Venezuelan Equine Encephalitis Peste Loca Venezuelan Encephalitis Venezuelan Equine Fever

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Transcript of Venezuelan Equine Encephalitis Peste Loca Venezuelan Encephalitis Venezuelan Equine Fever

  • Venezuelan Equine EncephalitisPeste Loca Venezuelan Encephalitis Venezuelan Equine Fever

    Center for Food Security and Public Health, Iowa State University, 2011

  • OverviewOrganismHistoryEpidemiologyTransmissionDisease in HumansDisease in AnimalsPrevention and ControlActions to Take Center for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • THE ORGANISM

  • The VirusVenezuelan equine encephalomyelitis virus Family TogaviridaeGenus AlphavirusSix subtypesEpizootic and enzooticMosquito-borneDiseaseEncephalitis in humans and horsesCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • Viral StrainsCenter for Food Security and Public Health, Iowa State University, 2011

    SubtypeCyclePathogenicI-AI-BI-CEpizootic/ EpidemicHighly virulent for equinesI-D III-E IIII-F IV V VIEnzootic/ EndemicNot for horses

    Limited cases in humans

    Center for Food Security and Public Health, Iowa State University, 2011

  • Viral StrainsEpizootic/EpidemicI-A, I-B, and I-CDisease in humans and horsesTransmission by many mosquito speciesNatural reservoir unknownHorses and donkeys act as amplifiersEnzootic/EndemicDisease in humansTransmission mainly by Culex (Melanoconion) species Natural reservoir is rodents living in swamps and forestsCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • HISTORY

  • VEE History1938Isolated from horse brain1962-1964Outbreak in Venezuela23,000 human cases 1967Outbreak in Colombia220,000 human cases Over 67,000 horse deathsCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • VEE History1969-1971Largest recorded outbreakCovered area from Costa Rica to Rio Grande Valley in TexasThousands of human encephalitis casesOver 100,000 horses died1995Venezuela and ColombiaOver 90,000 human casesCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • Countries with Confirmed VEE, 2007-2012Center for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • TRANSMISSION

  • Epizootic TransmissionCenter for Food Security and Public Health, Iowa State University, 2011Primary Vector multiple mosquito species Dead-end hostsHumansVertebrate Host HorsesOther species naturally infected but not amplifiers

    Center for Food Security and Public Health, Iowa State University, 2011

  • Enzootic TransmissionCenter for Food Security and Public Health, Iowa State University, 2011Primary Vector Culex (Melanoconion) species Dead end hostsHumansVertebrate HostRodentsP. Myers

    Center for Food Security and Public Health, Iowa State University, 2011

  • DISEASE IN HUMANS

  • VEE in HumansIncubation period: 1 to 6 daysUsually acute, mild, systemic diseaseClinical signsFever, chills, headache, myalgiaCoughing, vomiting, diarrheaCNS signsEncephalitis occurs in 4% of childrenLess than 1% of symptomatic adultsDeath is rareCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • VEE in HumansPregnant womenFetal encephalitis, placental damage, abortion/stillbirth, congenital diseaseDiagnosisPaired sera with rising titerELISA IgG or IgMTreatmentSupportive careNo vaccine availableCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • DISEASE IN ANIMALS

  • VEE in HorsesIncubation period: 1 to 5 daysHorses most susceptibleFever, anorexia, depression, flaccid lips, droopy eyelids and ears, incoordination, and blindnessDeath 5 to 14 days after clinical onsetCase-fatality rate: 50 to 90%In utero transmission results in abortion, stillbirthCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • VEE in AnimalsMost domestic animals do not show clinical signs or amplify the virusExperimentallyInfected rabbits and dogs die after inoculationLaboratory animals susceptibleAct as sentinelsGuinea pigs, mice, hamstersEnzootic strains do not cause disease in animalsCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • VEE in AnimalsDiagnosisVirus isolation SerologyPaired sera with rising titerELISA IgG or IgMTreatmentSupportive care Vaccine available for horsesCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • VEE as a Biological WeaponAerosolized VEEHuman and equine disease occur simultaneouslyFlu-like symptoms in humansPossible neurological signs in horsesLarge number of cases in a given geographic areaCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • PREVENTION AND CONTROL

  • Management ofMosquito-Borne DiseasesSource reductionSurveillanceBiological control Chemical controlLarvicideAdulticideEducating the publicHow to protect themselves

    Center for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • Source ReductionCenter for Food Security and Public Health, Iowa State University, 2011Mosquito habitatsMake unavailable or unsuitable for egg laying and larval developmentMinimize irrigation and lawn wateringPunch holes in old tiresFill tree holes with cementClean bird baths, outside waterers, fountains

    Center for Food Security and Public Health, Iowa State University, 2011

  • Source Reduction ContdDrain or fill temporary pools with dirtKeep swimming pools treated and circulatingAvoid stagnant water Open marsh water managementConnect to deep water habitats and flood occasionallyFish accessCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • SurveillanceSentinel chicken flocksBlood test and ELISA to monitor seroconversionCenter for Food Security and Public Health, Iowa State University, 2011Mosquito trapping and testing for viral presenceRecord keepingWeather data, mosquito larval populations, adult flight patterns

    Center for Food Security and Public Health, Iowa State University, 2011

  • Biological ControlPredators, natural and introduced, to eat larvae and pupaeMosquito fishGambusia affinis, G. holbrooki Fundulus spp., Rivulus spp., killifishOther agents have been used but are not readily availableCopepodsCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • Chemical ControlEssential when:Source reduction not effectiveSurveillance shows increased population of virus-carrying mosquitoesRequires properly trained personnelLarvicides, adulticidesToxic to many birds, fish, wildlife, aquatic invertebrates, honeybeesHuman exposure is uncommonCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • Chemical ControlFederal Food Drug and Cosmetic Act limits the quantity of adulticide usedDue to wind drift onto agricultural cropsMethod used variesType of target mosquitoType of targeted habitatAerial spraying covers wide areaFunding provided by state or local governmentRarely federalCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • LarvicidesUse when source reduction and biological control not feasibleMore effective and target-specificLess controversial than adulticidesApplied to smaller geographic areasLarvae concentrate in specific locations

    Center for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • LarvicidesCenter for Food Security and Public Health, Iowa State University, 2011

    NameProduct (Larvae, Pupae, Adult)TemephosAbate (L)MethopreneAltosid (L)OilsBVA, Golden Bear (L, P)Monomolecular filmAgnique (L, P)Bacillus thuringiensis israelensis (BTI)Aquabac, Bactimos, LarvX, Teknar, Dunks (L)Bacillus sphaericusVectoLex (L)PyrethrinsPyrenone, Pyronyl (A, L)

    Center for Food Security and Public Health, Iowa State University, 2011

  • AdulticidesNecessary when other control measures unsuccessfulLeast efficientProper type and time of application helps efficacyUltra low volume (ULV) foggers1 ounce per acreSmall droplets contact and kill adultsCenter for Food Security and Public Health, Iowa State University, 2011

    Center for Food Security and Public Health, Iowa State University, 2011

  • AdulticidesCenter for Food Security and Public Health, Iowa State University, 2011

    Chemical NameProductMalathionFyfanon, Atrapa, PrentoxNaledDibrom, TrumpetFenthionBatexPermethrinPermanone, AquaResilin, Biomist, Mosquito BeaterResmethrinScourgeSumithrinAnvil