Foot mouthdisease

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

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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

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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

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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