1. Andrew Monaghan National Center for Atmospheric Research
17 April 2015
On the edge: the climatically sensitive dengue vector mosquito Aedes aegypti in the Americas
Andrew Monaghan
National Center for Atmospheric Research
Mention mosquito immediately. And note dengue is most prevalent vector borne viral disease globally. Say I’m focusing on weather timescales rather than climate today. Describe what “On the edge means”. And perhaps mention “on the edge” in the conclusions. What factors are driving us toward the edge? 1

2. Acknowledgements: Collaborators
NCAR:
Mary Hayden
Daniel Steinhoff
Katherine Dickinson
Paul Bieringer
Ryan Cabell
Kevin Sampson
Other Institutions
Kacey Ernst, U. Arizona
Cory Morin, NASA MSFC
Jamie Cavanaugh, U. Colorado
Carlos Welsh Rodriguez, U. Veracruzana
Lars Eisen, Saul Lozano, Colorado State U.
Emily Zielinski-Gutierrez, CDC
Christopher Tittel, Florida Department of Health in Monroe County
Michael Doyle, Monroe County Mosquito Control,
Rolando Diaz Caravantes, Lucia Castro, Colegio de Sonora
Anne Cox, Nederland H.S.
And many others…
Note *university collaborators* and Mary in particular 2

3. Acknowledgements: Students!
Mention that do outreach with HS and university students both through UCAR programs and through participatory field approaches where students learn about dengue and mosquitoes firsthand and take this information back to their communities. We have benefited from their unique perspectives, innovative ideas and hard work. 3

4. Acknowledgements: Grants
Ae. aegypti at its high altitude margins (NSF: GEO )
Ae. aegypti early career investigator (NASA: NNX14AI89G)
Ae. aegypti in Key West and Tucson (NIH: NIAID R56AI09184)
Ae. aegypti in the Sonoran Desert (NIH: IR01AI )
Dengue biosurveillance (DTRA: HDTRA1-13-C-0081)
Our funding is broad 4

5. Presentation Outline Background Aedes aegypti, dengue and weather
Aedes aegypti, dengue and humans
Conclusions 5

6. Background 6

7. Aedes aegypti: a clever mosquito
Vector of dengue
Also a vector of chikungunya and yellow fever
Lives in close association with humans
Exploits artificial containers near and in homes for immature life stages
Adult females feed almost exclusively on human blood. Leg biter.
Females often rest and feed indoors
Feeds during daytime when humans are active
Mention that you’ll be talking about mosquito first, and dengue second.
Define what a vector is
cdc.gov 7

8. Aedes aegypti and Weather
Meteorological factors impact Ae. aegypti numerous ways:
Temperature ‘envelope’ determines survival and development rates
Daily temperature range regulates development rates
Rainfall provides the water required for the immature stages
Temperature affects adult feeding behavior
Temperature modulates dengue incubation period in mosquito
Humidity affects adult survival rates
cidd.psu.edu
tijerasrainbarrels.com 8

9. Dengue Fever Dengue Fever and Dengue Hemorrhagic
Fever are caused by dengue viruses
transmitted by Aedes mosquitoes
Annually, ~400 million people contract dengue worldwide
No approved vaccine available
Increasing number and severity of cases in the Americas, including U.S.
Nature.com
Becoming more severe due to the way serotypes work
Mention U.S. outbreaks in Tex/Mex and FL despite not being endemic.
Mention relationship of warm tropical temps to C statement.
Bvgh.org 9

10. Emergence of Dengue Ae. aegypti Dengue Virus Humans Environment 10
Emergence and propogated transmission of dengue requires presence of a competent vector, in this case Ae. aegypti, susceptible human populations and the dengue virus in an environmental context that supports each component individually and allows for interactions between all three. Only when all four components are aligned can transmission occur. 10

11. Aedes aegypti, dengue and weather11

12. WHATCH’EM: Water Height and Temperature in Container Habitats Energy Model
The heat storage (i.e., change in temperature) in the water container is equal to the balance of energy to/from the container
SW: Shortwave radiation
LW: Longwave radiation
H: Sensible heat
L: Latent heat
G: Ground heat
C: Conduction from container surfaces
S: Heat storage
Much like energy balance approaches used by meteorologists in land surface and atmospheric models. We are applying a process-based methodology widely employed in meteorology for an alternate application.
(Steinhoff et al. 2015, JME) 12

