted to ruminant livestock by insect vectors, that first appeared in northern Europe in 2006),4 and the citrus tristeza virus (an aphid-borne disease that has killed tens of millions of citrus trees worldwide, and which currently threatens California orange crops) (Chung and Brlansky, 2006; Bar-Joseph et al., 1989).

The considerable economic, ecological, and public health impacts of vector-borne diseases are expected to continue, given limited domestic and international capabilities for detecting, identifying, and addressing likely epidemics.5 Much remains to be discovered about the biology of these diseases, and in particular about the complex biological and ecological relationships that exist among pathogens, vectors, hosts, and their environments. Such knowledge is essential to the development of novel and more effective intervention and mitigation measures for vector-borne diseases.

The Forum on Microbial Threats of the Institute of Medicine (IOM) convened a public workshop in Fort Collins, Colorado, on June 19 and 20, 2007, in order to examine the global burden of vector-borne diseases of humans, animals, and plants, and to discuss prospects for successful mitigation and response strategies. Through invited presentations and discussions, participants explored the biological and ecological context of vector-borne diseases; their health and economic impacts; emerging domestic and global diseases; public, animal, and

2

A reservoir is a source from which an infectious agent may be disseminated, such as the deer mouse being a reservoir host for hantavirus (Hardy Diagnostics, 2007).

3

And Mexico and Canada, as well.

4

See Osburn in Chapter 2 and http://www.iah.bbsrc.ac.uk/John_Gloster_3apr07.htm.

5

An epidemic, often synonymous with an outbreak, is the occurrence of more cases of disease (or injury, or any other health condition) than expected in a given area or among a specific population during a particular period. Outbreaks are sometimes defined as highly localized epidemics. Pandemics are epidemics that occur in multiple countries or continents, usually affecting a substantial proportion of the population (HHS, 2006).



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement