Slide set II study guide

Question 1

Requirement of infection.

4 steps of infection.

Answer 1

1) entry via portal of entry
2) stay in establishment (adherence adhesion attachment»colonization/multiplication»invasion (penetration)+ spread to internal organ/tissue.
3) defeat host defense (evade and compromise host defense system)
4) Damage to host cells and tissue

Question 2

concept of active and passive defense barrier of pathogen.

Answer 2

pathogen defend themselves against host in 2 ways:

passive: built in
- cell wall/capsule/built in inherent structure
- barrier help avoid/escape host defense system

active: direct attack on host defense cell
- target cell belonging to 3rd line of defense, including B and T cells as well as macrophages, monocytes, and dendritic cells (which capture pathogen and carry it to lymph node to initiate immune response)

Question 3

Pathogen (virus or bacteria) and it’s specific target cell of the immune system

Answer 3

Virus:

HIV: target CD4 T helper cell
measles: target T/B cells
Dengue virus: target macrophage/monocyte
Ebola: target macrophage, dendritic, and endothelial cell (this is why we bleed everywhere)
Epstein Barr virus (mono): target B cell

_____________________________________________

Bacteria:
tuberculosis pathogen: target alveolar macrophages and multiply inside cells

listeria pathogen: target macrophages and phagocytes

Question 4

Portals of entry

Answer 4

1. skin
2. mucous membrane
3. conjunctiva and eye
4. placenta
5. parenteral route

Question 5

feature of anthrax pathogen entry (bacillus anthracis)

Answer 5

uses multiple rout of entry, causing different disease base upon entry site.

1) via inhalation of spores/cell = inhalation/pulmonary anthrax (most lethal)
2) ingestion of contaminated food= gastrointestinal anthrax
3) bacteria on skin surface= cutaneous anthrax (skin infection or wound)

Question 6

Salmonella typhii entry, reservoir, and continuous shedding of this bacteria

Answer 6

Salmonella enter the intestine via fecal oral route via contaminated food and make its way to gallbladder via blood vessel that supply intestinal tract.

establish reservoir there and shed for long period of time (chronic carrier)

origin: Mary Typhi (italian cook)

Question 7

3 lines of defense (ours)

Answer 7

innnate and adaptive immunity

innate immunity has our 1st and 2nd line of defense.
adaptive immunity has our 3rd line of defense

1st) physical barrier (skin/mucous membrane), chemical barrier (psoriasin prevent growth of E coli on skin), normal microflora, genetic barrier
2nd) inflammation, fever, phagocytosis, cytokinesis
3rd) (adaptive) B and T cells.

Question 8

Skin entry, how does parasitic larvae and fungus gain entry?

Answer 8

parasitic larvae:
enter via burrow through skin (especially larvae from helminths family) move in via corkscrew motion. some have even evolved and can secrete keritinase like fungi.

Fungi: secrete keritinase. digest/breakdown skin keritinised layer. make its way through for nutrient absorption.

Question 9

skin entry via bite for vertebrates and invertebrates

Answer 9

vertebrates: bite: rabies via skunk, bat, racoons, dogs, cats, etc.
invertibrates: bite

virus via mosquito (dengue, west wile, zika)

bacteria via ticks and fleas (ticks: lyme) (fleas: plaque)

protozoans via sandflies and mosquitoes:
(trypanosoma sleep sickness via sandflies)
(mosquito: malaria)

Question 10

Entry of rabies, rabies details

Answer 10

Via bite

very slow moving virus (thus if bitten from limbs, can receive vaccine to stop)

virus move toward CNS (thus dangerous if bitten in face)

rabies vaccine is effective

Question 11

Dengue: entry, type,

Answer 11

Type; Virus

dengue virus enter via mosquito bite.

FYI
Dengue fever is a mosquito-borne tropical disease caused by the dengue virus. Symptoms typically begin three to fourteen days after infection. These may include a high fever, headache, vomiting, muscle and joint pains, and a characteristic skin rash. Recovery generally takes two to seven days.

Question 12

West Nile: entry, type

Answer 12

type: virus

west nile virus enter via mosquito bite

FYI
There are no vaccines to prevent or medications to treat WNV in people. Fortunately, most people infected with WNV do not feel sick. About 1 in 5 people who are infected develop a fever and other symptoms. About 1 out of 150 infected people develop a serious, sometimes fatal, illness

Question 13

Zika Virus: entry, type, important info **

what is special about zika virus?

Answer 13

type: virus

Zika Virus enter via mosquito bite AND/OR SEXUALLY

**Zika virus is the ONLY virus with transmission mode of BOTH sexually and as well as mosquito bite

Most people infected with the Zika virus have no signs and symptoms. Some people have mild fever, rash and muscle pain. In rare cases, the Zika virus may cause brain or nervous system complications

*****Women who are infected with the Zika virus during pregnancy have an increased risk of miscarriage. Zika virus infection during pregnancy also increases the risk of serious birth defects in infants, including a potentially fatal brain condition called microcephaly (via placenta entry route)

Question 14

Lyme Disease: entry, type

Answer 14

Type: bacteria

entry via btie of TICKS

Question 15

plaque, entry, type

Answer 15

type: bacteria

entry via bite of fleas (vector), rodents (reservoir)

plaque pathogen is zoonitic, from rodents as reservoir to humans through fleas as vectors.

bacteria multiple and stay in fleas GUT. when flea bite us, it contains bacteria in its saliva.

Question 16

Trypanosoma (sleeping sickness): entry, type

Answer 16

type: protozoan

transmitted via bite of sandflies

sleeping sickness. 2 form: american and african.

Question 17

malaria: entry, type

Answer 17

type: protozoan

entry via bit of mosquito

Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause yellow skin, seizures, coma, or death. Symptoms usually begin ten to fifteen days after being bitten by an infected mosquito.

Question 18

HPV (Human papillion virus) entry, type, replication, target

Answer 18

type: virus

HPV targets basal epithelial cell (b/c virus only target living cell, skin is dead on surface)

enter via microabrasion, cuts, wounds on skin surface.

replication: synchronized with differentiation cycle of basal epithelial cell.

HPV sheds in semen (enter via microabrasion during intercourse)

HPV NEVER enter via blood (to avoid immune defense cell)

HPV is the most common sexually transmitted infection (STI

HPV Gardasil vaccine is effective to prevent, but NOT treat.

vaccine only effective in preventing 4 strains out of 30
(6, 11, 16, 18)

genital warts, cancer, cervical cancer, throat cancer, anal cancer

there are more vaccine now for diff strains.

Question 19

Psoriasin

Answer 19

skin secrete psoriasin to inhibit the growth of E coli on skin.

chemical antimicrobial agent.

Question 20

non invasive pathogen

Answer 20

dont enter body.

example: tetanus is a non invasive bacteria.

chills at wound site and secrete toxin closfridium tetani (tetanus).

toxin is picked up by blood and distributed throughout body, this is why tetanus is felt throughout the body and not in one spot)