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FLAVIVIRIDAE & CSFV

SUBMITTED TO :-

Dr. Sunil Maherchandani

By:- Tara Chand Nayak

COLLEGE OF VETERINARY &ANIMAL SCIENCES,BIKANER

DEPARTMENT OF VETERINARYMICROBIOLOGY

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Flaviviruses have been subdivided by theICTV into three genera:

GenusFlavivirusGenusPestivirusGenusHepacivirus

CLASSIFICATION &TOXONOMY

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Enveloped, spherical, about 50 nm in diameter. The

surface proteins are arranged in an icosahedral-likesymmetry.

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Monopartite, linear, ssRNA(+) genome ofabout 9.7-12 kb. The genome 3 terminus isnot polyadenylated but forms a loopstructure. The 5 end has a methylated

nucleotide cap (allows for translation) or agenome-linked protein (VPg).

GENOME

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The virion RNA is infectious and serves asboth the genome and the viral messengerRNA. The whole genome is translated in apolyprotein, which is processed co- and post-

translationally by host and viral proteases.

GENE EXPRESSION

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CYTOPLASMICVirus attaches to host receptors and is

endocytosed into vesicles in the host cell.Fusion of virus membrane with the vesicle

membrane; RNA genome is released into thecytoplasm.

The positive-sense genomic ssRNA is

translated into a polyprotein, which iscleaved into all structural and non structuralproteins.

REPLICATION

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Replication takes place at the surface ofendoplasmic reticulum. A negative-sensecomplementary ssRNA is synthesized usingthe genomic RNA as a template.

New genomic RNA is synthesized using thenegative-sense RNA as a template.

Virus assembly occurs at the endoplasmicreticulum. The virion buds at theendoplasmic reticulum, is transported to theGolgi apparatus, and then bud from the cellmembrane

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Hog Cholera,Peste du Porc,Colera Porcina,

Virusschweinepest

Classical Swine Fever

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Overview

OrganismEconomic ImpactEpidemiology

TransmissionClinical SignsDiagnosis and TreatmentPrevention and Control

Actions to Take

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Classical Swine Fever VirusFamily Flaviviridae

Genus Pestivirus

Lipid-enveloped, single-strandedRNA virus

Varies in virulenceEnvironmentally stable

In tissues (meat) Cold temperatures

ORGANISM

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History

First confirmed in US, 1833 Endemic in late 19th and 20th century

Eradicated by late 20th

Reported in the UK, 1864Recognized in 36 countriesEradication

Australia, Canada, New Zealand, and the US

Most of western and central Europe

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Economic Impact

Impact on production

Loss of import and export markets Pigs and pork products

Control Quarantine and slaughter

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Epidemiology

South & Central America, MexicoParts of Africa and Caribbean islandsMuch of Asia

Recent outbreaks Russia

Bulgaria

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Morbidity and Mortality

Age and immune status importantVaries with viral strain

AcuteHigh mortality (up to 100%)

SubacuteLower morbidity and mortality rates

ChronicFew animals affected always fatal

Some cases are asymptomatic

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Animal Transmission

Highly contagious Blood, saliva, urine, feces, tissues

Transmission

Ingestion of contaminated garbage or meatproducts

Direct or indirect contact (fomites)

Less common: aerosol, semen, vectors

Infected pigs are the only reservoir

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Clinical Signs

CSFV only infects pigsIncubation period: 2 to 14 daysDisease variable

Acutely fatal to asymptomaticPersistent viremia

Congenitally infected piglets

Shed the virus for months

Signs mimic other swine diseases

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Clinical Signs:Acute DiseaseHigh fever (105oF)Huddling, weaknessAnorexiaConjunctivitisDiarrheaStaggeringCyanosisSkin hemorrhagesDeath

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Clinical Signs:Subacute/Chronic DiseaseSubacute

Similar to acute form, but symptoms less severe Pigs may survive

Chronic Anorexia, depression, fever, diarrhea Poor reproductive performance including

abortions, stillbirths, and deformities Persistently infected piglets

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Post Mortem Lesions:Acute DiseaseHighly variableHemorrhageNecrotic foci in tonsils

Petechiae/ecchymoses onserosal and mucosalsurfaces Kidney, larynx, trachea,

intestines, spleen, lungs

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Post Mortem Lesions:Chronic DiseaseNecrotic foci (button

ulcers) Intestinal mucosa

Epiglottis

Larynx

Congenital infection Cerebellar hypoplasia, thymic atrophy,

hemorrhages, deformities

Photo courtesy of Dr. R. Panciera, Oklahoma StateUniversity

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Diagnosis

Suspect CSF in pigs with: Septicemia and high fever History of garbage/scrap feeding

Diagnosis impossible without

laboratory confirmationTonsil samples should be sent with every

submission to your state diagnostic lab

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Diagnostic Tests

Detect virus, antigens, nucleic acids Tissue samples (tonsils, spleen, kidneys, distal

ileum)

Whole blood

ELISA or direct immunofluorescence

Serology ELISA or virus neutralization

Comparative neutralization test**

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Treatment

SlaughterArea restrictions on pig movementsVaccination (live attenuated vaccines)

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QuarantineSuspicion or diagnosis

Confirmed cases, contact animals slaughtered Strict quarantine imposed to prevent spread of

disease

Prevention and Control

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Disease Control

Disinfectants Sodium hypochlorite Phenolic compounds

Virus sensitive to Drying Ultraviolet light pH 11

Killed at high temperatures 150oF for 30 minutes; 160oF 1 minute

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Prevention

Do not feed uncooked garbage or meatproducts to swine

Minimize visitors on the farm

Especially those who have traveled internationallyin the last 5 days

Implement biosecurity measures Clean/disinfect boots

Clean coveralls

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Prevention

Monitor animals forillness or signs of disease

Inspect animals daily Report sick animals

Clean and disinfect Vehicles Equipment Boots and clothing

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Prevention

Isolate ill animals immediatelyQuarantine newly introduced animals

Minimum of 30 days

New purchases, returning animals

Keep health records on every animal

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Thank you!