Module 8 Fleas Flashcards
flea taxonomy and general info
order siphonaptera ("sucking-wingless)
facultative ecotparasitesflea anatomy
small, wingless laterally flattened (different than other insects we have talked about) rows of specialized setae ctenidia (combs) strong legs for jumping
flea development
holometabolous (wings develop inside; egg - larva - pupa - adult)
larva feed on blood-rich feces of adults and don’t require host
human flea
Pulex irritans
will feed some on humans but mainly on dogs
lack ctenidia
cat flea
ctenocephalides felis
important pest of humans and pets
orriental rat flea
Xenopsylla cheopis
lacks ctenidia
main vector for plague and murine typhus
chigoe flea
Tunga pentrans (aka Jigger or Sand flea) major medical importance female invades host skin
plague
most significant flea-borne disease
parasite: Yersinia pestis
vector: transmitted to rats by Oriental rat flea (Xenopsylla cheopis)
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
bubonic plague
most common type in epidemics
grossly enlarged bubos (lymph nodes)
septicemic plague
parasite passes lymph nodes and enters deep into skin
erodes capillary walls and turns skin black
pneumonic plague
most life-threatening
caused by inhalation of Y. pestis
pneumonia-like symptoms
murine typhus (endemic typhus)
parasite: Rickettsia typhi
vectors: fleas of genus Xenopsylla (Orriental rat flea)
transmission cycle for murine typhus
bacteria ingested by flea
it invades midgut and replicates
then voided in feces (doesn’t kill flea)
tungiasis
vector: Tunga pentryns (Chigeo flea)
female burrows into skin of host which causes painful lesions and secondary inflammation
