Foot and Mouth Disease
FMD, Aftosa
Center for Food Security and Public Health Iowa State University - 2004
OverviewOverview
• Organism• Economic Impact• Epidemiology• Transmission• Clinical Signs• Diagnosis and Treatment• Prevention and Control • Actions to take
The Organism
Center for Food Security and Public Health Iowa State University - 2004
Foot and Mouth DiseaseFoot and Mouth Disease
• Picornaviridae, Aphthovirus−7 distinct serotypes−Not cross protective
• Affects cloven-hoofed animals• Inactivated at
−pH below 6.5 and above 11• Survives in milk, milk products,
bone marrow, lymph glands
Importance
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HistoryHistory
• 1929: Last case in U.S.• 1953: Last cases in
Canada and Mexico• 1993: Italy• 1997: Taiwan• 2001: United Kingdom
−Other outbreaks in 1967-68 and 1981
Center for Food Security and Public Health Iowa State University - 2004
Economic ImpactEconomic Impact
• Direct costs− Economic losses to
farmers and producers
− Eradication costs− Millions to billions of
dollars lost
Economically Devastating!!
• Indirect costs− Exports shut down− $3.1 billion in beef− $1.3 billion in pork− $14 billion in lost
farm income− $6.6 billion in
livestock exports− Consumer fear
Epidemiology
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Geographic DistributionGeographic Distribution
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Foot and Mouth Disease Distribution 2003
Foot and Mouth Disease Distribution 2003
Center for Food Security and Public Health Iowa State University - 2004
Morbidity/ MortalityMorbidity/ Mortality
• Morbidity 100% in susceptible animal population−United States, Canada, Mexico, others
• Mortality less than 1%−Higher in young animals and highly
virulent virus strains−Animals generally destroyed to prevent
spread
Transmission
Center for Food Security and Public Health Iowa State University - 2004
Animal TransmissionAnimal Transmission
• Respiratory aerosols−Proper temperature and humidity−Survives 1-2 days in human respiratory
tract• Direct contact
− Ingestion of infected animal parts−AI, biologicals, hormones
• Indirect contact via fomites
Center for Food Security and Public Health Iowa State University - 2004
Animal TransmissionAnimal Transmission
Species Host Carrier
Sheep Goats
Maintenance Pharyngeal tissue 4-6 months
Pigs Amplifier No
Cattle Indicator Pharyngeal tissue 6-24
months
Center for Food Security and Public Health Iowa State University - 2004
Human TransmissionHuman Transmission
• Very rarely develop mild clinical signs• Type O, C, rarely A• Act as a transmitter to animals
−Harbor virus in respiratory tract for 1-2 days
−Contaminated boots, clothing, vehicles−Spread to susceptible animals
• Ingestion of unprocessed milk or dairy products from infected animals
Animals and FMD
Center for Food Security and Public Health Iowa State University - 2004
Clinical SignsClinical Signs
• Incubation period: 2-12 days• Fever and vesicles
−Feet, mouth, nares muzzle, teats
−Progress to erosions• Abortion• Death in young animals• Recover in two weeks unless
secondary infections arise
Center for Food Security and Public Health Iowa State University - 2004
Clinical Signs in CattleClinical Signs in Cattle
• Oral lesions−Vesicles on tongue,
dental pad, gums, soft palate, nostrils, muzzle
−Excess salivation, drooling, serous nasal discharge
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Clinical Signs in CattleClinical Signs in Cattle
• Teat lesions−Decreased milk
production• Hoof lesions
− Interdigital space−Coronary band−Lameness−Reluctant to move
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Clinical Signs in PigsClinical Signs in Pigs
• Hoof lesions−More severe than in cattle−Coronary band, heel,
interdigital space−Lameness
• Snout vesicles• Oral vesicles
less common−Drooling is rare
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Clinical Signs in Sheep and GoatsClinical Signs in Sheep and Goats
• Mild, if any, signs−Fever−Oral lesions−Lameness
• Makes diagnosis and prevention of spread difficult
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Center for Food Security and Public Health Iowa State University - 2004
Foot & Mouth Disease
Vesicular Stomatitis
Swine Vesicular Disease
Vesicular Exanthema of
Swine
Clinical Signs by Species
All vesicular diseases produce a fever with vesicles that progress to erosions in the mouth, nares, muzzle, teats, and feet
Cattle
Oral & hoof lesions, salivation, drooling, lameness, abortions,
death in young animals, "panters";
Disease Indicators
Vesicles in oral cavity, mammary glands, coronary
bands, interdigital space
Not affected Not affected
Pigs
Severe hoof lesions, hoof sloughing, snout vesicles, less severe
oral lesions: Amplifying Hosts
Same as cattle
Severe signs in animals housed on
concrete; lameness, salivation,
neurological signs, younger more
severe
Deeper lesions with granulation tissue
formation on the feet
Sheep & Goats
Mild signs if any; Maintenance Hosts
Rarely show signs Not affected Not affected
Horses, Donkeys,
Mules Not affected
Most severe with oral and coronary
band vesicles, drooling, rub
mouths on objects, lameness
Not affected Not affected
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Post Mortem LesionsPost Mortem Lesions
• Clinically indistinguishable from other vesicular diseases, especially swine
• Single or multiple vesicles• Various stages of development
