Lec 1. Intro to Parasitism Flashcards

1
Q

A parasite that is impacting the Canadian arctic is called _____. You can get it from eating raw meat. It’s usually not a concern because of government regulations, but it’s very prevalent in the north

A

trichinosis

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2
Q

Traditional indigenous tea from Canadian Arctic made from rhododendron leaves could combat drug-resistant _____

A

malaria

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3
Q

Parasitic relationship=

A

a symbiotic relationship in which one partner (parasite) has a trophic relationship with the other partner (host)

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4
Q

Each parasite life cycle stage typically in ___ host(s)

A

one host per life cycle stage
- different life stages can affect different hosts

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5
Q

T/F

The parasite can let its host live, but often kills it

A

false

parasite often harms, but rarely kills the host. The host can’t benefit them if it’s dead!

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6
Q

The objective of parasites is to ___

A

reproduce

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7
Q

List 4 of the main forms of parasitism

Are these categories mutually exclusive?

A
  • Typical parasite
  • Trophically transmitted parasite
  • parasitic castrator
  • parasitoid

Not mutually exclusive, one parasite can fall under more than one of these categories

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8
Q

Typical parasite=

A
  • transmission does not require host death (may accidentally cause death)
  • host can usually still reproduce
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9
Q

Trophically transmitted parasite=

A
  • transmission requires host death (eg. predator-prey interaction)
  • parasite rarely kills host directly
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10
Q

Parasitic castrator

A
  • some typical or trophically-transmitted parasites castrate their host.
  • consume so much of the host’s tissue that the host becomes infertile (some parasites use chemicals)
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11
Q

What might be the purpose of a parasite castrating their host?

A

Then the host doesn’t put energy towards reproduction, so resources are put towards body maintenance, which benefits the parasite

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12
Q

Parasitoid=

A

Transmission requires parasite to kill host directly

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13
Q

Describe trophically-transmitted parasites

A

Parasites that infect each trophic level as it passes through (eg from producer to top predator)

Often different hosts= different life stages of the parasite

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14
Q

Give an example of a trophically-transmitted parasite

A

a typical trematode

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15
Q

Obligate parasite=

A

An organism that MUST be parasitic at some point in its life

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16
Q

Facultative/ opportunistic parasite=

A

An organism that can either be parasitic or free-living
- depends on conditions (host/ enviro)

17
Q

Endoparasite=

A

a parasite that lives inside the host

18
Q

Ectoparasite=

A

a parasite that lives outside the host

eg. lice/ ticks

19
Q

Hyperparasites

A

parasites of parasites

20
Q

If a parasite has a direct life cycle, how many hosts does it have?

21
Q

If a parasite has an indirect/ complex life cycle, how many hosts does it have? Describe what happens in the host(s)

A

Two or more hosts are required.

  • 1 definitive host: this is where the parasite grows, matures, & reproduces
  • 1 or more intermediate hosts: parasite might asexually reproduce here, or just grow
22
Q

Definitive host=

A

A host required for the development of a sexually mature (adult) parasite

Sexual reproduction happens in the definitive host

23
Q

Intermediate host=

A

A host required for a larval parasite to develop into the next stage

24
Q

Vector=

A

blood feeding invertebrate host
eg. mosquito

Can be intermediate (usually) or definitive)

25
For Malaria, is the mosquito or the human the definitive host?
The mosquito! Because that's where sexual reproduction happens
26
Reservoir hosts=
an animal that is infected by a parasite & serves as a source of infection for humans (zoonoses). = host in which parasites can mature & reproduce --> helps maintain the parasite when no normal hosts are available
27
Paratenic hosts=
hosts in which parasite development does not occur --> no parasite development, just a transport - may bridge ecological/ trophic gap in parasite's life cycle
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Prevalence=
proportion of hosts examined that are infected PrevALence= ALL cases/ population @ risk
29
Incidence=
Number of new occurrences of a disease in a population iNcidence= New cases/ Pop @ risk
30
Intensity=
Number of parasites per infected host = total # of parasites/ # infected hosts
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Abundance=
number of parasites per host that was examined = total # of parasites/ All hosts examined
32
Density=
number of parasites per unit of host tissue eg. 20 parasites per liver tissue eg. Parasitemia
33
How can we measure density when parasites are not easily counted?
Parasitemia! % parasitemia= (parasitized RBCs/ total RBCs) x100%
34
Explain the difference bewteen intensity & abundance
Intensity= how bad the infection is within each host (average) Abundance= an estimate of what's going on in the whole population
35
A parasite has a mean density of 2. What does that mean?
If you get this parasite, you'll probably get 2 of them (average)
36