Anisakis

Background

• Parasitic disease caused by anisakid nematodes
• Larvae ingested via undercooked fish or squid
• Worms invade stomach or intestinal walls

Anisakid in a herring

Clinical Features

• Abdominal pain/distension, nausea/vomiting, bloody/mucus diarrhea
  • Invasion of GI walls can cause peritonitis, appendicitis, SBO
• Mild fever
• Allergic-type reactions (e.g. rash, pruritus) including anaphylaxis can occur

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

Evaluation

• Evaluate for alternate diagnoses
• Definitive diagnosis made by visualizing worms on endoscopy

Management

• Endoscopic or surgical removal of worms
• Albendazole 400mg PO BID x 6-21d

Disposition

• Dependant on severity of presentation

References

• https://www.cdc.gov/parasites/anisakiasis/health_professionals/index.html