García-León, Annabel

Universitat Autònoma de Barcelona. Facultat de Biociències

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 First isolated: Japan (1943) Actually range: Africa, America, Eastern Mediterranean, SouthPacific and Europe Cycle: human-mosquitoes Transmission: only by the bite of the mosquito Disease: Dengue Fever, Dengue Haemorrhagic Fever and DengueShock SyndromeAnnabel García León, Faculty of Biosciences, Microbiology degree Universitat Autònoma de Barcelona, 2013EMERGING ARBOVIRAL DISEASESIn the past 50 years, many vector-borne diseases haveemerged. Some of these diseases are produced for exoticpathogens that have been introduced into new regions andothers are endemic species that have increased in incidence orhave started to infect the human populations for first time(new pathogens).Many of these vector-borne diseases are caused byarbovirus. Arboviruses are virus transmitted by arthropodsvectors, such mosquitoes, ticks or sanflys. The virus is usuallytransmitted to the vector by a blood meal, after replicates inthe vector salivary glands, where it will be transmitted to aother animal upon feeding. Thus, the virus is amplified bythe vector and without it, the arbovirus can’t spread.In 1991, Robert Shope, presented the hypothesis thatglobal warming might result in a worldwide increase ofzoonotic infectious diseases. Today, we can say that duringthe past 50 years patterns of emerging arbovirus diseaseshave change considerably. Can this be attributed to climatechange?GLOBAL WARMINGIMPACT  OF GLOBAL WARMING ON ARBOVIRAL DISEASESAedes albopictus is the fastest spreading vector over the past twodecades and is considered the most invasive mosquito species inthe world [2] It’s original from Southeast Asia. Now is present in North,Central and Southern America, parts of Africa, northernAustralia and several countries in Europe Is associated with the transmission of several arbovirus, suchDengue, West Nile, Chikungunya, Yellow fever andJapanese encephalitis Is adapted a temperate climates Can compete and eradicate resident speciesFigure [1]: Suitability of the establishment of the tiger mosquito under the minimum climate change scenario, long term (2030).(source: www.eea.europa.eu/data-and-maps/figures/suitability-of-the-establishment-of)Figure [2]: Aedesalbopictus (© James Gathany, CDC)THE SPREAD OF A DANGEROUS VECTOR EMERGING MOSQUITO-BORNE DISEASES Climate is a key determinant of the emergence of infectious diseases: it constrains the range of infectious diseases and influence pathogens, vectors,hosts defences and habitat. Arthropod vectors are cold-blooded (ectothermic) and thus especially sensitive to climatic factors [1].Climate is a factor that determine; the geographic and temporaldistribution of arthropods, the characteristics of arthropod lifecycles, the dispersal patterns and evolution of arbovirus andthe efficiency of the transmission.However, climate is only one of many factors which has influence inthe arboviral emergence. Others would be deforestation, land use,international trade and travel, host density or globalization [5].CONCLUSIONSIncrease temperature Intensify hydrological cycleEffects on vector Decreased survival of some mosquitoes Expansion to a new regions Change susceptibility to some pathogens Population growth Increase reproductive rate Increased feeding rate Reduce period of larval developmentEffects on arbovirus Reduce the extrinsic incubation period Promotes evolution of novel-vector virus associationsEffects on humans Modifies host susceptibility Changes human behaviour (more vector-human encounters)Effects on vector Decreased vector population (death and destruction  habitats by flooding) Increase breeding sites Increase vector survival  (↑ humidity)Effects on humans Increase the susceptibility Changes human behaviourBecause of the absence ofavailable vaccine, theprimary preventivemeasure to reduce dengueinfections is the control ofmosquito populations [4] Monitoring mosquito populations Source reduction Biological control Chemical adulticing Personal protections measures  Genetic modified mosquitoes Growth human populationIncreased per capita consumption of resources(water, energy, material, land, biodiversity)Accumulation  of greenhouse gasesin the atmosphere(burn fuels in electricity generation, transport, industry, agriculture and land use change, use of fluorinated gases in industry)The accumulation of greenhouse gases (GHG) in the atmosphere by human activity alteredthe balance of radiation of the atmosphere, altering the TEMPERATURE at the Earth's surface[1].↑ Air Temperature Near Surface↑ Specific Humidity↑ Ocean Heat Content↑ Sea Level↑ Sea-Surface Temperature↑ Temperature over the oceans↑ Temperature over the land↓ Snow Cover↓ Glacier mass balance↓ Sea-IceSome longwavesradiation from the sun are absorbed and re-emitted  to the Earth by GHG molecules The global temperature has risen 0.8 ºC over the past 150 years. A 2ºCrise is the point at which some of the most devastating and dangerousprocesses brought on by climate change could become unavoidable.!Dengue is the world's fastest-spreading tropical disease and represents apandemic threat [3].[1] Anthony J. McMichael, Rosalie E. Woodruff (2008) “14 - Climate change and infectious diseases”Social Ecology of Infectious diseases: 378-407.[2] Paupy C, Delatte H, Bagny L, Corbel V, Fontenille D (2009) “Aedes albopictus, an arbovirus vector:from the darkness to the light” Microbes Infect. 11(14-15):1177-85[3] WHO (2009). Dengue Guidelines for Diagnosis, Treatment, Prevention and Control. Geneva: WorldHealth Organization.[4] A Marm Kilpatrick, Sarah E Randolph. (2012) “Drivers, dynamics, and control of emerging vector-borne zoonotic diseases” The Lancet, Volume 380 (9857): 1946-1955.[5] Robert W. Sutherst (2004) “Global Change and Human Vulnerability to Vector-Borne Diseases”American Society for Microbiology, Volume 17(1): 136-173.Figure [3]: Dengue epidemiology (source: DengueMatters, www.denguematters.info/content/issue-11-spotlight-dengue)REFERENCES

Impact of global warming on arboviral diseases

http://ddd.uab.cat/pub/tfg/2013/113358/TFG_annabelgarcialeon.pdf

Impact of global warming on arboviral diseases

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