Abundance of West Nile Virus Mosquito Vectors in Relation to Climate and Landscape Factors Surrounding Richmond, Virginia

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Βάαλ Κωνσταντόπουλος
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1 Abundance of West Nile Virus Mosquito Vectors in Relation to Climate and Landscape Factors Surrounding Richmond, Virginia Jayne Deichmeister Center for Environmental Studies Virginia Commonwealth University December 2008

Richmond, Virginia Jayne Deichmeister Center for

2 Municipal Surveillance Programs Aim to reduce disease risk by Source reduction Larvacide treatment Population monitoring WNV testing Public outreach GIS mapping helps locate and prioritize surveillance sites

treatment Population monitoring WNV testing Public

3 Hypotheses Abundance increases arbovirus activity Urbanization increases vector abundance Precipitation increases vector abundance

4 My Study To examine the effect of climate variables Temperature Precipitation And landscape variables Canopy cover Building Footprint Drainage Infrastructure On the abundance of local vector species Culex pipiens Culex restuans Aedes albopictus

cover Building Footprint Drainage Infrastructure On the

5 Methodology Temperature and precipitation data from the National Climate Data Center Larval surveillance Henrico County, VA Adult trapping and species identification Study Site: LEGEND Landscape factors mapped through GIS Trap Site with 200 m buffer Stormwater Structures Buildings N 2005, 2006, 2007

species identification Study Site: LEGEND Landscape factors mapped through

6 CDC Light Baited Trap CDC Gravid Trap

7 Surveillance of Stormwater Drop Inlets

8 Methodology Data Analysis Landscape Is there a difference in WNV results between urban and suburban neighborhoods? Chi-square Analysis Is vector abundance correlated with positive WNV testing? Logistic Regression Climate Does temperature, precipitation or vector abundance vary significantly from year to year? One-way ANOVA Is there a difference in environment between urban and suburban neighborhoods? Paired T-Tests Are certain environmental factors correlated with higher vector abundance? Linear Regression Is temperature or precipitation correlated with vector abundance? Linear Regression

Logistic Regression Climate Does temperature, precipitation or vector abundance vary significantly from year to year?

9 Vector Abundance WNV Test Result Ave mosquitoes caught Vector abundance by WNV test result highly significant N=73 Chi-sq = p =

00 1 0 0 10 20 30 40 50 60 70 80 Ave mosquitoes

10 Larval Surveillance of Stormwater Structures Juvenile Observation: Both Species Early Instars Late Instars Pupae 6/25/2008 7/3/2008 7/11/2008 7/18/2008 7/25/2008 8/1/2008 8/8/2008 8/15/2008 8/22/2008 9/5/2008 9/12/2008 9/19/2008 9/29/2008 Average P ro p o rtio n o f D ro p In le ts w ith M o sq u ito es P re s en t /25/2008 7/2/2008 7/9/2008 7/16/2008 7/23/2008 7/30/2008 8/6/2008 8/13/2008 8/20/2008 8/27/2008 9/3/2008 9/10/2008 9/17/2008 9/24/2008 Proportion of Drop Inlets with Mosquito Adults Present Adult Observation Cx spp. Aedes albopictus

8/22/2008 9/5/2008 9/12/2008 9/19/2008 9/29/2008 Average P ro p o rtio n o f D ro p In le ts w ith M o sq u ito es P re s en t 0.9 0.8 0.7 0.6 0.5 0.4 0.

11 Temperature and Precipitation 2005 Precipitation cm) a Week Abundance # mosquitoes) Temperature ο C) Precipitation Vector Abundance Temperature

12 Temperature and Precipitation b 100 Precipitation cm) Abundance # mosquitoes) Temperature ο C) Week Precipitation Vector Abundance Temperature

35 40 Abundance # mosquitoes) Temperature ο C)

13 Temperature and Precipitation c Precipitation cm) Abundance # mosquitoes) Temperature ο C) Week Precipitation Vector Abundance Temperature

Abundance # mosquitoes) Temperature ο C) 25 30

14 All Years Precipitation cm) d Abundance # mosquitoes) Temperature ο C) Precipitation Vector Abundance Temperature

15 Landscape Results Urban Suburban P-value Stormwater Structures Building Footprint ) Canopy Cover ) Avg Cx. pipiens Abundance Avg Ae. Albopictus Abundance Urban Suburban P-value West Nile Virus Positive )

0911 Avg Cx. pipiens Abundance 40.9 21.3 0.0029 Avg Ae.

16 Culex spp. Ave pipiens Number of Stormwater Structures Cx. pipiens, Cx. restuans and stormwater drop inlets r² = 0.21 p= Ave pipiens Percent Building Coverage Cx. pipiens, Cx. restuans and building coverage r² = 0.09 p= 0.078

Structures Cx. pipiens, Cx. restuans and stormwater drop inlets r² = 0.21 p= 0.

17 Discussion Individual roles of temperature and precipitation are somewhat unclear Suggested correlation with drought Possible confounding factor: larvacide application

18 Discussion Cont. Urbanization correlated with: higher Culex spp. abundance More WNV positive mosquitoes Sampling in stormwater drains provides evidence that mosquitoes are using them as a habitat all season long

20 Acknowledgements Henrico County Public Works Department Lane Carr Randy Buchannan Aparna Telang Peter defur Jeff Sullard Michelle Fults John Frey Jon Swanson Jennifer Jones Kevin Caillouet Frank Deichmeister Elizabeth Macklin

Sullard Michelle Fults John Frey Jon Swanson Jennifer

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