13. WHATCH’EM Field Results: Veracruz, Mexico
The day-to-day temperature variability is resolved by WHATCH’EM.
There are big temperature differences among containers at the same site!
Full Sun – 5-gal Black
Full Shade – 5-gal Black
Slide 12: discuss optimal envelope and show that range on the plot.
Observations
WHATCH’EM
Date (2013)
(Steinhoff et al. 2015, JME)

14. Aedes/Dengue Risk Mapping System
Courtesy Paul Bieringer, NCAR, STAR, LLC 14

15. Results: # of Infected Female Ae. aegypti, 2013
5000
JAN
FEB
MAR
APR
4000
MAY
JUN
JUL
AUG
3000
Infected egg-laying female Ae. aegypti
2000
Note this is eastern Mexico near GOM, and that it is about 300 km wide. Population is represented as well.
SEP
OCT
NOV
DEC
1000 15
Courtesy Paul Bieringer, NCAR, STAR, LLC

16. Results: # of Infected Female Ae. aegypti, 2013
Infected egg-laying females
Explain what 3 maps are and that width is 25 km.
NCAR is participating in projects aimed at improving process-based models that simulate dengue ecology
As with weather and climate models, uncertainty in mosquito and dengue models is driven by inadequate knowledge of processes and parameters
The quality of meteorological data is typically not a major source of uncertainty in mosquito and dengue models
Our major challenge for model development is obtaining observations of mosquito abundance and dengue cases
Even if we can accurately simulate dengue risk, the bigger challenge is communicating the risk and eliciting action… 16
Courtesy Paul Bieringer, NCAR, STAR, LLC

17. Aedes aegypti, dengue and humans
The following research is an example of how we are working to better understand human perceptions and behavior toward vector-borne disease risk, with the ultimate goal of better understanding how we can get people to respond to elevated disease risk. 17

18. Household Survey in Key West, FL, 2012
Methods:
400 parcels randomly selected in Key West and Stock Island
Knowledge, Attitudes and Practices survey
Pupal collections concurrent with household surveys
Key west is important because Florida has had a number of recent dengue outbreaks, including 1 in key west w/ 95 cases in 2009/10.
Mention that we can produce maps with potential to reduce risk, but we need social science to make communication effective. The following research is aimed at understanding current dengue communication and awareness in Key West in order to improve it. 18
(Hayden et al. 2015, AJTMH)

19. In the past 2 months, have you seen (or heard) any dengue prevention materials?
66% 19
(Hayden et al. 2015, AJTMH)

20. Household survey: Do you know of any diseases that are transmitted by mosquitoes in the Keys?
Percentage of “Yes” responses
Only slightly more than 50% of the population was aware of dengue despite an outbreak 2 years earlier. 20% mentioned malaria which is not transmitted in the Keys.
West Nile
virus
Dengue
Malaria
None
Other 20
(Hayden et al. 2015, AJTMH)

21. How likely is it that you or a family member will get dengue in the next five years?
Percentage of total responses 21
(Hayden et al. 2015, AJTMH)

22. Results – Ae. aegypti indicators
5.9% Key West households had at least one Ae. aegypti pupa
1.6 (Key West) containers with water per house
Despite repeated dengue incidence in Key West, notable disparities exist in dengue awareness and experience.
Preparedness and response plans are critical for risk reduction and need to be guided by the best evidence, both epidemiological and ecological, to increase the capacity for local response.
The importance of the science-policy intersection cannot be overstated and requires forging local-level partnerships and emphasizing the role of credible scientific evidence to inform policy that supports disease risk reduction.
After human section mention we have follow on work planned to merge behavioral interventions into our modeling activities. 22
(Hayden et al. 2015, AJTMH)

23. Conclusions
Meteorological variables modulate the abundance of the vector mosquito Ae. aegypti and dengue risk.
This knowledge can be used to develop surveillance systems to inform public health, or to project climate change impacts on dengue.
However, even with accurate weather-based predictions of dengue risk, without properly developed behavioral interventions, few humans will likely be aware of the risk.
The involvement of the social scientists throughout the conception and execution of such projects is imperative to ensure that climate-based predictions will benefit society. 23