Organism Organism Economic Impact



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Organism

  • Organism

  • Economic Impact

  • Epidemiology

  • Transmission

  • Clinical Signs

  • Diagnosis and Treatment

  • Prevention and Control

  • Actions to Take





RNA Vesiculovirus

  • RNA Vesiculovirus

    • Family Rhabdoviridae
    • Major serotypes
      • VSV-NJ and VSV-I
  • Affects horses, cattle, swine, camelids, humans

  • Closely resembles exotic vesicular diseases including FMD





Early 1800s

  • Early 1800s

    • Horse illness resembling VSV
  • 1927: Virus identified

  • 1950s: Human infections recorded

  • 1982-83: Outbreak in western U.S.

    • Previously, epizootic waves typical
    • Now an annual occurrence in U.S.


1998-99: NM, CO, TX; 130 positives

  • 1998-99: NM, CO, TX; 130 positives

  • 2004-05: TX, NM, CO; 470 positives

  • 2005: Nine states; 786 positives

  • 2006: WY; 29 positives

  • 2009: TX, NM; 7 positives

  • 2010: AZ; 4 positives



1928: California dairy herds

  • 1928: California dairy herds

  • 1995: New Mexico beef herd

    • $53 lost per head
  • Losses due to:

    • Increased culling, increased mortality
    • Reduced milk production
    • Labor, medicine, veterinary costs




Western hemisphere

  • Western hemisphere

    • North, Central, and South America
  • Emergence in eastern hemisphere?

    • 2009: Bahrain, Laos (suspected)
    • 2009: Pakistan (limited regions)
  • Southwest U.S.

    • Outbreaks in warmer regions
  • Southeast U.S.: enzootic cycle



Morbidity





Vectors

  • Vectors

    • Sandflies
    • Blackflies
    • Seasonal outbreaks
  • Direct contact

    • Infected animals
    • Contaminated objects


Direct contact

  • Direct contact

    • Infected tissues, vesicular fluid, saliva
  • Insect bites

    • Blackfly, sandfly
  • Aerosol

    • Laboratory settings




Incubation period

  • Incubation period

    • 3 to 5 days
  • Fever and vesicles that resemble FMD

  • Horses severely affected

    • Oral lesions
    • Coronary band lesions


Cattle, pigs

  • Cattle, pigs

    • Vesicular lesions
      • Oral, mammary gland, coronary band, interdigital region
    • Usually isolated to one body area
    • Salivation, lameness
  • Recover within 2 weeks





Gross lesions

  • Gross lesions

  • Histopathology

    • Degeneration of epithelial cells




Before collecting or sending any samples, the proper authorities should be contacted

  • 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



Vesicular diseases are clinically indistinguishable!

  • Vesicular diseases are clinically indistinguishable!

  • But, symptoms in horses are suggestive

    • Salivation and lameness
  • VSV vs. FMD

    • VSV less contagious
    • VSV lesions generally found in one area of the body


Virus isolation

  • Virus isolation

  • Viral antigen detection

    • Vesicular fluid or epithelium
    • ELISA, complement fixation, virus neutralization
  • Antibody tests

    • Paired serum samples
    • ELISA, complement fixation, virus neutralization


No specific treatment available

  • No specific treatment available

  • Supportive care

    • Fresh, clean water
      • Electrolytes if necessary
    • Soft feeds
  • Antibiotics for secondary infection

  • Good prognosis

  • Production animals may suffer losses





Incubation period: 1 to 6 days

  • Incubation period: 1 to 6 days

  • Influenza-like symptoms

    • Headache, fever, retrobulbar pain, malaise, nausea, limb and back pain, oral vesicles (rare)
  • Self-limiting disease, supportive care

  • Recovery can be prolonged

  • Death is rare



Clinical diagnosis difficult

  • Clinical diagnosis difficult

  • Differentials include:

    • Coxsackie A group viruses (Hand, foot and mouth disease)
    • Herpes simplex
  • Diagnosis via serology



Low incidence of human illness

  • Low incidence of human illness

  • Chance of infection when handling contaminated tissues

    • Biosafety level 3
    • Personal protective equipment
  • Rarely causes vesicle formation

  • Recover in 4 to 7 days





IMMEDIATELY notify authorities

  • IMMEDIATELY notify authorities

  • Federal

    • Area Veterinarian in Charge (AVIC)
    • http://www.aphis.usda.gov/animal_health/area_offices/
  • State

    • State veterinarian
    • http://www.usaha.org/StateAnimalHealthOfficials.pdf
  • Quarantine



Easily inactivated

  • Easily inactivated

    • Area must be free of organic matter
    • Contact time of at least 10 minutes
  • Disinfectants

    • Phenolic, halogen-based disinfectants
    • Soda ash, 2% iodophores
    • Chlorine dioxide, 1% chlorine bleach
    • 1% cresylic acid
    • Quaternary ammonium


Vaccines used in some endemic regions of Central, South America

  • Vaccines used in some endemic regions of Central, South America

  • Vaccines may be available during an outbreak

    • Efficacy is unknown
  • Contact state veterinarian for availability information



Do not buy from positive herds for 3 months post-infection

  • Do not buy from positive herds for 3 months post-infection

  • Avoid grazing at peak insect feeding hours

  • Segregation and isolation necessary for controlling spread

  • Sanitation

  • Insect control programs



World Organization for Animal Health (OIE)

  • World Organization for Animal Health (OIE)

    • www.oie.int
  • U.S. Department of Agriculture (USDA)

    • www.aphis.usda.gov
  • Center for Food Security and Public Health

    • www.cfsph.iastate.edu
  • USAHA Foreign Animal Diseases (“The Gray Book”)

    • www.usaha.org/pubs/fad.pdf


Development of this presentation was funded by grants from

  • Development of this presentation was funded by grants from

  • the Centers for Disease Control and Prevention, the Iowa Homeland Security and Emergency Management Division, and the Iowa Department of Agriculture and Land Stewardship to the Center for Food Security and Public Health at Iowa State University.

  • Authors: Danelle Bickett-Weddle, DVM; Anna Rovid Spickler, DVM, PhD; Kristina August, DVM; James A. Roth, DVM, PhD

  • Reviewers: Bindy Comito Sornsin, BA; Kerry Leedom Larson, DVM, MPH, PhD




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