Arthropod Infections Flashcards
different types of louse infestations
head
body
nether
pediculus humanus capitis- head
pediculus humanus corporis- body
phthirus pubis- crab lous
all insects
epi louse
reservoir
worldwide
humans are the only reservoirs and definitive hosts
how louse transmitted
person to person
contact with fomites containing eggs or adults
life cycle louse
location of eggs
undergo incomplete metamorphosis
head lice- eggs in hair (nits)
body lice- eggs in clothes
crab lice- eyebrows and pubic region
the eggs hatch and develop into nymphs – develop into adults
path louse
sensitivity?
vectors???
suck blood ad inject lytic compounds that act as antigens
primary hypersensitivity 3-8 months after original infestation ( sensitivity to feces)
the lice serve as vectors for other viral bacterial diseases
ss louse
what can result
papules, ulcerations, anemia, intense itching
which can result in secondary bacterial infections
result in toxic follicular conjunctivitis due to hyper sensitivity
dx louse
history of contact
identification of insect
tx louse
malathion
bed bug caused by
cimex lenticularius (insect)
undergo incomplete metamorphosis
epi bed bug
found world wide-
humans and non humans
what temps are lethal to bed bug
above 98 or below 5 f
life cycle bed bug
stages?
adults suck blood from humans
lead eggs in bedding and cracks on walls
5 stages of nymph- which all need blood to feed on and grow to next
how can you see bed bug
harborage sites- brown black spots of dried blood - sheets, clothing skin- also have stink glands and smell
path bed bug
time?
characteristic of infection?
4 weeks from eggs to adults
feed at night and inject lytic substances under skin which act as Allergens*
characteristic- several bites in a row
immunity bed bug
lytic compounds produce allergic responses at lesions and site of bite
NO immunity
ss bed bug
white/ red it itching hard welts– develop into sores
allergic responses produce granulomas, hemorrhagic bullae or second act inf.
tx bed bug
steroids
myasis caused by
metamorphosis
cochiomyia- screw worm flies
dermatobia- bot flies
ceterebra- warble flies
cordylobia- mango flies
complete
epi myasis
world wide
human
non human
life cycle myasis
flies lay eggs on human skin
eggs hatch and invade healthy or necrotic tissue and develop into adult flies
path myasis
hosts?
location of larva determine significance
larva release lytic enzymes– penetrate tissues
eggs on food produce intestinal lesion
maggots- pus filed lesions
adult flies serve as intermediate hosts for other diseases
ss myasis
swollen PAINLESS lesions that are self healing after larva pupates and falls out
flies can also lay eggs on mucous membranes (nostrils eyes rectal etc)
dx myasis
history
contact with larva
tx myasis
larga removed surgically after vaseline and irrigation of wound
good sanitation
follicular acariasis caused by?
demodex folliculorum
arachnid
epi of follicular acariasis
reservoir
world wide
humans: reservoir and definitive hosts
life cycle follicular acariasis
adult mites: worm like with short capital,, long abdomen short legs
eggs laid hatch into larva and develop into adult mites- transmitted directly p2p
where can demodexx folliculorum found
hair follicles, sebaceous glands scalp and eyelids
path follicular acariasis
mites can produce keratitis
infested sebaceous glads can result in granulomas and acne
facial cream
ss follicular acariasis
what increases infection
infestation w acne– doesn’t cause inflammatory rxn unless secondary bacterial infections develop (in itself doesn’t produce symptoms)
use of cosmetics increase it
dx follicular acariasis
cigar shaped mites found in follicle, skin scrapings
tx follicular acariasis
lindane
trombidiosis caused by?
chiggers
eutrombicula alfreddugesi
aka chiggers (arachnid)
epi trombidiosis
transmission
world wide
domestic wild animals birds and humans
contact with tall weeds and grass that contain mite
life cycle eutrombicula
adult mites are herbivores that live in grassy terrains
eggs are laid in clusters
ectoparasites on humans and fall off ?
life cycle eutrombicula
50-70 days
which one of eutrombicula life cycle harms humans
mite larva
path trombidiosis
mite larva bite thru skin of humans– which inject saliva that has lytic compounds that dissolve tissue but DON’T suck blood
allergy trombidiosis
necrotic rxn and allergic rxn develop first exposure
ss trombidiosis
small itching red spots into dermatitis– pustules and wheals where clothing is tight*
last weeks until swelling subsides
can cause fever and bacterial infections
scabies caused by
aka
sarcoptes scabiei (arachnid)
seven year itch
epi scabies
hosts
worldwide
humans and dogs
common in slums jails and armies (crowded areas)
transmission by intimate human to human contact
life cycle scabies
mate on outside of skin and the penetrate
male burrow, females lay the eggs in tunnels
larvas leave tunnels to infect new hosts
path scabies
the mites live in cutaneous burrows* progress without symptoms being noticed
lesion are produced to allergic reactions to eggs larva and adult mites
ss scabies
reddish elevated tracts in kin between fingers forearms knees elbows crotch – can develop into rash like lesions
intense itching spreads infection can develop erythematous eruptions and granulomas
dx scabies
staining of follicle / skin scraping with rod mites with short legs
(hard to get rid off)
tx scabies
permethrin
hot soapy baths
tx trombidiosis
steroids
sea lice caused by
linuche unguiculata (thimble jellyfish )
epi sea lice
south florida mid may early july
feed on small crustaceans
life cycle sea lice
linuche unguiculata larva float freely onto shore line
path sea lice
stings- immediately or lesions develop later, sea lice become trapped and squeezed
different people have different reactions to stings- mild irritation or severe allergic rxn
ss sea lice
itchy red skin, develop into hives and swelling
multiple Stunts can result into difficulty breathing
dx sea lice
hx of swimming, and presence of cutanouse lesions
tx sea lice
histamines
