Respiratory Tract Infections Holland

Question 1

80% of Respiratory Tract Infections are caused by?

Answer 1

Viruses

Question 2

Protective mechanisms of respiratory tract?

Answer 2

Reduced temperature
Mucous (mucins)
Cilia
Toll-like receptors
interferons
IgA

Question 3

Why is influenza A unique among RNA viruses?

Answer 3

Replicates in the nucleus

Question 4

What is the role of hemagglutinin influenza

Answer 4

KEY TO INFECTION AND IMMUNITY

attachment AND penetration

Question 5

what happens to show the fusion peptide?

Answer 5

low pH induces conformational shift in HA, fusion peptide is exposed! inserts into target membrane. membranes are drawn close together, locally disrupted, FUSE.

Question 6

What role does neuraminidase play?

Answer 6

Removes sialic acid from cell surface (so do not reinfect same cell) removes sialic acid from mucins (serve as decoy receptors for virions, inactivating them!)

Question 7

What is the MOA of amaditine/rimiantidine?

Answer 7

target the m2 ion channel, blocking uncoating.

Question 8

Which antibodies are the strongest neutralizers?

Answer 8

ANTI-HA stronger than anti NA

Question 9

Antigenic drift for influenza

Answer 9

MINOR antigenic changes in HA and NA resulting from mutations. driven by selection for resistance…

reason why we need to change the vaccines annually!

Question 10

Antigenic Shift for influenza

Answer 10

MAJOR antigenic change in HAorNA or both!

How? genetic reassortment after one cell infected by 2 different viruses

Question 11

What process leads to a pandemic strain of flu?

Answer 11

ANTIGENIC SHIFT! little pre-existing immunity in the human population

Question 12

What population was most affected by the 1918 flu?

Answer 12

Young adults! 25-34 range

Question 13

Which virus from the orthomyxoviridiae family is most significant?

Answer 13

influenza (A, B, C)

Question 14

What are the characteristics of the paramyxoviridae family of viruses?

Answer 14

Enveloped with HN and F proteins, -ssRNA, nucleocapsid with helical symmetry

Question 15

What role does the F glygoprotein play in paramyxoviridae pathogenesis?

Answer 15

Fusion activity!activated by proteolytic cleavage. results in multinucleated cells

Question 16

What is the most common cause of croup?

Answer 16

HPIV-1

Question 17

What are the features of croup?

Answer 17

infection and inflamm of larynx,trachea, bronchi,narrowing the airway –>dyspnea
BARKING cough/stridor (sound on inhalation)

Question 18

What is the most common cause of laryngitis in adults

Answer 18

Human parainfluenza virus

Question 19

What is the primary cause of bronchiolitis in children?

Answer 19

Respiratory Synctial Virus- life threatening!!!!

Question 20

what are the two most common causes of lower respiratory tract infections in children?

Answer 20

1. RSV

2. human metapneumovirus

Question 21

Viral causes of pneumonia?

Answer 21

HPIV, RSV, hMSPV, influenzavirus,adenovirus,coronavirus

Question 22

What virus’ natural host is the fruit bat?

Answer 22

henipavirus.

human case fatality rate = 60%

Question 23

what are the manifestations of MUMPS?

Answer 23

after long incubation period (2-3wks)
painful swelling of parotid gland
swelling of cheeks and jaws
ear pain
fever and headache
less frequent- meningitis/orchitis/rash

Question 24

What are the manifestations of Measles

Answer 24

Respiratory spread, fever, malaise, cough, coryza, headache, CONJUNCTIVITIS, KOPLIKS SPOTS(blue-white spots on red buccal mucosa), rash (starts on FACE spread to trunk and limbs)

Question 25

What are the important characteristics of Rubella?

Answer 25

+RNA

lymph node swelling, maculopapular rash, fever, arthritis, congenitial syndrome

Question 26

EBV symptomology?

Answer 26

primary infections are asymptomatic (maybe sore throat/fever)
secondary infection- infectious mononucleosis

Question 27

What are heterophile antibodies?

Answer 27

Antibodies against unusual antigens, antigens to which a person has not been exposed. Caused by activation of B cells by EBV… result is secretion of antibodies even though cells were not exposed to antigen. basis for mono test

Question 28

What role does EBV play on B cells?

Answer 28

virus causes the B cells (G0 phase) to become activated and enter the cell cycle, leading to heterophile antibodies

Question 29

what is the most common childhood cancer in equatorial Africa?

Answer 29

Burkitt’s Lymphoma (associated with EBV)
Tumor cells are EBV+ B cells and express EBER (Epstein bar early rna) and viral protein, EBNA-1
myc overexpression

Question 30

what is nasopharyngeal carcinoma?

Answer 30

epithelial cell cancer. tumors contain EBV DNA.

viral genes: EBER, EBNA-1, LMP1 +2

Question 31

Where are tumors most prevalent in hairy oral leukoplakia

Answer 31

TRICK QUESTION!!! NOT TUMORS!! sites of active EBV replication.

white, wart-like lesions on sides of tongue. AIDS patients

Question 32

What is the main differentiating characteristic between cytalomegavirus and EBV?

Answer 32

ONLY EBV has heterophile antibodies!

Question 33

What are the modes of transmission for adenovirus?

Answer 33

Respiratory, fecal/oral, iatrogenic spread

Question 34

In what population is Acute Respiratory Disease from adenovirus most common?

Answer 34

Military recruits! crowded living under stress. vaccine for them, types 4, 7

Question 35

What are the features of pharyngoconjunctival fever?

Answer 35

Adenovirus infection, conjunctivitis + upper respiratory tract infection.

can initiate direct to eye. SWIMMING POOL transmission!

Question 36

Does the adenovirus cause GI disease?

Answer 36

Although most types replicate in the GI tract, normally do not cause disease in adults. Types 40and 41 associated with infant gastroenteritis

Question 37

What virus is responsible for “shipyard eye”?

Answer 37

adenovirus– epidemic keratoconjunctivitis

involves both cornea and conjunctiva, highly contagious.

Question 38

The adenovirus enters the cell by endocytosis. What receptor (s) bind the virus?

Answer 38

CAR and integrins

Question 39

What are the features of parvovirus?

Answer 39

VERY small, nonenveloped, linear, ssDNA

B19- fifth disease, transient aplastic crisis, hydrops fetalis.

Question 40

What is erythema infectiosum? what causes it?

Answer 40

Fifth disease caused by B19 infection. Two phases:

1. Nonspecific, flu-like, dispersion by viremia, immune complex form
2. deposition of immune complexes, eryth rash and transient arthritis

Question 41

How does B19 cause transient aplastic crisis?

Answer 41

Persons with hemolytic anemia have very few reticulocytes. B19 replicates in erythroid precursor cells in BONE MARROW– life threatening.