Parasites Flashcards

Question

Trichuris trichiura (Whipworm)

Answer 1

**Features:** "* Tropical/subtropical areas * S US" **Reservoir:** * Fecal oral: ingestion of eggs in soil **Transmission:** Eggs ingested --> adults live in lg intestine --> excreted in feces **Diseases:** "* Dysentery, abd pain, bloody diarrhea, weight loss * Cause rectal prolapse" **Diagnosis:** "Stool (eggs w plugged ends = tea tray) **Treatment:** * Albendazole | Helminths - Nematodes

Answer 2

**Features:** "* Topical/subtropical areas * Appalachian area of US" **Reservoir:** * Skin penetration by larvae in soil **Transmission:** "* Eggs hatch forming adults in intestine --> larvae that are shed in stool * Autoinfection: larvae penetrate GI mucosa or perianal skin & migrate to other organs causing infection (persists for many decades) * Hyperinfection: disseminated when larvae penetrate bowel in setting of immunosuppression" **Diseases:** "* Epigastric pain (adult worms live in sm intestine), NON-bloody diarrhea, eosinophilia * Hyperinfection: larvae confined to lungs/GI tract --> bacteremia, pneumonia, high mortality rate * Disseminated --> GN meningitis" **Diagnosis:** "* Epigastric pain (adult worms live in sm intestine), NON-bloody diarrhea, eosinophilia * Hyperinfection: larvae confined to lungs/GI tract --> bacteremia, pneumonia, high mortality rate * Disseminated --> GN meningitis" **Treatment:** * Ivermectin | Helminths - Nematodes

Answer 3

**Features:** "* Most common helminth in US " **Reservoir:** "Children & caretakers * Eggs survive in environment for 1-2 wk" **Transmission:** Pinworm eggs ingested --> adult worms live in cecum --> females exit & lay eggs at night on anus **Diseases:** * Significant perianal pruritis **Diagnosis:** * Scotch tape test **Treatment:** "* Albendazole * Laundering (hot water/dryer)" | Helminths - Nematodes

Answer 4

**Features:** "* Rat lungworm * SE Asia & tropical Pacific islands" **Reservoir:** "* Rat --> snails, slugs, freshwater crabs (IM hosts) * Ingestion of larvae in freshwater shrimp or crabs" **Transmission:**Humans consume entering GI tract --> blood -> meninges where larvae die -> immune response **Diseases:**"* Eosinophilic meningoencephalitis (> 10 eosinophils/CSF) * Larvae die in brain causing eosinophil driven immune response * Most cases are self-limited sometimes with neurologic sequelae" **Diagnosis:**"* No commercial tests * DOH labs (PCR on CSF) * CSF (eosinophilic pleocytosis, elevated protein, low/normal glucose) * Stool NOT HELPFUL (not passed in stool, larvae die in brain)" **Treatment:**None (steroids to decrease headache) | Helminths - Nematodes

Answer 5

**Features:** "* Racoon roundworm * Canada & US (NE mostly)" **Reservoir:** "* Racoons & rarely dogs * Ingestion of infective eggs" **Transmission:** Humans ingest eggs --> Larvae encyst in hosts in different sites **Diseases:** "* Symptoms depend on where larvae encyst * Visceral: skin infection, rash, abd pain, pneumonitis * Ocular: photophobia, retinitis, unilateral blindness * Neural: eosinophilic menigoencaphalitis, incoordination, ataxia, weakness, altered mental status, stupor, seizure, coma" **Diagnosis:** "* Lab findings: peripheral eosinophilia, CSF eosinophilic pleocytosis * CDC: serologic testing of CSF/serum * Ocular exam (migrating larva, larval tracts, lesions)" **Treatment:** * Albendazole + steroids | Helminths - Nematodes

