Term
| Causative agents of lymphatic filariasis |
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Definition
- Wucheria bancrofti (in sub Saharan Africa, Egypt, Inidian subcontinent, tropical regions of Americas)
- Brugia malayi
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Term
| morphology of Wucheria bancrofti |
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Definition
- sheathed microfilaria
- anteriorly, it is bluntly rounded
- posteriorly, it is free of nuclei and tapers to a point
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Term
| life cycle of Wuchereria bancrofti |
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Definition
- mosquito takes first blood meal, ingesting microfilariae
- infective larvae develop in mosquito
- mosquito take second blood meal
- larvae depositived on skin, enter bite wound
- larvae enter lymphatics
- adults mature in lymphatics (esp. inguinal)
- enter the blood stream
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Term
| clinical features of Wuchereria bancrofti (lymphatic filariasis) |
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Definition
- often asymptomatic even with circulating microfilariae
- first signs- adolescents who develop adenolymphangitis and fevers (filarial fevers)
- due to host inflam. response to dead and dying worms
- can go on to develop
- lymphatic obstruction
- lymphadema
- hydrocoele
- CT proliferation
- elephantiasis (lower limbs, scrotum, and labia)
- in India: tropical pulmonary eosinophilia (nighttime cough, wheezing)
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Term
| How do you preven lymphatic filariasis from going on to elephantiasis? |
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Definition
| keep affected region clean from secondary bacterial invasion |
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Term
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Definition
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suspect in individual in endemic region, beyond first decade of life, and has lymphoedema in extremities, genitalia
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ID microfilaria in thick blood smear
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take blood at night due to nocturnal periodicity of W. bancrofti, B malayi
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use blood conc. methods to increase chances of locating mf (Knott test)
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commercial serological assay targeting Ag available
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experimental PCR assays
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ultrasound imaging of lymphatic drainage changes, adult worm "nests"- filaria dance sign
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Term
| Tx philosophy on treating LF |
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Definition
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reduce number of circulating microfilariae, thereby interrupt transmission
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control morbidity (relief of suffering)
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Term
| epidemiology of Onchocerca volvulus (river blindness) |
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Definition
- mainly in Central and West Africa
- some cases in Guyanas, South America, an Central America
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Term
| clinical features of river blindness |
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Definition
- most pathology from nodules (aka ochoncercomata) and microfilariae
- major manifestations are:
- dermatologic
- pruritis
- depigmentation
- lichenification
- taken on orange peel like consistency
- loss of skin elasticity leading to hanging skin folds
- lymphadenopathy also present
- ocular (major effects take decades)
- secondary to punctuate opacities of anterior chamber of eye
- as they accum, cause:
- sclerosing keratitis that blocks light
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Term
| river blindness- dx, tx, prevalence |
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Definition
- dx- skin snips to look for microfilariae
- no sheath on microfilariae
- palpable ochecercoma may be present
- tx
- administer until asymptomatic
- ivermectin targets Onchocerca microfilariae in subQ tissue
- nodulectomy if nodule accessible
- prevelence- greatly reduced over past decade
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Term
| loa loa (loasis): African eye worm- epidemiology: where most commonly found |
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Definition
| rainforest areas of West and Central Africa |
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Term
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Definition
- fly takes first blood meal, ingests larvae
- infective larvae develop in fly
- fly takes second blood meeal and larvae crawl into bite wound
- adults mature and live on subQ tissue
- enter bloodstream
- pathology- calebar swelling
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Term
| pathology features of loa loa |
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Definition
- calabar swellings
- episodes of angioedema (transient inflammatory reactions)
- ocular conjunctivae
- microfilariae in peripheral blood w/diurinal periodicity
- sheathed microfilariae
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Term
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Definition
- dx- Mf in blood with diurinal periodicity, eosinophilia
- adults will be seen in eye
- tx- surgically remove adult worms, chemoprophylaxis with DEC for long term visitors in endemic regions
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Term
| Drancunculus medianensis (Guinea worm)- life cycle |
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Definition
- larvae inside copepods swallowed
- larvea freed from copepods in small intestines
- larvae penetrate small intestinal wall
- larvae enter abdominal wall
- larvae enter subQ tissue
- larvae migrate to lower extremities
- adults mature and live in subQ tissues
- blister ruptures, releasing larvae
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Term
| Guinea worm: epidemiology: where located? transmission |
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Definition
- been irradicated everywhere except Sudan, Ghana, Nigeria
- swallowing untreated drinking water with copepods
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Term
| clinical features of guinea worm |
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Definition
- blister and resulting ulcer
- secondary bacterial infection and cellulitis
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Term
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Definition
- appearance of lesion, worm, or larvae
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Term
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Definition
- extract adult worms by winding them around a stick
- filtering drinking water will block transmission by remeoving the copepods, the intermediate host
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