Review Topic
  • Helminths are macroscopic parasitic worms that are classified into three clinically relevant groups:
    • cestodes (tapeworms)
    • trematodes (flukes)
    • nematodes (roundworms)
  • General features of helminths
    • macroscopic (though the parasite’s eggs are usually microscopic)
    • multicellular
    • have three main life-cycle stages
      • eggs
      • larvae
      • adults
Tapeworms (Cestodes) 
Helminths Transmission Disease Treatment
Taenia solium (pork)
  • Ingestion of larvae in undercooked pork
  • Ingestion of eggs in food contaminated with human feces
  • Intestinal tapeworm (ingestion of larvae)
  • Neurocysticercosis (ingestion of eggs)
  • Praziquantel
  • Albendazole (for neurocysticercosis)
Taenia saginata (beef)
  • Ingestion of larvae in undercooked beef
  • Intestinal tapeworm
  • Praziquantel
Diphyllobothrium latum (fish)
  • Ingestion of larvae in raw freshwater fish
  • Megaloblastic anemia due to vitamin B12 deficiency
  • Praziquantel
Echinococcus granulosus/multilocularis
  • Ingestion of eggs in food contaminated with dog feces
  • Hydatid cyst disease (liver cysts)
  • Albendazole
Flukes (Trematodes) 
  • Penetration of skin by cercariae, usually in contaminated fresh water (snails are intermediate host)
  • Hepatosplenomegaly
  • Portal hypertension
  • Squamous cell carcinoma of the bladder (chronic infection with S. haematobium)
  • Praziquantel
Clonorchis sinensis (Chinese liver fluke)
  • Ingestion of undercooked fish
  • Clonorchiasis (biliary tract inflammation)
  • Cholangiosarcoma
  • Praziquantel
Paragoniums westermani (lung fluke)
  • Ingestion of undercooked crab or crayfish
  • Mimics pulmonary TB (hemoptysis)
  • Praziquantel
Roundworms (Nematodes) 
Transmitted by the Ingestion of Eggs ("EATT")
Enterobius vermicularis (pinworm)
  • Fecal-oral
  • Anal pruritis
  • Albendazole
  • Pyrantel pamoate
Ascaris lumbricoides (giant roundworm)
  • Fecal-oral
  • Colonic obstruction
  • Biliary obstruction
  • Intestinal perforation
  • Albendazole
Trichuris trichiura (whipworm)
  • Fecal-oral
  • Diarrhea
  • Rectal prolapse (with heavy infection
  • Albendazole
Toxocara canis
  • Fecal-oral
  • Visceral larva migrans
  • Albendazole
Transmitted by the Invasion of Larvae through Skin ("SANd")
Strongyloides stercoralis (threadworm)
  • Penetration of the skin by larvae
  • Gastrointestinal upset
  • Albendazole
  • Ivermectin

Ancylostoma braziliense

Necator americanus (hookworm)

  • Penetration of the skin by larvae
  • Microcytic anemia
  • Albendazole
  • Pyrantel pamoate
Transmitted by the Ingestion of Larvae
Trichinella spiralis
  • Ingestion of larvae in undercooked pork
  • Myalgia
  • Albendazole
Transmitted by Arthropods
Wucheria bancrofti
  • Arthropod vector (mosquito)
  • Lymphatic filariasis
  • Diethylcarbamazine 
Loa loa (African eye worm)
  • Arthropod vector (Deer, horse, or mango fly)
  • Skin swelling
  • Worm in conjunctiva
  • Diethylcarbamazine 
Onchocerca volvulus
  • Arthropod vector (blackfly)
  • River blindness 
  • Ivermectin
Dracunculus medinensis (Guinea worm)
  • Ingested copepod in contaminated freshwater
  • Skin inflammation and ulceration
  • Worm eruption from skin
  • Niridazole



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