26. Arthropods (fleas, part 2) Flashcards

1
Q

do fleas have wings?

A

no

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2
Q

what shape are fleas?

A

oval

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3
Q

what is specially adapted in fleas?

A

the hind legs to enable them to jump long distances

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4
Q

what is morphologically different about a fleas head?

A

it is disproportionally small

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5
Q

how many species of fleas exist?

A

over 2000

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6
Q

in which direction are fleas bodies compressed? why is this helpful?

A

laterally, so they may move through the feathers and hairs on the hosts body

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7
Q

what are fleas mouthparts adapted for?

A

piercing skin and sucking blood

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8
Q

what do fleas require?

A

a blood meal

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9
Q

what color are fleas?

A

light to deep brown in color

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10
Q

why are fleas of clinical significance to humans?

A

because they are vectors for many other diseases

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11
Q

what kind of infections do fleas transmit to humans and other animals?

A
  • bacterial
  • viral
  • protozoan
  • helminth
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12
Q

what are examples of the bacterial infections transmitted by fleas?

A

Fleas have helped cause epidemics by transmitting the bubonic plague between rodents and humans by carrying Yersinia pestis bacteria

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13
Q

what are examples of the protozoan infections transmitted by fleas?

A

Trypanosome protozoans such as those of the subgenus Herpetosoma, use a variety of flea species as vectors

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14
Q

what are examples of the helminth infections transmitted by fleas?

A

fleas are intermediate hosts for tapeworms, including the cestodes Hymenolepis and Dipylidium

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15
Q

what are the life cycle steps of fleas?

A
  • eggs
  • larvae
  • pupae
  • adults
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16
Q

who sheds the flea eggs into the environment? (male/female)

A

the female

17
Q

do fleas multiply rapidly or slowly?

A

rapidly

18
Q

what are the four main species of fleas that infest humans?

A
  • Cat flea (Ctenocephalides felis)
  • Dog flea (Ctenocephalides canis)
  • Human flea (Pulex irritans)
  • Oriental rat flea (Xenopsylla cheopis)
19
Q

why are Ctenocephalides spp. of medical importance?

A

they are vectors of rickettsial diseases - example Rickettsia typhi

20
Q

what are the three groups that Rickettsia is classified into?

A
  • spotted fever
  • typhus
  • scrub typhus
21
Q

what can Ctenocephalides spp. serve as an intermediate host for?

A

tape worms, including Hymenolepis and Dipyladum

22
Q

what are morphological characteristics of Ctenocephalides felis?

A

Similar to the dog flea, except:

  1. head is elongated,
  2. front comb (ctenidia) is almost as long as the rest of the combs.
23
Q

what are morphological characteristics of Ctenocephalides canis?

A

Similar to the cat flea, except:

  1. head is strongly rounded,
  2. front comb (ctenidia) is half the size of the rest of the combs.
24
Q

which species does the Pulex irritans infect?

A

humans

25
Q

what is different about the head of the Pulex irritans flea of humans?

A

Head without ctenidia (i.e. comb structures).

Front head smoothly rounded.

26
Q

is Pulex irritans an efficient vector of flea-borne diseases?

A

no, this species is not an efficient vector of any flea‐borne diseases, but its bite can cause allergic reactions due to salivary proteins

27
Q

what is the vector of Yersinia pestis (bubonic plague)?

A

Xenopsylla cheopis

28
Q

in North America, what us the cycle of plague?

A

Xenopsylla cheopis and prairie dogs

29
Q

what is a form of typhus transmitted by Xenopsylla cheopis?

A

Murine typhus, also called endemic typhus

30
Q

what organism is Murine typhus in contrast to? what is that transmitted by?

A

epidemic typhus, which is transmitted by lice

31
Q

what is the rat flea?

A

Xenopsylla cheopis

32
Q

what is characteristic about the head of the rat flea?

A

Head without ctenidia (i.e. comb structures)

Front head rounded

33
Q

how can the itching assiciated with flea bites be treated?

A

with anti-itch creams, such as antihistamines or hydrocortisone

34
Q

what is critical to flea survival?

A

humidity

35
Q

why is humidity key to flea survival?

A

eggs need relative humidity of at least 70–75% to hatch, and larvae need at least 50% humidity to survive

36
Q

what temperatures are characteristic for flea life?

A
  • fleas thrive at higher temperatures, but need 21°to 32°C to survive.
  • lower temperatures slow down or completely interrupt the flea life cycle
37
Q

what would interrupt the flea life cycle?

A

Using dehumidifiers with air conditioning and vacuuming will interrupt the flea life cycle