1 / 20

Vibrio vulnificus Calculator

Vibrio vulnificus Calculator. VMC/Gulf Regulators Conference Call August 1, 2008. ISSC adopted Vv illness reduction plan–1999?. 60% illness reduction goal (per capita) Core states: CA, TX, LA & FL Baseline 1995-1999: 21.4 cases/yr Education and increasing PHP capacity

Albert_Lan
Télécharger la présentation

Vibrio vulnificus Calculator

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Vibrio vulnificus Calculator VMC/Gulf Regulators Conference Call August 1, 2008

  2. ISSC adopted Vv illness reduction plan–1999? • 60% illness reduction goal (per capita) • Core states: CA, TX, LA & FL • Baseline 1995-1999: 21.4 cases/yr • Education and increasing PHP capacity • 7 year plan with reductions based on ave # cases in 2007 & 2008

  3. Current Status • 2007 cases=19 • 24.8% reduction from baseline • Adjusted for population increase • 2008 partial cases=3 • Plan does not reach goal if 20 or more cases occur in 2007 & 2008 combined • Goal will not be met • Goal shortfall cannot be determined until after 2008

  4. Consequences of not achieving goal • Seasonal closures (100% effective) • Diversion to PHP (100% effective) • Label “for cooking only” OK for Vv? (100% effective) • Other means? • Time/temperature controls • High salinity relaying • ISSC Spring Executive Board Mtg • Gulf States submit control plan by Aug. 15, 2008 (amended?) • States implement plans in 2010

  5. Time/Temperature Controls • GSASSC New Orleans June 2008 • Gulf regulators requested that FDA develop risk calculator similar to that proposed for VPCP • Vv Risk calculator • Based on 2005 FAO/WHO VVRA • Dose response based on reported cases in US

  6. Beta Poisson vs Exponential

  7. Vv Calculator Features • Derived from FAO/WHO VVRA • Monte Carlo simulations • Time consuming • Expensive software • Trained operators • Vv risk calculator • Based on regression fits to a set of Monte Carlo simulation output • Calculates Vv levels & risk instantly • Flexible to evaluate diverse scenarios and different end points for desired level of illness reduction

  8. Average monthly maximum water temperature (AMMWT) • Determines Vv levels at harvest based on relationship between water temperature & Vv level from Vv risk assessment (VVRA) • State determines scale: area, basin or entire state (buoy, sampling) • Gulf-wide

  9. Effect of Temperature on Vv densities in Gulf Coast oysters

  10. Average monthly air temperature • Surrogate for oyster temperature • Determines Vv growth rate • Ave. air temperature determination • Ave. monthly noon air temperature • Ave. monthly maximum temperature • Ave. monthly air temperature during harvest period (i.e. 6-11 AM) • Ave. oyster temperature during harvest period

  11. Baseline: max. time to refrigeration • Controls that were in place during the baseline period of 1995-99 • Vary from state to state • Alternatively 10h for summer month? • Represents control used for most Gulf oyster harvest

  12. Baseline: Max cool down time • Time from when oysters are first placed into refrigeration until reach no growth temperature of 13C or 55F • 10 hour is assumption used in both FDA VPRA and FAO/WHO VVRA • Ave cool down between 1 to 10 hours

  13. Demonstration of using Vv risk calculator • Baseline (1995-99) controls • Effect of VPCP on Vv risk • Risk at harvest (best case scenario)

  14. Calculator Inputs • Average monthly water temperature • Average monthly air temperature • Maximum time to first refrigeration • Maximum cool down time

  15. Calculator Outputs • Vv levels at consumption • Vv risk per 100,000 meals • Number of cases per month (Nation wide) • % change in number of cases from the baseline

  16. Baseline Demonstration Open Excel Vv Calculator Tab

  17. Effect of VPCP on Vv Risk <5h if >81F Tab

  18. Vv Risk at Harvest Risk at Harvest Tab

  19. Caveats • Dose response not linear & does not provide outputs above 90F and >15h to first refrigeration • Controls changed in 1997 during baseline period (1995-99) • Controls vary across Gulf states • Implementation of VPCP in 2008 • Max. time to refrigeration • Changes in volume of harvest for raw consumption? • % raw consumption varies across Gulf states

  20. Summary • Scenario analysis • Manage on monthly scale • Modify time to refrigeration and cool down times • Outputs • Vv levels at consumption • Vv risk per 100,000 meals (at risk population) • Expected number of cases • Change from baseline

More Related