Title: Rift Valley Fever a potential emerging threat to wildlife, livestock,
1Rift Valley Fever a potential emerging threat to
wildlife, livestock, humans in the U.S.
- Christy Tedrow, Maj, USAF
- Doctoral Candidate, Biodefense Program
African outbreak history based on research by
Dr. Charles Bailey, GMU Committee Chair Dr. Ken
Linthicum, USDA Committee Member
Dr. Assaf Anyamba, NASA GCFC Committee
Member Dr. Seth Britch, USDA
2Rift Valley fever in AfricaA Mosquito-transmitted
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 Eggs
3Rift Valley Fever
- Distribution of Rift Valley Fever, 2002
4Rift Valley Fever Virus
- Family Bunyaviridae, genus Phlebovirus
- Mosquito-borne In Africa gt 40 species in
the genera Aedes, Anopheles, Culex, Eretmapoites
and Mansonia have been infected with the virus
- Outbreaks generally occur in otherwise dry areas
following periods of heavy rainfall - Zoonotic primarily affects animals (livestock)
- Affects pastoral people in the Rift Valley of
Africa (living in close quarters with animals may
be key)
5Rift Valley Fever VirusSusceptible Animals
Severe illness Abortion Mortality
Viremia Abortion
Infection Viremia
Refractive to infection
Mortality 100
- Lambs Sheep Monkeys
Horses Guinea pigs - Calves Cattle Camels
Cats Rabbits - Kids Goats Rats
Dogs Pigs - Puppies Water buffalo Gray squirrels
Monkeys Hedgehogs -
- Kittens Humans
Tortoises
6Rift Valley Fever Wet Dambo Habitat
7Vector Population Rainfall Dynamics
8Rift Valley Fever Transmission Cycle
9Why focus on RVF virus?
- Has moved from Sub-saharan Africa
- Ecological infrastructure in place for RVF to
thrive in the U.S. - Could spread via mosquitoes across the U.S. at
least as rapidly as WNV - Competent Vectors in North America
10 SPECIES
POTENTIALAedes albopictus
Ae. aegypti
Ochlerotatus
canadensis O. cantator
O. excrucians
O. sollicitans
O. taeniorhynchus
O. triseriatus
Potential for Selected North America Mosquito
Species to Transmit Rift Valley Fever
? 10 11 - 25
25 - 40 ? 40
11 SPECIES
POTENTIALAnopheles bradleyi-crucians
0Culex pipiens
C. salinarius
C. tarsalis
C. territans
Potential for Selected North America Mosquito
Species to Transmit Rift Valley Fever
? 10 11 - 25
25 - 40
12Why focus on RVF virus?
- Risk of OIE trade ban, beyond potentially huge
losses of wildlife and livestock - USDA APHIS select agent threat to human and
animal health - Laterally transfer preparations for RVF to those
for other emerging mosquito-borne diseases
13Product Risk Map
- GIS model that identifies high-risk areas for
increased vector populations - Regions susceptible to RVF - intersection of
vectors, hosts, climatic conditions - Delineate vulnerable regions requiring additional
protection/monitoring - Where and when to target disease
surveillance/control team - Enhance vaccination, vector-control, local
quarantine - Minimize cost of surveillance over large areas
- Reduce impacts of export embargoes /quarantines
14Input Data (2000-2006)
Using Geographic Information Systems and Remote
Sensing Technology for Rift Valley Fever Risk
Assessment in the U.S.
GIS Layers
Virginia Mosquito Surveillance Data
Elevation
Water
Land Cover
NDVI
NASS (Livestock)
Deer Abundance
Human Demographics
15(No Transcript)
16Input Data (2000-2006)
GIS Layers
Virginia Mosquito Surveillance Data
Elevation
Water
Land Cover
NDVI
NASS (Livestock)
Deer Abundance
Human Demographics
17Risk Mapping based on climate ecological
dynamics
3 months of above normal NDVI risk of RVF (red)
in endemic areas (green savannah mask)
http//www.geis.fhp.osd.mil/GEIS/SurveillanceActiv
ities/RVFWeb/indexRVF.asp
18Input Data (2000-2006)
GIS Layers
Virginia Mosquito Surveillance Data
Elevation
Water
Land Cover
NDVI
NASS (Livestock)
Deer Abundance
Human Demographics
19NASS Data
Backyard beef cattle (combined cow/calf, feedlot,
and stocker operations) lt 10 animals
Map from Melius et al. 2006, Developing Livestock
Facility Type Information from USDA Agricultural
Census Data for Use in Epidemiological and
Economic Models
20Input Data (2000-2006)
GIS Layers
Virginia Mosquito Surveillance Data
Elevation
Water
Land Cover
NDVI
NASS (Livestock)
Deer Abundance
Human Demographics
212004 Virginia Private Land Deer Relative
Population Abundance by County
6.5 Very High
4.9
6.5
5.0
4.1-5.4 High
4.4
1.5
4.6
5.4
3.7
4.4
2.8
2.8-3.9 Moderate
3.0
3.2
2.6
3.3
3.3
2.7
3.9
2.4
2.7
1.7-2.8 Low
3.4
3.8
3.3
2.6
1.9
2.3
2.9
3.3
2.8
2.4
3.2
2.4
2.0
2.0
0.7-1.5 Very Low
2.9
3.3
3.4
4.5
3.2
3.8
2.5
4.1
3.4
2.3
4.9
4.1
3.6
2.3
2.4
1.9
2.1
4.3
5.0
4.8
3.4
1.5
2.5
3.5
2.3
3.4
3.4
2.7
2.9
0.7
3.2
2.8
2.1
3.5
3.2
3.6
3.0
1.7
3.8
1.9
2.6
3.5
1.9
2.0
0.7
1.8
1.9
1.8
3.1
2.4
2.7
3.1
2.2
2.6
2.8
1.1
2.6
2.1
2.9
1.2
2.3
1.9
4.1
2.4
4.3
1.8
3.4
1.8
Index (Antlered Buck Kill / Deer Habitat in
Square Miles) 3 Year Average based on 2004 Data
22Input Data (2000-2006)
GIS Layers
Virginia Mosquito Surveillance Data
Elevation
Water
Land Cover
NDVI
NASS (Livestock)
Deer Abundance
Human Demographics
23Relational Database in MS Access
24Access Form to Query Data
25Mosquitoes Per Year
26Mosquitoes Per Collectionin 2006
27Mosquitoes By City/County
28Number of Mosquitoesin 2006
29Ae albopictus Per Epi Week in 2006
30Acknowledgements
Thanks to the people who have kindly and
generously shared their data, expertise, and time
for this research . . .
31Questions?
- Christy Tedrow
- (703) 356-7223
- christy.tedrow_at_verizon.net