Finals: Paramyxoviridae Flashcards
Some of the most devastating diseases of animals, birds, and humans are caused by Paramyxoviruses. What are some of these diseases?
Rinderpest Canine distemper virus Newcastle disease virus Nipah Measles Mumps
Fortunately, vaccines have helped reduce the impact of these viruses
Of concern are paramyxoviruses in the _______ genus whose natural host is the _____ bat but are highly infectious for swine and humans.
Henipavirus
Fruit
What are the 2 subfamilies of Paramyxoviridae and their genera?
Paramyxovirinae: Respirovirus, Avulavirus, Henipavirus
Rubulavirus
Morbilivirus
Pneumovirinae: Pneumovirus and Metapneumovirus
Bovine parainfluenza virus 3 affects what species and what diseases does it cause?
Cattle, sheep,other mammals
Respiratory diseases in cattle and sheep
Avian paramyxovirus 1 (Newcastle Disease virus-virulent isolates) infects what animals and causes what disease signs?
Domestic and wild fowl
Severe generalized disease with CNS signs
Canine distemper virus infects what animals and causes what disease signs?
Dogs and members of the families Procyonidae, Mustelidae, Felidae
Severe generalized disease with CNS signs
Nipah virus infects what species and causes what disease signs?
Swine and humans
Acute respiratory distress syndrome in swine and humans
Bovine respiratory syncytial virus infects what species and causes what disease?
Cattle, sheep, goats
Respiratory disease
Turkey rhinotracheitis virus infects who and what does it cause?
Turkeys, chickens
Severe respiratory disease in turkeys, swollen head syndrome of chickens
There are several members of Paramyxoviridae that are still waiting classification to existing genera. What are they?
Paramyxvovirus of reptiles
Salem virus of equine
Viruses of peguins
Atlantic Salmon paramyxoviruses
Tell me about paramyxovirus characteristics
Pleomorphic - spherical or filamentous
Genome consists of linear, ss, - sense RNA
What are the important genera of paramyxoviridae and what are the number of genes in those groups? Where are the gene products found?
Respirovirus, Avulavirus, Henipavirus and Morbilivirus - 6 genes
Rubulaviruses - 7 genes
Pneumovirus - 10 genes
Metapneumoviruses - 8 genes
Paramyxovirinae - 9-12 genes
Pneumovirinae - 8-10 proteins
Most of the gene products are found within the lipid envelope or complexed with the virion RNA
What is the virion structure of paramyxoviruses?
Lipid bilayer
3 membrane proteins: maxtrix, fusion and hemagglutinin
3 nucleocapsid proteins (RiboNucleoProteins): RNA-binding protein, phosphoprotein, large polymerase
Hemagglutinin-neuraminidase or glycoproteins are attachment proteins
Non-structural proteins- C, NS1, and NS2, protein V (cystein rich), small integral membrane, transcription factors M2-1 and M2-2
Enveloped spikes are composed of 2 glycoproteins F and G or F and HN or F and H
The spike glycoproteins of paramyxovirus play an important role in what?
Pathogenesis
The antibodies directed against these proteins that help with attachment and fusion of paramyxovirus are usually what?
Neutralizing antibodies - important in protection against paramyxovirus infection
Where does replication of paramyxoviruses occur?
In the cytoplasm of infected cells.
Can also take place in the presence of actinomycin D or enucleated cells - no nuclear function required
T/F: HN, H or G bind to compatible ligand on target cells.
True
For Rubulaviruses, Respiroviruses and Avulaviruses the HN molecule binds to what?
Sialic acid residues - either glycolipids or glycoproteins
Morbilivirus, the receptor is located on lymphocytes dendritic cells or macrophages - what is the receptor?
CD150
For Henipaviruses, the receptor is ephrin B2 and B3 cell surface proteins on what types of cells?
Endothelial cells
Brain stem neurons
For Pneumoviruses, the receptor is?
Heparin sulfate
The F protein of paramyxovirus mediates what?
Fusion of the viral envelope lipid membrane with the target cell membrane
The nucleocapsid on the paramyxovirus is released into where?
The cytoplasm and the RNA remains associated with the N, L, and P proteins
The RNA-dependent RNA polymerase complex initiates what?
RNA synthesis at the single site on the 3’ end of the genomic RNA
Replication of paramyxoviruses leads to lysis of infected cells or formation of?
Syncytia
Paramyxoviruses produce?
Cytoplasmic acidophilic inclusion bodies, composed to ribonucleoprotein structures
Morbiliviruses produce what and what is it composed of?
Acidophilic intranuclear inclusion bodies composed of nuclear elements and protein N
Hemoadsorption is a distinctive feature of what?
Paramyxoviruses
Express the H or the HN protein
Newcastle disease is caused by what virus? Who are the family and genus of that virus?
Newcastle disease virus
Paramyxoviridae
Avulavirus
How many serotypes are there of avian paramyxovirus?
10
Designated APMV-1 to APMV-10 and NDV is dedicated as APMV-1
How many pathogens are there based on the clinical signs of APMV-1 infected chickens and what are they?
5 Viscerotropic velogenic Neurotropic velogenic Mesogenic Lentogenic or respiratory Asymptomatic
T/F: Chickens are highly resistant to AMPV-1 disease
False, susceptible
Turkeys do not develop severe signs
Wild birds and waterfowl may harbor virus subclincially
Disease has been recorded in ostriches and penguins
T/F: the morbidity and mortality rates remain constant among species of Newcastle disease?
