Rhabdoviridae Flashcards
(40 cards)
T or F: Viruses of the family Rhabdoviridae are non-enveloped, have a nucleocapsid of helical symmetry in a cylindrical shape.
F. They are ENVELOPED!
Match the following Rhabdovirus proteins with their functions: A. Large (L) protein B. Nucleoprotein (N) C. Phosphoprotein (P) D. Matrix (M) protein E. Glycoprotein (G) 1. Mediates attachment of L protein to nucleocapsid 2. Attachment of nucleocapsid and viral envelope 3. RNA-dependent RNA polymerase (transcriptase) 4. Forms envelope spikes 5. Associates with RNA to form the nucleocapsid
A. 3 B 5 C. 1 D. 2 E. 4
Which of the following is NOT TRUE of Rhabdoviruses? A. One molecule of single-stranded, negative-sense RNA B. Replicate in the cytoplasm C. Maturation is through budding through the ER membrane D. Some viruses in this family are rapidly cytopathic, whereas others are non-cytopathic.
C These virions bud through the PLASMA MEMBRANE!!!
T or F: Although genus Lyssavirus of family Rhabdoviridae contains 11 genotypes, there is only one genotype that is referred to as Rabies Virus, genotype 1.
True
Which of the following countries is NOT on the list of NO-RISK countries for Rabies virus? A. St. Kitts B. Japan C. Singapore D. Antarctica E. New Zealand F. Finland
F. Finland St. Kitts is a NO-RISK country (along w/ several Caribbean islands)! Wow, so St. Kitts actually got something right? Or could it be because they are too lazy to test animals for Rabies and they want to collect the funds from the quarantines and import fees? You decide.
Which of the following animals are HIGHLY susceptible to Rabies?
A. Cats
B. Cattle
C. Dogs
D. Humans
E. A and B only
A and B only
Cats and cattle- the C’s CATCH rabies easily!
The following animals are MODERATELY susceptible to Rabies, EXCEPT:
A. Primates (incl humans)
B. Dogs
C. Horses
D. Goats/sheep
E. Cattle
E. Cattle
Remember, cattle are HIGHLY susceptible to rabies
T or F:
Aerosol transmission and transmission via organ transplant has been reported for Rabies virus.
True! Scary!
Bat caves, laboratories
Wear a mask!
For organ transplants, its mostly corneas but could be visceral organs
T or F:
In the urban rabies cycle, the dog is the main reservoir host, and this cycle is predominant in North America and Europe.
False!
It is true that the dog is the reservoir host in the urban cycle, but this cycle predominates in Asia, Africa, and areas of Central and South America.
***Remember, in India and Africa and areas like that people don’t spay or neuter their dogs or vaccinate them and let them run free, so its intuitive that dogs will be transmitting a lot of Rabies to people!
The sylvatic cycle of Rabies transmission is associated with:
A. Predominance in Europe and N. America
B. Up to 3 wildlife species often perpetuating the given strain
C. Can often occur simultaneously with the urban cycle
D. Also known as the wildlife cycle
E. A, B, and C only
F. All of the above
T or F:
Dead-end hosts for Rabies virus include humans, dogs, cattle, goats and other moderately susceptible animals
False!
Humans and Herbivores (most of the moderately susceptible, but susceptibility doesn’t seem to correlate with whether they’re a dead end host)!!!
Dogs are NOT dead-end hosts!!!!
An increasingly important reservoir responsible for human cases of Rabies in North America has been:
A. Vampire bats
B. Insectivorous bats, such as the Silver Haired Bat
C. Raccoons
D. Opossoms
B. Insectivorous bats
T or F:
Vampire bats are associated with a significant proportion of cattle rabies in North, Central and South America, and can also cause human cases.
False
Everything is true except NOT in N. America
Insectivorous bats= North America (except Mexico)
Vampire Bats=Central and South America, and Mexico!!!
T or F:
Fruit bats, one species being the Flying Fox, have been implicated in Rabies cases in Australia.
