tissue invasive nematodes Flashcards

1
Q

what are filariae?

A

threatlike, tissue invasive roundworms transmitted by insect vectors

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2
Q

what did patrick manson do?

A

demonstrated that mosquitoes transmit filariae (first demonstration that mosquitoes can harbor infectious disease)

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3
Q

filarial infection local to.. 1) tropics worldwide? 2) asia? 3) africa/americas? 4) africa?

A

1) wuchereria bancrofti 2) brugia species 3) onchocerca volvulus (river blindness) 4) loa loa (crawls across eye)

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4
Q

what filarial parasite is endemic to the US?

A

heartworm (dirofilaria immitis) infects dogs!

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5
Q

general life cycle of filarial parasites

A

microfilarial stage L1 increase in size to infectious stage L3 enters human not through saliva like malaria but through biting parts L3 stage enters lymphatics molt to adults (thin and long) mate and make microfilaria again

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6
Q

lymphatic filariasis 2 causative agents? vector? location of adults? of microfilaria?

A

wuchereria bancrofti and brugia malayi mosquitoes (lots of species) adults in lymphatics, microfilaria in blood (increased at night)

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7
Q

loa loa causative agents? vector? location of adults? of microfilaria?

A

loa loa eye worm chrysops flies adults in SQ tissues (moving around) microfilaria in blood (daytime)

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8
Q

river blindness causative agent? vector? location of adults? of microfilaria?

A

onchocerciasis blackflies adults in SQ tissues (nodules) microfilaria in skin

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9
Q

treatment of 1) lymphatic filariasis 2) loa loa 3) onchocerciasis

A

1) DEC (diethylcarbamazine) 2) DEC (but contraindicated if the microfilaria level is super high –> inflammatory response would be too high and cause death) 3) ivermectin (DO NOT USE DEC)

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10
Q

adverse effect if DEC is used in loa with high microfilaremia

A

encephalopathy and death due to high inflammatory reaction

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11
Q

adverse effect if you try to treat onchocerciasis with DEC?

A

severe skin inflammation (microfilaria in skin) and blindness (microfilaria in cornea)

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12
Q

lymphatic filariasis presentation

A

asymptomatic or lymphangitis and lymphatic obstruction distal lymphedema (scrotal hydrocele and elephantiasis of legs) retrograte lymphangitis dermatolymphangioadenitis (bacterial/soft tissue infections)

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13
Q

tropical pulmonary eosinophilia

A

due to excessive immuine response to microfilaria in lung vasculature; complication of filariasis causes paroxysmal nocturnal asthma, pulmonary infiltrates, peripheral blood eos (>3000), elevated IgE in serum, high filarial antibody titers rapid response to anti-filarial therapy

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14
Q

lymphatic filariasis diagnosis

A

microfilaria in nighttime blood circulating antigen test in blood filaria dance sign on ultrasound positive for antibodies

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15
Q

microfilaria peak at midnight indicates

A

lymphatic filariasis

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16
Q

onchocerciasis caused by? vector? disease? transmission/lifecycle? symptoms?

A

caused by Onchocerca volvulus vector = black flies (simulium species) – mate near rivers a chronic, progressive disease called RIVER BLINDNESS high morbidity: eye, skin, lymphatic disease adult worms in SQ nodules; microfilaria in skin males are small, females are up to 80 cm! –> males travel between nodules inseminating females symptoms: nodules, dermatitis, itchy, eye disease (punctate keratitis = crawl across eye and leave scar) can cause sclerosing keratitis and blindness, hanging groin (boggy LNs)

17
Q

ivermectin drug mechanism

A

hydrogenated form of avermectin opens gated-chloride channels that are only in susceptible helminths and arthropods.(doesnt hurt us!) This causes influx of chloride ions, hyperpolarization of cells, and paralysis. Also interact with GABA receptors use for strongyloides and onchocerca volvulus microfilaricidal BUT doesnt kill adult worms - continue treatment for 10-15 years

18
Q

what can be targeted in adult onchocerca worms?

A

wolbachia bacteria are needed inside them add doxycycline to ivermectin

19
Q

loiasis (loa loa)

A

Vector: Chrysops spp. (deerfly) Host: human Microfilariae: blood-borne in DAYTIME Adult worms: subcutaneous tissue symptoms: non specific (fatigue, urticaria, arthralgias, myalgias), calabar swellings (transient, hard and migratory swelling), and eyeworm worm in eye DOES NOT CAUSE BLINDNESS

20
Q

loa loa treatment

A

DEC unless mf level is >2500

21
Q

angiostrongylus cantonensis

A

rat lungworm; found in SE asia (thailand, malaysia) and hawaii caused by ingestion of parasites in snail or slugs (vegetables) or paratenic hosts (prawns, crabs) in humans, cause eosinophilic meningitis (go to CNS) symptoms = headache, paresthesias, neck stiffness, photophobia CSF eosinophilia and elevated protein (glucose normal or low)

22
Q
A

trichinellosis

23
Q

trichinellosis

A

T spiralis and T nelsoni

Eat meat containing cysts (pork, boar, horse, wild game) –> Larvae are released from cysts by gastric acid.

Adults invade sm. bowel and mature into adults over 1-2wks –> ABDOMINAL CRAMPS,

DIARRHEA IF HEAVY INFXN

Adults (who only live for about a month) make larvae –> Larvae migrate to striated mm, encyst, and live in “nurse cells”

–>MUSCLE PAIN

PERIORBITAL EDEMA

EOSINOPHILIA

OCC CNS AND HEART DAMAGE

ddx with muscle biopsy showing L1 larvae

24
Q

treatment for trichinellosis

A

frequent natural recovery

analgesics, antipyretics, and prednisone

specific Rx with mebendazole, albendazole, or thiabendazole for intestinal and muscle stages in heavy infxns

25
Q

toxocariasis

A

Caused by dog (Toxocara canis) and cat (Toxocara catis) ascarids –> ingestion of eggs in dog or cat feces

larvae hatch in intestine and go to liver, spleen, lungs, brain, and/or eye.

Symptoms

——Visceral Larva Migrans (VLM) = 2-5 year olds with fever, eosinophilia, hepatomegaly and also wheezing, pneumonia, splenomegaly

—— Ocular Larva Migrans (OLM) = often in 10-15 year olds with retinal lesions that appear as solid tumors, often near the macula

26
Q

anisakis simplex

A

Acquired by ingestion of raw or undercooked seafood

In humans, parasite buries its head into gastric mucosa

— since not the right host, worm eventually dies

—-can penetrate mucosa and cause intraabdominal abscess

Symptoms

1) due to invasion of worm (pain, vomiting)
2) due to allergic rxn to worm

(mild urticaria, itchy throat, anaphylactic shock)

Treatment= endoscopic removal

27
Q

blood microfilaria at night?

A

lymphatic filariasis

28
Q

SQ nodules or skin microfilaria?

A

onchocerca volvulus

29
Q

blood microfilaria during day?

A

loa loa

30
Q

muscle pain + eosinophila?

A

trichinella

31
Q

eosinophilic meningitis?

A

angiostrongylus

32
Q

abd pain after sushi?

A

anisakis

33
Q

eosinophilia + fever + elevated liver enzymes in child?

A

visceral larva migrans