Parasitic Infections

Flashcards summarizing key terms and definitions related to various parasitic infections, including nematodes, cestodes, trematodes, and treatments.

What are the two species of Hookworm?

Ancylostoma duodenale (Old World) and Necator americanus (New World).

What is the infective stage of Hookworms?

Filariform larva (L3) that penetrates human skin.

How is Hookworm transmitted?

Skin contact with contaminated soil.

What is the life cycle summary of Hookworms?

Eggs → soil larvae → skin → lungs → intestine → eggs in feces.

What are the symptoms of Hookworm infection?

Itching, cough, anemia, fatigue.

What species do Whipworms belong to?

Trichuris trichiura.

What is the infective stage of Whipworms?

Embryonated egg containing larva.

How is Whipworm transmitted?

Ingestion of embryonated eggs from contaminated soil.

What is the life cycle summary of Whipworms?

Soil egg → ingestion → colon → egg release → soil.

What are the symptoms of Whipworm infection?

Diarrhea, rectal prolapse, anemia (children).

What species do Threadworms belong to?

Strongyloides stercoralis.

What is the infective stage of Threadworms?

Filariform larva (L3) that penetrates skin.

How is Threadworm transmitted?

Contact with contaminated soil; may autoinfect.

What is the life cycle summary of Threadworms?

Soil larvae → skin → lungs → intestine → eggs/larvae → soil or autoinfection.

What are the symptoms of Threadworm infection?

Diarrhea, cough, anemia, eosinophilia.

What species do Pinworms belong to?

Enterobius vermicularis.

What is the infective stage of Pinworms?

Embryonated egg.

How is Pinworm transmitted?

Ingestion or inhalation of eggs from surfaces.

What is the life cycle summary of Pinworms?

Egg → ingestion → intestine → perianal eggs → reinfection.

What are the symptoms of Pinworm infection?

Anal itching, insomnia.

What species does Giant Roundworm belong to?

Ascaris lumbricoides.

What is the infective stage of Giant Roundworm?

Embryonated egg containing L2 larva.

How is Giant Roundworm transmitted?

Ingestion of contaminated food or soil.

What is the life cycle summary of Giant Roundworm?

Soil egg → ingestion → liver/lungs → intestine → feces.

What are the symptoms of Giant Roundworm infection?

Intestinal blockage, cough, malnutrition.

What species does Guinea Worm belong to?

Dracunculus medinensis.

What is the infective stage of Guinea Worm?

L3 larva in copepod.

How is Guinea Worm transmitted?

Drinking contaminated water.

What is the life cycle summary of Guinea Worm?

Copepod → human → skin blister → water → copepod.

What are the symptoms of Guinea Worm infection?

Painful blister, secondary infection.

What are examples of Filarial Worms?

Wuchereria bancrofti, Brugia malayi, Loa loa, Onchocerca volvulus, Mansonella ozzardi.

What is the infective stage of Filarial Worms?

L3 larvae transmitted by insect bite.

What are the vectors for Filarial Worms?

Mosquito, Chrysops fly, Simulium fly, midge.

What are the symptoms of Filarial Worm infection?

Elephantiasis, limb swelling, eye migration, skin nodules.

What is the life cycle summary of Filarial Worms?

Insect bite → human tissue → adult → microfilariae → insect.

What species does Dwarf Tapeworm belong to?

Hymenolepis nana.

What is the infective stage of Dwarf Tapeworm?

Embryonated egg.

What is the life cycle of Dwarf Tapeworm?

Egg → intestine → cysticercoid → adult → egg (direct cycle).

What species do Beef and Pork Tapeworms belong to?

Taenia saginata (beef) and Taenia solium (pork).

What is the infective stage of Taenia?

Cysticercus larva in meat.

How is Taenia transmitted?

Eating undercooked beef or pork.

What is the life cycle of Taenia?

Human → animal → meat → human.

What is the risk associated with Taenia solium?

