Respiratory Viruses- Lobel

Question 1

Similarities between orthomyxoviridae and paramyxoviridae

Answer 1

General structure, lipid membrane
ssRNA (-)
Two proteins extending from the membrane
For now, it seems that all viruses in these families that infect humans do so in the respiratory tract

Question 2

Differences between Orthomyxoviridae and Paramyxoviridae

Answer 2

Segmented genome vs. continuous
Paramyxoviridae are somewhat larger
Genetic stability
Mode of entry into the host cell
Location of genome replication

Question 3

What are the respiratory viral families?

Answer 3

Orthomyxoviridae, paramyxoviridae, coronaviridae, adenoviridae, picornaviridae

Question 4

Increased risk populations for influenza complications

Answer 4

>50yo, chronic pulmonary/CV disease, chronic metabolic disease, renal dysfunction, hemoglobinopathies, immunosuppression, children and teens taking aspirin, women in 2/3 trimester,

Question 5

What are the two proteins on orthomyxoviridae?

Answer 5

Hemagglutinin and neuraminidase (HA and NA)

Question 6

What is the mechanism of replication of orthomyxoviridae?

Answer 6

Taken into endosomes, doesn’t merge with cell envelope. Transcription and replication take place in the nucleus of the host cell. Makes 8 ss(-)RNA segments through +RNA with stolen caps. Needs to be cleaved from host proteases based on proteins around cleavage site. The easier, the more virulent. Endocytic vessels acidifies vesicle, pH change causes confirmational change in HA, H+ entrance through M2 channels, fusion of membranes, enables genetic component release.

Question 7

What are the major surface proteins of paramyxoviridae?

Answer 7

HN (G) and F (fusion)

Question 8

How is strain designation named?

Answer 8

Virus strain/place of isolation/isolate number/year+HA and NA designaqtion

Question 9

What antibody response is there to influenza?

Answer 9

Against HA: IgM, IgG (vaccine) and nasal IgA.

Question 10

What is the incubation period of influenza?

Answer 10

1-4 days.

Question 11

What virus should be suspected with blue fingernails and difficulty breathing?

Answer 11

RSV even without typical barking cough of croup.

Question 12

What is the incubation period of SARS

Answer 12

Up to 10 days. Causes diarrhea and respiratory distress.

Question 13

What virus causes epidemic keratoconjunctivitis (EKC)?

Answer 13

Adenovirus

Question 14

What viruses can cause intussusception? (In decreasing order)

Answer 14

Adenovirus, influenza

Question 15

What are the types of enteroviruses?

Answer 15

Poliovirus, enterovirus, echovirus, coxsackie virus

Question 16

What are the two classes picornaviridae?

Answer 16

Enteroviruses and Rhinovirus