Viral infections of the Upper Respiratory Tract

Question 1

features of viral respiratory infections

Answer 1

transmission by fomites or aerosol. epithelial cells are the first site of virus/host interaction. infected cells release cytokines leading to fever, aches. Temperature differential in respiratory tract has consequences for pathogenesis (rhinoviruses replicate preferentially in URT). Infants and elderly have more severe respiratory infections

Question 2

what viruses show as acute infection with replication confined to respiratory mucosal surface?

Answer 2

picornavirus (rhinovirus), coronavirus, paramyxovirus (parainfluenza and respiratory syncytial virus), orthomyxovirus (influenza)

Question 3

what viruses present as persistent replication on respiratory mucosal surface?

Answer 3

EBV, adenovirus, papillomavirus

Question 4

what viruses present as systemic replication after primary replication in the respiratory tract?

Answer 4

paramyxocirus (mumps, measles)
herpesvirus
rubella
picornavirus (polio)

Question 5

coronaviruses

Answer 5

named for crown of spikes. (+) ssRNA virus. most strains cause cold-like symptoms. Rare new strains cause lethal respiratory diseases. (SARS, MERS)

Question 6

myxoviruses

Answer 6

myxo is greek for mucus. These viruses bind to mucin protein on RBCs

Question 7

orthomyxoviruses

Answer 7

straight/right/proper. this is the flu. the researchers were looking for this virus so they named it ortho, or “right”

Question 8

paramyxoviruses

Answer 8

besides, resembling. measles virus is similar to the orthomyxoviruses, but not the same so they called it para

Question 9

orthomyxoviridae representatives, replication, genome, and structure

Answer 9

influenzavirus. 3 types, A, B, C. nuclear replication. Segmented (-) ssRNA. enveloped.

Question 10

paramyxoviridae representatives, replication, genome, and structure

Answer 10

mumps, measles, respiratory syncytial virus. Cytoplasmic replication. non-segmented (-) ssRNA. enveloped structure.

Question 11

how influenza virus causes disease

Answer 11

1. aerosol inoculation of virus.
2. replication in respiratory tract
3. desquamation of mucus secreting and ciliated cells
4. T cell responses and interferon induction
5. influenza syndrome (symptoms)

Question 12

flu treatments and prevention

Answer 12

tamiflu and relenza work on influenza A and B. fluzone and flumist are vaccines. Trivalent vaccines used yearly, quadrivalent vaccines sometimes too.

Question 13

croup

Answer 13

parainfluenza virus and RSV. peak incidence in winter. starts like cold in adults and kids. infants may develop a distinctive barking cough, called croup. commonly treated at home with steam and humidifiers. complications include pneumonia and respiratory distress

Question 14

adenovirus respiratory infections

Answer 14

widespread in nature, infecting birds, many mammals, and humans. isolated from adenoidal tissue. 47 serotypes can infect humans. post people haev been infected by 1 by the age of 15. common, usually asymptomatic. most involve the respiratory or GI tracts or the eye.

Question 15

adenovirus pathogenesis

Answer 15

transmitted by aerosol, close contact, fecal oral, fingers/ophthalmologic instruments. infects mucoepithelial cells of respiratory and GI tract, conjunctiva, cornea. virus persists in lymphoid tissue. antibody is essential for recover from infection

Question 16

adenovirus epidemiology

Answer 16

common in army boot camp, bad swimming pools, daycare centers. vaccine available for military only