infections of the skin, soft tissue, and muscle caused by parasites/arthropods Flashcards
1
Q
Leishmaniasis
pathogenesis
population
reservoirs
A
- opportunistic pathogen-female SAND FLY bites infected individual and gets the parasite in the macrophages it ingests
- the parasite (leishamaniasis) reproduces in the gut of sand fly and then then sandfly bites someone else
- infected new indiviual’s macrophages are infiltrated by leishamaniasis spp and are killed for further spread to other macrophages
- usually in HIV pt primarily in Mediterranean
- IMPORTANT re- dogs and rodents
2
Q
what are the three clinical presentations of leishmaniasis
A
- visceral
- cutaneous (L. major, tropica, mexicana)
- mucocutaneous (L. braziliensis)
3
Q
what does cutaneous leishmaniasis cause
A
- dry crusty lesions at site where parasite was inoculated- looks like a volcano- enlarges and ulcerates
causing SCARRING AND IS DEBILITATING
-self limiting but immunity can help
4
Q
mucocutaneous leishamaniasis
A
- caused by L. braziliensis
- at first, it looks like a typical cutaneous lesion and months or years later, it will come back as ulcerative lesions at the septum or nasal mucosa
- thought to be a result of parasite metastasis and an AGGRESSIVE IMMUNE RESPONSE
- USUALLY THIS STRAIN IS IN SOUTH AMERICA AND CENTRAL AMERICA
- NO RESOLUTION BESIDES CHEMO
5
Q
what type of immunity is best for leishamaniasis
A
- cell mediated to kill macrophages
- anitbodies are useless because most are intracellular
6
Q
treatment for leishamaniasis
A
- heavy metals that are toxic and control via eliminating vectors or reservoirs to interrupt transmission
7
Q
what is onchoceriasis
A
- river blindness
- caused by Onchocerca volvulus
- causes nodules of nematodes in the skin and can cause itching and they can get to eyes where they cause blindness -10yrs
8
Q
pathogenesis of onchoceriasis
A
- nematode in infected individual
- BLACK FLY THAT LIVES NEAR WATER- bites infected individual and picks up larvae
- larvae reproduces in black fly
- black fly bites another individual and infects them
9
Q
where is onchocerciasis found?
A
Africa but sometimes in central and south America
10
Q
what is important to note about the onchoceriasis volvulus species that causes disease?
A
- only the replicating or young ones cause pathology
- adult ones are knotted together in subcutaneous nodules
11
Q
diagnosis and treatment of ochocerciasis?
A
- microfilariae in skin snips or eyes
- treat- IVERMECTIN -REPEATED DOSING
12
Q
mansonella spp what is it? how transmitted reservoirs symptoms
A
- a filarial nematode
- transmitted by a bite of infected MIDGE (Marilyn manson is NOT a midg-et)
- non-human primates may be reservoirs
- most infections are asymptomatic but can cause itching, edema, JOINT pain, NOT AS SEVERE AS OCNCHOCERIASIS
13
Q
diagnosis of mansonella
A
- observing microfilaria on stained blood smears of skin snips
14
Q
dracunculus medinensis
A
- guinea worm = LARGE
- infected people get blister from females making toxin that causes lesion
- infected person gets in the water causing the blister to rupture releasing the worm into the water
- people drink contaminated water and the cycle begins again
15
Q
how is dracunculus medinensis almost irradicated?
A
- ensured delivery of clean water
- when find, wind worm out on a stick and break it
16
Q
cutaneous larval migrans
A
- caused by ancylostoma (hookworms) that normally infect cats and dogs- a. braziliense and a. canium
- in dogs, dogs poop on soil, humans step on soil and larvae penetrate skin
- larvae don’t know where to go as they fail to enter blood stream so instead burrow in deeper layers to the epidermis- larvae survive and migrate for 7-10 days
- causes a HUGE inflammatory reaction called “CREEPING ERUPTION”- AND ALSO SERPENTINE TRACKS
17
Q
sarcoptes scabiei
A
- scabies mite
- small roundish, eight-legged arthropods
- mites of birds and animals but can infect humans
- homeless pop, overcrowding
18
Q
what does scabies present as?
A
- itching and usually in the WEBBING and sides of fingers later spreading to wrists, elbows, and trunk
- lesions appear short, SERPENTINE, slightly raised, cutaneous track along which the mites have burrowed
- can spread to unrelated areas
19
Q
what does a progressed infection of scabies look like?
