infections of the skin, soft tissue, and muscle caused by parasites/arthropods Flashcards Preview

Micro last plus one anatomy 5 > infections of the skin, soft tissue, and muscle caused by parasites/arthropods > Flashcards

Flashcards in infections of the skin, soft tissue, and muscle caused by parasites/arthropods Deck (41):
1

Leishmaniasis
pathogenesis
population
reservoirs

- 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

what are the three clinical presentations of leishmaniasis

-visceral
-cutaneous (L. major, tropica, mexicana)
-mucocutaneous (L. braziliensis)

3

what does cutaneous leishmaniasis cause

- 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

mucocutaneous leishamaniasis

-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

what type of immunity is best for leishamaniasis

-cell mediated to kill macrophages
- anitbodies are useless because most are intracellular

6

treatment for leishamaniasis

- heavy metals that are toxic and control via eliminating vectors or reservoirs to interrupt transmission

7

what is onchoceriasis

-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

pathogenesis of onchoceriasis

- 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

where is onchocerciasis found?

Africa but sometimes in central and south America

10

what is important to note about the onchoceriasis volvulus species that causes disease?

- only the replicating or young ones cause pathology
- adult ones are knotted together in subcutaneous nodules

11

diagnosis and treatment of ochocerciasis?

- microfilariae in skin snips or eyes
-treat- IVERMECTIN -REPEATED DOSING

12

mansonella spp
what is it?
how transmitted
reservoirs
symptoms

- 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

diagnosis of mansonella

- observing microfilaria on stained blood smears of skin snips

14

dracunculus medinensis

- 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

how is dracunculus medinensis almost irradicated?

- ensured delivery of clean water
-when find, wind worm out on a stick and break it

16

cutaneous larval migrans

-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

sarcoptes scabiei

-scabies mite
- small roundish, eight-legged arthropods
-mites of birds and animals but can infect humans
-homeless pop, overcrowding

18

what does scabies present as?

- 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

what does a progressed infection of scabies look like?

- 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

scabies diagnosis and treatment

- scrape infected skin and seeing under microscope
-treat- topical treatment and may have to treat family, clean all surfaces

21

lice

-pediculosis
-3 species infect humans- p humanus (body louse), humanus capitis (head louse), phthirus pubis (crab louse)

22

why is the crab louse called the crab louse

- front legs are smaller than the second and third sets of legs which are clawed like crabs

23

symptoms of lice infestations

- itching
- pruritic, reddened papules
- can get secondary bacterial infections

24

head lice

- inhabit hair on head
- combs, brushes, hats etc
-FREQUENTLY CONCENTRATED ON THE BACK OF THE NECK AND EARS

25

body lice

- 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

crab lice

- tx thru sexual contact
-inhabit hairs of the pubic and perianal region
-can be found on axillary and facial hair

27

what's important about head and crab lice infection

- they are mostly sedentary residing at the same hair shaft for days while feeding

28

life cycle of head and pubic lice

-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

life cycle of body lice

- 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

Diagnosis of lice
treatment?

- 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

myiasis

- 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

treatment for myiasis

- removed surgically
- can be forced to surface by covering the lesion with petroleum jelly to block their air hole facilitating their removal

33

chagas disease

- 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

diagnosis of chagas?

-acutely- find it in peripheral blood
-chronically- serology
-travel hx

35

trichinosis

-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

symptoms of trichinosis

- 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

diagnosis of trichinosis

- 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

Loiasis- loa loa

- central and west Africa
- bite of MANGO FLIES
- EYE WORM
- little pathology besides "CALABAR SWELLING"
-PASSAGE THRU CONJUNCTIVA

39

diagnosis of loiasis?

- eosinophilia and microfilariae in the blood

40

lung flukes

-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

symptoms of lung flukes

- blood tinged sputum
- lung abscess
-blood and dark eggs in sputum to give RUSTY SPUTUM