SHORS - RABIES MOD13

1. Which test is used for rabies diagnosis in animals?

A) Plaque assay

B) Western blot

C) Direct fluorescent antibody

D) PCR

C — Direct fluorescent antibody

2. Which of the following is a characteristic of dumb rabies?

A) Hydrophobia

B) Hyperactivity

C) Seizures

D) Ascending paralysis

E) All of these are correct.

D — Ascending paralysis

3. In which country has human rabies not been observed?

A) Australia

B) United Kingdom

C) China

D) Mexico

A — Australia

4. How long does immunity from the human rabies vaccine last?

A) 15 years

B) 2 years

C) Lifetime

D) 5 years

B — 2 years

5. A rabies virus with a mutated, nonfunctional L protein would be unable to:

A) travel to the neuronal cell body.

B) attach to host cells.

C) uncoat.

D) polyadenylate viral mRNA.

D — polyadenylate viral mRNA.

6. The shape of rabies virus particles has been described as:

A) pleomorphic.

B) brick-shaped.

C) spherical.

D) bullet-shaped.

D — bullet-shaped.

7. Which of the following is not a characteristic of the rabies virus genome?

A) Nonsegmented

B) Positive sense

C) Single-stranded RNA

D) Negative sense

B — Positive sense

8. Which scientific theory did Pasteur disprove with his experiments involving goose-necked flasks?

A) Trephination

B) Panspermia hypothesis

C) Miasma theory of disease

D) Spontaneous generation

D — Spontaneous generation

9. Which of the following is not a characteristic of rabies virus entry?

A) Clathrin-coated pits

B) Endosomes

C) High pH

D) Attachment to nicotinic acetylcholine receptors

C — High pH

10. Why has the use of nerve tissue rabies vaccines been discontinued in most parts of the world?

A) Vaccine-induced immunity is short-lived.

B) Vaccines carry a high risk of neurological effects.

C) Vaccines can only be used in individuals aged 2 to 49 years.

D) Vaccines require multiple boosters.

B — Vaccines carry a high risk of neurological effects.

1. True or False? Most cases of human rabies in the United States are caused by dog bites.

TRUE

2. True or False? Postexposure vaccination is successful in preventing rabies because the virus travels slowly to the brain.

FALSE

3. True or False? No human has ever survived the symptomatic phase of rabies.

FALSE

4. True or False? Rabies virus uncoating takes place in the axons of neurons.

FALSE

5. True or False? Street (wild) strains of rabies virus differ in their tropisms and persistence.

TRUE

1. __________ is recommended for people traveling to medium- and high-risk areas who may come in contact with dogs and other animals that carry rabies.

Pre-exposure vaccination

2. The annual _____________ aims to raise awareness about rabies and seeks to promote rabies prevention and control efforts.

World Rabies Day

3. The majority of humans contracting rabies experience symptoms of __________ within the first 20 to 60 days of exposure.

encephalitis

4. Before the advent of antiviral drugs and vaccines, common practice was to _________ bite wounds caused by rabid animals in an attempt to prevent disease.

cauterize

5. Virologists use ___________ of virus cultured in the laboratory when studying rabies virus biology.

fixed strains

1. Explain the cellular location of rabies virus replication inside neurons.

The axon of neurons lacks the protein synthesis machinery needed for replication, transcription, and protein synthesis. As such, the virus must be transported from the axon to the cell body before it can uncoat and initiate its replication cycle.

2. Explain why rabies in the wild has been so difficult to control.

Rabies in the wild is difficult to control due to its long latent incubation periods, which means that animals may carry the virus without detection. Additionally, the disease causes behavioral changes in wildlife, making them aggressively attack humans and other animals, thus transmitting the virus. Lastly, it is improbable that all wildlife in the world could be successfully vaccinated against the virus.

3. Detail the process of diagnosing rabies in animals.

Animals that are behaving abnormally or exhibiting signs of disease are tested when a potential exposure to other animals or humans has occurred. The brain of the suspected animal is harvested and the direct fluorescent antibody test is performed on tissue collected from the brain stem, cerebellum, and hippocampus.

4. Identify the wildlife in the United States that is most commonly infected with rabies.

Raccoons, skunks, foxes, coyotes, and bats are the wild animals most commonly infected with rabies in the United States.

5. You and your friend are out hiking. A raccoon suddenly jumps out from the bushes, bites your friend on the arm, and then runs off. You quickly rush your friend to the emergency room for medical care. Detail the standard postexposure prophylactic (PEP) treatment your friend is likely to receive at the hospital.

Postexposure prophylactic (PEP) for rabies involves three steps. First, the bite wound is washed thoroughly with soap and water and then irrigated with a virucidal agent. Second, unvaccinated individuals bitten by an animal suspected of being rabid are injected with human rabies immunoglobulin. Lastly, the individual is given four doses of the human rabies vaccine.

6. List the clinical features of rabies in dogs.

Dogs suffering from rabies exhibit excessive salivation, excitability, increased aggressiveness, loss of fear of people, biting without provocation, biting of objects, and change in voice.

7. Explain why the ELISA test cannot be used to determine if an individual has been recently exposed to rabies.

The ELISA test cannot be used because antibodies are not produced during the incubation period of rabies virus infection. Virus-specific IgM antibodies are only detectable after the onset of clinical symptoms and after the virus is widely disseminated throughout the CNS.

8. Contrast the formulations of the human and wildlife rabies vaccines.

The wildlife vaccine against rabies is an oral recombinant virus vaccine. This vaccine consists of a vaccinia virus engineered to express the rabies virus glycoprotein, and it is administered in the wild as edible baits. Conversely, the human rabies vaccine consists of inactivated virus grown in cell culture. The human vaccine is administered intramuscularly and is given over four doses.

1. Animal bite

Step 1

2. Replication in muscle

Step 2

3. Entry into neurons

Step 3

4. Crossing synapses into spinal ganglia

Step 4

5. Movement into the brain stem, medulla, and hippocampus

Step 5

6. Dissemination through peripheral nerves

Step 6

7. Replication in organs and salivary glands

Step 7

8. N - Rabies virus gene with the protein it encodes

Nucleocapsid protein

9. P - Rabies virus gene with the protein it encodes

Phosphoprotein

10. M - Rabies virus gene with the protein it encodes

Matrix protein

11. G - Rabies virus gene with the protein it encodes

Surface glycoprotein

12. L - Rabies virus gene with the protein it encodes

RNA-dependent RNA polymerase