viral properties and disease

Question 1

8 modes of virus transmission

Answer 1

respiratory, faecal-oral, contact (lesions, saliva, fomites), zoonoses (insects, animals), blood, sexual contact, maternal-neonatal, germ line

Question 2

5 viral routes of entry

Answer 2

skin, mucosal surfaces, conjunctiva (eye), blood (viraemia), bites

Question 3

5 transmission terminologies

Answer 3

iatrogenic (health care workers - needles); noocomial (hospial acquired); vertical; horizontal; germ line

Question 4

stages of dissemination from sire of entry

Answer 4

local infection, primary varaemia, amplification, secondary varaemia (to another site), target organ

Question 5

define tropism

Answer 5

cells and tissues of a host that support growth and replication of a particular virus (viruses have a predilection to infect certain tissues)

Question 6

what defines tropism

Answer 6

susceptibility (receptor interactions), permissivity (ability to use host cell to complete replication) and accessibility (ability to reach tissue)

Question 7

features of HIV tropism

Answer 7

need CD4+ and CCR5+ (macrophages) or CXCR4+ (T cells) receptors on cells

Question 8

features of measles tropism

Answer 8

CD155/SLAM receptor on dendritic cells - targeted for immunosuppression

Question 9

features of influenza tropism

Answer 9

only respiratory affected as proteases to cleave haemagglutinin only found in tract

Question 10

define pathogenicity

Answer 10

ability of virus to cause disease

Question 11

virulence

Answer 11

capacity of virus to cause disease