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Flashcards in Bugs/stings/bites Deck (46):
1

Location/transmission/presentation of American trypanosomiasis chagas disease

central and south america, Texas, florida;
transmission: T. cruzi infected reduviid bugs and infected blood
Present: systemic=> ANS, heart, GI

2

What sign is associated with American trypanosomiasis chagas disease? describe it

Romana sign=> edema of palpebral and periocular tissue from entry through conjunctiva

3

What is the life cycle of T. cruzi?

T. cruzi in feces of reduviid bug; bite then defecates into bite; T. cruzi enters wound; invades cells and amastigotes (multiplies); amastigotes change into trypomastigotes and enter blood; bug bites infected human again

4

When is Trypanosoma cruzi cause clinical disease?

once the trypomastigotes invade cells and change into amastigotes and multiply

5

What is the acute phase of chagas disease clincially?

localized erythema, LAD; anorexia; facial edema; lower extremity edema
Romana sign

6

How does chronic chagas disease present clinically?

occurs years to decades later with heart and GI manifestations

7

How is chagas disease treated?

Nifurtimox; Benzimidazole

8

What is the life cycle of Trypanosoma brucei?

bite then multiply in the midgut leading to metacyclic form->binary fission to trypomastigote then back to infecting the Tsetse fly again

9

How does the african trypanosomiasis present clinically?

Trypanosome chancre; node enlargement; neurologic manifestations (irritable, personality changes, day time restlessness)

10

What is the Tx for african trypanosomiasis

Suramin; Pentamidine; Eflornithine (CNS, hemolymphangitic)

11

What causes onchocerciasis (river blindness)?

onchocerca volvulus that is transmitted by the simulium black fly causing cutaneous and ocular tissue infestation (blind if chronic)

12

Who is at risk for Onchocerciasis?

humans living in tropical African belt and S. america

13

How does onchocerciasis present clinically?

Subcutaneous nodules over bony prominences; intermittent intensely pruritic dermatitis; microfilariae in conjunctivae cause sclerosing keratits, uveitis, optic atrophy, glaucoma

14

Onchocerciasis Tx

Nodulectomy; Ivermectin;

15

What is very important to avoid when doing a nodulectomy for onchocerciasis?

Mazzotti rxn causing fever, chills from immune response due to a breakup of the organism

16

Location/transmission/presentation of Tungiasis

endemic in Central and South america, caribbean, Africa, pakistan and india;
impregnated female flea burrows causing nodule and erythema;

17

Tungiasis Tx

may spontaneously resolve; early lesions (removal w/ needle); late lesions (excision); apply topicals;
PREVENT: WEAR SHOES

18

What is cutaneous myiasis?

infestation of skin by fly larvae that inhabit skin (scalp, face, forearms, legs)wound or burrow into dermis like a boil => sensation of movement

19

What is the Tx for myiasis?

self limiting that can be suffocated out via bacon

20

How can a person take precaution to prevent human botfly infections?

avoid activities that increase risk of myiasis (no wet cloths, no resting on sandy areas, use insect repellent; AVOID BELIZE)

21

Cimicids (bedbugs) have what distinguishing characteristic?

feed at night (mattress) by biting in linear groups of 3 (breakfast, lunch, dinner)

22

Name the name and location for the different types of lice

Pediculosis capitis (head lice at schools)
Pediculosis corporis (body lice from war/poor)
Phthiriasis pubis: (pubic lice from sex)

23

What is the life cycle of a louse?

female 300 eggs; lives for 30 days; human host blood dinner

24

How is head lice transmitted and treated?

transmitted by direct contact or fomites
Tx with 1% permethrin cream rinse and comb to remove nits

25

What are the Sx of body lice and view histologically?

Pruritis and give a maculae ceruleae of bluish/brown hemosiderin laden macules

26

Pubic lice from sexual contact is found where and causes what?

not limited to pubic areas but can be present in eyebrows, eyelashes, hair and scalp => cause maceulae ceruleae

27

Location/transmission/presentation of scabies

world wide;
femal mite scabiei that lives w/in epidermis;
severe pruritus in INTERDIGITAL WEB SPACE, wrist flexors, elbows, penis

28

How is scabies diagnosed?

skin scraping demonstrating mites, scybala, eggs

29

What are characteristics of a brown recluse spider?

fiddle back; warmer climates; non agressive; not bite unless disturbed

30

If a brown recluse does bite, how will it present clinically?

central mottling and blister with blanched halo and erythema;

31

Why is it not good to surgically remove scab from spider bite?

toxin will become systemic =>shock, hemolysis, renal insufficiency and DIC

32

What is the pathogenesis of a brown recluse spider bite?

Sphingomyelinase D major toxin; interacts with serum amyloid protein; Hyaluronidase allows eschars to spread in gravity dependent fashion

33

What is the best Tx for a brown recluse bite?

R.I.C.E. with prednisone

34

What is the characteristics of a Hobo spider?

large(4-5cm), hairy aggressive found in dark, moist areas

35

What is the clinical presentation of a Hobo spider bite? Tx?

not painful; ensuing necrosis may lead to amputation
Supportive Tx

36

What are the characteristics of the black widow spider?

North america, large, shiny spiders with hourglass on abdomen

37

What are the clinical Sx of a black widow spider bite?

local erythema, sweating piloerection; venom causes depletion of Ach at release of catecholamines => leads to abdominal pain and muscle spasm

38

Tx for black widow spider bite?

IV calcium gluconate, analgesics

39

Lice associated diseases

typhus, relapsing fever, trench fever

40

Fleas associated diseases

bubonic plague; typhus; tungiasis;

41

budbugs associated diseases

possibly HBV

42

flies, mosquitos associated diseases

cutaneous myiasis, malaria, yellow fever, dengue fever, viral encelphalitis onchocerciasis, sleeping sickness, West nile fever

43

Reduviid bugs associated diseases

chagas disease

44

spiders associated diseases

necrotic arachnidisim, paralysis

45

Ticks associated diseases

granuloma formation; lyme borreliosis, RMSF, Q fever; tularemia

46

Mites associated diseases

hypersensitivity dermatitis; scrub typhus; scabies; rosacea