MID 2 - Lecture 12

Question 1

Pathogenic protists and transmission to humans

Answer 1

Protozoa - adapted to every type of habitat on earth
1. arthropod vectors
2. contaminated food and water
3. Direct contact

Question 2

Malaria (transmitted and cycles)

Answer 2

-5 species of plasmodium
By bite of infected female mosquito
-exoerythrocytic cycle (liver)
-Erythrocytic cycle (red blood cell)
-mosquito/sporogonic cycle

Question 3

Mosquito stage

Answer 3

Gametocytes are ingested by mosquito, making an oocyst, then injects sporozoites into a human, goes through liver, then blood cells

Question 3

Human stage (A and B)

Answer 3

A. In liver, sporozoites form schizonts, merozoites form and rupture level cells and goes into blood stream
B. invade blood cells, and replicate asexually, destroy blood cells

Question 3

Malaria (clinical)

Answer 3

Shaking chills, fever, and sweating, anemia, cerebral malaria in children, immunocompromised = deadly
Treatment: Vaccine approved in Africia (recombinant vaccine for children), bednets and insecticide spray

Question 4

Leishmaniasis

Answer 4

Protozoan parasite (leishmanias), sandflies when take blood meal (inject into human)

Question 4

Leishmania life cycle

Answer 4

Sandfly blood meal (ingests macrophages infected), amastigotes into promastigote, sandfly takes blood meal (put promastigote stage in human), transforms into amastigotes again

Question 4

Trypanosomiasis (general)

Answer 4

Human african Trypanosomiasis (african sleeping sickness), caused by T. brucei, tsetse flies, fever, headache, exteme fatigue, muscle and joint aches

Question 5

T. brucei cycle

Answer 5

Tsetse fly blood meal, trypomastigotes into procyclic trypomastigotes into espimastigotes, tsetse fly blood meal (into human), turns back into trypomastigotes

Question 6

Covid history (2 viruses before 2019)

Answer 6

1. SARS-CoV - 2002
2. Middle east respiratory syndrome coronavirus (MERS-CoV) - 2012
3. SARS-CoV-2 - december 2019

Question 7

Covid virus characteristics (4 structural proteins and general make up)

Answer 7

Coronaviridae
-enveloped, unsegmented single strand positive sense RNA genome
- 4 structural proteins - spike(glyco), envelope (glyco), membrane (glyco), nucleocapsid (proteins)

Question 8

Covid entry into host (portals how it gets in - general)

Answer 8

nasal/oral passage, conjunctiva of eyes through nasolacrimal duct, oral cavity/esophagus

Question 9

Covid (once transmitted entry) ACE2

Answer 9

-S proteins bind to host cells (by angiotensin) converting enzyme 2 (ACE 2)
-ACE2 proteins in tissues (kidneys, lungs, heart, arteries, gastro tract)
-s proteins embedded in viral envelope bind to ACE2 on host cells and trigger viral endocytosis or membrane fusion

Question 10

Mechanisms of pathogenicity (covid)

Answer 10

1. virus takes over replicative machinery and multiplies
2. Immune system triggers inflammatory response
3. Non specific immune cells release chemokine that stimulate a targeted attack on infected cells, crippling normal function

Question 11

Vaccine (what kind of microbes are used)

Answer 11

-preparation of microbial antigens used to induce protective immunity
- Killed, living, weakened microbes or inactived bacterial toxins, purified cell material, recombinant vectors, DNA

Question 12

Immunization

Answer 12

result obtained when vaccine stimulates immunity

Question 13

Adjuvant (some examples)

Answer 13

ingredient in some vaccines that enhances the rate and degree of immunization
- aluminium salts, lipids, synthetic DNA

Question 14

Example of viral vaccines

Answer 14

chickenpox, hepatitis, HPI, Influenza, measles

Question 15

Examples of bacterial vaccines

Answer 15

Anthrax, cholera, meningococcal, TB

Question 16

Comparison of vaccine types (live cell, vs acellular, vs DNA)

Answer 16

whole cell: live - virus, strong T response, strong B cell
Inactivated - bacteria, weak T, Strong B
Acellular - antigens from microbe, Very strong T, very strong B
Recominant and DNA - virus or vector, very strong T, very strong B

Question 17

Whole cell vaccines (and some problems)

Answer 17

most current active against bacteria and viruses have microbes that are either killed or live (avirulent)
problems - could be weaker, immunosuppressed at risk of getting disease

Question 18

Viral vector vaccines (example)

Answer 18

gene for pathogen antigen inserted into genome of non-pathogenic virus, released products result in immunity
AstraZeneca

Question 19

Acellular or subunit vaccines and forms of it

Answer 19

purified molecules from microbes, avoids some risks of whole cell vaccine
-Capsular polysaccharides
-Recombinant surface antigens
-Inactivated exotoxins

Question 20

Vaccine phases

Answer 20

1. preclinical (cells then animals)
2. phase 1 safety trials (small number of people)
3. Phase 2 expanded trials (hundreds)
4. Phase 3 efficacy trials (thousands)
5. Approval (10-15 years)

Question 21

Pfizer/BioNTech vaccine

Answer 21

mRNA encodes for spike protein, cell that uptake mRNA produce spike protein, immune system recognizes and makes defensive response, antibody production (2 doses over 3 weeks)