− White area, 2mm-10cm − Fluid filled blister− Red erosion, fibrin coating
• Dry lesions• Tiger heart
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Differential DiagnosisDifferential Diagnosis
• In swine− Vesicular stomatitis− Swine vesicular disease− Vesicular exanthema
of swine− Foot rot− Chemical and thermal burns
• In cattle− Rinderpest, IBR, BVD, MCF, Bluetongue
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SamplingSampling
• Before collecting or sending any samples, the proper authorities should be contacted
• Samples should only be sent under secure conditions and to authorized laboratories to prevent the spread of the disease
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Clinical DiagnosisClinical Diagnosis
• Clinically vesicular diseases are indistinguishable
• Salivation, lameness with vesicles requires further testing
• Tranquilization may be necessary
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DiagnosisDiagnosis
• Laboratory Tests− Initial diagnosis
Virus isolation and identification
−Antigen or nucleic acid detection−Complement fixation−ELISA and virus neutralization
• Notify authorities and wait for instructions before collecting samples
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Treatment Treatment
• No treatment available• Supportive care to those afflicted• U.S. outbreak could result in
−Quarantine−Euthanization−Disposal
• Vaccine available− Ramifications are many and discussed later
FMD in Humans
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Human Clinical SignsHuman Clinical Signs
• Very low incidence of human disease−40 cases since 1921−Most reports ended when FMD was
eradicated in Europe• Incubation period: 2-6 days• Clinical signs
−Mild headache, malaise, fever−Tingling, burning sensation of fingers,
palms, feet prior to vesicle formation
Center for Food Security and Public Health Iowa State University - 2004
Human Clinical SignsHuman Clinical Signs
• Vesicles 2 mm to 2 cm in diameter−Fluid-filled
• Oral blisters on tongue, palate−Painful− Interfere in eating, drinking, talking−Diarrhea
• Vesicles dry up in 2-3 days• Recover within a week of last blister
appearing
Center for Food Security and Public Health Iowa State University - 2004
Diagnosis and Treatment Diagnosis and Treatment
• Clinically FMD in humans resembles−Coxsackie A group viruses
Hand, foot and mouth disease Herpangina
−Herpes simplex virus Primary herpetic gingivostomatitis
−Vesicular stomatitis• Virus isolation or antibody identification
required for diagnosis• Treatment is supportive care
Hand, Foot & Mouth Disease
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Public Health SignificancePublic Health Significance
• FMD in humans is not a public health concern
• 40 cases since 1921 documented in humans−Europe, Africa, South America
Prevention and Control
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PreventionPrevention
• USDA APHIS: Strict import restrictions−Prohibit live ruminants, swine, and their
products from FMD-affected countries−Monitor travelers and belongings at
ports of entry• 450 FADD to investigate suspicious lesions• State planning/training exercises• Biosecurity protocols for livestock facilities
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Recommended ActionsRecommended Actions
• Notification of Authorities−Federal:
Area Veterinarian in Charge (AVIC) www.aphis.usda.gov/vs/area_offices.htm
−State veterinarian www.aphis.usda.gov/vs/sregs/official.html
• Quarantine
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Recommended ActionsRecommended Actions
• Confirmatory diagnosis
• Depopulation may occur−Proper destruction
of exposed cadavers, litter, animal products
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DisinfectionDisinfection
• Effective solutions include −2% sodium hydroxide (lye)−4% sodium carbonate (soda ash)−5.25% sodium
hypochlorite (household bleach)
−0.2% citric acid• Areas must be free of organic matter
Center for Food Security and Public Health Iowa State University - 2004
VaccinationVaccination
• Killed vaccine, serotype specific• North American Foot-and-Mouth
Vaccine Bank−Plum Island, NY
• Monitor disease outbreaks worldwide and stock active serotypes and strains
• It is essential to isolate virus and identify the serotype to select the correct vaccine
Center for Food Security and Public Health Iowa State University - 2004
VaccinationVaccination• U.S. has no need to vaccinate
−Have not had animals affected since 1929• May be used to control an outbreak• Huge implications if we do vaccinate
−Annual re-vaccination required Costly, time consuming
−Does not protect against infection, just clinical signs Spread infection to other animals
− International trade status harmed
Additional Resources
Center for Food Security and Public Health Iowa State University - 2004
ResourcesResources
• World Organization for Animal Health (OIE) website−www.oie.int
• USDA APHIS Veterinary Services −www.aphis.usda.gov/vs
• 1-866-SAFGUARD is a toll-free hotline with recorded messages for international travelers
Acknowledgments
Development of this presentation was funded by a grant from the Centers for Disease Control and Prevention to the Center for Food Security and Public Health at Iowa State University.
Author:
Co-authors:
Reviewer:
Danelle Bickett-Weddle, DVM
Anna Rovid Spickler, DVM, PhDKristina August, DVMJames Roth, DVM, PhD
Bindy Comito Sornsin, BA
Acknowledgments