Virology Prufung 4

Question 1

What is genetic variation in Paramyxoviruses limited by?

Answer 1

The RNA genome being in one piece - being antigenically stable. Contrast with Orthomyxovirus (experiences antigenic shift via genetic reassortment)

Question 2

This is the complete replacement of 1 or more of the RNA genome segments with a completely new RNA segment (from another Influenza A virus) when the same cell is infected 2 different influenza A viruses.

Answer 2

Genetic reassortment of influenza A virus

Question 3

Do influenza (orthomyxovirus) and parainfluenza (paramyxovirus) viruses cause local or non-local infection?

• Systemic or non-systemic?
• Viremic or non-viremic?

Answer 3

Local
Non-systemic
Nonviremic

Question 4

Do mumps/measles (Paramyxoviruses) cause infections that are:

• systemic or non-systemic
• viremic or non-viremic

Answer 4

systemic, viremic

Question 5

Is the incubation pd shorter or longer for mumps and measles? Why?

Answer 5

Longer b/c more cycles of multiplication in several sites in succession are required.

Question 6

Do mumps and measles cause life-long or short-lived immunity, why?

Answer 6

Lifelong immunity in those who have had the disease. they produce obligatory viremia, which allows neutralization by IgG.

Question 7

Mumps is caused by _____ virus that is antigenically related to the ______.

Answer 7

Paramyxovirus

Parainfluenza viruses

Question 8

How many serotypes are there of mumps virus?

Answer 8

1

Question 9

Who (animals, humans) are the reservoir(s) of mumps?

Answer 9

HUMANS

Question 10

How is mumps transmitted and what is the incubation pd?

Answer 10

Respiratory droplets, average incubation 18-21 days.

Question 11

What is the usual key symptom of mumps?

Answer 11

PAROTIDITIS –> mumps virus grows in the swelled, enlarged painful parotid salivary glands. Becomes excreted in saliva before/after swelling begins.
- Swelling of things in tight capsules (orchitis)

Question 12

After the incubation pd, what first develops in mumps?

Answer 12

Prodromal period with fever, malaise, anorexia, quickly followed by unilateral/bilateral swelling of the parotid gland.

Question 13

Is there antiviral therapy for mumps?

Answer 13

No.

Question 14

What organs are affected by mumps?

Answer 14

MENINGES (aseptic meningitis)
Pancreas
Ovary

Question 15

What type of vaccine is available?

Answer 15

Live attenuated - is a part of the MMR vaccine, is given 2x to confer protection w/o serious side effects.

Question 16

measles is caused by what type of virus?

Answer 16

paramyxovirus, antigenically UNRELATED to any other paramyxoviruses

Question 17

What is the most contagious disease known?

Answer 17

Measles.

Question 18

Does measles cause subclinical infections?

Answer 18

no

Question 19

When do most local epidemics of measles take place (BEFORE the vaccine era)?

Answer 19

every 3 years, in winter.

Question 20

How is measles transmitted?

Answer 20

Respiratory droplets, infects via respiratory tract; multiplies in epithelium and local lymph nodes and conjunctiva.

Question 21

can there be asymptomatic infections in measles?

Answer 21

rarely.

Question 22

What is the Sx-ology like?

Answer 22

• Before the rash, PRODORMAL SX appear (nonspecific Sx that appear before the definitive Sx): fever, cold-like Sx, runny nose, red eyes
• Before hte definitive sx of the measles rash, Koplik spots (red lesions w/white central spot on buccal mucosa) are seen and are predictive of the measles rash appearing in 1-2 days.
• Appearance of rash, fever, runny nose, coughing/sneezing, conjuctivitis, photophobia

Question 23

incubation pd for measles

Answer 23

14days, after which the rash begins.

Question 24

What is the rash in measles like?

Answer 24

generalized maculopapular erythematous rash