Malaria and yellow fever have plagued humanity for generations.\u00a0 I grew up in Cleveland, and local history there indicated that after Moses Cleaveland planned the city, early settlers focused their attention on the \u201cheights\u201d to avoid the malaria carried by mosquitoes in the Cuyahoga River valley.\u00a0\u00a0 Through the 1800s, malaria also plagued Tucson, and yellow fever outbreaks frequented New Orleans.\u00a0 Draining swamps, spraying pesticides, and installing window-screens virtually eliminated malaria, yellow fever and dengue from the U.S., although the latter shows new inroads of establishment in Florida and Puerto Rico.<\/p>\n
Malaria and yellow fever are diseases that are transmitted by vectors\u2014here mosquitoes of the genera Anopheles <\/em>and Aedes<\/em>, respectively. \u00a0These mosquitoes don\u2019t guarantee the presence of the disease, but they are a necessary condition for the occurrence of malaria and yellow fever.\u00a0 About 1 million people each year die from malaria, largely in tropical climates.<\/p>\n In the past couple of years we\u2019ve heard about new mosquito-borne diseases, including West Nile Virus, which arrived in the U.S. in 1999 and Zika, which arrived in Brazil in 2013. \u00a0Carried by the Culex <\/em>mosquito, West Nile virus has now been recorded in 45 states, and Zika has been brought to the U.S. by travelers contracting it from Aedes <\/em>mosquito bites in South and Central America.\u00a0 Zika has the potential to cause devastating birth defects, especially microcephaly.\u00a0 West Nile and Zika virus are examples of Emerging Infectious Diseases.\u00a0\u00a0\u00a0 Malaria and Yellow Fever were bad enough; why are we now plagued by these new diseases?<\/p>\n Two aspects seem germane to understanding the spread of mosquito-borne disease.\u00a0\u00a0 First, with the rapid, interconnection of modern air travel and transport, a disease from anywhere is likely to be transported everywhere.\u00a0\u00a0 If it arrives in a spot where the local mosquito populations are appropriate for further transmission of the virus, an outbreak is possible.\u00a0 West Nile virus was a tropical disease, now thought to have arrived by air in New York City, and by 2003, it had spread across the country.<\/p>\n Secondly, with the ongoing changes in global climate, particularly warming, which brings us shorter and less severe winters, the tropical mosquitoes that carry these diseases are expanding northward in the United States and elsewhere.\u00a0 The mosquitoes are following similar changes in the distribution and abundance of migratory birds, which show earlier spring arrivals and more northerly nesting populations in recent years. \u00a0Indeed, some birds, like tree swallows, are likely following the insects. \u00a0Warming climate is also implicated in the northward spread of Lyme disease, which seems destined to afflict eastern Canada by mid-century.<\/p>\n Long, cold winters do not favor reproduction in mosquitoes, whereas hot, wet summers allow rapid development of larvae and additional generations.\u00a0 Shannon LaDeau and her colleagues at the Cary Institute of Ecosystem Studies find that some of these mosquitoes can overwinter successfully in the buried sewer systems and stream culverts of urban areas.<\/p>\n Unfortunately, most of the emerging infectious diseases have no vaccine and no immediate cure.\u00a0 Even malaria, which has been around for centuries, has no vaccine and shows increasing resistance to some of the better drugs known to prevent it.\u00a0 Many communities engage in broadcast spraying of pesticides to kill mosquitoes, with incomplete knowledge of the side effects of those pesticides on humans.\u00a0 \u00a0Although some promising programs using sterile genetically-modified mosquitoes are being tested in certain regions, window screens and liberal use of DEET-based insecticides are recommended this summer. (See http:\/\/blogs.nicholas.duke.edu\/citizenscientist\/cant-beat-the-deet\/<\/a> ).