Rift Valley Fever Rift Valley Fever a potential emerging threat to wildlife, a potential emerging threat to wildlife, livestock, & humans in the U.S. livestock, & humans in the U.S. Christy Tedrow, Maj, USAF Christy Tedrow, Maj, USAF Doctoral Candidate, Doctoral Candidate, Biodefense Biodefense Program Program Dr. Charles Bailey, GMU Dr. Charles Bailey, GMU Committee Chair Committee Chair Dr. Ken Linthicum, USDA Dr. Ken Linthicum, USDA Committee Member Committee Member African outbreak history based on research by African outbreak history based on research by Dr. Dr. Assaf Assaf Anyamba Anyamba , NASA GCFC , NASA GCFC Committee Member Committee Member Dr. Seth Dr. Seth Britch Britch , USDA , USDA
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Rift Valley Fever Rift Valley Fever a potential emerging threat to wildlife, a potential emerging threat to wildlife,
livestock, & humans in the U.S. livestock, & humans in the U.S.
Dr. Charles Bailey, GMUDr. Charles Bailey, GMUCommittee ChairCommittee ChairDr. Ken Linthicum, USDADr. Ken Linthicum, USDACommittee MemberCommittee Member
African outbreak history based on research by African outbreak history based on research by Dr. Dr. AssafAssaf AnyambaAnyamba, NASA GCFC, NASA GCFCCommittee MemberCommittee MemberDr. Seth Dr. Seth BritchBritch, USDA, USDA
Rift Valley fever in AfricaRift Valley fever in AfricaA MosquitoA Mosquito--transmitted hemorrhagic fevertransmitted hemorrhagic fever
Zoonotic disease first described in
Kenya by Daubney et al in 1931,
after causing a fatal epizootic in
sheep on a farm north of Lake
Naivasha
RVF Infected EggsRVF Infected Eggs
Rift Valley FeverRift Valley FeverDistribution of Rift Valley Fever, 2002Distribution of Rift Valley Fever, 2002
Rift Valley Fever VirusRift Valley Fever Virus
Family Family BunyaviridaeBunyaviridae, , genus genus PhlebovirusPhlebovirus
MosquitoMosquito--borne: In Africa borne: In Africa > 40 species in the genera > 40 species in the genera AedesAedes, , AnophelesAnopheles, , CulexCulex, , EretmapoitesEretmapoites and and MansoniaMansoniahave been infected with the have been infected with the virusvirus
Outbreaks generally occur in otherwise dry areas following Outbreaks generally occur in otherwise dry areas following periods of heavy rainfallperiods of heavy rainfall
ZoonoticZoonotic –– primarily affects animals (livestock)primarily affects animals (livestock) Affects pastoral people in the Rift Valley of Africa (living in Affects pastoral people in the Rift Valley of Africa (living in close close
quarters with animals may be key)quarters with animals may be key)
Rift Valley Fever VirusRift Valley Fever VirusSusceptible AnimalsSusceptible Animals
Puppies Water buffalo Gray squirrels Monkeys HPuppies Water buffalo Gray squirrels Monkeys Hedgehogsedgehogs
Kittens Humans Kittens Humans TortoisesTortoises
ViremiaViremiaAbortionAbortion
InfectionInfectionViremiaViremia
RefractiveRefractiveto infectionto infection
Severe illnessSevere illnessAbortionAbortionMortalityMortality
Mortality Mortality 100%100%
Rift Valley Fever Rift Valley Fever Wet Wet DamboDambo HabitatHabitat
Vector Population & Rainfall DynamicsVector Population & Rainfall Dynamics
Rift Valley Fever Rift Valley Fever Transmission CycleTransmission Cycle
Why focus on RVF virus? Why focus on RVF virus?
