01. Intro to Parasitology

Question 1

What kind of parasite is Ascaris lumbricoides?

Answer 1

Roundworm/nematode

Question 2

What kind of parasite is Trichuris trichiura? what is its common name?

Answer 2

Human whipworm - nematode

Question 3

What kind of parasite is Clonorchis sinensis? What organ does it infect?

Answer 3

Liver fluke

Question 4

What is the parasite responsible for Chagas’ disease?

Answer 4

Trypanosoma cruzi

Question 5

What parasite causes leishmaniasis?

Answer 5

Leishmania

Question 6

What parasite causes african sleeping sickness?

Answer 6

Trypanosoma brucei

Question 7

What are common parasites in North America?

Answer 7

Pinworms
Giardia
Dog roundworm (dog heartworm)
Toxoplasma (cat feces)
Ticks (lyme disease)

Question 8

Are bacteria or viruses parasites?

Answer 8

No, only eukaryotic organisms can be classified as parasites

Question 9

What are the requirements to be a parasite?

Answer 9

May be an animal or a plant (eukaryotic)
Not bacterial or viral
Can be unicellular (malaria/toxo) or multicellular (worm/insect)
Can live in or on a host

Question 10

Definition of parasite?

Answer 10

eukaryotic organism that acquires some of its basic nutritional requirements through its intimate contact with another living organism.

Question 11

What are unicellular parasites called?

Answer 11

Protozoa

Question 12

What are multicellular parasites called?

Answer 12

Metazoa

Question 13

Define ectoparasite

Answer 13

lives on the external surface of another living organism

ex: head louse, tick, flea

Question 14

Define endoparasite

Answer 14

lives within an organism

can be metazoan (Hookworm, tapeworm, roundworm, pinworm) or protozoan (Leishmania, Plasmodium, Trypanosoma, Giardia)

Question 15

Define hemiparasite

Answer 15

Parasitic plant that derives some or all of its sustenance from another plant (ex: mistletoe)

Question 16

Define definitive host

Answer 16

when the parasite reached sexual maturity in that host (ex: mosquito for malaria, cat for toxo)

Question 17

Define intermediate host

Answer 17

parasite always asexual in this host; where the parasite completes a part of its life cycle and undergoes morphological changes and physiological changes (ex: human for malaria, mice for toxo)

Question 18

Define reservoir host

Answer 18

alternate host from which the parasite can be transmitted to human or domestic animals. The parasite can still go through its life cycle - important source of infection in epidemiology (ex: rat for toxo)

Question 19

Define accidental host

Answer 19

host that accidentally harbours an organism that is not usually parasitic in this host and cannot be transmitted. it is a dead end for the oarasite and can damage the host (ex: human and pork tapeworm Taenia solium, causes cysticercosis (in brain and eye)

Question 20

Define vector

Answer 20

plays an active roll in Tmission of parasite, can be definitive or intermediate. transports the parasite from an infected to a non-infected host (ex: female Anopheles mosquito that Tmits malaria

Question 21

Parasitism (process)

Answer 21

1) encounter: parasite meets the host
2) entry (may not be the location where damage occurs)
3) spread (this is at proper location, the parasite will propagate here)
4) multiplication
5) Damage: by parasite and or host response
6) outcome: parasite or host wins or coexist

Question 22

what are the main modes of transmission?

Answer 22

• skin, respiratory, gastrointestinal, urogenital

- vector borne, blood transfusion, or organ transplant

Question 23

what is external transmission? is there growth of the pathogen during this step?

Answer 23

• the passive carriage of the pathogen on the body or vector

- no

Question 24

what is internal transmission?

Answer 24

• when the pathogen is carried within the vector

Question 25

what are the two types of internal transmission?

Answer 25

- harbourage transmission: pathogen does not undergo changes within the vector (mechanical vector) - biological transmission: pathogen undergoes changes within the vector (biological vector)

Question 26

define infectivity

Answer 26

ability of the organism to establish a discrete, focal point of infection

Question 27

define invasiveness

Answer 27

ability of organism to spread to adjacent or other tissues

Question 28

penetration of host's mucous membranes can be ______ or ______

Answer 28

- active | - passive

Question 29

give examples of passive penetration

Answer 29

- skin lesions - insect bites - wounds

Question 30

once below the mucous membrane, what does a parasite require for spread to deeper tissues?

Answer 30

- production of specific products and/or enzymes that promote spreading - circulatory system gives the parasite full access to the body

Question 31

define symbiosis

Answer 31

two species of organisms that lived together, with no implication regarding the length or outcome of the association

Question 32

what are the 4 types of symbiosis?

Answer 32

- phoresis - commensalism - mutualism - parasitism

Question 33

which symbioses are considered "loose" associations?

Answer 33

phoresis and commensalism

Question 34

which symbiosis are considered "intimate" associations?

Answer 34

mutualism and parasitism

Question 35

define phoresis

Answer 35

- to carry - an association in which one species provides shelter, support, or transport for another organism of a different species

Question 36

define commensalism

Answer 36

- "at the same table together" - one member of the association benefits (one way benefit) while the other is not affected. no harm is exerted in either direction

Question 37

define mutualism

Answer 37

- reciprocal - highly inter-dependent association, to the extent that the both species benefit from the association in terms of their growth and survival - two way benefit, no harm

Question 38

define parasitism

Answer 38

- intimate relationship between two organisms in which one (the parasite) lives on, off or at the expense of the other (host)

Question 39

define helminth

Answer 39

multicellular parasitic worms that include flukes, tapeworms, and roundworms

Question 40

define protozoa

Answer 40

unicellular endoparasites that include flagellates, amoebas, malarial organisms

Question 41

define arthropods

Answer 41

multicellular ectoparasites that include insects (lice, fleas) and arachnids (ticks, mites) that are carriers (vectors) of diseases