West Nile and Zika Virus Update. Brandon Scott Bennett, Code Compliance Director August 23, 2016

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1 West Nile and Zika Virus Update Brandon Scott Bennett, Code Compliance Director August 23, 2016

2 Purpose Tarrant County Public Health is requesting input from all cities: Would the City be interested in participating in county wide aerial spraying? Would the City be willing to share in the costs of aerial spraying? Aside from the Tarrant County request, the anticipated impact of the Zika Virus and potential outbreak of West Nile Virus in the coming years requires a clear understanding of public health risks, tactics, desired results and policy 2

3 WNV vs ZIKA West Nile Virus Nighttime biter Symptoms appear 2 14 days after bite 80% of victims have NO symptoms 1% of victims develop severe illness requiring hospitalization Zika Virus Daytime biters Symptoms appear 3 7 days after bite Symptoms are mild Birth defects linked to babies of infected mothers Also sexually transmitted by infected person to partner 3

4 Collaborative & Supportive Systems 4

5 2016 Trap Locations TCPH recommends 45 traps Fort Worth deploys 62 traps routinely and additional traps are added in high risk areas Fort Worth also deploys 8 traps to capture mosquitos that might carry the Zika Virus 5

6 Phased Response Since WNV Virus Mosquito Pools & Related Human Cases Isolated + WNV Mosquito Pools Start of Season Off season Planning Education Outreach Education Outreach Surveillance Larvicide Education Outreach Surveillance Larvicide Optional Targeted Spraying WNV Outbreak in Progress Education Outreach Surveillance Current Status Recommended Targeted Ground Spraying Education Outreach Surveillance Larvicide Aggressive Targeted Ground Spraying *IF aerial spraying is recommended by TCPH consider at option

7 Strategy Analysis Greatest Long Term Benefit Least Long Term Benefit Education Larvacide Sweeps Ground Spray Aerial Spray More Environmentally Friendly Less Environmentally Friendly 7

8 Spraying Details Targeted Ground Spraying typically runs between $40,000 and $60,000 per season and could exceed $250,000 with an outbreak of Zika or West Nile Virus Tarrant County manages the contract for aerial spraying and the cost is $1.89 per acre Wide Area Aerial spraying/application for Forth Worth (205,000 acres) would cost approximately $390,000 per single mission or $1.2 mil for three consecutive missions during an outbreak Targeted aerial spraying for one mile would reduce the spray area to approximately 40,000 acres or $75,000 per mission or up to $250,000 per season The City Manager has the authority to approve aerial spray missions 8

9 Historic Disease Trend 9

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11 2012 Human Case Comparison JURISDICTION DEATHS WNND WNF TOTAL CASES WNND CASES PER 100,000 Dallas Co Tarrant Co * 5.6 Denton Co City of Fort Worth * 4.2 Source: Texas Department State Health Services * Source: TCPH 11

12 WNV Trends 2016 virus activity started earlier than 2015; however, activity has been overall lower than

13 Positive Trap Sample Comparison Positive samples and human cases are following a typical rise and fall pattern

14 Positive Traps 2016 for the Season 14

15 2016 Positive Traps by Frequency 15

16 Current Positive Traps 16

17 2016 Human Cases 17

18 Recommendations 1. Recommend that staff continue to focus on education, source pool reduction and targeted ground spraying. 2. Do not recommend aerial spraying at this time. 3. Risk factors can change quickly; therefore, it is recommended that the City does not object to Tarrant County deploying aerial spraying, at County expense, provided that they hold no fewer than four public meetings (North, Central, East and West) to explain the benefits of aerial spraying/answer questions 18

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20 Aerial Application of Pesticide Clarke Duet Water based Adulticide Ultra Low Volume Nighttime Application Kills Mosquitoes effectively, yet biodegrades in sunlight Approved by the EPA for Aerial Application Approved to be applied over crops, pastures and agricultural areas 20

21 Trap Yield There was an early rise/abundance of trapped mosquitoes and then a dramatic decrease While trap yields are down, virus activity remains active 21