Insects, Rodents and Global Climate Change Marc L. Lame, Indiana University, School of Public and Environmental Affairs 1 1
C C C C C C C C News to us W. Kenya Malaria spread from 3 to 13 districts Sweden rise in tick-borne encephalitis Netherlands reports of Asian Tiger mosquitoes (dengue) Mexico --Dengue fever spreads to higher elevations. Dengue fever has spread from 3,300 feet to 5,600 feet. Central America --Dengue fever spreads to higher elevations. From 3,300 ft. to above 4,000 feet. WMV in Saskatchewan, Canada Malaysia nipah virus fruit bats and forest fires Peru biting rate of Anopheles darlingiwas more than 278 times higher in deforested areas 2
Mosquitoes They are a major health hazard in many parts of the World and are responsible for the transmission of: 1. yellow fever 2. malaria 3.dengue fever 4. encephalitis 5.many other serious diseases Malaria parasites 3
Climate Changes which affect Arthropods 1. Increased temperatures 2. Increased rainfall flooding 3. Decreases rainfall.drought (implicated in the SW Hantavirus out break) 4. Rise in atmospheric CO2 4
Flooded School Play Field 5
Increased temperatures 1. Distribution and abundance of vertebrate host species 2. Range extension north, south and UP! 3. Phenologicalchanges 4. Shorten time for pathogens to mature to an infectious state (P.falciparum takes 26 days to develop at 68 degrees vs. 13 days at 77.) 6
Phenological changes Phenological changes C North America -Ecologists have identified the first genetic adaptation to global warming in the North American mosquito Wyeomyiasmithii. Modern mosquitoes wait nine days more than their ancestors did 30 years ago before they begin their winter dormancy, with warmer autumns being the most likely cause. Higher temperatures, enhancing mosquito survival rates, population growth and biting rates, can increase the risk of disease transmission. 7
Increased rates of C populations development breeding sites C Growth lengthen breeding season C migration and C over-wintering All of which may not coincide with natural enemies possibly allowing for a worse situation 8
Increased Precipitation 1. More breeding sites for vectors 2. Distribution and abundance of vertebrate host species forced interaction and double wammy particularly those with a decreased capacity of immunological defenses in individuals, due to malnutrition 9
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Question: 1. Will increased temperatures alone cause more malaria? Know your malaria history! 11
Northern Expansion in Ranges due to climate change 1. Odonata 2. homoptera 3. Othroptera 4. Lepidoptera 5. spiders 12
Rodents C Ecology of Rats seems to have changed in NYC over the past 10 years 13
Rodents C A change in ecto-parasites on Rats is pointing in an interesting directions 14
Climate Change 1. Increase in vectored disease 2. Increase in pests (crops and urban.house dust mites ) 3. Increase in pesticide use 4. Unknown affect of the extinction of insect species on the food chain? 15
The Debate 2009 New Scientist Bob Holmes, April 2009 CKevin Lafferty, disease ecologist - warming climate could favor some diseases in certain regions while inhibiting them in others. Cchange might allow malarial mosquitoes to spread to new areas. Hotter and drier conditions may also eliminate mosquitoes from areas where they currently thrive (Ecology, vol 90, p 888). 16
Debate 2009 New Scientist Bob Holmes, April 2009 CEurope/US have good sanitation and insect control programs which prevent diseases from becoming prevalent even if climatic conditions were suitable. Cclimate change could wipe out many species. Infectious pathogens depend on their hosts for survival so they too may become endangered -especially if, like malaria, they rely on more than one host (Ecology, vol 90, p 888). 17
Debate 2009 New Scientist Bob Holmes, April 2009 C Mercedes PascualU of MI -large human populations in the east African highlands, just outside of the existing range of malarial mosquitoes, as temperatures rise, the mosquitoes will reach these areas. This will more than offset any benefits from decreased risk elsewhere (Ecology, vol 90, p 906). 18
The Debate 2009 New Scientist Bob Holmes, April 2009 C Ecologists agree on one point: predicting where a disease is going to go next involves far more than just climate. They all agree that health concerns should continue to play a critical role in climate policy, and the debate shouldn't be regarded as weakening the case for action on global warming. 19
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Questions and Comments The End Dr. Marc Lame, Indiana University 21 21
Now go bug someone! 22
sources C The implications of predicted climate change for insect pests in the UK, with emphasis on non-indigenous species, RAYMOND J. C. CANNON, Sand Hutton, York YO41 1LZ, UK, Global Change Biology, Volume 4,Number 7, October 1998, pp. 785-796(12). C Global warming and malaria: knowing the horse before hitching the cart, Paul Reiter, Insects and Infectious Disease Unit, InstitutPasteur, 25-28 rue du Dr Roux, 75724 Paris, France, Malaria Journal 2008, 7(Suppl):S3doi:10.1186/1475-2875-7-S1-S3 C Paul R Epstein, Center for Health and the Global Environment, Harvard Medical School, Boston, MA 02115, USA C Will climate change spread disease? New Scientist Bob Holmes, April 11, 2009 23