Answer 6

**Features:** * Europe & US **Reservoir:** * Ingestion of undercooked meat **Transmission:**Ingested larvae --> adults in sm intestine that release larvae that invade GI tract --> blood --> muscles **Diseases:**Fever, eosinophilia, myalgia, periorbital edema **Diagnosis:**"* Serum ab * Muscle biopsy (high risk of sampling error, encysted larvae in muscle)" **Treatment:*** Albendazole + steroids if severe | Tissue Nematodes

Answer 7

**Features:** **Reservoir:** "* Ingestion of undercooked meat * Definitive host = puppies & cats" **Transmission:**Ingestion of eggs --> larvae in gut to blood to tissues where larvae cannot develop further, but cause local inflammatory rxn & mechanical damage instead **Diseases:**"* Visceral larvae migrans: fever, rash, coughing, pneumonitis, hepatomegaly, eosinophilia * ocular larvae migrans: uveitis, retinitis, blindness * neuro larvae migrans: eosinophilic meningitis, rare" **Diagnosis:**"* ELISA Ab test * Muscle biopsy" **Treatment:*** Albendazole | Tissue Nematodes

Answer 8

**Features:** * W & Central Africa **Reservoir:** "* Chrysops fly bite * Only infects humans" **Transmission:** Fly bites releasing larvae --> develop into adults in human --> adult worms migrate throughout tissues AND live in them between layesr of CT releasing microfilariae in bood during day **Diseases:** * Adult worm migration through eye & subcutaneous tissues causes calabar swelling **Diagnosis:** "* After removal from eye * Blood smear collected during day (adults release microfilaria during the day)" **Treatment:** * Diethycarbamazine (DEC): heavy infection with tx risks brain inflammation; kills both adult & microfilariae forms | Blood Nematodes - Filiaria

Answer 9

**Features:** "* Rivers * Africa, Central/S America" **Reservoir:** * Black fly (lives near rivers) **Transmission:** Larvae enters bite & mature into adult worms that live in nodules in skin & release microfilariae **Diseases:** "* Release of microfilaria in skin causes itching * Microfilariae in eye causes inflammation & scarring --> blindness" **Diagnosis:** "* Release of microfilaria in skin causes itching * Microfilariae in eye causes inflammation & scarring --> blindness" **Treatment:** "* Surgical (nodule removal) * Ivermectin - kills microfilariae & sterilizes female worms * Doxycyline - kills microfilariae" | Blood Nematodes - Filiaria

Answer 10

**Features:** * 90% cases are caused by Wuchereria **Reservoir:** * Mosquito **Transmission:**Larvae enters bite & mature into adults worms that produce microfilaria --> lymph & blood at night --> adults live in lymphatics & damage it **Diseases:*** Elephatiasis: lymphedema from adults living in lymphatics mostly in legs --> hardening/thickening of skin (can also live in male scrotum) **Diagnosis:**"* Blood smear at night (microfilaria) * antifilarial ab test" **Treatment:**Diethycarbazamine, Ivermectin, Albendazole | Blood Nematodes - Filiaria

Answer 11

**Features:** "* Fish tapeworm * Infection can last up to 25 yrs" **Reservoir:** "* Cold bodies of water * Undercooked fish" **Transmission:**Consume larvae-containing fish --> Uses scolex to attach to intestine & grows into adult --> proglottids release eggs into feces **Diseases:**"* Most often asymptomatic * GI side effects * megaloblastic anemia (consumed by worm)" **Diagnosis:**"* Most often asymptomatic * GI side effects * megaloblastic anemia (consumed by worm)" **Treatment:*** Praziquantel | Helminths - Trematodes & Cestodes (tapeworm)

Answer 12

**Features:** "* Pig Tapeworm * Scolex: head of worm contains hooks" **Reservoir:** * Contaminated pork **Transmission:**Consume infected muscle in meat --> adult tapeworm attaches to intestinal wall --> proglottids filled with eggs pass in feces **Diseases:** "* Consume larvae --> Mild abd symptoms * Consume eggs --> Neurocysticercosis: Eggs -> larvae that travel to brain & other tissues forming cystic lesions with small hyperintense dot on some; seizures" **Diagnosis:**"* Stool (eggs) * Brain CT/MRI: ring-enhancing cystic lesion with scolex in center (small opaque dot); calcifications (dead) * Serum Ab" **Treatment:** "* Albendazole (kills cysts) + corticosteroids (minimize inflammation) * Anti-epileptics may be needed if only dead calcified lesions are present" | Helminths - Trematodes & Cestodes (tapeworm)

