Predicting the Distribution of Vibrio vulnificus in Chesapeake Bay.

Matt RhodesJHT @ NOAA’s Oxford LabJuly 16, 2013matt.rhodes@noaa.gov

Vibrio spp.• Gram negative,halophillic bacteriaendemic to Coastalwaters• V. cholerae, V.vulnificus, and V.parahaemolyticus• Gastroenteritis, woundinfection, necrosis,septicemia.

Chesapeake Region Vibrio Infections100Number of Reported Cases8060402001997-98 1999200020012002200320042005200620072008CDC, COVIS Surveillance Program

Goals and Objectives• Develop empirical models for species and strains ofvibrio in Chesapeake Bay.• V. cholerae, V. vulnificus, and V. parahaemolyticus• Demonstrate their utility in ecological forecasting• Use models for understanding the regionaldistribution of Vibrio spp. and future scenarios.• Work with the public health community to refineproducts for management needs.

Chesapeake Bay Pathogen Monitoringand Forecasting SystemManagementandEducationResearch andMonitoringModelingandForecasting

Example: Vibrio vulnificus• Gram negative, halophillicpathogens endemic to Coastalwaters• Responsible for 95% of allseafood related mortalities, 50%mortality rate when septic.• Most cases wound infections inChesapeake Bay• Infection of increasing concern,especially for those imunocompromisedand with liverdisease.• Strain is important!

Statistical ModelingJacobs et al. (2009) Jacobs et al. (2010)Environmental Gradient Analysis (PCA)Formal Model Selection

Multiple models evaluated…Model Variable AIC ∆AIC % Concordance % Discordance P 1 c 2Vv Occurrence PC1, PC2, PC3 82.0 17.8 0.07 0.82(Presence/absence) Wtemp 1309.0 0.0 78.3 21.2 0.04 0.77Salopt, Wtemp 1290.0 19.0 86.6 13.2 0.25 0.87Salopt, Wtemp, Secchi 1266.0 24.0 88.9 11.0 0.14 0.89Vv Abunance PrPres 330.1 0.0 92.6 6.8 0.88 0.93(High/Low) Wtemp, Salopt, Secchi 330.1 0.0 93.4 6.3 0.91 0.94PrPres, DO 329.3 0.8 94.4 5.5 0.97 0.94PrPres, DO, Chla 326.9 2.4 95 4.9 0.95 0.95Vcg Occurrence PO4f 358.0 0.0 70.3 29.3 0.02 0.71(Presence/Absence) PO4f, Wtemp 311.0 47.0 77.2 22.8 0.65 0.77PO4f, Wtemp, Chla 307.4 3.6 78.2 21.8 0.98 0.78PO4f, Wtemp, Chla, Salopt 301.3 6.1 80.6 19.4 0.51 0.811 Hosner and Lemeshow goodness of fit test2 Area under the ROC curve

Internal and ExternalStatisticalModelingValidationBoostraped Model vs Development SetRandom Datasets N = 1222Bootstraped Model vs Validation SetRandom Dataset (N=414)Observed Frequency of Occurence1.21.00.80.60.40.2Y = .0014 + 1.00XR 2 = 0.940.00.0 0.2 0.4 0.6 0.8 1.0 1.2Predicted Frequency of OccurrenceObserved Frequency of Occurrence1.21.00.80.60.40.2Y = -0.056+1.09XR 2 = 0.980.00.0 0.2 0.4 0.6 0.8 1.0 1.2Predicted Frequency of Occurrence

ChesROMS Grid andImplementation(chief architects, Dr. Jiangtao Xuand Dr. Wen Long)Forecastsand otherProducts• Chesapeake Bay implementation ofthe Regional Ocean Modeling System(ROMS)• Curvilinear horizontal grid• Coarse mesh for model development(100 * 150) – 5 – 0.5 km spatialresolution• Includes major tributaries• C and D canal: treated as a river• Hindcast and operationalimplementations completed

