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

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Presentation on theme: "Vibrio vulnificus Calculator VMC/Gulf Regulators Conference Call August 1, 2008."— 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) 60% illness reduction goal (per capita) Core states: CA, TX, LA & FL Core states: CA, TX, LA & FL Baseline : 21.4 cases/yr Baseline : 21.4 cases/yr Education and increasing PHP capacity Education and increasing PHP capacity 7 year plan with reductions based on ave # cases in 2007 & year plan with reductions based on ave # cases in 2007 & 2008

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

4 Consequences of not achieving goal Seasonal closures (100% effective) Seasonal closures (100% effective) Diversion to PHP (100% effective) Diversion to PHP (100% effective) Label “for cooking only” OK for Vv? (100% effective) Label “for cooking only” OK for Vv? (100% effective) Other means? Other means? –Time/temperature controls –High salinity relaying ISSC Spring Executive Board Mtg 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 GSASSC New Orleans June 2008 –Gulf regulators requested that FDA develop risk calculator similar to that proposed for VPCP Vv Risk calculator 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 Derived from FAO/WHO VVRA –Monte Carlo simulations –Time consuming –Expensive software –Trained operators Vv risk calculator 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) 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) State determines scale: area, basin or entire state (buoy, sampling) Gulf-wide Gulf-wide

9 Effect of Temperature on Vv densities in Gulf Coast oysters

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

11 Baseline: max. time to refrigeration Controls that were in place during the baseline period of Controls that were in place during the baseline period of –Vary from state to state Alternatively 10h for summer month? 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 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 10 hour is assumption used in both FDA VPRA and FAO/WHO VVRA Ave cool down between 1 to 10 hours Ave cool down between 1 to 10 hours

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

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

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

16 Baseline Demonstration Open Excel Vv Calculator Tab

17 Effect of VPCP on Vv Risk 81F Tab 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 Dose response not linear & does not provide outputs above 90F and >15h to first refrigeration Controls changed in 1997 during baseline period ( ) Controls changed in 1997 during baseline period ( ) Controls vary across Gulf states Controls vary across Gulf states Implementation of VPCP in 2008 Implementation of VPCP in 2008 –Max. time to refrigeration –Changes in volume of harvest for raw consumption? % raw consumption varies across Gulf states % raw consumption varies across Gulf states

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


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