Cysticercosis from egg ingestion.

What species does Hydatid Tapeworm belong to?

Echinococcus granulosus.

What is the infective stage of Hydatid Tapeworm?

Embryonated egg.

How is Hydatid Tapeworm transmitted?

Contact with infected dog feces.

Who are the definitive and intermediate hosts for Hydatid Tapeworm?

Definitive host: dog; intermediate: sheep or human.

What is Hydatid disease?

Hydatid cysts in organs.

What species does Fish Tapeworm belong to?

Diphyllobothrium latum.

What is the infective stage of Fish Tapeworm?

Plerocercoid larva in fish.

How is Fish Tapeworm transmitted?

Eating undercooked fish.

What is the life cycle of Fish Tapeworm?

Water → copepod → fish → human.

What is a symptom of Fish Tapeworm infection?

Vitamin B12 deficiency.

What species does Intestinal Fluke belong to?

Fasciolopsis buski.

What is the infective stage of Intestinal Fluke?

Metacercaria on aquatic plants.

How is Intestinal Fluke transmitted?

Eating raw aquatic plants.

What is the life cycle of Intestinal Fluke?

Snail → plant → human → feces → water → snail.

What species does Liver Fluke belong to?

Fasciola hepatica.

What is the infective stage of Liver Fluke?

Metacercaria on water plants.

How is Liver Fluke transmitted?

Eating raw vegetation.

What is the life cycle of Liver Fluke?

Snail → plant → liver → bile ducts → eggs → snail.

What species does Chinese Liver Fluke belong to?

Clonorchis sinensis.

What is the infective stage of Chinese Liver Fluke?

Metacercaria in fish.

How is Chinese Liver Fluke transmitted?

Eating raw/undercooked fish.

What is the life cycle of Chinese Liver Fluke?

Snail → fish → human → eggs → snail.

What species does Lung Fluke belong to?

Paragonimus westermani.

What is the infective stage of Lung Fluke?

Metacercaria in crab or crayfish.

How is Lung Fluke transmitted?

Eating undercooked crab.

What is the life cycle of Lung Fluke?

Snail → crab → human → sputum/feces → snail.

What are the symptoms of Lung Fluke infection?

Cough, bloody sputum, chest pain.

What species do Blood Flukes belong to?

Schistosoma mansoni, S. japonicum, S. haematobium.

What is the infective stage of Blood Flukes?

Free-swimming cercaria.

How are Blood Flukes transmitted?

Cercariae penetrate skin in contaminated water.

What is the life cycle of Blood Flukes?

Snail → cercaria → human → blood → eggs → water.

What are the symptoms of Blood Fluke infection?

Intestinal bleeding, Katayama fever, hematuria.

What is the general life cycle summary for Nematodes?

Soil/vector → infective egg/larva → human → adult → eggs → environment.

What is the general life cycle summary for Cestodes?

Egg → intermediate host → larval form → human → adult → egg.

What is the general life cycle summary for Trematodes?

Snail → secondary host → human → egg → water → snail.

What is the action of the antiparasitic drug Albendazole/Mebendazole?

Blocks glucose uptake; treats nematodes.

What is the action of Ivermectin?

Paralyzes worms; treats filarial and threadworm.

What is the action of Praziquantel?

Increases calcium permeability; treats flukes and tapeworms.

What is the action of Diethylcarbamazine?

Treats filarial infections.

What is the action of Niclosamide?

Kills tapeworms via oxidative uncoupling.

What is the action of Metronidazole?

Breaks protozoan DNA strands.

What are common intermediate hosts for parasitic infections?

Snail, copepod, fish, crab, mosquito, fly, cow, pig, dog, sheep.

What is a hallmark lab finding for parasites?

Eosinophilia.

What are examples of autoinfection?

Strongyloides stercoralis, Enterobius vermicularis.

What are key transmission types for parasitic infections?

Ingestion, skin penetration, vector bite, contaminated water.