I Topic: Introduction into parasitology

Question 1

pathogenicity vs virulence

Answer 1

Pathogenicity is the ability of a microorganism to produce a disease.

Virulence is the degree of pathogenicity so the severity of the disease produced.

Question 2

Colloquial names for:
nematode
cestode
trematode

Answer 2

nematode = round worms
cestode = tapeworms
trematode = flukes

Question 3

define acaroses

Answer 3

infectious diseases caused by parasitic mites and ticks

Question 4

define Entomoses

Answer 4

infectious diseases caused by parasitic insects

Question 5

difference between acaroses and entomoses

Answer 5

the number of legs

Question 6

define scolex
(plural scolices or scoleces or scolexes)

Answer 6

The structure at the front end of a tapeworm which, in the adult, has suckers and hooks by which it attaches itself to a host.

Question 7

define proglottids

Answer 7

each segment in the strobila (segmented body) of a tapeworm, containing a complete sexually mature reproductive system.

Question 8

Examples of Regressive development in parasites:

Answer 8

• Helminths lack locomotive organs
• Many parasitic insect lack wings
• Endoparasites lack eyes
• Intestinal organ parasites lack their
  own intestinal organs
• Most endoparasites lack respiratory
  organs

Question 9

Examples of Progressive development in parasites:

Answer 9

• Hypertrophy of parasites’ reproductive organs
• Many are hermaphrodites
• Many attachment organs are larger (suckers, bothrids, hooks, etc.)
• Extremely high fertility
• Helminths eggs very resistant in the environment
• Metabolism of parasites is intensive and they have rapid growth

Question 10

what kingdom to protozoa belong to?

Answer 10

eukaryotes

along with helminths and arthropods of course

Question 11

Endoparasite location within the host: (4)

Answer 11

• Lumen parasites
• Cavity parasites
• Tissue parasites
• Cell parasites

Question 12

sporozoite
merozoite
trophozoite
schizont

Answer 12

forms/life stages of certain endoparasites

Sporozoites invade liver cells, replicate, and produce merozoites.

Rupture of infected hepatocytes releases merozoites into the blood strewn.

Merozoites enter red blood cells and appear as ring-shaped trophozoites.

Nuclear division occurs, producing a multinucleated schizont.

Question 13

Obligate parasites vs facultative

Answer 13

Depend upon the host entirely throughout the life eg. Babesia spp.

Facultative parasites are able to live free as well eg. many ectoparasites.

Question 14

define imago/imaginal (adj.)

Answer 14

In biology, the imago (Latin for “image”) is the last stage an insect attains during its metamorphosis, its process of growth and development; it is also called the imaginal stage, the stage in which the insect attains maturity.

It follows the final ecdysis (exoskeleton moult) of the immature instars.

Question 15

define Monoxenous vs heteroxenous

Answer 15

Monoxenous = living on only one kind of host throughout its life cycle (geohelminths)

• Simple life cycle
• Direct transmission
• Many nematodes

heteroxenous: infesting more than one kind of host. especially : requiring at least two kinds of host to complete the life cycle.

Question 16

define Heteroxenous

Answer 16

Heteroxenous = infesting more than one kind of host. Especially: requiring at least two kinds of host to complete the life cycle.
(biohelminths)

• Complex life cycle with several hosts
• Transmission to final host through many hosts
• Most of the cestodes and trematodes

Question 17

define Paratenic host

Answer 17

Paratenic also known as reservoir host

Paratenic hosts are typically defined as hosts that occur at some stage before the definitive host, but in which the parasite shows no apparent growth or development.

Alternatively, an optional intermediate host is one which the larvae usually enters passively, along with ingested food.

Question 18

Definitive host
vs
Intermediate host

Answer 18

Definitive = A host where the parasite becomes an adult and produces eggs/cysts.

Intermediate = Organism that harbors sexually immature parasite and the parasite must undergo development in order to complete life cycle. “transport host”

Question 19

define monoecious and dioecious

Answer 19

monoecious = essentially Hermaphrodite
Reproductive organs in one organism.

Dioecious
Reproductive organs are separate organs
– female and male. 2 sexes within species.

Question 20

Incubation period in parasitoses =

Answer 20

period between infection of an individual by parasite and the manifestation of the disease

Question 21

Prepatent period =

Answer 21

period between infection with a parasite and the demonstration of the parasite in the body (= discovery of parasite infective forms from the blood/feces)

Question 22

Patent period =

Answer 22

time during which the parasitic organism can be demonstrated in the body

Question 23

3 examples of Indirect horizontal transmission

Answer 23

through Intermediate host

through vectors (contamination,
inoculation (bite, sting, blood))

fomites (feed, water, etc)

Question 24

General host defense mechanisms toward parasites: (3)

Answer 24

1. Physical and Chemical Barriers (Innate Immunity)
2. Nonspecific Resistance (Innate Immunity)
3. Specific Resistance (Acquired Immunity)