RNA - Picornaviridae Flashcards
Is picornviridae enveloped or nonenveloped?
nonenveloped
How do picorn virions appear in electron micrographs?
smooth and circular
What is the genome RNA protein of picorn? Is the genomic RNA infectious or noninfectious?
Genomic RNA has a protein, VPg, linked covalently to its 5’- end.
Genomic RNA is infectious.
T/F: Most picornaviruses cause rapid cell death with characteristic CPE (cytopathic effects)
True
Picron consists of how many genera?
29
What distinguishes the different genera of picorn?
their stability at low pH
Etiology of FMD?
Alpthovirus
aptha means smal ulcer
How many serotypes of FMD? Subtypes?
7, 80
Which species is genetically resistant to FMD
Horses.
All hooved animals can get FMD
Where is FMD still enzootic?
FMD is still enzootic in much of Africa, Asia and the Middle East.
Stability of FMD - what is FMD is sensitive to?
virus is sensitive to acid and alkaline pH [stable at pH 6-9], sodium hydroxide, sodium carbonate and citric or acetic acid are effective disinfectants.
How is FMD transmitted?
Inhaled/Aerosol. Can spread over countries
Patho of FMD?
Inhalation/Ingestion Oropharyngeal infection Viremia Spread to different organs & tissues Replication in epidermal cells Characteristic vesicular lesions.
Which disease would you find the Tiger Heart and what species?
Commonly seen in fatal FMD cases in young calves, lambs, goats, pigs and buffaloes
When is FMD detectable in Cattle and sheep?
Cattle: up to 2 years Sheep: up to 6 months
Is FMD persistent in swine?
No woman!
T/F:
FMD virus may persist in the pharynx of some animals for a prolonged period after recovery.
True
T/F: FMD clinical signs: Most severe in pigs and intensively reared cattle
False. Vice versa
Disease in Cattle?
- Fever, anorexia, depression, and a marked decrease in milk production.
- Drooling and vesicles appear on tongue and gums, interdigital skin, coronary band, teats.
- The vesicles soon rupture, producing large, crater-like ulcers
FMD
Disease in Cattle?
- In calves up to 6 months of age = death.
- Tiger Heart
- Abortion
-
Hairy Panters
- Chronic syndrome of anemia, diabetes mellitus, overgrowth of hair and poor heat tolerance.
- Probably due to Endocrine damage.
FMD
What is the first sign of FMD in swine?
lameness is often the first sign
Clinical signs of FMD in Sheep?
Mostly subclinical infections
If disease occurs, it is usually very mild
How do you sample FMD?
Samples of vesicular epithelium or vesicular fluid should be sent in phosphate-buffered saline (pH 7.4) .
Samples must be kept as close as possible to pH 7.4 to prevent destruction of the FMD virus and antigen.
What is the most preferred way to test FMD?
ELISA
How do you distinguish infected animals from vaccinated animals (DIVA) with FMD.
Tests for antibodies to the nonstructural proteins (NSP) of FMD virus
Is FMD reportable?
yes
Is FMD zoonotic?
yes
Etiology of Avian Encephalomyelitis?
Tremovirus
What age is AE commonly found
1-3wk chicks
Transmission of AE?
Fecal Oral.
Via egg during viremia phase of laying the eggs
What is the incubation of vertical transmission?
1-7 days
What is the incubation of horizantal transmission?
11 days
Are gross lesions seen in the infected brain of a bird with AE?
No woman!
What is strongly suggestive of avian encephalomyelitis?
Central chromatolysis of neurons in the medulla oblongata
T/F: Avian encephalomyelitis infection is seen as two distinct syndromes depending on the age when the susceptible chicken is infected
True
Disease in chickens?
- Ataxia and leg weakness that varies from sitting on hocks to paresis that progresses to paralysis and recumbency.
- Fine tremors of the head and neck are evident in some birds and are characteristic of the disease (Epidemic tremors).
- Prostration, blindness, coma and death.
Avian Encephalomyelitis
What type of chickens would you find AE affecting the nervous system
Young chickens
What type of chickens would you find AE showing no neurologic signs
Laying chickens
side note: hatchability may drop due to lateembryonic mortality
Birds that survive an acute infection of avian encephalomyelitis may develop what?
- cataract (a blue opacity of the lens).
- CNS deficiencies.
Describe the vaccine for avian encephalomyelitits
AE vaccine is usually combined with fowlpox vaccine and given by wing-web inoculation.
T/F: AE virus causes disease in people or other mammals.
False
Etiology of encephalomyocarditis
Cardiovirus
What is the natural host of encephalomyocarditits?
Rodents
In what species has fatality been reported in encephalomyocarditits?
swine and wildlife especially elephants
How is encephalomyocarditits transmitted?
contaminated water or feed with rodent urine or feces
transplacental
T/F: Acute and subacute deaths are almost always attributed to the destructive effects of the virus on the myocardium.
True
Disease in pigs?
Nonsuppurative meningoencephalitis.
Cases of reproductive failure due to near-term abortions (107–111 days of gestation), stillbirths, and mummifications
Encephalomyocarditis
