stings, bites, and bugs

Question 1

T. cruzi causes_________

Answer 1

T. cruzi causes American trypanosomiais

Question 2

T. brucei causes

Answer 2

T. brucei causes African trypanosmiaisis

Question 3

american trypanosomiasis =

Answer 3

American Trypanosomiasis=Chagas disease

Question 4

where is Chagas disease endemic?

Answer 4

Central and South America

Question 5

Test question: how is chagas disease transmitted?

Answer 5

Transmission of T. cruzi through infected reduviid bugs and occasionally infected blood

Question 6

what doe Chagas disease affect in body?

Answer 6

Serious systemic disease that primarily affects the autonomic nervous system, heart and GI tract

Question 7

what is Romana sign of chagas disease?

Answer 7

Romana sign- edema of the palpebral and periocular tissue due to entry through the conjunctiva

Question 8

what is the unique feature about the life cycle of t. cruzi?

Answer 8

infected bug bites human, defecates and depostis T. cruzi trypomastigotes.

Question 9

symptoms of acute phase of Chaga’s disease?

Answer 9

Localized erythema ,swelling regional lymphadenopathy (chagoma)

_ROMANA sign - _Painless edema of palpebrae occurs in 80% of cases infected this route

Fever, malaise, anorexia, edema of face and lower extremities

Question 10

when does the chronic phase of chagas disease occur?

what are the cardiac manifesations of the chronic phase?

what are the GI manifestations of the chronic phase?

Answer 10

• *Occurs many years to decades later**
• *Cardiac manifestations: **Cardiac failure, arrythmias, heartblock
• *Gastrointestinal manifestations: **Megacolon, Megaesophagus

Question 11

which two drugs are used to treat chagas disease?

Answer 11

Nifurtimox: acute phase parasitologic cure 50% of the time

Benzimidazole; acute phase more effective

Question 12

how is African trypanosomiasis transmitted?

which species in West Africa?

which species in East Africa?

Answer 12

Trypanosomes transmitted by several species of Tsetse flies

West Africa- T. brucei gambiense
East Africa- T. brucei rhodesiense

Question 13

what is the clinical presentation of african trypanosomiasis?

Answer 13

Trypanosome Chancre
Enlargement of lymph nodes
Neurologic manifestations

Question 14

what are the neurologic manifestations of african trypanosomiasis?

Answer 14

Irritability
Personality changes
Day time somnolence, restlessness, insomnia

Question 15

what are the treatments for african trypanosomiasis?

Answer 15

Suramin

Pentamidine

Eflornithine: effective for both hemolymphangitic and CNS involvement

Question 16

onchocerciasis = ____

Answer 16

riverblindness

Question 17

what does onchocerciasis predominantly effect?

Answer 17

Filarial infestation that predominantly affects cutaneous and ocular tissue

Question 18

what causes onchocerciasis? how is it transmitted?

Answer 18

Cause by Onchocerca volvulus
Transmitted by Simulium black fly

Question 19

where is onchocerciasis most common

Answer 19

Exclusively in humans living in tropical African belt and south America

Question 20

Subcutaneous nodules that are located over bony prominences
Intermittent intensely pruritic dermatitis describes which disease?

Answer 20

onchocerciasis

Question 21

how does chornic onchocerciasis present?

Answer 21

Chronic Onchocerciasis: thickened , wrinkled skin with hyperpigmentation (lizard or elephant skin)

Question 22

most severe affect of onchocerciasis?

Answer 22

blindness

Question 23

how is onchocerciasis treated

Answer 23

ivermectin: 1 week microfilaries dissapear from skin; 3 months microfilarie dissapear from eye

nodulectoy

older drugs: suramin and DEC associated with severe hypersensitivity and dangerous toxic rxns

mazzotti reaction

Question 25

what is tungiasis? where is tungiasis endemic? what causes the disease? what is tungiasis rarely associated with?

Answer 25

Infestation caused by the burrowing flea, Tunga penetrans Endemic in Central and South America, the Caribbean Islands, Africa, Pakistan and India Impregnated female flea burrows into skin causing 1 cm nodule and erythema Rarely associated with gangrene, tetanus and auto amputations

Question 26

how is tungiasis treated? how are eary lesions treated? how are late lesions treated? what are some preventative measures?

