Chapter 4 Page 2 Flashcards
Family Demodicidae:
unusual family of mites (that become specialised skin parasites of humans and other mammals.
-They are HOST-SPECIFIC.
Demodex cati
Cat
Demodex equi
horses
Demodex phylloides
pigs
Demodex bovis
cattle
Demodex musculi
mice
Demodex caviae
guinea pigs
Two species that live on humans:
Demodex folliculorum
Demodex brevis
Demodex Folliculorum:
carrot shaped and lives in the hair follicle of simple hair.
Demodex Brevis
has a shorter stumpy body and lives in the sebaceous glands of vellus hair.
The life cycle of Demodex Folliculorum:
consists of an egg, larval, protonymph, deutonymph, and adult stage. (Takes about 14-18 days)
1) mites feed on ….
2) eggs are laid on …
1) host cells
2) hosts skin
Family Sarcoptidae:
contains scabies mites:
Sarcoptes scabiei
Knemidocoptes mutans (scaly legs in hens)
Notoedres cati: cats/dogs
Genus Sarcoptes:
Sarcoptes scabiei exists as a variety of Host-Specific Sub-Species.
Example of sarcoptes host-specific sub-species
1) Humans are infected by Sarcoptes scabiei var hominis
2) Dogs are infected by Sarcoptes scabiei var canis
Mite infestation can be an indicator of
poverty/neglect
The mites are protected within their burrows and are not removed by frequent washing i
hot soapy water
Scabies is a problem with cramped unhygienic circumstances
in the urban squatter settlements and refugee camps.
Sarcoptes scabiei are small circular-shaped mite with small legs.
Front 2 pair of legs terminate in structure called pedicels that look a bit like SINK PLUNGERS.
Scabies are transmitted by
15-20 minutes of close physical contact and depends on the # of mites involved.
Scabies can be a particular problem for poor people and children b/c they
wear fewer clothes in the tropical countries due to the heat.
Night = sleeping together on a bed, bunk, hammock there is more skin contact increasing chances of getting it
