picornaviridae Flashcards Preview

VIRO final > picornaviridae > Flashcards

Flashcards in picornaviridae Deck (23):

picornaviridae general

spherical, non enveloped, visions appear smooth and round
single molecule linear + sense RNA, VPg protein links to 5' end and genomic RNA is infectious


picornaviridae genome

cytoplasmic replication, virion RNA acts as mRNA and is translated to polyprotein to yield 11-12 proteins, most cause cytopathic effects and rapid cel death, very stable at low pH, 29 genera


foot and mouth disease FMD

seven serotypes, 80 subtypes, OAC in SA, OAC sAT 123 in Africa western europe and north and central america virus free


FMD hosts

all cloven footed domestic and wild animals, horses are genetical resistant


FMD distribution

africa, asia, middle east, none in North and Central America


FMD stability

stable pH6-9, broken down by citric or acetic acid


FMD transmission

mostly through inhalation, can move in wind or inside animal carriers


FMD path

inhalation/ingestion->oropharyngeal infection->viremia->spread to different organs and tissues->replication in epidermal cells->characteristic vesicular lesions
**vesicles filled with clear fluid


FMD path myocardial lesion

tiger heart, focal necrosis of cardiac muscle
-seen in fatal FMD cases in young animals, streaks of irregular size and shape are visible in myocardium, sudden death from heart failure


FMD Path

usually founding the pharynx, needs prolonged period of recovery, virus detectable in cattle up to two years and sheep after six months, virus persistence doesn't occur in swine


FMD clinical signs

most severe in cattle and intensively reared pigs, sheep and goat develop subclinical infections, morbidity high and mortality low


FMD cattle clinical signs

fever anorexia depression
decreased milk production, drooling, vesicles around coronary band, crater ulcers from ruptured vesicles
secondary bacterial infections, myocarditis in calves up to 6 months of age, abortion, chronic Diabetes mellitus from endocrine damage


FMD clinical sign in swine

lameness is often the first sign of foot and mouth disease, vesicles in mouth less prominent, more on snout


FMD in sheep and goats

mostly subclinical infections, if disease occurs its mostly mild



sampling fluid, ELISA, test for antibodies


FMD control

notifiable disease, quarantines in disease free countries, infected carcasses must be disposed of properly, vaccination around affected areas, rodent control, ban on swill feeding


FMD zoonosis

most human infections are subclinical, clinical signs show fever anorexia, vesiculation


avian encephalomyelitis

most seen in chickens 1-3 weeks old, fecal oral transmission or by egg


avian encephalomyelitis path

incubation period depends on the route of infection, vertical transmission 1-7 days, horizontal 11 days or more. no gross lesions
histology of central chromatolysis of neurons in the medulla oblongata


avian encephalomyelitis clinical signs

young chickens exhibit nervous disease -ataxia leg weakness , paralysis and recumbency, prostration blindness coma and death, may develop cataracts
laying chickens-no neuro signs, no deterioration in egg shell, hatch ability may drop, late embryonic mortality


avian encephalomyelitis Dx and control

Dx-virus isolation from brain and duodenum with pancreas, yolk sac of embryonated eggs, demonstration of AE virus antigen brain, spinal cord and other tissues, immunoflourescent staining. for control immunize with breeder pellets, commercial live vaccine AE vaccine combined with fowlpox, AE doesn't infect humans or other mammals


genus: cardiovirus

tropic to heart and brain, hosts are rodents, epizootics to swine and other wildlife, pigs infected from water contamination and transplacental infection


encephalomyocarditis clinical features

myocardial effects contribute to acute and subacute deaths, nonsuppurative meningoencephalitis in young pigs, reproductive issues/late term abortions