Answer 26

May spontaneously resolve **Early lesions: **Removal of gravid female with a needle **Late lesions: **Surgical curettage, electrodessication, excision **Topicals: **Chlorophenothane, 4% formaldehyde, chloroform, turpentine Niridazole Tetanus prophylaxis **Preventative measures: **Wear shoes, void sitting directly on beaches

Question 27

what causes cutaneous myiasis? usually cutaneous mysiasis is minimal morbidity unless it involves \_\_\_\_\_\_and\_\_\_\_\_\_\_\_

Answer 27

Cause: Infestation of skin by fly larvae how: Larvae inhabit skin wound or burrow into the dermis causing boil-like lesions Usually cause minimal morbidity unless they involve **nasal cavity** and **sinuses**

Question 28

what type of lesions does dermatobia hominis cause? where are these lesions on the poby? what happens after 24 hours? is sensation of movement observed?

Answer 28

Causes boil-like lesions **Usually on scalp, face ,forearms and legs 24 hours after penetration pruritic papules form 1-3 cm in diameter** Lesions may be painful, tender and may become crusted and purulent **Sensation of movement may be observed**

Question 29

how do you treat dermatobia hominis? should you remove forcibly? how can you occlude/suffocate the bug?

Answer 29

Myiasis is a self limiting infestation Do not remove forcible **Occlusion/suffocation: **Bacon, petroleum jelly ,beeswax , nail polish Injection of lidocaine at base of lesion Surgical removal

Question 30

which activities increase risk of myiasis?

Answer 30

Do not wear wet clothes Do not rest on sandy areas Use insect repellents Avoid trips to **Belize**

Question 31

**test question:** how do cimicid bedbugs bite? where do they hide during the day?

Answer 31

Bites often in linear groups of three: BREAKFAST, LUNCH and DINNER Hide in cracks and crevices, behind peeling paint during day

Question 32

bedbuds may be Maybe vectors for ______ and \_\_\_\_\_\_

Answer 32

Maybe vectors fo**_r hepatitis B\ Chagas disease_**

Question 33

bedbug dung may play a role in \_\_\_\_\_\_\_

Answer 33

asthma

Question 34

how do you treat bedbugs?

Answer 34

Elimination of cracks and crevices Removal of roosting bats or birds Use of insecticides (dichlorvos) Use of insect repellents **_Cannot starve them, survive 1 year without feeding_**

Question 35

which bugs are know as kissing bugs? which causative agent of Chagas disease do they spread? what is unique about their life cycle? how do trypanosomes spread?

Answer 35

AKA kissing bug due to predilection to bite on or near the lips Spread **_T. cruzi_** the causative agent of Chagas disease **_Kissing bug takes blood meal then turn around and defecate immediately after feeding_** Trypanosomes spread by **_victim scratching_**

Question 36

what is head lice called? what is body lice called? what is pubic lice called?

Answer 36

Pediculosis capitis: Head Lice Pediculus humanus var. capitis Pediculosis corporis: Body Lice Pediculus humanus var. corporis Phthiriasis Pubis: Pubic Lice Phthirus pubis

Question 37

how many eggs can a female louse lay? how long do lice live? how do they survive? how long can they live off a human host?

Answer 37

Range from 1.5 -4.5 mm in length Female may lay up to 300 eggs (nits) Live for approximately 30 days Pierce skin every few hours to receive blood meal Can live off human host for 2 days

Question 38

how are head lice transmitted? how are they treated? what is used in resistant cases? which is more common: reinfection or resistance?

Answer 38

Transmitted by direct contact or through fomites ( combs, brushes, hats bedding) Treat with **_1% permethrin cream rinse_** Leave on 10 min. Thoroughly rinse. **_0.5% malathion lotion_** in resistant cases Fine tooth comb to remove nits Re-infection more common than resistance

Question 39

body lice how common are they? where do they hide? what may be the only symptom? what is the clinical presentation? what are maculae ceruleae?

Answer 39

**Less common in general population Lice hide in seams of clothing and nits attach to clothing Pruritus may be only symptom Red papules under arms ,upper shoulders, neck Maculae ceruleae- bluish/brown hemosiderin laden macules ( intradermal hemorrhage at lice feeding sites)**

Question 40

what are body lice vectors for? (3) how to you treat body lice (3)?

