RNA Viruses 1: Paramyxoviridae, Rhabdoviridae Flashcards
Do DNA or RNA viruses have a greater replication rate?
RNA
-Higher chance for mutation
+ Sense meaning
the SSRNA can connect to the ribosome and replicate on its own
- sense meaning
the SSRNA must use RNA dependent RNA polymerase to replicate using the host cells ribosome
2 main Mononegvirales virus families
Paramyxoviridae
Rhabdoviridae
Characteristics of Mononegvirales
- Enveloped
-Single genome (NegSense)
-Must use RNA dependent RNA pol
Paramyxoviridae: envelopes or non-enveloped?
- Enveloped
Size of paramyxo
- Diameter 150-300 nm
Symmetry of paramyxo
- Symmetry: helical
Does paramyxo use transcriptase?
- Transcriptase: positive
Paramyxo genome
- SSRNA (NegSense)
How paramyxo transmission occur?
-Transmission by aerosol or close contact
How does paramyxo release from cell?
- Release by budding
Special proteins released by paramyxo forms what type of cells in the host?
- Produces fusing protein leading to syncytia
Capacity of paramyxo host range?
- Narrow host range
Rinderpest viruses causes what?
Lesions on the mouth/nose?
How common is the rinderpest virus?
COMPLETELY ERADICATED
How did eradication of the rinderpest virus happen?
- Efficacious vaccine
- Reliable diagnostic testing
- Absences of carrier animals and wildlife resviors
What is the Morbilli Virus
- In the paramyxoviridae family
- Canine distemper
- Highly infectious
What is the rinderpest virus?
In the paramyxoviridae family
-RNA virus
Can the Morbilli virus infect other species? Is it zoonotic?
Yes it can affect other species but no it is not zoonotic
What human virus is the morbilli virus related to?
Measles
Where does the morbilli virus create inclusion bodies?
- Intranuclear AND intracytoplasmic
**Differential of canine distemper virus
What cell types does Morbilli infect?
Epithelium
Lymphoid
oligodendrocytes (Neurological)
What body parts does Morbilli affect?
Skin, respiratory, GIT, Urinary tract, brain
When does infection occur? How long is immunity?
3-6 months once mothers antibodies decline
- VERY immunogenic: long lasting immune response
Acute clinical signs of Morbilli virus
- Subclinical, followed by lifelong immunity
- Mild cough
Severe generalized clinical signs of Morbilli signs
Leukopenia
V, d
Conjunctivitis
nasal discharge
Hardening of nose and footpads
Old dog encephalitis
Enamel hypoplasia
Perivascular cuffing
What is old dog encephalitis? How does it occur?
- Severe neurological disease (chatter)
Occurs years after recovery and results in neurologic deterioration and death.
What is enamel hypoplasia?
Failure to development enamel
What is perivascular cuffing?
Inflammatory cells around blood vessel.
- leads to leakage of fluid from blood vessels into CSF causing neurological damage
Bovine respiratory disease complex types (4)
IBR, BVD, PI3, RSV
What does BVRC do?
damages cells of respiratory tract. Early development can lead to compromise of host cells allowing for secondary infection
PI3- bovine parainfluenza virus 3: clinical signs and immunity length
Subclinical (no signs)
- Vaccines available but immunity is short-lived
BRSV- bovine respiratory syncytial virus. Clinical signs and immunity?
Moderate to severe disease affecting beef and dairy cattle -
- Pneumovirus
- Infection is immunosuppressant
- Adults-atypical interstitial pneumonia
- Vaccines but immunity is short-lived
BRSV- bovine respiratory syncytial virus. Replication site and effects on cells?
-Replicates in the ciliated cells of the respiratory tract
- Induces synticia and intracytoplasmic inclusion bodies
Rhabdoviridae characteristics
Diameter: 180 x 75 nm
Enveloped
Symmetry: helical
Transcriptase: postive
Genomes: ss(-)
Types of Rhabdoviridaes
Rabies lyssavirus
Vesicular stomatitis
-Indiana
-New Jersey
Who does Rabies Lyssavirus infect?
All mammals- ZOONOTIC disease
Where is Rabies Lyssavirus not endemic?
Australia and antartica
If concern of Rabies Lyssavirus why must we submit a sample of brain tissue?
There is no reliable diagnostic test premortem
- Must check neurologic tissue for Negri Bodies
What are negri bodies?
Eosinphilli intracytoplasmic inclusions present in the nervous tissue
Carriers/transmitters of Rabies Lyssavirus in the US
-Skunk
-Racoon
-Fox
Where does Rabies Lyssavirus infection begin? And what does replication look like there?
Peripheral nerve endings.
- Very limited replication
How is Rabies Lyssavirus transported to the CNS?
By retrograde axoplasmic flow
-Movement from axon back up to cell body
This can lead to infection of non-nervous tissue too (i.e Salivary glands)
What is the incubation pertion period and clinical course of Rabies Lyssavirus?
Incubation period: 6 months
Clinical course: few days to weeks
Vaccines for dogs/cats, wildlife?
Dogs/cats: only need one vaccine and very effective
Wildlife: Rabies vaccine bait
What part of the body does vesicular stomatitis?
Mucosal epithelium
What virus produces Bovine papular stomatitis?
Parapox Virus
What virus produces vesicular stomatitis?
Rhabdoviridae- vesicular stomatitis virus
What virus produces malignant catarrhal fever?
Gamma herpes virus
What virus produces rinderpest?
Paramyxovirus
Species affected by the vesicular stomatitis?
Rhabdovirus: Pigs, sheep, cattle, horse
Species affected by foot and mouth disease?
Picornavirus: pigs, sheep, cattle
NOT HORSE
Eradicated in the US
Species affected by swine vesicular disease?
Picornavirus: pigs
Who does Vesicular Stomatitis virus infect?
All mammals- ZOONOTIC
- Resembles the Flu in humans
Is Vesicular Stomatitis virus a reportable disease?
YES because it looks like foot and mouth disease which is a foreign animal disease since it is eradicated in the US
How is Vesicular Stomatitis virus transmitted?
- By vector: sand flies, midges, black flies
- Direct contact
Where is Vesicular Stomatitis virus considered to be endemic?
Central America
South America
United States
Common rate of diseased animals in the infected population
~15%
