6: Smallpox

Question 1

virulence

Answer 1

low
- host and pathogen well adapted to each other
- spread by keeping host alive

high
- pathogen less adapted to host
- spread by getting host sick or killing host

Question 2

smallpox virus

Answer 2

variola major/minor

not hugely antigenic variation
- just 2 strains and not a lot of different subtypes there

Question 3

typical course of smallpox

Answer 3

7-19 incubation period
- therapeutic use of vaccine since there’s enough time to vaccinate and stimulate adaptive immune system before they get disease

fever before a rash but still shedding virus before a rash

macules, papules, vesicles (fluid containing virus), pustules, scabs

Question 4

smallpox mortality

Answer 4

people don’t die from pox
- not well understood

some type of systemic inflammatory response

rare cases develop into hemorrhagic smallpox, flat-type smallpox, etc.

Question 5

chickenpox vs. smallpox

Answer 5

centrifugal rash (everything on the outer part)

chickenpox
- rash on abdomen and maybe face

smallpox
- rash on the face, hands, feet and legs

Question 6

success of the variola pathogen

Answer 6

smallpox produces proteins which bind to cytokines like a viral TNF receptor which binds to human TNF and inhibits inflammation
- fake TNF receptors which bind to TNF and block them from binding to other immune cells which can activate immune responses

smallpox proteins inhibit immune lysis by complement

Question 7

father of vaccination

Answer 7

edward jenner

Question 8

smallpox vaccine

Answer 8

vaccinia
- live virus vaccine
- weird form of cowpox and smallpox

never grown in a person but only laboratory
- used as a common viral vector

elicits protective antibodies, T helper cells and CTL responses

extremely efficacious (only one dose necessary)

Question 9

smallpox eradication

Answer 9

mass vaccination campaigns to reach 80% herd immunity

development of surveillance systems to find cases/outbreaks

ring vaccination as the containment strategy

Question 10

smallpox as a bioterrorism agent

Answer 10

highly virulent

highly infectious

can be delivered in aerosol form

little to no natural immune resistance in humans

hardly in lyophilised form

can be engineered for greater virulence

Question 11

monkeypox origin

Answer 11

first human case in DRC in 1970

classic zoonosis where people got it from animals

Question 12

monkeypox in 2022

Answer 12

non-endemic in countries which means it’s not in the animals
- going human-to-human
- transitioning for human eminence

nowhere near as virulent as smallpox which was adapted for humans

Question 13

monkeypox transmission

Answer 13

close contact through primarily respiratory secretions or skin lesions of an infected person
- prolonged face-to-face contact

Question 14

monkeypox disease

Answer 14

6-13 day incubation period

fever, intense headache, lethargy and swollen lymph nodes
- similar to chickenpox/measles

Question 15

monkeypox vaccine

Answer 15

many highly conserved structural antigens similar to smallpox
- use a modified form of vaccinia

genetically modified live non-replicating vaccinia strain which has reduced virulence but still immunogenic

modification of vaccinia
- deleted TNF receptors and all immune evasion molecules
- less toxic with less reactions