Lice and Fleas Flashcards
What are the three types of human lice?
Pediculus humanus capitis (head louse)
Pediculus humanus corporus (body louse)
Pthirus pubis (pubic/crab louse)
Which lice type is known to spread disease?
only the body louse
How are lice spread?
through person-person contact, NOT through animals
How do lice move?
crawling. cannot hop or fly
they are wingless but have claws
What are some defining physical characteristics of lice?
wingless
have 6 legs
antennae have no more than 5 segments
abdomens are longer than wide
How can head lice potentially cause disease?
secondary bacterial infections caused by scratching
What do adult head lice do to avoid detection?
they can change colour to be the same as the host’s hair
How can you get rid of head lice?
use insecticide shampoo for the adults, and use a nit comb to pull out the nits from the hair
How long does it take for the nits to hatch?
one week
Where do body lice live?
in the seems and linings of unwashed clothing, blankets and sheets.
only move to the skin to feed because people do not usually have a lot of body hair
When will body lice die?
after 1-2 weeks of not having a blood meal
Which diseases can body lice spread?
epidemic typhus, trench fever, and louse-borne relapsing fever
How can linens be rid of body lice?
washing in very hot water
Where on the body are pubic lice found?
attached to coarse hair, including pubic hair, eyebrows, eyelashes, beard, moustache, chest, armpits, etc
their bodies are wider and their legs further dispersed to grasps these hairs
How can you be rid of pubic lice?
using insecticide shampoo and a nit comb for the eggs
When will pubic lice die?
after 24-48 hours of not having a blood meal
What are the distinctive features of fleas?
6 legs wingless have long hind legs that allow them to jump a disproportionate small head bodies are laterally compressed no attaching appendages
What kind of pathogens can fleas transmit?
bacteria (bubonic plague), protozoa, and helminthes (Dipylidium caninum)
What are the four main species of fleas that infest humans?
cat flea: Ctenocephalides felis
dog flea: Ctenocephalides canis
human flea: Pulex irritans
rat flea: Xenopsylla cheopis
How can the cat and dog flea be differentiated?
the cat flea has mouth combs that are approximately all the same length
the front dog comb is half the length of the second comb
Which diseases can Ctenocephalides species cause?
rickettsial diseases including Rickettsia typhi
also spotted fever, typhus, and scrub typhus
intermediate hosts for some tapeworms
How can the human flea species be distinguished from the rest?
it does not have any combs
What does the human flea do?
salivary proteins can cause allergic reactions
What diseases does the rat flea transmit?
bubonic plague (Yersinia pestis) and endemic typhus (aka murine typhus)
Does the rat flea have ctenidia (combs)?
no
How can flea infections be treated?
itching can be treated with antihistamine or hydrocortisone creams using dehumidifiers (eggs need humidity to hatch) + air conditioning (adults need a certain temp) + vacuuming