Sea SurfaceTemperaturePathogenForecastingSystemVibrioempiricalmodelsSalinityBrown, C.W., R. R. Hood, W. Long, J. Jacobs, D. L.Ramers, C. Wazniak, J. D. Wiggert, R. Wood, and J.Xu. (2013). Ecological Forecasting in Chesapeake Bay:Using a Mechanistic-Empirical Modeling Approach. Journalof Marine Systemshttp://www.sciencedirect.com/science/journal/aip/09247963

Current Experimental Products• Nowcasts and 3 day forecast – UMCES and NOAA• 14 and monthly forecasts - UMD ESSICForecastsand otherProducts14 day Monthly

Vibrio abundance65Full Modely=0.068+1.15x+2.925x 2R 2 = 0.97, f = 115.68, 2,9 df, P

Virulence correlated gene (vcg)• PCR assay applied toenvironmental samples (Baker-Austin, et al., 2009)• Assay tested againstenvironmental and clinical strainswith high repeatability• At present – non-quantitative• Initial model development

Virulence correlated gene (vcg)8Number of Vcg positve Samples6420POTOMAC RIVERYORK RIVEREASTERN BAYMAGOTHY RIVERMOBJACK BAYELIZABETH RIVERPATUXENT RIVERCHESAPEAKE BAYTANGIER SOUNDBACK RIVER (VA)ELK RIVERPOCOMOKE SOUNDWICOMICO RIVERBACK CREEKPAMUNKEY RIVERPOCOMOKE RIVERMANOKIN RIVERTRANSQUAKING RIVERPATAPSCO RIVER2007-2010 data

yHow doManagementapplicationwe usethesemodels?

• Currentlyavailablethrough webbased systemonly to publichealth officials• MDE HealthyBeaches Vibrioawareness andlinks to NCCOS

Mean CB Water Temperature (°C)20191817CB Water Temp 1MD,VA,PA Infections 21009080706050Reported Vibrio Infections(Number of Cases)1620052006200720082009401 Mean water temperature from March - August from 9 CBP mainstem monitoring stations2Reported Vibrio infections for MD, VA, and PA provided by CDC

NOAA Climate Prediction• 6 day to 3 monthoutlooks on regionaltemperature andprecipitation• Working to refine forlocal region and users.• Used to triggereducational releases?

Climate VariabilityResearch/gapanalysisAugust 1st1996 1999Collaborationwith Dr. RitaCollwell andESSIC (Banikeret al. 2011)CDC BRACEaward – MDDHMH (2012 –2016)Wet YearDry Year

Where we are....Model Beta Quant Strain Roms Valid Web NWSOPVvVp 2013 ?? 2014Vc ** 2013? 2013?Va 2014?** Constantine de Magny, Colwell, et al.

CBOFS• Fully operationalimplementation ofROMS• Finer resolution• 48 hour predictions

Where we aregoing…• NWS operationalforecasts.• Skill assessment.• Region to Nationapproach (DE Bay, Gulf,Puget Sound).• Risk assessment.

Wen Long,Elizabeth North,Raleigh Hood

A National Network of OperationalCirculation Models….ColumbiaRiverGreat LakesNew York/New JerseyDelaware BayChesapeake BaySt. Johns RiverTampa BayGOMGalveston BayNOAA/COOPS

CurrentMonitoringStations(2011- )

Where we aregoing…• NWS operationalforecasts.• Skill assessment• Region to Nationapproach (DE Bay, Gulf,Puget Sound).• Risk assessment.What we need toget there…• Better tools for ID ofvirulent strains.• Coordination ofenvironmental andclinical data sets.• Dose response.• Continuous observationsover time.

AcknowledgementsJohn Jacobs, Kathy Brohawn,Christopher Brown, Rita Colwell,David Green, Rick Hoffman,Raleigh Hood, AK Leight, WenLong, Guillaume Constantin deMagny, Bruce Michael, CliffMitchell, Elizabeth North, BalaKrishna Prasad Mathukumalli,Raghuram Murtugudde, DebbieRouse, Brian Sturgis, CathyWazniak, and Robert Wood