Hookworm
Hookworm is a topic covered in the Johns Hopkins ABX Guide.
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MICROBIOLOGY
- Members of the family Ancylostomatoidea (nematodes):
- 18 total genera
- Two species account for most human infections:
- Ancylostoma duodenale (AD)
- Necatur americanus (NA)
- Epidemiology: About 500 million people infected worldwide
- Hookworm prevalence is highest in adults, although children are also commonly infected.
- Infections are common in the tropics and subtropics; rare in regions with < 40 inches of annual rainfall.
- AD found in Mediterranean countries, Iran, India, Pakistan, and the Far East.
- NA found throughout sub-Saharan Africa, the Americas, Asia, and the South Pacific.
- Anemia is the major source of morbidity related to infection, driving global productivity losses that may exceed $100 billion per year.
- Adult hookworms are 5-11mm (males) or 9-13mm (females). Identification based on size, number and arrangement of teeth, length of the esophagus, size of eggs, the morphology of bursa (males), or position of ova (females). Eggs are morphologically indistinguishable.
- Life cycle: [Fig 3]
- Eggs [Fig 4] are passed in the stool and hatch into rhabditiform larvae after 1-2 days.
- Rhabditiform larvae grow in the soil, molt and become infective filariform larvae after 5-10 days.
- Filariform larvae penetrate human skin, mostly feet, (AD can also enter via ingestion of contaminated food) and travel through venous circulation to lungs, through alveoli, to the pharynx and are swallowed into the GI tract where they mature and attach to the walls of the small intestine.
-- To view the remaining sections of this topic, please log in or purchase a subscription --
MICROBIOLOGY
- Members of the family Ancylostomatoidea (nematodes):
- 18 total genera
- Two species account for most human infections:
- Ancylostoma duodenale (AD)
- Necatur americanus (NA)
- Epidemiology: About 500 million people infected worldwide
- Hookworm prevalence is highest in adults, although children are also commonly infected.
- Infections are common in the tropics and subtropics; rare in regions with < 40 inches of annual rainfall.
- AD found in Mediterranean countries, Iran, India, Pakistan, and the Far East.
- NA found throughout sub-Saharan Africa, the Americas, Asia, and the South Pacific.
- Anemia is the major source of morbidity related to infection, driving global productivity losses that may exceed $100 billion per year.
- Adult hookworms are 5-11mm (males) or 9-13mm (females). Identification based on size, number and arrangement of teeth, length of the esophagus, size of eggs, the morphology of bursa (males), or position of ova (females). Eggs are morphologically indistinguishable.
- Life cycle: [Fig 3]
- Eggs [Fig 4] are passed in the stool and hatch into rhabditiform larvae after 1-2 days.
- Rhabditiform larvae grow in the soil, molt and become infective filariform larvae after 5-10 days.
- Filariform larvae penetrate human skin, mostly feet, (AD can also enter via ingestion of contaminated food) and travel through venous circulation to lungs, through alveoli, to the pharynx and are swallowed into the GI tract where they mature and attach to the walls of the small intestine.
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Last updated: January 12, 2020
Citation
Crowell, Trevor A. "Hookworm." Johns Hopkins ABX Guide, The Johns Hopkins University, 2020. Johns Hopkins Guide, www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540275/all/Hookworm.
Crowell TA. Hookworm. Johns Hopkins ABX Guide. The Johns Hopkins University; 2020. https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540275/all/Hookworm. Accessed January 28, 2023.
Crowell, T. A. (2020). Hookworm. In Johns Hopkins ABX Guide. The Johns Hopkins University. https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540275/all/Hookworm
Crowell TA. Hookworm [Internet]. In: Johns Hopkins ABX Guide. The Johns Hopkins University; 2020. [cited 2023 January 28]. Available from: https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540275/all/Hookworm.
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T1 - Hookworm
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Y1 - 2020/01/12/
BT - Johns Hopkins ABX Guide
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PB - The Johns Hopkins University
DB - Johns Hopkins Guide
DP - Unbound Medicine
ER -