Hookworm infection, a hallmark of poverty nowadays, is a disease mainly caused by Necator americanus and Ancylostoma duodenale, nematodes typically found in tropical and subtropical areas of Latin America, Asia, and sub-Saharan Africa. The disease may be asymptomatic, but affected individuals may be malnourished and anemic as a consequence of infection. Individual eradications may be achieved, but patients may become reinfected as a result of unsuitable living conditions. This condition is especially dangerous for pregnant women and may cause prematurity and low birth weight children due to maternal anemia or even hookworm infection in the newborn, as the parasite is excreted in the human colostrum and milk.
Presentation
After infection, the first symptom patients notice is a palm or sole irritation, that is pruritic and either vesicular or erythematous, that should be differentiated from cutaneous larva migrans. As nematodes migrate to the lungs, cough, wheezing and exertion dyspnea appear; if symptoms are severe and accompanied by pleurisy, hemoptysis, and low fever, Löffler syndrome should be suspected [1]. On the other hand, hookworm infection can also lead to hypothermia, severe enough to lower fever caused by malaria [2].
Gastrointestinal infection leads to abdominal pain, nausea, diarrhea, flatulence and anorexia, that makes the iron deficit even more severe [3]. Some patients may have pica and ingest dirt, which puts them at further risk for infection and Wakana syndrome, characterized by and pharyngeal itching, hoarseness, nausea, vomiting, and cough [4]. Intestinal hookworms cause persistent blood loss, which might manifest as melena and cause anemia, which may trigger symptoms like a headache, palpitations, fatigue and impaired memory and learning capabilities. Eosinophilic enteritis causes severe abdominal pain that might lead to confusion with appendicitis or intestinal perforation.
Other symptoms include weight loss, impotence, joint and sternal pain and pain in the lower extremities [3] [5].
Entire Body System
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Anemia
CONCLUSION: The prevalence of hookworm is higher and it is associated with anemia in East Wollega zone. [ncbi.nlm.nih.gov]
The skin might reflect the chronic character of the anemia, as it becomes wax-like and has green-yellow color, typical to tropical chlorosis. [symptoma.com]
ARTÍCULO BREVE Hookworm infection and anemia in adult women in rural Chiapas, Mexico Anemia e infección por Necator americanus en mujeres en Chiapas, México. Paula E. Brentlinger, MD, MPH I Linnea Capps, MD, MPH II Melinda Denson, RN, MPH. [scielosp.org]
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Fever
We studied the temperature at admission of 200 patients with mild malaria and observed that after adjusting for body mass index, the presence of other helminths, and other confounders, only hookworm-infected patients had lower fever at admission that [ncbi.nlm.nih.gov]
On the other hand, hookworm infection can also lead to hypothermia, severe enough to lower fever caused by malaria. [symptoma.com]
A fever, coughing, and wheezing may be caused by the migration of the larvae through the lungs. Adult worms often cause pain in the upper abdomen. Iron deficiency anemia and low levels of protein in the blood can result from intestinal bleeding. [dawahnigeria.com]
At first, people may have an itchy rash where the larvae penetrate the skin, then fever, coughing, and wheezing or abdominal pain, loss of appetite, and diarrhea. [msdmanuals.com]
Lung inflammation with cough, wheezing, and fever rarely occur while the larvae migrate through the lungs. Several weeks after exposure to this hookworm, a loss of appetite and weight loss may occur. Chronic infections can lead to poor nutrition. [healthychildren.org]
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Malnutrition
Both cause anaemia and malnutrition, and schistosomiasis also results in substantial intestinal, liver and genitourinary pathology. [ncbi.nlm.nih.gov]
It was found that those suffering chronic infection were also suffering from protein energy malnutrition as well as anaemia. [www2.shu.ac.uk]
The delicate balance may be upset by malnutrition and inter–current infections. Little is known about host immunity. [aarogya.com]
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Weight Loss
Vaccination of canines with Na-APR-1(mut) and heterologous challenge with A. caninum resulted in significantly reduced parasite egg burdens (P 0.034) and weight loss (P 0.022). [ncbi.nlm.nih.gov]
Other symptoms include weight loss, impotence, joint and sternal pain and pain in the lower extremities. The skin might reflect the chronic character of the anemia, as it becomes wax-like and has green-yellow color, typical to tropical chlorosis. [symptoma.com]
These signs may be followed by abdominal pain, diarrhea, loss of appetite and weight loss, and anemia. Hookworm can also cause difficulty breathing, enlargement of the heart, and irregular heartbeat. [medicinenet.com]
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Fatigue
Intestinal hookworms cause persistent blood loss, which might manifest as melena and cause anemia, which may trigger symptoms like a headache, palpitations, fatigue and impaired memory and learning capabilities. [symptoma.com]
Severe, chronic infections can cause loss of blood and anemia that is sometimes severe enough to cause fatigue and occasionally heart failure and widespread swelling. Doctors diagnose the infection by identifying hookworm eggs in a stool sample. [msdmanuals.com]