False, vary among species and vary within the strain of virus
Can humans become infected with Newcastle disease?
Yes
Manifested by unilateral or bilateral reddening, excessive lacrimation, edema of the eyelid, conjunctivitis and sub-conjunctival hemorrhage
How is Newcastle Disease transmitted?
Direct contact - ingestion or inhalation
Fomites
Hatching chicks through egg
Incubation period is 2-15 days with average 5-6
What is the occurrence of Newcastle disease?
Velogenic NDV is endemic in areas of Mexico, Central and South America, widely spread in Asia, the Middle East and Africa, and in double-crested wild cormorants in the US and Canada.
Lentogenic strains of NDV are ________ in their distribution
Worldwide
How do we diagnose NDV?
Clinical signs vary and are dependent on factors such as: virus/pathotype, host species, age of host, co-infection with other organisms, environmental stress, immune status.
Clinical signs alone do not present a reliable basis for diagnosis of ND
Lentogenic strains of NDV are usually associated with what type of disease? And what are the clinical signs of this strain?
Subclinical disease
Mild respiratory symptoms, coughing, gasping, sneezing and rales
If other co-infectious agents are circulating, can result in severe signs
Mortality is negligible
Mesogenic strains of NDV cause what type of disease? Is mortality high or low?
Acute respiratory disease with neurologic signs in some species. Mortality is low.
If there is co-infection with other agents, the disease can result in severe signs
Velogenic strains of NDV cause what type of disease in chicken? Is mortality high or low? What are the clinical signs?
Severe disease with high mortality.
Signs are mainly respiratory or nervous
Initial clinical signs: lethargy, inappetence, ruffled feathers, edema.
Later: greenish or white watery diarrhea, dyspnea, inflammation of the head and neck with cyanotic discoloration.
Neurologic signs may be tremors, tonic/clinic spasms, wing/leg paresis, torticollis, and aberrant circling behavior
Will you see a drop in egg production with the velogenic strain of ND?
Yes
Eggs contain a watery albumin and abnormally colored, rough or thin shells
Velogenic strains result in what? Will you see clinical signs?
Sudden death with few or no signs
Morbidity and mortality rates may approach ____ in unvaccinated chickens?
100%f
What are the lesions seen with NDV?
No pathognomonic gross lesions.
Final diagnosis must await virus isolation and ID
Only velogenic strains produce significant gross lesions:
Swelling of eyes or entire head
Edema, hemorrhage or degeneration of ovaries
Ulcerations of respiratory/digestive lymphoid tissue
(Edematous comb containing foci of hemorrhage, conjunctival hemorrhage is most severe in nictitans, tracheal and laryngeal mucosa hemorrhage, cecal tonsil necrosis
What are the lab diagnosis that can be done?
Samples collected from recently dead or moribund bird
Samples should be sent to reference lab
Dead birds: Oro-nasal swabs, lung, kidneys, intestine, cecal tonsils, spleen, brain, liver and heart tissues, separately or as a pool
Live birds: tracheal or oropharyngeal and cloacal swabs
Clotted blood or serum for serology
Inoculation of embryonated specific pathogen free eggs and tested for hemagglutination activity
ELIDA
Validated specific molecular methods (PCR)
DDx for NDV?
Fowl cholera Highly pathogenic avian influenza Laryngotracheitis Fowl pox Psittacosis Mycoplasmosis Infectious bronchitis Aspergillosis
How do we prevent and control NDV with medical prophylaxis?
Vaccination with live vaccines. 2 groups of conventional live virus vaccines: lentogenic vaccines and mesogenic vaccines.
Live virus vaccines administered by incorporation in drinking water, as a coarse spray (aerosol) or intranasal or conjunctival instillation
How do we prevent and control NDV with sanitary prophylaxis?
No treatment
Bird-proofing houses, feed and water
Proper carcass disposal
Pest control in flocks
Avoid contact with birds unknown health status
Control human and vehicular traffic
One age group per farm (all in all out) breeding is recommended
Tell me about the nipah virus
Sungai Nipah village
An emerging zoonosis that causes severe disease in both animals and humans
Causes encephalitis and respiratory illness
The Nipah virus belongs to what genus? Was discovered when? What is seen with the virus, signs,and mortality rate?
Genus Henipavirus, discovered 1999
Severe, rapidly progressive encephalitis in humans. Highly mortality rate. Transmitted by close contact.
Severe, respiratory disease in pigs
Who are the reservoir species for Nipah?
Flying foxes (fruit bats) - carry the virus but aren't affected. Virus is found in the urine and in partially eaten fruit (saliva).
No known secondary host. Virus that infects man comes from another animal.
Dogs and cats can be infected
Vertical transmission
I activated at 60C for 60 minutes
Susceptible to common soaps and disinfectants
Survives for days in fruit bat urine and contaminated fruit juice
How do we diagnose Nipah?
Incubation period in pigs is approximately 7-14 days
Experimentally in cats, 6-8 days
Average incubation is 4-20 days
What are the clinical signs of Nipah in pigs?
Sucking piglets (<1 mo): labored breathing and muscle tremors with limb weakness, mortality in piglets can be high (40%) Young swine (>1-6 mo): acute fever, labored breathing, nasal discharge and loud non-productive cough (barking pig or one-mile cough), neurologic signs, mild to fulminant disease with high morbidity and low mortality Older animals (>6 mo): marked neurologic signs, respiratory signs: open-mouthed breathing, nasal discharge, and sialarrhea Morbidity up to 100%, abortions
What BSL is Nipah?
4