True!
Which of the following is an IMPORTANT reservoir for wildlife and cattle rabies cases in the Central U.S.?
A. Raccoons
B. Skunks
C. Insectivorous bats
D. Red fox
E. All of the above
B Skunks
Skunks are the major reservoir for the CENTRAL U.S. Although raccoons have been and still are the overall most frequently reported wildlife rabies reservoir, skunks are associated specifically with cases in the Central U.S. and specifially in cattle.
T or F:
Transmission of Rabies virus to humans from rabid cats who themselves became infected by raccoons is a major public health concern in the U.S.
The following are true of Rabiesvirus pathogenesis EXCEPT:
A. Virus enters through myocytes, and then either replicates there until a sufficient concentration of virus is present or directly enters peripheral nerves.
B. Virus glycoprotein adheres to the terminal of the host cell by binding to a lipoprotein receptor, including those for acetylcholine.
C. The greater degree of innervation of the area of the bite, the shorter the incubation period.
D. The closer to the brain the bite is (i.e. to the face), the shorter the incubation period.
E. All of the above are true.
T or F:
The second stage of Rabies virus begins when the virus reaches the CNS by travelling in a retrograde fashion up the axoplasm of central and peripheral nerves.
True.
He may also use the word centripetal to mean upward
If he uses the word centriFUGAL, that would mean outward from the CNS to the peripheral nerves and that would be false! (Don’t think he would do that but ya never know)
Choose the INCORRECT statement about Rabies pathogenesis:
A. Virus replication in the limbic system results in the “furious” form, the classically known signs of Rabies
B. Replication in the brain cortex, usually after the furious form, results in the “dumb” paralytic signs of rabies.
C. Late in infection, virus moves centripetally via peripheral nerves toward many organs in the body.
D. Late in infection, virus moves into the salivary glands via the cranial nerves, where it extensively replicates to reach very high concentrations.
T or F:
The brains of animals with Rabies may display some inflammation, but there are no characteristic gross findings for the Rabies animal. There are only modest histological findings, suggesting the primary neuronal lesion is functional rather than structural.
True
Choose the INCORRECT statement about Rabies:
A. The fact that the virus is non-cytopathic, along with neuronal cells being unable to express MHC I, causes little antigen to be released, limiting host immune response to the virus.
B. Antibodies appear in serum early in infection, and CSF later in infection.
C. Animals are non-contagious during the prodromal period.
D. Ptyalism can be present in both the furious and paralytic stages.
The following statements are true regarding the dumb stage of rabies, EXCEPT:
A. Ataxia, muscle weakness and loss of sensation will be seen relatively early in the dumb stage
B. Later in the dumb stage, you will see seizures, respiratory arrest and coma
C. Death usually occurs 2-14 days after onset of INITIAL clinical signs
D. A higher proportion of dogs, cats and horses exhibit the dumb form than cattle and other ruminants
D.
A higher proportion of dogs, cats and horses exhibit the FURIOUS form than cattle and other ruminants
Which of the following is considered the most sensitive and reliable test for rabies, and thus is recommended by WHO and OIE?
A. Demonstration of Negri bodies in brain tissue
B. Intracerebral innoculation of weanling mice
C. RT PCR
D. Direct FAT of brain tissue impression smears.
D. Direct FAT
All of these are diagnostic methods, but Negri bodies only show up in about 75% of human cases and less for wildlife; intracerebral innoculation will be positive if weanling mice develop encephalitis within 14 days.
A dog comes into your clinic who has just been in a fight with a raccoon. The dog has never been vaccinated for Rabies. What do you do?
A. Euthanize the dog immediately.
B. Place the dog in secure quarantine for 6 months; vaccinate dog 1 month before release .
C. Just give him a rabies vaccination and send him home
D. Either A or B would be considered appropriate.
D. Either euthanize or secure quarantine for 6 months.
Should depend on quarantine options, owner finances and compliance of the owner; the raccoon might not have even had rabies but you should err on the side of caution.