Answer 13

**Features:** * Beef tapeworm **Reservoir:** * Contaminated pork **Transmission:**Consume infected muscle in meat --> adult tapeworm attaches to intestinal wall --> proglottids filled with eggs pass in feces **Diseases:**"* Consume larvae --> Mild abd symptoms * Consume eggs --> Neurocysticercosis: Eggs -> larvae that travel to brain & other tissues forming cystic lesions with small hyperintense dot on some; seizures" **Diagnosis:**"* Stool (eggs) * Brain CT/MRI: ring-enhancing cystic lesion with scolex in center (small opaque dot); calcifications (dead) * Serum Ab" **Treatment:** "* Albendazole (kills cysts) + corticosteroids (minimize inflammation) * Anti-epileptics may be needed if only dead calcified lesions are present" | Helminths - Trematodes & Cestodes (tapeworm)

Answer 14

**Features:** * Hydatid cyst disease **Reservoir:** "* Sheep-raising areas * Ingestion of eggs in dog feces (dogs = def host, produces infective eggs) * Humans are incidental hosts (cannot pass to other humans)" **Transmission:**Ingest eggs that migrate from GI --> blood --> liver or lungs & become larger hydatid cyst **Diseases:**"* Enlargement of cyst causes symptoms * Liver: RUQ pain, nausea, vomiting, jaundice * Lung: cough, SOB, hemoptysis * Cyst rupture --> anaphylaxis" **Diagnosis:**"* US/CT (hydatid cyst in liver or lungs) * Ab: serology is supportive, but NOT diagnostic" **Treatment:**"* Resection of cyst * Albendazole" | Helminths - Trematodes & Cestodes (tapeworm)

Answer 15

**Features:** **Reservoir:** "* Skin penetration in freshwater * Snails (IM host) release cercariae which contact human skin in freshwater" **Transmission:*** Adult worms coat themselves w host antigens (antigenic mimicry) to evade host immune system **Diseases:**"Acute Diseases * Cercarial Dermatitis (Swimmer's itch): uritcarial plaques or pruritic papules in exposed areas (not under bathing suit) * Katayama Fever: in previously unexposed pts at onset of egg laying (3-8wk) with fever, myalgia, abd pain, diarrhea, HA, eosinophilia, elevated LFTs Chronic Disease: re-exposure in endemic areas * Bowel: ulceration, inflammation, blood loss, scarring (see below)" **Diagnosis:**"* Stool O&P (negative w Katayama fever since eggs are just forming) * Serology * Eosinophilia" **Treatment:*** Praziquantel | Flukes in Blood

Answer 16

**Features:** **Reservoir:** **Transmission:** **Diseases:** **Diagnosis:** **Treatment:** | Flukes in Blood

Answer 17

**Features:** "* Africa & Middle East * Terminal spine (end) on egg" **Reservoir:** "* Skin penetration in freshwater * Snails (IM host) release cercariae which contact human skin in freshwater" **Transmission:** * Adult worms live in braches of venous plexus (liver) --> migrate into bladder **Diseases:**"* Bladder disease due to chronic deposition of eggs in bladder wall --> hematuria, fibrosis/calcification of bladder, granulomatous inflammation Long-term consequences: * pseudopolyps, urinary tract obstruction --> renal failure & inflammation * Squamous cell carcinoma of bladder can occur without tx * Infertility due to infection of genital tract" **Diagnosis:*** URINE O&P (eggs) **Treatment:*** Praziquantel | Flukes in Blood

