Parasitic Helminths Vocabulary Flashcards

Vocabulary flashcards covering human parasitic nematodes, trematodes, and cestodes, including scientific names, diseases, infection routes, key clinical characteristics, diagnostic methods, and treatment regimens.

Angiostrongylus cantonensis

Also known as the rat lungworm; causes angiostrongyliasis following the ingestion of uncooked freshwater snails, shrimp, freshwater crabs, monitor lizards, frogs, or contaminated vegetables containing embryonate ova. It can involve the CSF, eye, or brain, and is treated with symptomatic management plus albendazole.

Ascaris lumbricoides

The large roundworm causing ascariasis when embryonated eggs (measuring $60 \times 50\,\text{um}$) are ingested from contaminated food, water, or soil. Larval migration causes tissue damage and intense immune response, while wandering adults cause intestinal obstruction. Treated with albendazole $400\,\text{mg}$ once.

Anisakis simplex

A nematode causing anisakiasis acquired by digesting 3rd-stage larvae in raw or undercooked sea fish or squid. Humans are accidental hosts in which larvae cannot mature or lay eggs (no stool eggs); treated primarily by endoscopic removal of larvae and albendazole.

Capillaria philippinensis

A nematode causing capillariasis through ingestion of uncooked freshwater fish contaminated with infective stage in the fish's intestine. Characterized by stomach rumbling and chronic diarrhea, and treated with albendazole $400\,\text{mg/day}$ for $20\,\text{days}$ or mebendazole $400\,\text{mg/day}$ for $30\,\text{days}$.

Trichuris trichiura

Also known as whipworm; causes trichuriasis via ingestion of embryonated eggs in contaminated food, water, or soil contact. Adults reside in the cecum/ascending colon, and severe infection leads to rectal prolapse. Treated with albendazole $400\,\text{mg}$ daily for $3$ consecutive days.

Enterobius vermicularis

Also known as pinworm; causes enterobiasis via person-to-person transmission, inhalation, or retro-infection around perianal folds where females lay eggs. Diagnosed using the SCOTCH-TAPE technique and treated with albendazole $400\,\text{mg}$ once, treating the entire family/same group.

Macracanthorhynchus hirudinaceus

The giant thorny-headed worm causing acanthocephaliasis following ingestion of uncooked infected bugs or insects. May require physical removal and abdominal dissection alongside mebendazole and symptomatic treatment.

Gnathostoma spinigerum

A parasite causing gnathostomiasis, contracted by eating raw meat, freshwater fish, amphibians, reptiles, pond water with Cyclops, or applying raw meat to wounds. Migrating larvae cause moving swelling, pain, and itching; treated with albendazole $400\,\text{mg}$ morning and evening for $21\,\text{days}$ or surgical removal.

Necator americanus

The Necator hookworm causing necatoriasis via skin penetration by filariform L3 larvae during soil contact. Parasites attach in the intestine using cutting plates, leading to significant blood loss. Treated with albendazole $400\,\text{mg}$ once.

Strongyloides stercoralis

Also known as threadworm; causes strongyloidiasis through skin penetration of filariform L3 larvae during soil contact. Capable of autoinfection and featuring both free-living and parasitic cycles. Treated with ivermectin $200\,\text{ug/kg}$ within $12\,\text{days}$ or listed albendazole regimens.

Toxocara canis / Toxocara cati

Zoonotic nematodes causing toxocariasis in accidental human hosts through ingestion of eggs from dog/cat environments. Larvae become trapped in human tissues without producing eggs in stool; T. cati features characteristic broad alae with striations.

Fasciolopsis buski

The large intestinal fluke causing fasciolopsiasis after eating uncleaned aquatic plants such as water chestnut, water hyacinth, and morning glory. Diagnosed via fecal egg examination and treated with praziquantel $15\,\text{mg/kg}$ once.

Fasciola gigantica

A liver fluke causing fascioliasis via ingestion of uncleaned Chinese water chestnut, morning glory, water mimosa, or water chestnut. Diagnosed via fecal eggs or adult dissection/radiology and treated with praziquantel $12\,\text{mg/kg}$ once.

Haplorchis taichui

A small intestinal fluke causing haplorchiasis through ingestion of uncooked white-scale fish. Confirmed via fecal eggs, post-treatment gravid segments, or PCR, and treated with praziquantel $15\,\text{mg/kg}$.