Answer 40

``` Vector for: Epidemic typhus (Rickettsia prowazekii) Trench fever (Bartonella quintana) Relapsing fever (Borrelia recurrentis) ``` Treatment Eradicate lice from clothing Laundering in hot water Drying at high temperature

Question 41

pubic lice aka crab lice how are they transmitted? are they limited to the pubic area? can they also cause maculae ceruleae?

Answer 41

* *_ transmitted by sexual contac_**t but can be obtained through contact with clothing or infested hairs * *Not limited to pubic area** * *May effect eyebrows, eyelashes, hair and scalp** * *Can also cause maculae ceruleae**

Question 42

how are pubic lice treated?

Answer 42

Same as head lice Permetherin 1 % lotion for 10 min. Eyelids- use occlusive ophthalmic ointment applied to eyelid margins for 10 days Treat sexual partners too!

Question 43

which disease = seven year itch?

Answer 43

Scabies

Question 44

what is scabies caused by? what about the distribution? scabies lives its entire life where? is it a known vector for disease? how long has it been a companion of humans?

Answer 44

Caused by female mite sarcoptes scabiei var. hominis World wide distribution **Lives entire life within epidermis Not a known vector for disease** Common companion of humans over 2500 years

Question 45

when is the pruritis of scabies worse? what is its primary lesion? where is it commonly found in body? where is it involved in the infant?

Answer 45

**Severe pruritus, often worse at nigh**t **Burrow** is the primary lesion Most commonly found in **interdigital web (very common place)** space wrist flexor surfaces of the elbows, areola and penis, scrotum, umbilicus belt line Secondary papules, pustules vesicles more prominent than burrows **Involvement of head and face in infant**

Question 46

how is scabies diagnosed?

Answer 46

skin scraping demonstrating: mites scybala eggs

Question 47

how is scabies treated? do you need to treat the entire family? can patients itch one month after tx?

Answer 47

**_Permethrin 5 %_** **_overnight to all skin surfaces_**. Wash cream off in morning **Treat all family members Repeat in 1 week** Wash all clothing and bedding after treatment in hot water **Patients may itch for 1 month after treatment**

Question 48

what are some other tx of scabies?

Answer 48

5-10 % precipitated sulfur in petrolateum (overnight for 3 nights) lindane overnight out of favor due to potential toxicity crotamitin ivermectin repeat in 1 week

Question 49

what are the main spiders of concern in the US?

Answer 49

brown recluse hobo spider black widow

Question 50

describe the brown recluse spider's appearance? wehre is it most abundant? is it aggressive?

Answer 50

**_Fiddle back or violin spider_** due to dark brown markings on head and thorax **Most abundant in warmer climates they have been identified from Florida to Maine Non aggressive spider Will not bite unless disturbed**

Question 51

what is the range of severity for the bite of the brown recluse spider? how does the bite appear? wihch 4 systemic reactions can occur due to bite of brown recluse?

Answer 51

**Vary from mild local reaction to ulcerative necrosis with eschar** Only ~25% get necrotic reaction Bite often appears with **central mottling and blister with surrounding blanched halo and erythema** **_Systemic reactions i_**nclude **shock, hemolysis, renal insufficiency and DIC**

Question 52

what is the major toxin of the brown recluse spider? what does it interact with? how does hylauronidase allows for eschars to do what?

Answer 52

**_Sphingomyelinase D_** major toxin produced by brown recluse spider Interacts with **_serum amyloid protein_** **_Hyaluronidase allows eschars to spread in gravity dependent fashion_**

Question 53

how do you tx brown recluse spider bite?

Answer 53

Rest, **_ice(decreases immune response, may inactivate toxin),_** elevation Interdermal injection of polyclonal anti-Loxoxceles Fab fragments Hyperbaric oxygen **Dapsone: Check G6PD first** **Prednisone**

Question 54

what type of web does it build? is the hobo spider aggressive? where is it found?

Answer 54

**One of many aggressive spiders that build funnel shaped webs Large, hairy, aggressive _Found in dark, moist areas, especially basements_ T. agrestis is 4-5 cm in diameter, mostly found in the pacific northwest**

Question 55

are hobo spider bites painful? can bites lead to ensuing necrosis and \_\_\_\_\_-? what are the systmeic symptoms? note: hemolysis and thrombocytopenia have been reported

Answer 55

Bites are typically not painful **Ensuing necrosis can lead to amputation** Systemic symptoms include **headache, nausea and weakness** **Hemolysis and thrombocytopenia reported**

Question 56

what is the tx for hobo spider?

Answer 56

largely supportive no specific antivenin

Question 57

what is clinical presentation of black widow bite in 1st 30 minutes? what does venome cause depletion of ? what type of pain does black widow bite produce? can you die from black widow bite?

Answer 57

Local erythema, sweating piloerection at wound site with in first half hour Venom causes **depletion of acetylcholine at motor nerve endings** and **release of catecholamines at andrenergic ending**s May produce **abdominal pain(very severe),**muscle spasm mimic an acute abdomen Headache, paresthesias, nausea, vomiting, hypertension paralyisis **Death is uncommon**

Question 58

how do you treat black widow spider bite? (3)

Answer 58

**Intravenous calcium gluconate** Analgesics **L mactans antivenin for severe cases**