Hookworm

Aka: Hookworm, Necator americanus, Ancylostoma duodenale, N. americanus, New World Hookworm, A. duodenale, Old World Hookworm

II. Pathophysiology

  1. Human Hookworm: Blood sucking Nematode
  2. Size of both species
    1. Length: 10-12 mm females, 6-8 mm males
    2. Eggs: 60-70 um
  3. Life cycle
    1. Eggs hatch into rhabditform larvae
    2. Ingest soil Bacteria
    3. Molt into filariform larvae
    4. Larvae infect humans via pores, Hair Follicles, skin
    5. Larvae mature in blood
    6. Invade via alveolar capillaries into lung
    7. Ascend Bronchial tree to be swallowed
    8. Mature worm attaches to Small Intestine wall
    9. Worm feeds and lays eggs in Small Intestine
  4. Species
    1. Necator americanus (New World Hookworm)
      1. Predominates in Americas and Carribean
      2. Mouth with both dorsal and ventral cutting plates
    2. Ancylostoma duodenale (Old World Hookworm)
      1. Predominates in Asia, Africa and Europe
      2. Mouth with 2 pairs of cutting teeth

III. Epidemiology

  1. Second to Pinworm as most common US Helminth infection
  2. Widespread endemic areas
    1. Asia (China, India, Japan)
    2. Mideast
    3. Africa
    4. Southern Europe
    5. Caribbean
    6. Central America
    7. South America

IV. Symptoms

  1. Initial (usually asymptomatic)
    1. Pruritic erythematous dermatitis
    2. Mild respiratory symptoms
  2. Later: Gastrointestinal (onset 6 weeks after infection)
    1. Symptoms related to Anemia (see below)

V. Complications

  1. Anemia due to blood loss
    1. Hookworm ingests 0.25 ml of blood per day
  2. Results of Anemia in Children
    1. Malnutrition
    2. Failure to Thrive
    3. Mental Retardation

VI. Labs

  1. Microscopy for Ova and Parasites exam
    1. Examine stool at room Temperature
    2. Rhabditiform Larvae hatch
      1. Contrast with Strongyloides
  2. Complete Blood Count
    1. Hypochromic Microcytic Anemia
    2. Eosinophilia

VII. Management

  1. Treat concurrent Iron Deficiency Anemia
  2. Eradication of Helminth infection
    1. Mebendazole 100 mg PO bid for 3 days (not available as of 2012)
    2. Albendazole 400 mg PO for one dose
    3. Pyrantel pamoate 11 mg/kg up to 1 gram for one dose

VIII. Prevention

  1. Always wear shoes in endemic areas
  2. Ensure adequate sanitation system

IX. References

  1. Kucik (2004) Am Fam Physician 69(5):1161-8 [PubMed]

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Related Studies

Ontology: Hookworms (C1265425)

Concepts Eukaryote (T204)
SnomedCT 359760006, 284047004, 243666005, 75838009, 359762003
English hookworm, Ancylostomatidae (organism), Hookworm (living organism) (organism), Ancylostomatidae, Family Ancylostomatidae, Hookworm, Family: Ancylostomatidae, Hw - Hookworm, Hookworm (organism), Hookworms, Hookworm, NOS, Hookworm (living organism) [Ambiguous], Ancylostomatidae [Ambiguous]
Spanish anquilostoma (organismo vivo), anquilostoma, uncinaria, anquilostoma (concepto no activo), familia: Ancylostomatidae (organismo), familia: Ancylostomatidae, lombriz intestinal
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Ancylostomiasis due to Ancylostoma duodenale (C1384687)

Concepts Disease or Syndrome (T047)
MSH C538433 , D000724
ICD9 126.0
SnomedCT 85807000, 7386008
English Ancylostomiasis due to ancylostoma duodenale, infection by Ancylostoma duodenale, infection by Ancylostoma duodenale (diagnosis), Ancylostomiasis due to Ancylostoma duodenale, Ancylostoma duodenale, Ancylostoma duodenale infection, Ancylostomiasis due to Ancylostoma Duodenale, Ancylostomiasis due to Ancylostoma duodenale (disorder)
Dutch ancylostomiasis door Ancylostoma duodenale, Ancylostoma duodenale-infectie
French Infection à Ancylostoma duodénale, Ankylostomiase à Ancylostoma duodenale, Ankylostomose à Ancylostoma duodenale
German Ancylostomiasis, verursacht durch Ancylostoma duodenale, Ancylostoma duodenale Infektion
Italian Infezione da Anchilostoma duodenale, Anchilostomiasi da Ancylostoma duodenale
Portuguese Ancilostomíase por Ancylostoma duodenale, Infecção por Ancylostoma duodenale
Spanish Infección por Ancylostoma duodenale, Anquilostomiasis por Ancylostoma duodenale, anquilostomiasis por Anquilostoma duodenale, anquilostomiasis por Anquilostoma duodenale (concepto no activo), ancilostomiasis por Ancylostoma duodenale (trastorno), ancilostomiasis por Ancylostoma duodenale
Japanese ズビニ鉤虫症, ズビニ鉤虫感染, ｽﾞﾋﾞﾆｺｳﾁｭｳｼｮｳ, ｽﾞﾋﾞﾆｺｳﾁｭｳｶﾝｾﾝ
Czech Ankylostomóza vyvolaná parazitem Ankylostoma duodenale, Infekce Ancylostoma duodenale
Hungarian Ancylostoma duodenale fertőzés, Ancylostoma duodenale okozta ancylostomiasis
Derived from the NIH UMLS (Unified Medical Language System)

Related Topics in Helminth Infestation

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