RNA viruses

Question 0

What are the 3 types of Paramyxoviruses?

Answer 0

1-Rubeola virus
2-Parainfluenza
3-Mumps

Question 1

What are the 2 categories of RNA viruses?

Answer 1

Paramyxoviruses and Togaviridae

Question 2

What is the basic description of paramyxoviruses?

Answer 2

Enveloped, negative strand RNA viruses, Helical symmetry

Question 3

Measles is known as what?

Answer 3

Rubeola virus

Question 4

Rubeola virus has what? but also lacks?

Answer 4

Rubeola Has- hemagglutin(surface glycoprotein) for attachment to host cell, Lacks- neuraminidase (aids in the efficiency of virus release from cells)

Question 5

What is the main route of infection for Rubeola?

Answer 5

inhalation of respiratory secretions

Question 6

Does Rubeola show outward symptoms?

Answer 6

Yes, almost all infected individuals show signs of disease

Question 7

Rubeola virus is broken down into 2 forms(measles)

Answer 7

Measles uncomplicated and measles complications

Question 8

What is the pathogenesis of measles uncomplicated?

Answer 8

Fever, running nose, caugh, conjunctivitis, Koplick’s spot on mucosal membranes (small, irregular, white spots, with bluish halo), Maculopapular rash which extends from the face to the extremities

Question 9

What are the possible measles complications?

Answer 9

• impaired cell mediated immune response(continued growth of the virus in the lungs-can be fatal) rare
• Otitis media and bacterial pneumonia are quite common
• 1in 1000 cases get encephalitis
• Sub-acute sclerosing pan encephalitis-progressive neurological disorder characterized by inflammation of the brain

Question 10

What are the ways measles is controlled?

Answer 10

Rubeola virus has only one serotype(antigenic type)
Provides life long immunity
Attenuated live vaccine -MMR

Question 11

What is the second type of paramyxoviruses?

Answer 11

Parainfluenza

Question 12

How many types of parainfluenza are there and what do they all do?

Answer 12

4 types, all of which can cause upper respiratory infections or lower respiratory infections especially important in children because it is responsible for approximately 40-50% of croup cases

Question 13

What is the 3rd type of Paramyxovirus?

Answer 13

Mumps

Question 14

What does mumps cause and what does it infect?

Answer 14

Causes swelling of salivary glands (parotid glands), virus infects upper/lower respiratory tract leading to local replication. The virus spreads to lymphoid tissue which leads to viremia(when a virus enters the blood stream and has access to the rest of the body)

Question 15

What are two possible complications with mumps?

Answer 15

Orchitis(testicular inflammation) and aseptic meningitis

Question 16

What is used to control mumps?

Answer 16

MMR-vaccine (single serotype of mumps, life long immunity)

Question 17

2nd of the two groups of RNA viruses is?

Answer 17

Togaviridae

Question 18

Togaviridae is known as?

Answer 18

Rubella(german measles)

Question 19

Basic description of German measles?

Answer 19

Positive strand RNA virus
Enveloped
Icosahedral symmetry
only member of the rubrivirus genus of the Togavirus family

Question 20

What is the transmission and infection of german measles?

Answer 20

• Transmitted by respiratory secretions
• Initial site of infection is the upper respiratory tract. The virus replicates locally in the lymph nodes leading to viremia and spread to other tissues
• Rash (if it occurs) starts after an incubation period of approximately 2 weeks

Question 21

Togaviridae congenital infection has the highest risk to the fetus when?

Answer 21

In the first few weeks of pregnancy and then declines in terms of both frequency and severity but continues on into the second trimester

Question 22

Togaviridae congenital infection infects the fetus how?

Answer 22

through infection of the placenta

Question 23

Togaviridae congenital infection in non-immune mothers can lead to what in 80% of neonates?

Answer 23

• Hearing loss
• Mental retardation
• Congenital heart problems
• Neurologic problems
• Ophthalmic problems
• Congenital infections can infect others after birth for a year