Has moved from SubHas moved from Sub--saharansaharan AfricaAfrica ““Ecological infrastructureEcological infrastructure”” in place for in place for
RVF to thrive in the U.S. RVF to thrive in the U.S. Could spread via mosquitoes across the Could spread via mosquitoes across the
U.S. at least as rapidly as WNVU.S. at least as rapidly as WNV Competent Vectors in North AmericaCompetent Vectors in North America
SPECIES POTENTIALSPECIES POTENTIAL
Aedes albopictus Aedes albopictus ++Ae. aegypti Ae. aegypti ++Ochlerotatus canadensis Ochlerotatus canadensis ++++++++O. cantator O. cantator ++O. excrucians O. excrucians ++O. sollicitans O. sollicitans ++++++O. taeniorhynchus O. taeniorhynchus ++++++++O. triseriatus O. triseriatus ++++
Potential for Selected North America Potential for Selected North America Mosquito Species to Transmit Mosquito Species to Transmit
Culex Culex pipienspipiens ++++++C. C. salinariussalinarius ++C. C. tarsalistarsalis ++++++C. C. territansterritans ++
+ = 10%++ = 11 - 25%+++ = 25 - 40%
Potential for Selected North America Potential for Selected North America Mosquito Species to Transmit Mosquito Species to Transmit
Rift Valley FeverRift Valley Fever
Why focus on RVF virus? Why focus on RVF virus?
Risk of OIE trade ban, beyond potentially Risk of OIE trade ban, beyond potentially huge losses of wildlife and livestockhuge losses of wildlife and livestock USDA APHIS select agent: threat to USDA APHIS select agent: threat to
human and animal healthhuman and animal health LaterallyLaterally transfer preparations for RVF to transfer preparations for RVF to
those for other emerging mosquitothose for other emerging mosquito--borne borne diseasesdiseases
Product: Risk MapProduct: Risk Map
GIS model that identifies highGIS model that identifies high--risk areas for risk areas for increased vector populationsincreased vector populations
Regions susceptible to RVF Regions susceptible to RVF -- intersection of vectors, hosts, intersection of vectors, hosts, climatic conditionsclimatic conditions
Delineate vulnerable regions requiring Delineate vulnerable regions requiring additional protection/monitoringadditional protection/monitoring Where and when to target disease Where and when to target disease
surveillance/control teamsurveillance/control team Enhance vaccination, vectorEnhance vaccination, vector--control, local control, local
quarantine quarantine Minimize cost of surveillance over large areasMinimize cost of surveillance over large areas Reduce impacts of export embargoes /quarantinesReduce impacts of export embargoes /quarantines
Using Geographic Information Using Geographic Information Systems Systems and Remote Sensing Technology for Rift and Remote Sensing Technology for Rift Valley Fever Risk Assessment in the U.S.Valley Fever Risk Assessment in the U.S.
Input Data (2000Input Data (2000--2006)2006)
NASS (Livestock)
Human Demographics
Land Cover
Elevation
Water
Virginia Mosquito Surveillance Data++
GIS Layers
Deer Abundance
NDVI
Input Data (2000Input Data (2000--2006)2006)
NASS (Livestock)
Human Demographics
Land Cover
Elevation
Water
Virginia Mosquito Surveillance Data++
GIS Layers
Deer Abundance
NDVI
Risk Mapping: Risk Mapping: based on climate & ecological dynamicsbased on climate & ecological dynamics
3 months of 3 months of aboveabove normal NDVI = risk normal NDVI = risk of RVF (of RVF (redred) in endemic areas () in endemic areas (green green ““savannah masksavannah mask””))http://www.geis.fhp.osd.mil/GEIS/SurveillanceActihttp://www.geis.fhp.osd.mil/GEIS/SurveillanceActi
