Necator americanus
Necator americanus | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Nematoda |
Class: | Chromadorea |
Order: | Rhabditida |
Family: | Ancylostomatidae |
Genus: | Necator |
Species: | N. americanus
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Binomial name | |
Necator americanus (Stiles, 1902)
| |
Synonyms | |
Uncinaria americanus Stiles, 1902 |
Necator americanus is a species of
Necator americanus has been proposed as an alternative to Trichuris suis in helminthic therapy.[3]
Morphology
This
Habitat
N. americanus is primarily found in tropical and temperate areas. This parasite thrives in warmer climates because to hatch, the eggs require a moist, warm, and shaded environment. The thin, smooth shells of this species cause the eggs and juveniles to die in freezing temperatures or with soil desiccation. Therefore, the type of soil where the parasite resides is also very important for their ideal living conditions. Ideal soil conditions tend to be in areas where water is able to drain at a standard pace, and the size of the soil particles is neither too large nor too small. That way, the degree of dampness, as well as the openings in the soil, allow the parasites to burrow to the surface and attach to the skin of their next host. High transmission rates seem to be congruent with the heavy rains and warm temperatures that are characteristic of tropical climates. One anomaly of this species is that it appears to prefer male hosts to female hosts, likely because of the division of labor in regions of its prevalence.[5]
Lifecycle
This worm starts out as an
Pathogenesis and symptoms
The pathology of N. americanus is divided into two stages – larvae and adults. The larvae penetrate the uninfected skin and travel through various organs, including the
Epidemiology
In the United States, 95% of human hookworm cases are caused by N. americanus, primarily in young school children in economically deprived rural areas. Historically, there have been high rates of infection among children in the American South.[12] Juveniles cannot survive freezing temperatures, so the highest prevalence occurs in areas with warmer temperatures and greater rainfall. The greatest incidence of infections occurs in Asia and sub-Saharan Africa, especially in poverty-stricken areas with poor sanitation.[8] A. duodenale infections occur at a lesser rate and are seen primarily in Europe and the Mediterranean.[13]
Genome
A draft assembly of the genome of Necator americanus has been sequenced and analyzed.
Diagnostics
The most common method for diagnosing N. americanus is through identification of eggs in a fecal sample using a microscope. N. americanus eggs have a thin shell and are oval shaped, measuring roughly 56–74 by 36–40 μm.[16]
Treatments
The most common
Pregnant women should not be treated within their first trimester.[9]
During the 1940s, the treatment of choice was tetrachloroethylene,[20] given as 3 to 4 cc in the fasting state, followed by 30 to 45 g of sodium sulfate. Tetrachloroethylene was reported to have a cure rate of 80 percent for Necator infections, but 25 percent in Ancylostoma infections, and often produced mild intoxication in the patient.
Prevention and control
Infection and
Economic burden
N. americanus causes hookworm diseases, which are associated with
References
- ^ a b "Necator americanus". Animal Diversity Web. Archived from the original on 2018-04-18. Retrieved 2018-04-21.
- from the original on 2018-08-20. Retrieved 2018-08-20.
- PMID 16344586.
- ^ Roberts, Janovy & Schmidt 2010
- ^ "Necator americanus". Animal Diversity Web. Archived from the original on 2018-04-18. Retrieved 2018-04-21.
- ^ "Hookworm (Intestinal) | CDC-DPDx". September 17, 2019. Archived from the original on 2009-12-15. Retrieved 2021-11-11..
- ^ "Hookworm disease". Encyclopædia Britannica. 2009. Archived from the original on 2021-11-11. Retrieved 2021-11-11.
- ^ PMID 15783256.
- ^ a b c "Necator americanus". Archived from the original on 2018-04-19. Retrieved 2018-04-21.
- ISSN 1381-6128.
- PMID 24516284.
- PMID 24146438.
- ISBN 978-0-323-27764-8.
(N. americanus) is the native hookworm of Africa south of the Sahara and the only one found in parts of India. Ancylostoma and Necator occur together elsewhere in India, in much of China, in southeast Asia, in the islands of the South and Southwest Pacific, and in parts of Australia. ..., it is probable that the geographic boundaries between the two genera of human hookworms will disappear.
- PMID 24441737.
- PMID 20030661.
- ISBN 978-1555813710.
- S2CID 8425278.
- PMID 18430913.
- ^ "Drug resistance in hookworms". Archived from the original on 2018-04-21. Retrieved 2018-04-21.
- ^ "Clinical Aspects and Treatment of the More Common Intestinal Parasites of Man (TB-33)". Veterans Administration Technical Bulletin 1946 & 1947. 10: 1–14. 1948. Archived from the original on 2022-02-25. Retrieved 2021-07-14.
- ^ "Prevention & Control". Parasites: Hookworms. Centers for Disease Control and Prevention, U.S. Department of Health & Human Services. 2013. Archived from the original on 2017-05-24. Retrieved 2017-04-30.
- S2CID 4945916.
Further reading
- Hotez, P.J.; Pritchard, D.I. (June 1995). "Hookworm infection". Scientific American. 272 (6): 68–74. PMID 7761817.
- Murray, P.R.; Rosenthal, K.S.; Pfaller, M.A. (2015). "§ 7 Parasitology. 74 Nematodes". Medical Microbiology (8th ed.). Elsevier Health Sciences. pp. 748–65. ISBN 978-0-323-35952-8.
- Roberts, L.S.; Janovy, J.; Schmidt, G.D. (2010). Foundations of parasitology (8th ed.). McGraw-Hill. pp. 472–73. ISBN 978-0071311038.