Hookworm

Background

• Necator americanus
• Larvae penetrate through intact skin on contact with feces-contaminated soil
  • Enter the bloodstream, ascend the trachea, descend the esophagus to differentiate into adult worms, and migrate to the upper intestine where they attach to the mucosal wall and feed on host blood
• Commonly occurs in warmer climates (tropics, Southeast United States).

Clinical Features

• Morbidity is related to number of worms harbored in intestines
• Light infections often asymptomatic
• Heavier infections with variety of manifestations including GI symptoms (abdominal pain, diarrhea, blood in stool, rectal prolapse), malaise, weakness, impaired cognitive / physical development, malnutrition</ref>
• Iron-deficiency anemia
• Hypochromic microcytic anemia
  • Adult worms attach to intestinal wall to feed, causing ongoing luminal blood loss

Differential Diagnosis

Helminth infections

Cestodes (Tapeworms)

• Taenia saginata
• Taenia solium (Cysticercosis)
• Diphyllobothrium latum
• Hymenolepis nana
• Echinococcus granulosus

Trematodes (Flukes)

• Fasciola hepatica
• Fasciolopsis buski
• Opistorchis viverrini
• Schistosoma spp
  • Schistosomiasis
• Chlonorchis sinensis
• Paragonimus spp.

Nematodes (Roundworms)

• Ascaris lumbricoides
• Enterobius vermicularis (Pinworm)
• Filarial worms
  • Loa Loa
  • Onchocerciasis
  • Lymphatic filariasis (Elephantiasis)
    • Wuchereria bancrofti
    • Brugia malayi
    • Brugia timori
• Hookworm
  • Necator americanus
  • Ancylostoma duodenale
  • Cutaneous larva migrans (Ancylostoma braziliense)
• Dracunculiasis
• Strongyloides stercoralis
• Trichuris trichiura (Whipworm)
• Anisakis
• Toxocara spp.
• Trichinosis

Management

• Albendazole 400 mg x 1 dose (high efficacy) OR mebendazole 500 mg x 1 dose (low to moderate efficacy)
• Iron supplements in anemia

See Also

• Worm Infections
• Travel Medicine