Answer 18

**Features:** "* East Asia * Nubby spine (round egg)" **Reservoir:** "* Skin penetration in freshwater * Snails (IM host) release cercariae which contact human skin in freshwater" **Transmission:*** Adult worms live in branches of mesenteric veins & migrate into portal venous system/liver to mature **Diseases:**"* Liver disease * Peri-portal fibrosis due to egg deposition in portal venous system * Portal HTN: Blocks portal bloodflow -> hepatosplenomegaly, ascites, esophageal varices, cirrhosis" **Diagnosis:** * Stool O&P (eggs) **Treatment:** * Praziquantel | Flukes in Blood

Answer 19

**Features:** "* Africa & S America * Lateral spine on egg" **Reservoir:** "* Skin penetration in freshwater * Snails (IM host) release cercariae which contact human skin in freshwater" **Transmission:*** Adult worms live in branches of mesenteric veins & migrate into portal venous system/liver to mature **Diseases:**"* Liver disease * Peri-portal fibrosis due to egg deposition in portal venous system * Portal HTN: Blocks portal bloodflow -> hepatosplenomegaly, ascites, esophageal varices, cirrhosis" **Diagnosis:** * Stool O&P (eggs) **Treatment:** * Praziquantel | Flukes in Blood

Answer 20

**Features:** * East Asia (Chinese Liver Fluke) **Reservoir:** * Undercooked freshwater fish **Transmission:*** Eggs ingested by snails are released & infect fish --> encysts in duodenum of human --> adult form that travels through biliary duct & lays eggs --> eggs pass in feces **Diseases:**"* Acute: fever, abd pain, anorexia, urticaria 10-26 days post-consumption * Chronic: biliary obstruction; associated w cholangiocarcinoma" **Diagnosis:**"* Stool (eggs 4 wk after) * Eosinophilia" **Treatment:**Praziquantel | Flukes in Liver

Answer 21

**Features:** "* SE Asian Liver Fluke * S China/Vietnam" **Reservoir:** **Transmission:** **Diseases:** "* Acute: fever, abd pain, anorexia, urticaria 10-26 days post-consumption * Chronic: biliary obstruction; associated w cholangiocarcinoma" **Diagnosis:**Eggs/adults indistinguishable **Treatment:** | Flukes in Liver

Answer 22

**Features:** **Reservoir:** "* Fecal-oral * Raw watercress or contaminated plants" **Transmission:**Mature in biliary duct & eggs are excreted in feces **Diseases:**RUQ pain, fever, eosinophilia **Diagnosis:**"* Stool (eggs, not seen during migratory phase) * adult flukes in biliary tree * Eggs are indistinguishable from Faciolopsis buski*" **Treatment:**Triclabendazole | Flukes in Liver

Answer 23

**Features:** "* Largest intestinal fluke * Asia & India" **Reservoir:** * Pigs and freshwater plant consumption **Transmission:** **Diseases:**Asymptomatic to diarrhea, abd pain, fever, ascistes, asasarca & intestinal obstruction **Diagnosis:**"* Serology * Feces/Vomit (eggs - scanty & intermittent production) * Eggs are indistinguishable from Fasciola hepatica*" **Treatment:**Praziquantel | Flukes in Intestine

Answer 24

**Features:** "* P westermani - SE Asia & Japan * P kellicotti - N America" **Reservoir:** * Consumption of raw/undercooked crab or crayfish **Transmission:*** Ex-cyst into duodenum & mature --> adults lay eggs that enter lung & are excreted in sputum OR can be swallowed & pass through stool **Diseases:**"* Early: (2 mo) fever, diarrhea, abd pain, urticaria * Larvae penetrate diaphragm into pleural cavity --> chest pain, cough, malaise * Late: inflammation, fibrosis, hemoptysis" **Diagnosis:*** Sputum/Bronchoalveolar lavage (eggs) **Treatment:**"* Praziquantel * Triclabendazole" | Flukes in Lung

Parasites Flashcards

(48 cards)