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.The Impact of Climate Change on the Epidemiology and Control of Rift Valley FeverV. Martin, V. Chevalier, P. Ceccat, A. Anyamba, L. De Simone, J. Lubroth, S. de La Rocque and J. Domenech
Article Presented by Kristy Jones
Project Overview
• Introduction• What is Rift Valley Fever?• What areas have been affected?
• Discussion on Climate• Climate and its affiliation with outbreaks.
• Forecasting of the virus• Determining outbreaks
• Conclusion
Introduction
• Transmission• Epidemiology
What areas have been affected?
• History of major outbreaks
• Important recorded outbreaks
What is Rift Valley Fever?
Transmission
http://journal.frontiersin.org/article
Animals and Humans • Vectors• Direct or indirect
contact with the blood • Unpasteurized or
uncooked milk
No human-to-human transmission
Transmission Vectors
• Virus transmitted to eggs
• Virus transmitted from female infected vector to host
• Females typically lay up to 300 eggs, but only live 14-21 days
www.theverge.com/2015/5/21/8634813/mosquitoes-disease-sex-dengue-yellow-fever
Epidemiology
Animals • Cattle, buffalo, sheep, goats, and
camels.• Causes abortions in pregnant animals
and high mortality in young animals. • Massive hepatic necrosis and
pantropic hemorrhage.
Humans• Mild to severe influenza-like disease. • Can progress to hemorrhagic fever,
hepatitis, encephalitis, ocular disease and sometimes death.
History of Major Outbreaks
• Major Outbreaks• Southern Africa
• 1950• 1974-1975
• Zimbabwe, Zambia and Mozambique www.travelnotes.org/Africa
Important Recorded Outbreaks
Pictures from www.worldatlas.com/webimage/countrys/af.htm
1973• Sudan• Near
irrigation.
1977• Egypt• After the
flooding of Aswan dam near irrigation.
1987 and 1988• West
Africa• Newly
constructed dam.
1997-1998• East
Africa• High
rainfalls which resulted in flooding
Important Recorded Outbreaks
Pictures from www.worldatlas.com/webimage/countrys/af.htm
1997• Kenya and
Somalia• Humans
and livestock affected
1998• Hodh El
Gharbi• First
identified through humans.
2000• Saudi
Arabia and Yemen
• First time outside of Africa.
2006• Kenya• Reemerg
ed and emerged in Somalia & Tanzania.
Recorded Outbreaks
Epidemic Outbreaks with Climate Relation
• East Africa - plateau grasslands• High rainfalls
• Saudi Arabia and West Africa• Semi-arid zones
• Egypt and Yemen• Irrigated zones
Discussion on Climate
Climate and its Affiliation with Outbreaks
• Increased Vectors• Rainfall• Global Warming
Climate and its Affiliation with Outbreaks
Increased Vectors
Precipitation
Increased Rain
Flooding
El Niño
Flooding
Global Warming
Alters Biology of
VectorsFloods and Droughts
Rainfall
https://extension.entm.purdue.edu/publichealth/images/downloads/delayed-hatching.jpg
Aedes mosquitoes
• Life cycle• Virus
transmission• Population
explosion
Rainfall
Other vectors• New vectors
spread virus
El Niño• East Africa
affected• Aedes breeding
habitats http://journal.frontiersin.org/article
RainfallTypical tropical conditions versus El Niño
http
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logs
• Precipitation• Trade winds
• Tropical circulation• Global mean
temperature
RainfallEl Niño with Africa
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• Precipitation• Trade winds
• Tropical circulation• Global mean
temperature
Rainfall
• Precipitation• Trade winds
• Tropical circulation• Global mean
temperature
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Trade winds versus tropical regions
Global Warming
Extremes in the hydrological cycles• Global warming
enhances floods and droughts
• Extends rainfall activity, spreading across the continent
Picture 2 - www.timeslive.co.za/africa/2012/10/02/nigeria-seasonal-floods-kill-148-red-crossPicture 1 - www.standardmedia.co.ke/lifestyle/article/2000111390/experts-predict-massive-el-nino-weather-from-july
Picture 2
Picture 1
Global Warming
Affecting the biology of the vector• Increasing feeding frequency• Increase egg production.• Decreasing length of development cycle.• Decrease incubation period.
Results in increased vectors• Similar vectors in surrounding areas
display this ability.
Global Warming
Dry day prediction
Martin et al 2008
Global Warming
Precipitation prediction
Martin et al 2008
Forecasting of the virus
Determining Outbreaks
• Measure rainfall and vegetation• Tracking of vector populations • Emergency Prevention System for
Transboundary Animal Diseases program
Determining Outbreaks Measure of rainfall and
vegetation• Remote-sensing • High resolution radiometer sensors
Tracking vector populations • Comparison of vegetation and
viral activity• Continuously collecting data
Potential risk for Rift Valley fever (RVF) in February 2007 – Martin et al 2008
Determining Outbreaks Emergency Prevention
System for Transboundary Animal Diseases programs
• Set up by the Food and Agriculture Origination of the United Nations (FAO)
• Ability to report early outbreaks• Assistance in containing the
virus.• Monitoring climate activity
Conclusion
Ongoing Concerns• Climate• Global
Warming
Ongoing Concerns
Climate Change
1. Major threat involving both human and animal health issues• Impacts food production, access and
distribution
2. Abnormal changes in temperature and rainfall• Increase frequencies floods
3. Public concern• Spread of the diseasewww.businessinsider.com/six-innovations-to-help-
humans-make-it-through-the-droughts-and-floods-of-climate-change-2012-8
Ongoing Concerns
Global Warming
1. Vectors learn to adapt • Increases their populations
2. Rift Valley Fever in new areas• In 2000 vectors started migrating to Saudi Arabia • New vectors pick up virus and start spreading
disease
Both Climate and Global Warming Lead to:
3. Forecasting epidemics early• Idea is still new• Not entirely fault proof
Storms do not always produce the same amount of precipitation !!http://dnr.wi.gov/org/caer/ce/eek/
earth/groundwater/precip.htm
Works Cited
Daubney, R., J.R. Hudson, and P.C. Garnham. 1931. Enzootic hepatitis or Rift Valley fever. An undescribed virus disease of sheep, cattle and man from East Africa. The Journal of Pathology and Bacteriology. 34:545– 79.
Martin, V., V. Chevalier, P. Ceccat, A. Anyamba, L. De Simone, J. Lubroth, S. de La Rocque and J. Domenech. 2008. The Impact of Climate Change on the Epidemiology and Control of Rift Valley Fever. Revue Scientifique Et Technique Office International des Epizooties 27: 413-426.
Questions
• Does the preventative measures that the Food and Agriculture Origination of the United Nations (FAO) use assist with prevention of Rift Valley Fever? How could it be more effective?
• Since the original outbreak of the virus it has slowly migrating north into Saudi Arabia what are the most likely causes?