Module 8 Fleas Flashcards Preview

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Flashcards in Module 8 Fleas Deck (15):
1

flea taxonomy and general info

order siphonaptera ("sucking-wingless)
facultative ecotparasites

2

flea anatomy

small, wingless
laterally flattened (different than other insects we have talked about)
rows of specialized setae
ctenidia (combs)
strong legs for jumping

3

flea development

holometabolous (wings develop inside; egg - larva - pupa - adult)
larva feed on blood-rich feces of adults and don't require host

4

human flea

Pulex irritans
will feed some on humans but mainly on dogs
lack ctenidia

5

cat flea

ctenocephalides felis
important pest of humans and pets

6

orriental rat flea

Xenopsylla cheopis
lacks ctenidia
main vector for plague and murine typhus

7

chigoe flea

Tunga pentrans (aka Jigger or Sand flea)
major medical importance
female invades host skin

8

plague

most significant flea-borne disease
parasite: Yersinia pestis
vector: transmitted to rats by Oriental rat flea (Xenopsylla cheopis)

9

life cycle of parasite in plague

-bacteria is consumed from blood meal of rat
-bacteria multiplies in gut
-more blood cannot pass bacteria obstruction
-it is contaminated by the bacteria and then regurgitated back into bite by flea

10

bubonic plague

most common type in epidemics
grossly enlarged bubos (lymph nodes)

11

septicemic plague

parasite passes lymph nodes and enters deep into skin
erodes capillary walls and turns skin black

12

pneumonic plague

most life-threatening
caused by inhalation of Y. pestis
pneumonia-like symptoms

13

murine typhus (endemic typhus)

parasite: Rickettsia typhi
vectors: fleas of genus Xenopsylla (Orriental rat flea)

14

transmission cycle for murine typhus

bacteria ingested by flea
it invades midgut and replicates
then voided in feces (doesn't kill flea)

15

tungiasis

vector: Tunga pentryns (Chigeo flea)
female burrows into skin of host which causes painful lesions and secondary inflammation