General Concepts in parasitology

Question 1

Are parasites bacteria, eukarya, or archaea?

Answer 1

Eukaryotes

Question 2

Symbiont

Answer 2

Any organism that spends a portion or all of its life intimately associated with
another living organism of a different species, independently of the nature of the
association

Question 3

Commensalism

Answer 3

is a type of symbiosis in which spatial proximity allows the
commensal to feed on substances captured or ingested by the host. The two
partners can survive independently, for example hermit crabs and the sea
anemones they carry on their borrowed shells

Question 4

Phoresis

Answer 4

the phoront, usually the smaller organism, is mechanically carried by
the other, usually larger, organism, the host. Unlike commensalism, there is no
dependency in the procurement of food by either partner.

Question 5

Mutualism

Answer 5

• is an association in which the mutualist and the host depend on each
  other physiologically. A classic example of this type of relationship occurs between
  certain species of flagellated protozoans and the termites in whose gut they live.
  The flagellate synthesizes and secretes cellulases the termites need to digest
  wood.

Question 6

Parasitism

Answer 6

a parasite usually the smaller of the two, and a host which the parasite is physiologically dependent.
-can be permanent or dependent
-parasites derive essential nutrients directly from the host

Question 7

Endoparasites

Answer 7

live within the body of the host at sits such as the alimentary tract, liver, lungs, urinary bladder

Question 8

Ectoparasites

Answer 8

are attached to the outer surface of the host or are superficially embedded in the body surface. Ex. lice or ticks

Question 9

Protozoan

Answer 9

microscopic eukaryotic single organisms that are free living or parasitic in nature. only 70 are parasitic

Question 10

Metazoans

Answer 10

multicellular eukaryotic invertebrates with tube-like or flattened bodies
exhibiting bilateral symmetry. Many helminths are free-living organisms in aquatic and
terrestrial environments. Approximately 340 species are pathogenic parasites.

Question 11

Direct Life Cycle

Answer 11

-one host cycle(monoxenous parasite)
-usually called hand to mouth
-ex: roundworms

Question 12

Indirect Life Cycle

Answer 12

-requires two or more hosts (heteroxenous parasite)
-ex: toxoplasma Gondii

Question 13

A host is definitive when…

Answer 13

A parasite attains sexual maturity

Question 14

a host is intermediate when…

Answer 14

It serves as a temporary environment for the development of the parasite

Question 15

A host is classified as a transfer or paramedic host when….

Answer 15

when it is not necessary for the completion of the parasites life cycle but is utilized as a temporary refuge.

Question 16

A host is classified as a reservoir host when…

Answer 16

-when its a “living source” of the parasite and not host of primary concern.
-Ex: rodents

Question 17

Vector

Answer 17

arthropod or some other invertebrate that serves as a host as well as a
carrier for a parasite. Unlike the transfer, it is required for the parasite to complete
its life cycle.

Question 18

Mechanisms of entry

Answer 18

-oral
-sexual
-inhalation
-direct contact
-anthropod vector

Question 19

R strategist

Answer 19

large numbers of offspring with no density-dependent
restraints, little/no competition

Question 20

K strategist

Answer 20

K- strategist: Tsetse fly produces one egg at a time, lice produce
1-few eggs and invest much energy into offspring.

Question 21

Parasite reproductive strategies

Answer 21

-common to have sexual and asexual reproduction
-having one or more hosts

Question 22

Immune evasion strategies

Answer 22

-antigenic variation
-seek out niches that the host immune response cannot reach such as naked cytoplasm of the cell
-inhibit host protective human responses
-produce a long dormant stage

Question 23

Non immune evasion strategies

Answer 23

-produce environmentally resistant stage

Question 24

Mechanisms of pathogenesis

Answer 24

-cell death
-virulence factors
- by products of parasite metabolism
- damage during migration
-mechanical impacts
-triggering of immune response