Test 3: Intro to Parasites

Question 1

Before the 1700’s, what did they think cause tooth decay?

Answer 1

worms
- proven due to bacteria

Question 2

How are parasites relevant in oral disease?

Answer 2

• 2 protozoa are

Question 3

If it benefits both organism and other organism?

Answer 3

mutalism

Question 4

What is the definition of a parasite?

Answer 4

• when one organism lives in close association with and usually at the expense of another
• usually do not kill
• due to result of long co-evolutationary histories

Question 5

Why don’t parasites kill?

Answer 5

• because they require the host to survive and have adapted overtime

Question 6

Is TB considered to be in parasitology?

Answer 6

• no, only because they thought TB germs would kill although they fit the other criteria

Question 7

What does parasitology usually have in common in regards to the disciplines/criteria?

Answer 7

medical entomology (insects)

Question 8

What is the definition of a definitive host?

Answer 8

• where sexually mature adult parasite lives
  (zygote type of protozoan)

Question 9

What is the definition of intermediate host?

Answer 9

• supports a stage in parasite development

Question 10

What is the definition of a dead-end host?

Answer 10

• on where the parasite does not replicate or transmit, but dies which can potentially cause more significant disease

Question 11

What are protozoans?

Answer 11

• single-celled eukaryotes
• greek for first animals
• originally classified by type of motility: flagellates

Question 12

Does sporozoa move?

Answer 12

No! It does NOT move

Question 13

What is another word for helminths?

Answer 13

• worms and flukes

Question 14

How are the major human infections involved in helminths spread? (the big 3)

Answer 14

• soil-transmitted

Question 15

What are the big 3 helminths?

Answer 15

• giant roundworm (ascaris lumbercoides)
• whipworm (trichuris trichuria)
• hookworms (necator and ancylostoma)

Question 16

Which are arguably the most common infectious agents?

Answer 16

helminths

Question 17

Who does pinworms infect?

Answer 17

infect nearly all children and adults are asymptomatic

Question 18

What is toxoplasma gondii?

Answer 18

• an intracellular protozoan
• risk of congenital transmission/ocular disease so only a problem with pregnant women
• often asymptomatic with rates at 50%

Question 19

What is trichomonas vaginalis?

Answer 19

• often asymptomatic venereal disease

Question 20

What is giardia?

Answer 20

• most common acute symptomatic human parasite disease
• no geographic boundaries
• commonly seen in urban and rural

Question 21

What percent of humans have parasite infections?

Answer 21

• an estimate of 50% with 4.46 billion

Question 22

How many US people were parasite positive in the stool specimen research?

Answer 22

• 10-33%

Question 23

What are blastocysts?

Answer 23

algae-like protozoan
- have some common symptoms with GI problems

Question 24

What are the 4 modes of parasitic infections transmission?

Answer 24

• ingestion
• direct skin penetration
• direct person to person
• insect bites

Question 25

What is the one distinctive feature of all parasites?

Answer 25

- malnutrition (lose weight)

Question 26

Why are many parasitic infections less acute compared to viral/bacterial diseases?

Answer 26

- co-evolution favors reduced host damage

Question 27

What is the hygiene hypothesis have to do with parasites?

Answer 27

- big families and the kids have a lot less autoimmune diseases - worms are our friends and we shouldn't eliminate them or we will have more autoimmune disease

Question 28

How are parasites transmitted?

Answer 28

- egg cysts/ larvae - penetrate skin as adult parasites - toxoplasma= congenitally

Question 29

How can we reduce parasite infection?

Answer 29

- clean water infrastructure, sanitation

Question 30

What is the tx for parasites?

Answer 30

- most commonly respond well to tx - anti parasitic drugs target eukaryotic cells - **for protozoans: metronidizaole (flagyl)** - **for worms: benzamidazoles**

Question 31

How does metronidazoles work?

Answer 31

- convert to an active agent by anaerobic metabolism which then causes DNA damage - for protozoans - not much resistance to it because it's not specific

Question 32

How does benzamidazoles work?

Answer 32

- interfere with nematode tubule function, killing worm movement and worms in several days - for worms

Question 33

What is the prevention for parasites?

Answer 33

- not many vaccines for parasites - really just improve sanitation and hygiene and insect vector control programs - insect nets treated with pyarthin

Question 34

What should travelers consider for parasitic invention?

Answer 34

- wearing minimal shoes to avoid hookworms - mosquito netting, insect repelling - avoid swimming in fresh water - eating food more cooked - remain hydrated

Question 35

What ribosome grouping does ciliates have?

Answer 35

16s (not 18s like eukaryotes)

Question 36

What ribosome grouping does ciliates have?

Answer 36

16s (not 18s like eukaryotes)

Question 37

What is the insect parasite worth mentioning?

Answer 37

head louse - spread head-to-head

Question 38

What is nightsoil fertilizer?

Answer 38

good fertilizer where many worm eggs live and survive in it