Necatoriasis

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This article is about the infection. For the organism, see Necator americanus.
Necatoriasis
SpecialtyInfectious diseases Edit this on Wikidata

Necatoriasis is the condition of infection by

neglected tropical disease
.

Signs and symptoms

When adult worms attach to the villi of the small intestine, they suck on the host's blood, which may cause abdominal pain, diarrhea, cramps, and weight loss that can lead to anorexia. Heavy infections can lead to the development of iron deficiency and hypochromic microcytic anemia. This form of anemia in children can give rise to physical and mental retardation. Infection caused by cutaneous larvae migrans, a skin disease in humans, is characterized by skin ruptures and severe itching.[2]

Cause

Lifecycle of a hookworm
Cutaneous larvae migrans

Necatoriasis is caused by

dyspnea, pain in lower extremities and in joints, sternal pain, headache, fatigue, and impotence.[5] Death is rare in humans.[citation needed
]

Diagnosis

The standard method for diagnosing necatoriasis is through identification of N. americanus eggs in a fecal sample using a microscope. Eggs can be difficult to visualize in a lightly infected sample so a concentration method is generally used such as flotation or sedimentation.[6] However, the eggs of A. duodenale and N. americanus cannot be distinguished; thus, the larvae must be examined to identify these hookworms. Larvae cannot be found in stool specimens unless the specimen was left at ambient temperature for a day or more.[citation needed]

The most common technique used to diagnose a hookworm infection is to take a stool sample, fix it in 10% formalin, concentrate it using the formalin-ethyl acetate sedimentation technique, and then create a wet mount of the sediment for viewing under a microscope.[citation needed]

Prevention

Education, improved

endemic areas helps reduce the prevalence of infection.[citation needed
]

Treatment

An infection of N. americanus parasites can be treated by using

benzimidazoles: albendazole or mebendazole. A blood transfusion may be necessary in severe cases of anemia. Light infections are usually left untreated in areas where reinfection is common. Iron supplements and a diet high in protein will speed the recovery process.[7] In a case study involving 56-60 men with Trichuris trichiura and/or N. americanus infections, both albendazole and mebendazole were 90% effective in curing T. trichiura. However, albendazole had a 95% cure rate for N. americanus, while mebendazole only had a 21% cure rate. This suggests albendazole is most effective for treating both T. trichiura and N. americanus.[8]

Cryotherapy by application of liquid nitrogen to the skin has been used to kill cutaneous larvae migrans, but the procedure has a low cure rate and a high incidence of pain and severe skin damage, so it now is passed over in favor of suitable pharmaceuticals. Topical application of some pharmaceuticals has merit, but requires repeated, persistent applications and is less effective than some systemic treatments.[9]

During the 1910s, common treatments for hookworm included

2-naphthol, chloroform, gasoline, and eucalyptus oil.[10] By the 1940s, the treatment of choice was tetrachloroethylene,[11] 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.

Epidemiology

Necator americanus was first discovered in Brazil and then was found in Texas. Later, it was found to be indigenous in Africa, China, southwest Pacific islands, India, and Southeast Asia. This parasite is a tropical parasite and is the most common species in humans. Roughly 95% of hookworms found in the southern region of the United States are N. americanus. This parasite is found in humans, but can also be found in pigs and dogs.[citation needed]

Transmission of N. americanus infection requires the deposition of egg-containing feces on shady, well-drained soil and is favored by warm, humid (tropical) conditions. Therefore, infections worldwide are usually reported in places where direct contact with contaminated soil occurs.[citation needed]

References

  1. S2CID 8040066
    .
  2. ^ "Necator americanus Material Safety Data Sheets (MSDS)". Public Health Agency of Canada. 2001. Retrieved 4 December 2009.
  3. S2CID 24495300
    .
  4. S2CID 2281145
    .
  5. PMID 18171264
    .
  6. ^ Gantz, Nelson Murray (2006). "Helminths". Manual of Clinical Problems in Infectious Disease. Philadelphia: Lippincott Williams & Wilkins. p. 443.
  7. ^ "hookworm disease". Encyclopædia Britannica Online. Encyclopædia Britannica. 2009. Retrieved 6 December 2009.
  8. S2CID 19551476
    .
  9. PMID 10816151
    .
  10. ^ Milton, Joseph Rosenau (1913). Preventive Medicine and Hygiene. D. Appleton. p. 119.
  11. ^ "Clinical Aspects and Treatment of the More Common Intestinal Parasites of Man (TB-33)". Veterans Administration Technical Bulletin 1946 & 1947. 10: 1–14. 1948.

External links

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