Paramyxoviridae Flashcards
Paramyxoviridae viruses have ____ stranded, _____ sense RNA
Single stranded (linear) Negative sense
What is unique about the shape of the nucleocapsid of paramyxoviruses?
“herring bone” shaped
What paramyxovirus has been completely eradicated?
Rinderpest
T/F: paramyxoviruses have an envelope
TRUE
Envelope with glycoprotein spikes
What shape are paramyxoviruses?
PLEOMORPHIC - spherical or filamentous
What are the 3 major membrane proteins within the envelope of paramyxoviruses?
MATRIX (M)
- *FUSION (F) - mediates fusion of the viral envelope with the host cell membrane
- HEMAGGLUTININ (H)
What are the 3 major nucleocapsid proteins (Ribonucleo proteins) of paramyxoviruses?
RNA Binding Protein (N)
Phosphoprotein (P)
Large Poymerase (L)
What are the attachment proteins of paramyxoviruses?
Hemagglutinin neurominidase (HN) and glycoprotein (G)
What are the combinations of proteins to makes the glycoprotein envelope spikes in paramyxoviruses?
F and G (fusion and glycoprotein)
F and HN (fusion and hemagglutinin neurominidase)
F and H (fusion and hemagglutinin)
T/F: the host cells will produce antibodies to neutralize the envelope glycoproteins.
TRUE
antibodies directs against these proteins are most commonly neutralizing - important protection mechanism against paramycoviruses
Where do paramyxoviruses replicate in the host cell?
Cytoplasm
What receptor do morbilliviruses used to invade host cells?
CD150
How do Rubula, Respro, and Avulaviruses invade host cells?
HN molecules bind to sialic acid residues (glycolipids/glycoproteins)
What cell surface receptors do Henipaviruses use to invade host cells? What role does this have in their pathogenesis?
Use ephrin B2 and ephrine B3 receptors
These are located on the cell surface of endothelial cells and on brain stem neurons (viruses tend to be fatal if they enter the brain stem)
What receptor do Pneumoviruses use to invade host cells?
Heparan sulfate
What is the order of paramyxovirus replication inside the host cell?
(Negative sense) RNA –> mRNA –> RNA –> viral proteins
What cellular effect do paramyxoviruses have on host cells?
Lysis or syncytia (joining together to create lg cells)
Replication will leave acidophilic cytoplasmic inclusion bodies and/or acidophilic intranuclear inclusion bodies (even though replication is in cytoplasm only)
What disease does Avian paramyxovirus-1 cause?
New Castle Disease - Chickens
To which genus does New Castle Disease belong?
Avulavirus
What are the 5 pathotypes of Avian paramyxovirus-1?
- Viscerotropic velogenic (most pathogenic)
- Neurotropic velogenic
- Mesogenic
- Lentogenic or Respiratory
- Asymptomatic
T/F: paramyxoviruses cause hemoadsorption of infected cells
TRUE
Agglutination of RBCs around infected cells - can be used as a dx test on the farm
T/F: New castle disease is common in North America
FALSE
good vax protocol has significantly decreased the prevalence of this dx in North America
T/F: New castle disease is not a zoonotic pathogen
FALSE
this is zoonotic - vets and farmers are most as risk
What are the modes of transmission of Avian paramyxovirus-1?
*secreted through feces
Direct contact - fomites
Infection through egg
T/F: Lentogenic strains of new castle dz are common.
TRUE - these are found all over
*subclinical - mild respiratory signs - low mortality
T/F: Mesogenic strains of New Castle dz have a high mortality rate
FALSE
Mortality less than 10%
acute respiratory dz - neuro signs
What are clinical signs of Velogenic Avian Paramyxoviruse-1?
HIGH MORTALITY - up to 100%
Resp. signs, CNS - torticollis/tremors, lethargy, anorexia, green/white dhr, peri-tracheal edema, cecal and tonsil necrosis, decrease in egg production
**birds that survive may never lay eggs again
What is an easy dx test that can performed on the farm if you suspect New Castle Dz?
haemagglutination test
What dx tests should be performed to confirm the dx of New Castle dz?
**isolating the virus is gold standard dx: this method uses SPF (specific pathogen free eggs) to culture virus
Other methods: ELISA and Rt-PCR
T/F: the best samples for testing for avian paramyxovirus-1 are collected at necropsy.
FALSE
It is best to get samples from live, sick chickens (that are close to death) - blood, tracheal, oropharyngeal swabs
What strains of avian paramyxovirus-1 are used to make the live vaccine for new castle disease?
What are the modes of administration for this vaccine?