Opisthorchis viverrini

A liver fluke causing opisthorchiasis from consuming raw freshwater fish (such as Koi Pla) infected with metacercariae. Adults ascend via the ampulla of Vater into biliary/pancreatic ducts; treated with praziquantel $40\,\text{mg/kg}$ once.

Paragonimus heterotremus

The lung fluke causing paragonimiasis following consumption of raw freshwater shrimp, waterfall crabs, or creek crabs containing metacercariae. Adults form lung cystic cavities and eggs appear in sputum or stool; treated with praziquantel $25\,\text{mg/kg}$ for a $2\text{-day}$ course.

Schistosoma mekongi

A blood fluke causing schistosomiasis through active skin penetration by cercariae during contact with contaminated river water. Diagnosed via fecal eggs or rectal biopsy and treated with praziquantel $30\,\text{mg/kg}$ ($2$ doses/day).

Taenia saginata

The beef tapeworm causing intestinal taeniasis saginata upon digesting beef containing cysts with oncospheres. Diagnosed via fecal examination for eggs or gravid proglottids and treated with praziquantel $20\,\text{mg/kg}$ once.

Taenia solium

The pork tapeworm causing intestinal taeniasis solium following ingestion of raw or undercooked pork containing cysticercus cellulosae cysts. Diagnosed by eggs or gravid segments in stool and treated with praziquantel $20\,\text{mg/kg}$ once.

Taenia solium metacestode

The larval stage of Taenia solium causing cysticercosis or neurocysticercosis when humans swallow T. solium eggs from contaminated vegetables, water, or hands. Larvae migrate to brain and organs; treated with praziquantel $50\,\text{mg/kg/day}$ for $15\,\text{days}$.

Dipylidium caninum

The dog tapeworm causing dipylidiasis from accidental ingestion of dog fleas (Ctenocephalides canis), cat fleas (Ctenocephalides felis), or human fleas (Pulex irritans) carrying infective larvae. Diagnosed by egg capsules or gravid segments and treated with praziquantel $10\,\text{mg/kg}$ once.

Diphyllobothrium latum

The fish tapeworm causing diphyllobothriasis via consumption of raw freshwater fish containing plerocercoid larvae, or procercoid larvae in Cyclops. Diagnosed via stool eggs and gravid segments, and treated with praziquantel $20\,\text{mg/kg}$ once.

Echinococcus granulosus

The parasite causing hydatidosis (hydatid cyst disease) acquired by swallowing eggs from dog-contaminated environments, specifically touching the nose/anus area of sheep dogs. Diagnosed by radiology/immunoblot and treated by surgical dissection or albendazole with dissection.

Echinococcus malayanum

Referred to as an echinostome in lecture slides; causes echinostomiasis through ingestion of infective stages in uncooked freshwater snails or tadpoles. Diagnosed by fecal egg examination and treated with praziquantel $15\text{-}30\,\text{mg/kg}$ once.

Hymenolepis diminuta

The rat tapeworm causing hymenolepiasis diminuta when food contaminated with cysticercoids in rat fleas (Xenopsylla cheopis) or bugs is eaten. Diagnosed by fecal eggs or gravid segments and treated with praziquantel $15\,\text{mg/kg}$ once.

Hymenolepis nana

The dwarf tapeworm causing hymenolepiasis nana transmitted via fecal-oral ingestion of embryonated eggs or cysticercoid-infected arthropods/rat fleas. Uniquely capable of autoinfection in humans; treated with praziquantel $15\,\text{mg/kg}$ once.

SCOTCH-TAPE Technique

The primary diagnostic technique for Enterobius vermicularis (pinworm) infection, performed by pressing adhesive tape against the perianal folds where female worms lay eggs.

Retro-infection

An infection pathway seen in Enterobius vermicularis where eggs hatch rapidly around the perianal fold and larvae migrate back into the intestine or vagina.

Autoinfection

A capability of certain parasites (such as Strongyloides stercoralis and Hymenolepis nana) to re-infect the host and complete life cycles without exiting the human body.

Cercariae

The free-swimming, infective larval stage of Schistosoma mekongi that actively infiltrates and penetrates human skin during exposure to contaminated river water.

Metacercariae

The encysted, infective stage found in intermediate hosts (such as freshwater fish, crabs, or shrimp) for trematodes including Opisthorchis viverrini and Paragonimus heterotremus.

Plerocercoid Larva

The infective larval stage of Diphyllobothrium latum present in uncooked freshwater fish that develops into the adult fish tapeworm upon human ingestion.