Map from Melius et al. 2006, Developing Livestock Facility Type Information from USDA Agricultural Census Data for Use in Epidemiological and Economic Models
Input Data (2000Input Data (2000--2006)2006)
NASS (Livestock)
Human Demographics
Land Cover
Elevation
Water
Virginia Mosquito Surveillance Data++
GIS Layers
Deer Abundance
NDVI
0.70.7--1.5; Very Low1.5; Very Low
6.5; Very High 6.5; Very High
2.82.8--3.9; Moderate3.9; Moderate
1.71.7--2.8; Low2.8; Low
4.14.1--5.4; High5.4; High3.7
4.9 5.0
4.4
6.5
4.6
4.43.0
2.73.93.8
3.3
4.54.1
5.04.9
4.8
4.3
3.53.23.6
3.1
2.6
4.1
1.82.2
0.71.9
0.7
1.92.6
1.82.8
3.1
3.8
2.9 2.6
3.8 3.2
3.3
2.83.5
3.43.6
2.13.4
1.9
2.3
2.4
1.8
1.8
2.3
1.9
2.4
2.4
3.0
1.9
2.4
1.5
2.6
1.9
2.0 2.0
2.0
2.1 1.2
2.7
2.82.9
2.5
2.31.5
1.1
2.8
3.23.3 3.3
3.23.3
2.63.4
3.4
2.7
3.5
2.9
3.42.3
4.34.1
2.4
2.7
2.1
2.9
3.4
1.73.2
5.4
Index = (Antlered Buck Kill / Deer Habitat in Square Miles)Index = (Antlered Buck Kill / Deer Habitat in Square Miles)3 Year Average based on 2004 Data3 Year Average based on 2004 Data
2004 Virginia Private Land Deer 2004 Virginia Private Land Deer Relative Population Abundance by Relative Population Abundance by
CountyCounty
3.4
2.5
2.3
2.4
Input Data (2000Input Data (2000--2006)2006)
NASS (Livestock)
Human Demographics
Land Cover
Elevation
Water
Virginia Mosquito Surveillance Data++
GIS Layers
Deer Abundance
NDVI
Relational Relational Database Database
in MS Accessin MS Access
Access Form to Query DataAccess Form to Query Data
Mosquitoes Per YearMosquitoes Per Year
0
100,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
900,000
1,000,000
2000 2001 2002 2003 2004 2005 2006
Year
# M
osqu
itoes
Mosquitoes Per CollectionMosquitoes Per Collectionin 2006in 2006
AcknowledgementsAcknowledgementsThanks to the people who have kindly and generously shared theirThanks to the people who have kindly and generously shared their data, data,
expertise, and time for this research . . .expertise, and time for this research . . .
Mr. Charles Abadam Suffolk County Mosquito Control Mr. Ben McLaurin Prince William County Mosquito ControlDr. Jorge Arias Fairfax Health Department Vector Control Dr. Andrew Lima Clarke Mosquito ControlMr. Randy Buchanan Henrico County Mosquito Control Dr. Sally Paulson VPI&SU Department of EntomologyMs. Lane Carr Henrico County Mosquito Control Dr. Jim Rindfleish York County Mosquito ControlMr. Mitch Burcham Langley AFB, VA Ms. Lisa Wagenbrenner Hampton Mosquito ControlMs. Patricia Ferrao Alexandria Health Department Vector Control Mr. Jason Williams Chesapeake Mosquito ComtrolDr. Aftab Hussain Arlington Health Department Vector Control Mr. Jason Pevear Chesapeake Mosquito ComtrolMr. Muhannad Tauseef Ahmad Arlington Health Department Vector Control Mr. George Wojcik Portsmouth Vector ControlMr. Norman Grefe Norfolk Health Department Vector Control Mr. Mike Harrison Portsmouth Vector ControlMs. Penny Smelser Norfolk Health Department Vector Control Dr. David Gaines State EntomologistDr. Valerie Stallings Norfolk Health Department Mr. Chris Barker UC Davis, Doctoral CandidateMr. Marcus Leeper Newport News Mosquito Control Mr. Andrew Fox United States Department of AgricultureMr. Tim DuBois Newport News Mosquito Control Mr. Rick Odom Virginia Department of Agriculture and Consumer ServicesMr. Jake Lekan Allighany, Covington, Roanoke Mr. Matt Knox Virginia Department of Game and Inland Fisheries Dr. Charles McComb Gloucester County Mosquito Survey Mr. Stu Blankenship Virginia Information Technologies AgencyMs. Dreda McCreary Virginia Beach Vector Control Dr. Korine Kolivras Assistant Professor, Virginia Tech
Mr. Ryan Miller United States Department of Agriculture
