Climate Change:: Vector-Borne Diseases and Their Control; Mosquitoes and Ticks.

Abstract

Human infectious diseases are sensitive to weather and climate in a variety of ways: impact on vector-borne disease transmission, pathogen survival outside the host, environmental contamination, food and water- borne infection, and disruptions of public health systems by disasters such as hurricanes and floods. One needs only consider the recent disasters on the United States mainland and in Puerto Rico as examples. In the continental United States during modern times, the most common mosquito-transmitted diseases are West Nile virus and several other encephalitis viruses. In southernmost areas of Florida and Texas, dengue and Zika viruses are found sporadically, usually resulting from travel to out-of-country endemic areas, although local transmissions can also occur. In the U.S. the most common diseases transmitted by ticks are Lyme disease, Rocky Mountain Spotted Fever, anaplasmosis and ehrlichiosis. Vector-borne diseases affecting humans can vary in frequency and intensity depending upon population abundances of the vectors transmitting disease pathogens. In turn, vector population abundances can be influenced by environmental and ecological factors such as temperature, precipitation, humidity, photoperiod, food availability, habitat type, predation, inter-species competition and other parameters. Among these factors, climate change and particularly warming temperature regimes can cause some vector populations to become more abundant in given regions or areas, or to be more prevalent longer throughout the year, and in happening can lead to more disease problems for humans. This paper examines such phenomena for mosquitoes and ticks, which are major arthropod vectors for several kinds of diseases affecting people.