Common Viral Pathogens IV

Question 1

Influenza basic structure

Answer 1

: Influenza virus is an RNA virus with a segmented genome. Its genome is made up of eight different pieces of single-stranded RNA, which encode several different viral proteins. Surrounding the core is a lipid envelope, with a lining of matrix protein on the inner side of the envelope. There are two subtypes: A (other animals as well) and B (only humans).

Question 2

Influenza important proteins and their roles in pathogenesis

Answer 2

hemagglutinin (H) and neuraminidase (N) glycoproteins. Both hemagglutinin and neuraminidase are surface proteins. Influenza viral subtypes are identified by the combination of H and N proteins on the viral coat (e.g. H1N1, H3N2 etc). Antigenic drift and shift lead to pathogenesis.

Question 3

RSV basic structure

Answer 3

Single stranded, non-segmented RNA virus, paramyxoviridae family
• There are 2 subtypes, A and B
— There is antigenic variability within the groups
— Get “drift” over time like influenza
— Type A shown to cause more severe disease in studies, more prevalent in epidemiologic studies

Question 4

RSV important proteins and their roles in pathogenesis

Answer 4

• – F protein: fusion of viral envelope to host cell; fusion of membranes of infected cells to each other to cause “syncytia”
• – G protein: Initial binding of virus to the host cell

Question 5

Ebola basic structure:

Answer 5

Family: Filoviridae (comes from word filament)
• Enveloped, negative-strand RNA, replicates in the cytoplasm
• 7 structural proteins and 2 non-structural proteins
• Virions are polyploid – with multiple genomes strung together (filamentous shape)

Question 6

Ebola important proteins

Answer 6

• – Glycoprotein
• – Matrix proteins VP40 and VP24
• – Nucleocapsid and nucleoprotein (VP30 and nucleoproteins)
• – Polymerase comples (VP35 and L)

Question 7

VP40

Answer 7

main part of the virion/matrix, important for structure, stability, assembly, budding

Question 8

VP24

Answer 8

assemply, budding, nucleocapsid

Question 9

Glycoprotein

Answer 9

part of viral envelope, also a secreted form; functions in attachment/entry (masks antibody binding sites), important for pathogenicity (blocks MHC in order to inhibit triggering an immune response)

Question 10

Nucleocapsid and nucleoprotein (VP30 and nucleoproteins)

Answer 10

form the nucleocapsid

Question 11

Polymerase comples (VP35 and L)

Answer 11

function in replication, RNA-dependent

Question 12

Influenza route:

Answer 12

respiratory -> Droplet and small particle aerosols generated by coughing and sneezing

Question 13

Influenza symptoms in adults

Answer 13

The signs and symptoms of influenza in adolescents and adults are dramatic. There is an acute onset of fever, chills, myalgias, headache and cough.

Question 14

Influenza symptoms in neonates

Answer 14

resemble that of bacterial sepsis, including lethargy, decreased eating and mottling. A high incidence of apnea (cessation of breathing) may also occur

Question 15

Influenza symptoms in infants and toddlers:

Answer 15

present with gastrointestinal symptoms (nausea, vomiting and diarrhea); fever; anorexia; and various respiratory syndromes, including undifferentiated febrile upper respiratory illness, acute laryngotracheobronchitis (croup), bronchiolitis, bronchitis and febrile convulsions

Question 16

Influenza symptoms in older children and adolesents

Answer 16

more like the classic presentation in adults: rapid onset of illness with high fever; cough; chills; malaise; and other symptoms, such as headache and sore throat.