Nematodes

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Filarial Roundworms

Organism Vector Distribution Notes
Lymphatic Filariasis
Wuchereria bancrofti Culex and other species mosquitoes
Brugia malayi
Brugia timori
Other Filarial Roundworms
Loa loa Chrysops flies
Mansonella perstans
Mansonella streptocerca
Mansonella ozzardi
Onchocerca volvulus Simulium black flies

Identification

  • Wuchereria and Brugia (and Loa loa) all have a sheath. Onchocerca is only pathogenic nematode that doesn't have a sheath.

Lymphatic filariasis

  • Pattern of nuclei in the tail (Loa loa goes all the way to the tail, others don't). Draw blood at midnight for lymphatic filariasis (elephants come out at night). Can also give small dose of DEC and then sample a few hours.
  • Stain blood with Giemsa for microfilaria. Treated with DEC +/- albendazole.

Onchocerca

  • Onchocerca transmitted by black fly
  • Subcut lumps and bumps, skin thickening and hyperpigmentation, eye involvement with dense cataract. Ivermectin every 6 months for 10 years, but rule out Loa first.

Loa loa

  • Crysops? transmits it. Eyeball with worm is almost always Loa. Calabar lump sp? In West Africa, after Crysops bite. May be on and off for years. If going to treat Onchocerca with ivermectin, need to rule out Loa, which can cause fatal encephalitis.

Intestinal Roundworms

Organism Distribution Treatment
Ascaris lumbricoides albendazole or mebendazole or ivermectin
Necator americanus albendazole or mebendazole or pyrantel pamoate
Ancylostoma duodenale albendazole or mebendazole or pyrantel pamoate
Strongyloides stercoralis ivermectin ± albendazole
Trichuris trichiura albendazole
Enterobius vermicularis albendazole or mebendazole or pyrantel pamoate
Capillaria mebendazole
Trichostrongylus pyrantel pamoate
Anisakis endoscopic removal
Gongylonema surgical removal or albendazole

Tissue-Invasive Roundworms

Organism Distribution Treatment
Trichinella spiralis albendazole plus steroids
Anyclostoma braziliense albendazole or ivermectin
Ancylostoma caninum albendazole or mebendazole or endoscopic removal
Dracunculus medinensis none
Toxocara canis albendazole or mebendazole
Toxocara cati albendazole or mebendazole
Angiostrongylus cantonensis controversial
Gnathostoma albendazole or ivermectin ± surgical removal
Baylisascaris procyonis albendazole + steroids
Dioctophyme renale

Guinea worm

  • Dracunculis medinensis
  • Spread through water, needs to life cycle through water borne Cyclops copapods? Now only present in small number of areas, down to very few cases, through clean water control.
  • May also be maintained in dogs, which may make eradication more difficult.