Parasites

Question 1

Difference between parasites and bacteria/viruses?

Answer 1

Nucleus and mroe complicated cell structure
Can be single-celled or multicellular

Question 2

Protozoan vs helminths?

Answer 2

Single celled vs multicellular

Question 3

Which major global parasitic infections have been prevented by vaccines?

Answer 3

None - possibly due to evolution allowing them to hide from immune response, possibly from lack of research

Question 4

Where are most parasitic locations? WHy?

Answer 4

Africa and south Asia due to poverty levels

Question 5

% of deaths from infectious disease in developped vs developping

Answer 5

5% in developped, 50% in developping

Question 6

Prevalence and at risk population of Ascariasis

Answer 6

807 million, 4.2 billion

Question 7

Prevalence and at risk population of Trichuriasis

Answer 7

604 million, 3.2 billion

Question 8

Prevalence and at risk population of Hookworm

Answer 8

576 million, 3.2 billion

Question 9

Prevalence and at risk population of Schistomiasis

Answer 9

207 million, 1.3 billion

Question 10

Prevalence and at risk population of lymphatic filariasis

Answer 10

120 million, 1.3 billion

Question 11

Prevalence and at risk population of onchoceriasis

Answer 11

37 million, 90 million

Question 12

Length, lifespan and eggs per day of Ascaris

Answer 12

20cm, 1 year, 200,000 eggs per day

Question 13

Length, lifespan and eggs per day of trichuris

Answer 13

5cm, 2 year, 5000 eggs per day

Question 14

Length, lifespan and eggs per day of hookworm

Answer 14

15mm, 5 year, 10,000 eggs per day

Question 15

What helminths fall into the category of STH (soil transmitted helminths) // how much of the world is at risk

Answer 15

Ascaris, Trichuris, Hookworm - 1/3

Question 16

Where do STH reside, how are they transmitted

Answer 16

gastrointestinal tract, transmitted into soil via eggs that are excreted in the feces (Ascaris and Trichuris - contamination of water, food) or by penetration of the larvae through the skin (hookworm)

Question 17

Effects of STH // deaths per year

Answer 17

malnutrition, growth stunting, cognitive defects and can suppress immune system
50,000 deaths per year

Question 18

Life cycle of Ascaris

Answer 18

1. small intestine (d)
2. fertilized eggs in feces contaminate environment (d) (unfertilized are not infectious)
3. larvae develop to infectivity (i)
4. ingestion
5. larvae hatches in small intestine
6. detour to lungs
7. back to GI tract

Question 19

Hookworm lifecycle

Answer 19

1. eggs in feces (d)
2. rhabditiform larva hatches
3. filaform larva
4. skin penetration (i)
5. travel to GI via lungs

Question 20

Conditions favoring STH

Answer 20

Poverty, poor water filitration, muddy/wet roads and infrastructure

Question 21

Measuring intensity of infection?

Answer 21

of eggs per gram of feces (microscopically analyzed)

Question 22

STH treatment (goal, drug types)

Answer 22

Treatment removes adult worms - reduces worm burden, although reinfection is almost inevitable
Regular treatment in schools (age 5-12)
Drugs: Benzimadoles & ivermectin

Question 23

Lymphatic filariasis: alternate name, life cycle

Answer 23

Elephantiasis: blocks flow of lymphatic fluid (swelling in feet)
1. L3 larvae enter skin from mosquito
2. adults in lymphatics
3. produce microfilariae into lymph and blood (d)
4. ingested by mosquito
5. develop into larvae

Question 24

Onchocerciasis: alternate name, transmission

Answer 24

River blindness: transmitted by blackflies, microfilaria accumulate in eye causing blindness (destroys retina)

Question 25

Theory concerning helminth infections and autoimmune

Answer 25

May reduce autoimmune disease by reducing the overall inflammation (prolongs survival of helminths in GI, but reduces risk of autoimmune diseases)

Question 26

DALY?

Answer 26

Disability adjusted life years (healthy years lost)

Question 27

Where is malaria most common?

Answer 27

Around equator, South America, Africa and South Asia (allows for year round transmission)

Question 28

Plasmodium: alternate name, life cycle

Answer 28

Malaria:
1.Infection (blood meal)
2. travel through blood to liver -> sporozoites
3. merozoites in RBCs
4. gametocytes (retransfer to mosquitos)
Stops blood flow by increasing blood stickiness, clots in brain kill

Question 29

Malaria noble prizes

Answer 29

1907: cause (parasite in blood)
1902: transmission (parasite in mosquito)
2015: medicine

Question 30

Human African Trypanosomiasis: alternate name, distribution, transmission, life cycle

Answer 30

Sleeping sickness, middle of Africa, Tsetse fly
1. injection of T. brucei into blood
2. multiplication by binary fission (blood, lymph, spinal fluid)
3. blood meal
4. multiplication in fly by binary fission
invades CNS, kills via encephalitis

Question 31

Two strands of trypanosomes: where, why

Answer 31

T. brucei in Africa
T. cruzi in south america
evolved differently, from Pangea

Question 32

T. cruzi: alternate name, distribution, life cycle

Answer 32

Chagas disease
From South America, migrated via travellers/blood donations
1. trypomastigote (i) transmission by assasin bug
2.replication into amastigote in muscle
3. replicates into trypomastigote, transmits back to assasin bug
muscle weakening until heart attack (disease carried until death)

Question 33

Forms of Leishmaniasis

Answer 33

Visceral: liver, spleen, bone marrow (deadly without treatment) -> Leishmania Donovani
Cutaneous: face, arms, legs (not deadly, lesions remain, self healing) -> Leishmania Major

Question 34

Leishmaniasis: distribution, life cycle, treatment

Answer 34

South america / Africa around equator (visceral also in Asia)
1. sandfly transmits promastigote, humans transmit amastigote
2. develops/ replicates in macrophage into amastigote
3. retransmission to sandfly
Treatment by ambisome

Question 35

Can post kala-azar dermal leishmaniasis be a reservoir for transmission? (also what is it)

Answer 35

leftover of visceral leishmaniasis, unable to confirm (mostly due to a too small sample size.