Lecture 11

Question 1

What are examples of DNA viruses?

Answer 1

Adenovirus and parvovirus.

Question 2

How many serotypes does adenovirus have?

Answer 2

Adenovirus has 52 serotypes.

Question 3

What are some characteristics of adenovirus?

Answer 3

Adenovirus is stable to low pH, bile, and proteases.
Adenovirus is 70-90 nm in size.
Adenovirus has an icosahedral shaped DNA.
Adenovirus can hemagglutinate red blood cells.

Question 4

What is the oncogenic property of adenovirus?

Answer 4

Adenovirus has the ability to transform cells in culture and cause cancer in animals but not humans.

Question 5

What is the therapeutic potential of adenovirus?

Answer 5

Adenovirus can be used as a vector to carry and express foreign genes for therapeutic purposes, e.g., gene therapy.

Question 6

What is the life cycle of adenovirus?

Answer 6

Adenovirus attaches to host cells by two-stage interactions, the initial stage the penton fibre attached with the host cell receptor. CD46 is the most common receptor for adenovirus. Attachment of the penton base occurs with the host cell’s αV integrin protein during the secondary interaction.
Internalization occurs via endocytosis, and the virus enters the host cell cytoplasm in a vesicle.
The viral DNA replicates in the nucleus, followed by bioassembly and release.

Question 7

How is adenovirus isolated in the lab?

Answer 7

Graham cells (HEK 293) are used to isolate adenovirus for types 40 & 41 (Enteric).

Question 8

What populations are at risk of acute respiratory illness caused by adenovirus?

Answer 8

Military recruits, boarding schools, etc.

Question 9

What disease does adenovirus cause in the eyes?

Answer 9

Keratoconjunctivitis.

Question 10

In what population can adenovirus cause invasive disease?

Answer 10

BMT and HSCT patients.

Question 11

How does coronavirus transmit?

Answer 11

By respiratory droplets.

Question 12

What is the structure of coronavirus?

Answer 12

Coronavirus is a spherical enveloped virus.

Question 13

What is the mechanism of coronavirus replication?

Answer 13

Coronavirus releases its RNA into the cells, which form proteins in the cytoplasm.

Question 14

How is coronavirus diagnosed in the lab?

Answer 14

Lab diagnosis of coronavirus involves RT-PCR and antigen detection for mass screening.

Question 15

What is the difference in infectiousness between SARS and COVID-19?

Answer 15

For SARS, there was 11 days between onset of illness and maximum infectivity, so the disease could be identified and quarantined before the patient became infectious, but COVID-19 patients are infectious 2 days before symptoms show.

Question 16

Why is SARS-CoV-2 more infectious than SARS?

Answer 16

SARS-CoV-2 binds up to 20 times tighter than SARS to ACE2.

Question 17

Why is SARS-CoV-2 threatening to the elderly?

Answer 17

SARS-CoV-2 is vasculotropic and causes endothelialitis, resulting in microvascular thrombosis.

Question 18

What are the severe symptoms of COVID-19?

Answer 18

Vascular leakage, pulmonary edema, clotting, and inflammation.

Question 19

What genetic mutation made SARS-CoV-2 more transmissible?

Answer 19

A D614G AA substitution in the spike glycoprotein.

Question 20

What are some characteristics of parvovirus?

Answer 20

Parvovirus is a small (18 - 26 nm) icosahedral virus that is non-enveloped and single-stranded DNA.
Erythrovirus-B19 is the main parvovirus.

Question 21

What is the most common age group affected by erythrovirus?

Answer 21

Erythrovirus is most common among 4-10 year olds.

Question 22

What is the duration of long-term epidemic cycles of erythrovirus?

Answer 22

The long-term epidemic cycles of erythrovirus are usually 4/5 years.

Question 23

How many phases does a parvovirus infection have?

Answer 23

A parvovirus infection has two phases.

Question 24

When does the first phase of parvovirus infection occur and what happens?

Answer 24

The first phase of parvovirus infection occurs 6-14 days post-infection and involves intense viraemia and nasal shedding

Question 25

What happens in the second phase of parvovirus infection?

Answer 25

The second phase of parvovirus infection causes rash and joint pains and occurs 15-17 days post-infection causes rash and joint pains.

Question 26

What is the cell receptor for B19 virus?

Answer 26

The P antigen is the cell receptor for B19 virus.

Question 27

Where is the P antigen present?

Answer 27

The P antigen is present on red blood cells, vascular endothelium, and foetal heart cells.

Question 28

What are the clinical diseases caused by B19?

Answer 28

Clinical diseases caused by B19 include asymptomatic infection, non-specific RTI, erythemia infectiosum, joint disease, aplastic crisis, infection in immunocompromised individuals, and infection in pregnancy.

Question 29

What is the highest risk period for primary B19 infection during pregnancy?

Answer 29

The highest risk period for primary B19 infection during pregnancy is the second trimester.

Question 30

How is B19 infection in pregnancy treated?

Answer 30

B19 infection in pregnancy is treated with an intrauterine blood transfusion.

Question 31

How can B19 infection be detected in a foetus?

Answer 31

In a foetus, B19 infection can be detected by IgM in the baby serum or detection of the virus in blood by CIE or immunoassay

Question 32

What is the treatment for B19 infection?

Answer 32

B19 infection can be treated with a blood transfusion.