Lentogenic and mesogenic
admin via aerosol spray, in drinking water, intranasal, conjunctival instillation
**this is ideal for commercial farms
T/F: The inactivated vaccine for Avian paramyxovirus is more cost effective for commercial farmers
FALSE
This vaccine is expense and must be injected into each bird - not ideal for commercial farming
What is the best form of treatment for New Castle Disease?
jk jk jk jk jk… CULL THEM ALL :(
make sure no wild birds or pests can get into chicken houses, practice “all in-all out” methods
T/F: The Nipah virus is a new emerging virus of high zoonotic concern
TRUE
This virus is considered a Biological weapon by the CDC
ZOONOTIC
BSL4
Who is the reservoir for Nipah virus?
Flying foxes aka fruit bats
To what genus does the Nipah virus belong?
Henipavirus
From which animal does the Nipah virus spread to humans?
PIGS
The virus starts in bats –> infects pigs –> pigs will infect humans, dogs, cats, horses, etc via DIRECT CONTACT
What are the dz names used for the Nipah virus?
Barking pig syndrome
Porcine respiratory and encephalitis syndrome
Porcine respiratory and neurologic syyndrome
T/F: The nipah virus can not survive long in bat urine or fruit juice
FALSE
It can survive for days in bat urine and fruit juice (suspected to be MOT to pigs - not confirmed yet)
What clinical signs do you see in piglets less than a month of age, infected with nipah virus?
Labored breathing - muscle tremors
Mortality = 40%
What clinical signs do you see in piglets between 1 - 6 months of age, infected with nipah virus?
Acute fever with respiratory signs, difficulty breathing, nasal discharge, ***loud non-productive cough
Neuro signs - muscular fasciculation, myoclonus, limb weakness and partial paresis
HIGH morbidity, LOW mortality
What clinical signs do you see in pigs over 6 months old, infected with nipah virus?
100% Morbidity
Acute fever, resp. distress, nasal discharge –> secondary infections
***Neuro signs - muscular fasciculation, myoclonus, limb weakness and paresis
Sows in first trimester = abortions
What dx test is required if you suspect Nipah virus?
Must ISOLATE VIRUS (2 cell lines are used: Vero, RK-13)
other dx: virus neutralization (plaque reduction), real time PCR, Immunohistochemistry
T/F: Pigs infected with Nipah virus must be culled
TRUE
cull and burn the carcasses
To which genus does canine distemper virus belong?
Morbilivirus
T/F: Canine distemper can infection wild cats
TRUE
but it DOES NOT infect domestic cat species
***canine and feline distemper DO NOT have the same epidemiology
What strain of Canine Distemper is present in the US? Who are the reservoirs?
American-1
Circulating in raccoons
T/F: America, Asia, Europe, and the Artic all have unique strains of canine distemper
TRUE
T/F: Vomiting and Diarrhea is not a clinical sign of canine distemper virus
FALSE
This can be noted in severe infections - perfuse watery dhr and vomiting
What kind of prognosis does a dog with neurological signs from distemper virus have?
POOR
What other clinical signs are usually associated with CNS signs in dogs infected with canine distemper?
Hyperkeratosis of paw pads and nose (due to the virus replication in those tissues)
CNS signs include - seizures and para/tetra-paresis
What secretions/excretions is the canine distemper virus shed in?
ALL OF THEM —- EVERYTHING
What are common clinical signs noted in patients with canine distemper virus?
Respiratory signs - Bilateral nasal discharge - starts serous –> mucopurulent (usually due to secondary infections), decreased appetite, FEVER, coughing, depression, conjunctivitis, leukopenia
Who is the most susceptible to the canine distemper virus?
puppies 4-6 months old
Where does canine distemper virus replicate?
What cells does it infect
First in the upper respiratory macrophages –> spreads to tonsils and LN –> viremia – can attack T and B cells and begin replicating in the epithelial cells of the lungs, bladder, and skin
***Distemper infects ALL CELLS expressing CD150
What is the fastest Dx test for canine distemper?
Real time PCR
Other tests - virus isolation (via lymphocytes - CD150) and immunofluorescence
T/F: if a dog recovers from a distemper infection, it will have temporary immunity from the virus.
FALSE - life long immunity
How do you treat canine distemper?
Symptomatically - quarantine
No anti-viral tx available
What type of vaccine is used for canine distemper?
MODIFIED LIVE
What can be given to a patient ASAP if they have come in contact with a distemper positive animal?
Hyper-immune serum
T/F: Paramyxoviruses can replicate in enucleated cells
TRUE