A
- hyperinfection involves thousands of mites and is known as a Norwegian or crusted scabies
- crusted lesions of hands feet and body
- VERY contagious due to large amount of female mites
20
Q
scabies diagnosis and treatment
A
- scrape infected skin and seeing under microscope
- treat- topical treatment and may have to treat family, clean all surfaces
21
Q
lice
A
- pediculosis
- 3 species infect humans- p humanus (body louse), humanus capitis (head louse), phthirus pubis (crab louse)
22
Q
why is the crab louse called the crab louse
A
- front legs are smaller than the second and third sets of legs which are clawed like crabs
23
Q
symptoms of lice infestations
A
- itching
- pruritic, reddened papules
- can get secondary bacterial infections
24
Q
head lice
A
- inhabit hair on head
- combs, brushes, hats etc
- FREQUENTLY CONCENTRATED ON THE BACK OF THE NECK AND EARS
25
Q
body lice
A
- aka cooties
- on clothing of infected individual
- adult lice move to body of frequently to get a meal and then hop back onto clothing
26
Q
crab lice
A
- tx thru sexual contact
- inhabit hairs of the pubic and perianal region
- can be found on axillary and facial hair
27
Q
what’s important about head and crab lice infection
A
- they are mostly sedentary residing at the same hair shaft for days while feeding
28
Q
life cycle of head and pubic lice
A
- females lay eggs called NITS and attach them to the hair shaft
- eggs hatch in a week and mature over 3 wks
- adults live less than one month and females lay 50-100 eggs in a lifetime
29
Q
life cycle of body lice
A
- primarily clothing living- lay eggs there
- eggs found in seams of infested garments
- hatch in a week and mature in 3
- adults last a month and lay 300 eggs in a lifetime
30
Q
Diagnosis of lice
treatment?
A
- ID lice or eggs in the hair or in the seams of garments
- use of microscope
- treatment- shampoos etc with slow-dose insecticides, retreat 1-2 weeks post initial treatment to kill new eggs
- clothing, beds etc washed
31
Q
myiasis
A
- human botfly
- caused by dermatobia hominis
- lands on top of a mosquito, mosquito bites you, it enters thru the hole, and then you get infestation of larvae/maggots in subcutaneous tissue.
-maintains air hole to break in skin
-matures and then drop to the environment to live and fly off
subcutaneous phase - can cause pain and foul smelling exudate from the opening in the skin
32
Q
treatment for myiasis
A
- removed surgically
- can be forced to surface by covering the lesion with petroleum jelly to block their air hole facilitating their removal
33
Q
chagas disease
A
- trypoanosoma cruzi
- transmission- bite and defecation of the infected bug on you and you either scratch it and inoculate yourself or it enters an eye somehow
-first sign: get a chagoma = romana sign-periorbital swelling
acute phase- fever malaise, myalgia and hepatosplenomegaly
-indeterminate phase- asymptomatic- few parasites, hi antibody-most individuals stay here
-chronic disease- infection of heart, GI and myenteric plexus- decades after
34
Q
diagnosis of chagas?
A
- acutely- find it in peripheral blood
- chronically- serology
- travel hx
35
Q
trichinosis
A
- caused by trichinella spiralis
- bear, pig or other wild animal infected with larval form of trichinosis in muscles
- we eat it-undercooked
- release in stomach, mature in small intestines and mature into adult forms and larvae enter circulation to encyst into striated muscles -WITHIN MUSCLE CELLS AND MAY SURVIVE FOR YEARS
- causes muscle pain, fever, periorbital edema, eosinophilia, infect diaphragm, occasional CNS or heart damage
36
Q
symptoms of trichinosis
A
- depends on where they encyst
- early infection- diarrhea, ab pain, vomit
- during larval migration and muscle penetration: fever, chills, eosinophilia and muscle pain
- pathology due to inflammation and mechanical damage
37
Q
diagnosis of trichinosis
A
- depends on observation of encysted larvae in muscle tissue
- aided by presence of eosinophilia, elevated muscle enzyme levels (CPK and LDH), dietary hx, and recognition of symptoms
38
Q
Loiasis- loa loa
A
- central and west Africa
- bite of MANGO FLIES
- EYE WORM
- little pathology besides “CALABAR SWELLING”
- PASSAGE THRU CONJUNCTIVA
39
Q
diagnosis of loiasis?
A
- eosinophilia and microfilariae in the blood
40
Q
lung flukes
A
- paragonimus westermani
- leaf like
- infected person poops, releases eggs in water, gets to freshwater crustaceans (crabs and crayfish)
- people eat crustaceans
- go into small intestine and exit thru blood to lungs
- makes it’s way to lungs and get BLOODY SPUTUM AND COUGH
- eggs are coughed up and swallowed and reproduce in small intestine where they make eggs that are pooped out
41
Q
symptoms of lung flukes
A
- blood tinged sputum
- lung abscess
- blood and dark eggs in sputum to give RUSTY SPUTUM