<\/p>\n You may doubt the reality of climate change, rising sea level, crop failures and drought.\u00a0 Perhaps a diminutive mosquito will change your mind\u2014perhaps even before the fall election.<\/p>\n <\/p>\n References<\/p>\n Faria, N.R., R. Azevdeo, M.U.G. Kraemer et al. 2016.\u00a0 Zika virus in the Americas: Early epidemiological and genetic findings.\u00a0 Science 352: 345-349.<\/p>\n Hales, S., N. de Wet, J. Maindonald, and A. Woodward.\u00a0 2002.\u00a0 Potential effect of population and climate changes on global distribution of dengue fever: An empirical model.\u00a0 Lancet 360: 830-834.<\/p>\n Harrigan, R.J., H.A. Thomassen, W. Buermann and T.B. Smith. 2014.\u00a0 A continental risk assessment of West Nile virus under climate change.\u00a0 Global Change Biology 20: 2417-2425.<\/p>\n Jones, K.E., N.G. Patel, M.A. Levy, A. Storeygard, D. Balk, J.L. Gittleman and P. Daszak. 2008.\u00a0 Global trends in emerging infectious diseases.\u00a0 Nature 451: 990-994.<\/p>\n LaDeau, S.L., B.F. Allan, P.T. Leisnham, and M.Z. Levy. 2015.\u00a0 The ecological foundations of transmission potential and vector-borne disease in urban landscapes.\u00a0 Functional Ecology 29: 889-901.<\/p>\n Leighton, P.A., J.K. Koffi, Y. Palcat, L.R. Lindsay, N.H. Ogden.\u00a0 2012.\u00a0 Predicting the spread of tick invasion: an empirical model of range expansion for the Lyme disease vector, Ixodes sapularis<\/em> in Canada.\u00a0 Journal of Applied Ecology doi: 10.111\/j.1365-2664.2012.02112.x.<\/p>\n Martens, P., R.S. Kovats, S. Nijhof, P. de Vries, M.T.J. Livermore, D.J. Bradley, J. Cox, and A.J. McMichael. 1999.\u00a0 Climate change and future populations at risk of malaria.\u00a0 Global Environmental Change\u2014Human and Policy Dimensions 9: S89-S107.<\/p>\n Vitale, J. and W.H. Schlesinger. 2011.\u00a0 Historical analysis of the spring arrival of migratory birds to Dutchess County, New York: A 123-year record.\u00a0 Northeastern Naturalist 18: 335-346.<\/p>\n","protected":false},"excerpt":{"rendered":" Tropical mosquitoes that carry these diseases are expanding northward in the United States and elsewhere.<\/p>\n","protected":false},"author":517,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[81,85,5],"tags":[],"coauthors":[6],"class_list":["post-488","post","type-post","status-publish","format-standard","hentry","category-climate","category-environmental-health","category-faculty"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p5KxUl-7S","post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/blogs.nicholas.duke.edu\/citizenscientist\/wp-json\/wp\/v2\/posts\/488","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.nicholas.duke.edu\/citizenscientist\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.nicholas.duke.edu\/citizenscientist\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.nicholas.duke.edu\/citizenscientist\/wp-json\/wp\/v2\/users\/517"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.nicholas.duke.edu\/citizenscientist\/wp-json\/wp\/v2\/comments?post=488"}],"version-history":[{"count":2,"href":"https:\/\/blogs.nicholas.duke.edu\/citizenscientist\/wp-json\/wp\/v2\/posts\/488\/revisions"}],"predecessor-version":[{"id":490,"href":"https:\/\/blogs.nicholas.duke.edu\/citizenscientist\/wp-json\/wp\/v2\/posts\/488\/revisions\/490"}],"wp:attachment":[{"href":"https:\/\/blogs.nicholas.duke.edu\/citizenscientist\/wp-json\/wp\/v2\/media?parent=488"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.nicholas.duke.edu\/citizenscientist\/wp-json\/wp\/v2\/categories?post=488"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.nicholas.duke.edu\/citizenscientist\/wp-json\/wp\/v2\/tags?post=488"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/blogs.nicholas.duke.edu\/citizenscientist\/wp-json\/wp\/v2\/coauthors?post=488"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}