Viruses

Question 1

what is the structure of a virus (4)

Answer 1

1. genome
2. capsid
3. envelope
4. glycoprotein spike

Question 2

what causes latency

Answer 2

a lack of a specific host cell protein needed to activate viral genes and turn on viral replication

Question 3

what are the stages of viral infection

Answer 3

1. prodomal or incubation
2. latency
3. activation of viral replication

Question 4

how do viruses cause damage (5)

Answer 4

1. hypersensitivity reaction (Type II and Type IV)
2. components toxic to the cell
3. transform a benigh cell to a malignant cell
4. alter immune response (humoral and cellular)
5. cause cytoplasmic and/or nuclear changes

Question 5

how are virses classified (6)

Answer 5

1. morphology
2. physiochemical properties
3. genome (RNA/ DNA)
4. macromolecules
5. antigenic properties
6. biological properties

Question 6

how many types of papillomavirus - HPV

Answer 6

more than 150
more than 30 are sexually transmitted

Question 7

what types of cancer are caused by HPV (6)

Answer 7

1. anal cancer - 91%
2. cervical cancer - 91%
3. vaginal cancer - 75%
4. oropharyngeal - 72%
5. vulvar cancer - 69%
6. penile cancer - 63%

Question 8

types of warts (4)

Answer 8

1. common warts
2. foot warts/ verrucae
3. flat warts
4. periungual warts

Question 9

herpes simplex has 2 types; what are they and what do they cause

Answer 9

1. HSV-1: cold sores
2. HSV -2: sexually transmitted

Question 10

which virus causes chicken pox and shingles

Answer 10

varecella zoster virus

Question 11

what does epstein-barr virus cause

Answer 11

mononucleosis 35-50% of time i.e., glandular fever

Question 12

what are the symptoms of glandular fever

Answer 12

1. fatigue, loss of appetite, headache
2. photophobia
3. sore throat
4. lymphatic swelling
5. cough
6. enlarged spleen
7. chills, fever, aches

Question 13

other herpes virus include:

Answer 13

1. cytomegalovirus (HHV-5)
2. hairy leukopakia (EBV HHV-4)
3. kaposi’s sarcoma (HHV-*)

Question 14

pox virus include

Answer 14

• smallpox (now irradicated)
• molluscum contagiosum

Question 15

what is a retrovirus

Answer 15

it inserts a copy of it RNA genome into the DNA of a host cell, thus changing the genome of that cell

Question 16

what enzyme does HIV use to replicate itself

Answer 16

reverse transcriptase
it destroys CD4 cells by damaging cell membranes

Question 17

what is the incubation period for HIV

Answer 17

1-10 years
causes a profound defect in cell-mediated immunity

Question 18

what virus is very very tiny, spread by the faeco-oral route

Answer 18

picornaviruses e.g., polio, hepatitis A

Question 19

polio can occur in various severities:

Answer 19

1. sub-clinical - none or very mild symptoms
2. non-paralytic
3. paralytic

Question 20

how is hepatitis B virus communicable

Answer 20

by contact with infected body fluids

Question 21

how do prions cause damage to cells

Answer 21

prions on the cell surface allow too much fluid to enter the cell, producing a spongry appearance when cross-sections of brain tissue are examined under a microscope