West Nile Virus Activity in Harris County, Texas Rudy Bueno, Jr., Ph.D. Division Director, HCPHES Mosquito Control

Transcription

1 West Nile Virus Activity in Harris County, Texas 2012 Rudy Bueno, Jr., Ph.D. Division Director, HCPHES Mosquito Control

2 Mission Statement HCPHES Mosquito Control protects the health and well-being of county residents from mosquito-borne diseases, such as West Nile Virus (WNV) and St. Louis Encephalitis (SLE) by implementing integrated mosquito management strategies which include surveillance, control, education, research, and technology.

3 Historical Highlights of Harris County Mosquito Control St. Louis Encephalitis Outbreak Harris County Mosquito Control District established 1965 Asian Tiger Mosquito identified Mosquito Control merged with Harris County Public Health Department West Nile Virus identified in Harris County 2002 Hurricane Ike 2008 Texas: Epicenter of WNV Resurgence

4 Countywide Program 1,778 square miles 1,729 square miles - land 49 square miles - water Population of 4.1 million (US Census 2010 American Community Surveys)

5 Mosquito Control Program Evidence Based, Comprehensive, Integrated, and Self-Contained Disease Surveillance Disease Diagnostics Insecticide Resistance Surveillance Insecticide Resistance Management Control Measures Education Applied Research

6 Life Cycle Four Developmental Stages Egg Larva or Wiggler Pupa or Tumbler Adult

7 Southern House Mosquito (Culex quinquefasciatus) Legs and Proboscis Un-banded Abdomen Basal Bands Crescent

8 Common Urban Habitats

9 West Nile Virus

10 Mosquito Surveillance Mosquito surveillance is the eyes of the program 268 mosquito traps are set throughout the county Mosquito traps are collected on a routine basis for disease testing

11 Mosquito Surveillance Underground: CDC light trap Above Ground: Gravid Trap

12 Mosquito Trap Collection

13 Mosquito Identification Disease Detection

14 Mosquito Surveillance Results Mosquito Collections Number of Traps Females Collected Number of Pools Tested Number of Females Pooled WNV Confirmed Pools Minimum Infection Rate (MIR)

15 WNV in Mosquito Populations in Week WNV Total Females Collected 0 WNV Number of Female Mosquitoes 60000

16 Avian Surveillance Sera Collection Dead Bird Collection and Testing

17 Dead Bird Surveillance Results Dead Bird Tested WNV Confirmed % WNV Confirmed WNV Species

18 Dead Bird Surveillance Results Dead Bird Tested 594 WNV Confirmed 210 % WNV Confirmed 35.3 WNV Species 7

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20 Ground Based ULV Operation

21 Aerial Spray Operation

22 Aquatic Predators

23 Aquatic Predators

24 Bats/Purple Martins Both prefer larger insects: moths, butterflies and beetles Humans increase exposure to rabies by attracting bats

25 WNV Symptoms in Horses Stumbling, tripping, inability to stand up Wandering or circling Loss of appetite, inability to swallow Muscle weakness, twitching, partial paralysis Depression or lethargy Head pressing or tilt, impaired vision Convulsions, coma, death

26 Vaccinate Horses for WNV

27 2012 Comparative WNV Human Case Incidence County Total Cases Incidence Rate/100,000 Dallas Tarrant Denton Travis Harris From Texas Department of State Health Services, Oct. 26, 2012.

28 Harris County WNV Human Cases Year Number of Cases Deaths (thru 11/14) 40 0 Total 198 9

29 WNV in Humans Incubation period 5 15 days As in SLE, most show no or only mild symptoms Disease most severe in people over 50 years of age Symptoms include: fever, headache, body aches, occasionally skin rash and swollen lymph glands Severe infection: headache, high fever, neck stiffness, disorientation, coma, convulsions, paralysis, and, rarely, death

30 Community Connections at Work Community Event Participation and Community Presentations

31 Community Connections at Work Exhibit at the Houston Museum of Natural Science Brown Hall of Entomology Community Education Partnership Examples Nothing But Nets at the Children s Museum of Houston

32 Citizen Education Larval Treatment When Necessary

33 Manage Water-Holding Containers Remove, empty, or invert any containers that may hold water Birdbaths and flower pot saucers should be emptied and refilled twice weekly Pet water bowls should be emptied and refilled twice weekly

34 GIS Technology

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37 Vehicle Tracking/ Chemical Usage

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39 Personal Protection Use mosquito repellents, always read the label first Limit exposure to mosquitoes at dusk and dawn Wear light colored clothing Wear long sleeves and pants

40 Products Mosquito dunks Contains bacterium that infects mosquito larvae Host specific Effective in reducing mosquitoes in small areas Citronella Candles Plant derived scent Effective when calm or in confined area Bug Zappers Attracts larger insects Kills few mosquitoes Kills some beneficial insects

41 More Products Electronic Repellers Emits high frequency sound which mimics male mosquito Do not repel mosquitoes Misting Systems Emits ULV pyrethrum spray Kills mosquitoes and day time insects like butterflies, bees, lady beetles Increases likelihood of insecticide resistance Expense- average price $4K

42 Office of Public Information

43 WNV in 2012 Local & National Media Came Calling

44 What About 2013? Continued WNV resurgence? Similar pattern, Optimal weather conditions? Mild winter, early/wet spring, dry/hot summer Loss of immunity in bird populations? Increased viral amplification in birds Increased transmission to mosquitoes? Greater county coverage Different WNV strain? Increased neuro-invasive cases in humans

45 Protect Yourself and Loved Ones