Stings, Bites, and Bugs Flashcards
What two organisms cause Trypanosomiasis?
T. Brucei(African) and T. cruzi (american)
Where is Chagas dz found?
Central and South America
How is T cruzi transmitted?
Through infected reduviid bugs and occasionally infected blood
What bug is the kissing bug?
Raduviid bug
What’s unique about the life cycle of Raduviid?
It bites you and then defecates in it
What is chagas dz?
Serious systemic disease that primarily affects the autonomic nervous system, heart and GI tract.
What is the Romana sign?
Edema of the palpebral and periocular tissue due to entry through the conjunctiva
Describe the acute phase of Chagas dz?
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
Acute Phase Chagas disease
Describe the chronic phase of chagas dz
Occurs many years to decades later. Cardiac manifestations including Cardiac failure, arrythmias, heartblock and Gastrointestinal manifestations: Megacolon, Megaesophagus
Chronic chagas dz
Tx for Chagas dz?
Nifurtimox (acute phase) and Benzimidazole (more effective acute phase)
How are T. bruceii transmitted?
Tsetse flies
What are the names of the two African Trypanosomiasis causing species?
West Africa- T. brucei gambiense
East Africa- T. brucei rhodesiense
What are the clinical manifestations of trypanosomiasis?
Trypanosome Chancre, enlargement of lymph nodes, neurologic manifestations include: irritability, personality changes and day time somnolence, restlessness, insomnia
Trypanosome Chancre
African TrypanosomiasisTreatment?
Suramin=DOC for early stages; Pentamidine; other organic arsenicals; and Eflornithine which is effective for both hemolymphangitic and CNS involvement
What are synonyms for Onchocerciasis?
River blindness, Enfernedad de robles, Erysipelas de la costa
What is onchoceriasis?
Filarial infestation that predominantly affects cutaneous and ocular tissue. Caused by Onchocerca volvulus
How is the dz onchocerciasis transmitted?
Simulium black fly
Where is onchocerciasis found?
Exclusively in humans living in tropical African belt and south America
What is the clinical picture of onchocerciasis?
Subcutaneous nodules that are located over bony prominences. Intermittent intensely pruritic dermatitis. Microfilariae in conjunctivae move through cornea into the anterior and posterior chambers of the eye. Conjunctivitis, sclerosing keratitis, uveitis ,optic atrophy and glaucoma. Blindness in severe cases
What does chronic onchocerciasis look like?
Thickened , wrinkled skin with hyperpigmentation (lizard or elephant skin)
Onchocerciasis
Onchocerciasis
OnchocerciasisTreatment?
- Ivermectin: in 1 week microfilariae disappear from skin
and 3 months microfilariae disappear from eye - Nodulectomy
- Older drugs : suramin and DEC associated with severe hypersensitivity and dangerous toxic reactions
(Mazzotti reaction)
What dz is know as Tunga penetrans, Chigoe flea, jiggerflea, burrowing flea, sand flea, Pique, Nigua?
Tungiasis
Where is tungiasis found?
Endemic in Central and South America, the Caribbean Islands, Africa, Pakistan and India
Tungiasis dz?
Impregnated female flea burrows into skin causing 1 cm nodule and erythema. Rarely associated with gangrene, tetanus and auto amputations
Tungiasis
Tungiasis Tx?
May spontaneously resolve. For early lesions
you removal gravid female with a needle. For late lesions use surgical curettage, electrodessication, excision.
Topicals=Chlorophenothane, 4% formaldehyde, chloroform, turpentine. You can also use Niridazole, and Tetanus prophylaxis.
How do you prevent tungiasis?
Wear shoes, avoid sitting directly on beaches
What are the synonyms for cutaneous myiasis?
Maggots, screw worm, blowflies, fleshflies and tumbu fly
Myiasis dz?
Infestation of skin by fly larvae. The larvae inhabit skin wound or burrow into the dermis causing boil-like lesions. It usually causes minimal morbidity unless they involve nasal cavity and sinuses
Dermatobia hominis clinical presentation?
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
Cutaneous Myiasisd
Cutaneous Myiasis
Dermatobia hominis Tx?
Myiasis is a self limiting infestation Do not remove forcibly. Occlusion/suffocation. Bacon, petroleum jelly beeswax , nail polish Injection of lidocaine at base of lesion. Surgical removal
Human botfly preventive measures?
Avoid activities which increase risk of myiasis. Do not wear wet clothes. Do not rest on sandy areas. Use insect repellents. Avoid trips to Belize
What are bedbugs (Cimicids)?
They are true bugs with flat oval body; about the same size as a tick; red brown in color; blood sucking, feed at night. The bites are often in linear groups of three. They hide in cracks and crevices and behind peeling paint during day
Multiple bedbugs
Bed bug bites
Bed bugs: breakfast, lunch and dinner!
What is the clinical picture of bed bugs?
Linear bites in groups of three (Breakfast, lunch and dinner). Maybe vectors for hepatitis B\ Chagas disease.
Bedbug dung may play a role in asthma
Bedbug tx?
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
What are Reduviid Bugs?
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
Reduviid Bug
What is Pediculosis capitis?
Head Lice
Pediculosis corporis?
Body Lice
Phthiriasis Pubis?
Pubic lice
Lice facts?
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
How is head lice transmitted?
Direct contact or through fomites ( combs, brushes, hats bedding)
How do you tx head lice?
1% permethrin cream rinse
Leave on 10 min. Thoroughly rinse.
Fine tooth comb to remove nits
0.5% malathion lotion in resistant cases
Is lice re-infection common?
Re-infection is more common than resistance
Head lice
Is body lice as common as head lice?
Nope
What are the symptoms of body lice?
Pruitis may be the only symptom. Can see red papules under arms, upper shoulders, and neck. Maculae ceruleae are bluish/brown hemosiderin laden macules (intradermal hemorrhage at lice feeding sites)
Body louse
Body lice can be a vector for what dz’s?
Epidemic typhus (Rickettsia prowazekii), Trench fever (Bartonella quintana), and Relapsing fever (Borrelia recurrentis)
How is pubic lice transmitted?
Usually transmitted by sexual contact but can be obtained through contact with clothing or infested hairs
Is pubic lice limited to the pubic area?
No. May effect eyebrows, eyelashes, hair and scalp. Can also cause maculae ceruleae
Pubic lice
Pubic lice Tx?
Same as head lice: permetherin 1 % lotion for 10 min.
For eyelids, use occlusive ophthalmic ointment applied to eyelid margins for 10 days. Treat sexual partners too!
What else is Scabies called?
Itch mite infestation, Pruritic eruption, infectious eczema, seven year itch
What causes scabies? Vector?
Caused by female mite sarcoptes scabiei var. hominis. There is no known vector
Where is scabies found?
Everywhere in the world
Where does scabies live?
Spends entire life in the epidermis
What does scabies look like clinically?
Severe pruritus that’s often worse at night. Burrow is the primary lesion. Most commonly found in interdigital web space wrist, flexor surfaces of the elbows, areola and penis, scrotum, and umbilicus belt line. Secondary papules, pustules vesicles more prominent than burrows
Involvement of head and face in infants
Scabies
Scabies
Scabies
Dx of scabies?
Skin Scraping demonstrating: Mites, Scybala, Eggs.
Be sure to scrape a lot and deep enough
Tx for scabies?
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. 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
