Picornaviridae (Final) Flashcards
What are the four genera of Picornaviridae?
Main disease caused by each?
- Aphthovirus: FMD
- Cardiovirus: encephalomyelitis
- Enterovirus: swine vesicular
- Teschovirus: porcine
General features of Picornaviridae
- structure
- genome
- environmental stability
- replication location
- non-enveloped, icosahedral
- single stranded, pos sense RNA
- genomic RNA is infectious
- stable in mucus and feces, can withstand strong sunlight, humidity preferred
- replication in cytoplasm
Swine Vesicular Disease
- family, genus
- host
- transmission
- resistance
- picornaviridae, enterovirus
- swine are only natural host, but enzootic
- can be transmitted in pork products
- virus infects swine via skin abrasions and mucosa be ingestion and inhalation, also direct contact (fecal-oral)
- resistant to sodium carbonate
Clinical features of Swine Vesicular Disease
- sudden appearance of lameness
- fever
- vesicles on junction between heel and coronary band
- lesions on snout, lips, and tongue
- may develop encephalomyelitis
Foot and Mouth Disease
- family, genus
- hosts
- picornaviridae, aphthovirus
- in cloven hoofed animals
- zoonotic, foreign animal disease
Clinical signs of FMD
- early signs: fever, salivation, nasal discharge
- lesions on buccal area and buccal cavity
- vesicles on coronary bands and interdigital spaces
- lesions on teats
- abortion
- death in young animals
Transmission of FMD
- respiratory aerosols
- direct contact
- indirect contact (fomites)
What are 4 genera of Paramyxovirinae, and what is the main disease each causes?
- Respirovirus: bovine parainfluenza virus 3
- Avulavirus: Newcastle disease
- Henipavirus: Nipah virus
- Morbilivirus: canine distemper
General features of Paramyxoviridae
- structure
- genome
- location of replication
- pleomorphic, spherical, or filamentous
- enveloped with glycoprotein spikes
- herringbone shaped nucleocapsid
- linear, single stranded, neg sense RNA
- replication in cytoplasm
What proteins are present on/in paramyxoviruses
3 membrane proteins: matrix, fusion, hemagglutinin
3 nucleocapsid proteins: RNA-binding protein, phosphoprotein, large polymerase
Newcastle Disease
- family, genus
- host
- 5 pathotypes
- paramyxoviridae, avulavirus
- chickens highly susceptible
- viscertropic velogenic
- neurotropic velogenic
- mesogenic
- lentogenic or respiratory
- asymptomatic
Newcastle Disease transmission
- direct contact with secretions (ingestion or inhalation)
- fomites
- chicks infected through egg
- survival in feces
Lentogenic strains of Newcastle disease
- types of disease caused
- signs
- subclinical disease
- mild respiratory symptoms
- coughing, gasping, sneezing, and rales
- mortality negligable
Mesogenic strains of Newcastle disease
- type of disease caused
- signs
- acute respiratory disease
- neurological signs
- mortality low
Velogenic strains of Newcastle disease
- type of disease caused
- signs/effects
- severe disease, high mortality
- greenish or white, watery diarrhea, dyspnea, inflammation of head/neck, cyanosis
- neurologic: tremors, wing/leg paresis, torticollis
- drop in egg production
- sudden death with little signs
Newcastle disease lesions
- not pathognomonic
- velogenic only
- swelling of periorbital area or entire head
- edema, hemorrhages, degeneration of ovaries
- ulcerations of resp/digestive lymphoid tissue
Prevention/Control of Newcastle disease
- live vaccines: Ientogenic, Mesogenic
- inactivated and recombinant vaccines
- no treatment
Nipah Virus
- family, genus
- hosts
- type of disease caused
- risk
- Paramyxoviridae, Henipavirus
- pigs and humans
- encephalitis in humans
- respiratory disease in pigs
- BSL 4 agent, bioterrorism
Nipah virus transmission
- flying foxes (fruit bats) are carriers
- virus found in urine and partially eaten fruit
- dogs and cats may transmit virus
- vertical transmission in pigs
Nipah virus clinical signs
Suckling piglets: high mortality
- labored breathing, muscle tremors
Young pigs: low mortality
- fever, labored breathing, nasal discharge, loud cough, neurological signs
Older pigs:
- neurological signs, respiratory signs, abortions
Diagnosis of Nipah virus
- virus isolation
- virus neutralization
- RT-PCR
- immunohistochemistry
Canine Distemper virus
- family, genus
- main reservoir in America
- transmission
- paramyxoviridae, morbilivirus
- raccoons with America-1
- shed in all secretions/excretions
- direct contact, droplets, aerosols
- unstable in environment
Canine Distemper clinical signs
- 50% are subclinical or mild: nasal discharge, coughing, labored breathing
- severe: fever, inflammation of upper resp tract, leukopenia, conjuncitivitis
- vomiting, diarrhea
- puppies: pneumonia, enteritis, conjunctivitis, rhinitis, tracheitis
- CNS signs, indicate poor prognosis
- hyperkeratosis of footpads and nose
Pathogenesis of Canine Distemper
- replicates in upper resp tract macrophages
- spreads to tonsils and lymph nodes
- infects all cells expressing CD150
- enters bloodstream and infects T and B cells
- infection of epithelial cells in lungs, bladder, and skin
Orthomyxoviridae
- what are the 5 genera?
- hosts of each
- Influenza A: humans, equine, swine, poultry
- Influenza B: humans
- Influenza C: human and swine
- Thogotovirus: tick-borne in livestock and humans
- Isavirus: infectious salmonid anemia