Symptoms may include: Abdominal discomfort Cough Diarrhea Fatigue Fever Gas Itchy rash Loss of appetite Nausea, vomiting Pale skin Most people have no symptoms once the worms enter the intestines. [medlineplus.gov]
Respiratoric
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Cough
Some patients may have pica and ingest dirt, which puts them at further risk for infection and Wakana syndrome, characterized by and pharyngeal itching, hoarseness, nausea, vomiting, and cough. [symptoma.com]
At first, people may have an itchy rash where the larvae penetrate the skin, then fever, coughing, and wheezing or abdominal pain, loss of appetite, and diarrhea. [msdmanuals.com]
Infected individuals are often unaware of the larvae travelling through the lungs but they may have a mild cough and throat discomfort. [dermnetnz.org]
Their presence within the lungs usually causes enough irritation to produce coughing. The larvae are coughed up into the throat and mouth, and are then swallowed and passed into the small intestine. [medical-dictionary.thefreedictionary.com]
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Dyspnea
After a single dose of pyrantel pamoate, his symptoms including dyspnea on exertion and edema diminished. And also hemoglobin and B-type natriuretic peptide (BNP) had improved dramatically. [ncbi.nlm.nih.gov]
As nematodes migrate to the lungs, cough, wheezing and exertion dyspnea appear; if symptoms are severe and accompanied by pleurisy, hemoptysis, and low fever, Löffler syndrome should be suspected. [symptoma.com]
As iron deficiency anemia develops and worsens, the patient may become indolent and have weakness, palpitations, fainting, dizziness, dyspnea, mental apathy and headache. [isradiology.org]
When infection with A. duodenale occurs by the oral route, the early migrations of third-stage larvae cause a syndrome known as Wakana disease, which is characterized by nausea, vomiting, pharyngeal irritation, cough, dyspnea, and hoarseness. [nejm.org]
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Dry Cough
When the larvae are in the lungs, there may be a dry cough and a mild fever. When the larvae burrow into the skin, there may be mild itching and a rash. It is not uncommon, however, for mild infections to show no symptoms at all. [humanillnesses.com]
Within 1 to 2-weeks, pulmonary symptoms may develop which are usually mild and transient, consisting of a dry cough, sore throat, asthmatic wheezing and slight fever. A chest x-ray will usually be negative. [isradiology.org]
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Hemoptysis
As nematodes migrate to the lungs, cough, wheezing and exertion dyspnea appear; if symptoms are severe and accompanied by pleurisy, hemoptysis, and low fever, Löffler syndrome should be suspected. [symptoma.com]
Gastrointestinal
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Diarrhea
The diarrhea and eosinophilia subsided after this treatment. [ncbi.nlm.nih.gov]
While a light infection may cause no symptoms, heavy infection can cause anemia, abdominal pain, diarrhea, loss of appetite, and weight loss. Heavy, chronic infections can cause stunted growth and mental development. [web.archive.org]
Hookworm: An intestinal parasite that usually causes diarrhea or cramps. Heavy infestation with hookworm can be serious for newborns, children, pregnant women, and persons who are malnourished. [medicinenet.com]
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Abdominal Pain
Gastrointestinal infection leads to abdominal pain, nausea, diarrhea, flatulence and anorexia, that makes the iron deficit even more severe. [symptoma.com]
Hookworm can also produce abdominal pain, weight loss and diarrhea. [livestrong.com]
In hookworm endemic areas, when empirical treatment for dyspepsia and upper abdominal pain with acid suppressive agents does not offer remedy, antihelminthic agents should be considered even when stool for ova or parasites is negative. [ncbi.nlm.nih.gov]
While a light infection may cause no symptoms, heavy infection can cause anemia, abdominal pain, diarrhea, loss of appetite, and weight loss. Heavy, chronic infections can cause stunted growth and mental development. [web.archive.org]
Additional symptoms may include abdominal pain, the desire to eat soil (geophagy) and lethargy. Cardiac and pulmonary symptoms can arise as a result of the migrating larvae. [msu.edu]
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Epigastric Pain
Dyspepsia and epigastric pain are common presenting symptoms of patients with either hookworm infection or peptic ulcer disease. [ncbi.nlm.nih.gov]
pain and tenderness, nausea, exertional dyspnea, pain in the lower extremities, palpitations, joint and sternal pain, headache, fatigue, and impotence. 27,28 Some patients crave bulky substances and ingest dirt (pica). [nejm.org]
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Recurrent Abdominal Pain
Some patients have been reported to experience increasingly severe recurrent abdominal pain, which may be analogous to a response to repeated insect stings. [emedicine.medscape.com]
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Chronic Diarrhea
Therapeutic helminth infection of macaques with idiopathic chronic diarrhea alters the inflammatory signature and mucosal microbiota of the colon. PLoS Pathog. 8, e1003000 (2012). 25. Li, R. W. et al. [nature.com]
Skin
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Cutaneous Larva Migrans
migrans Cutaneous larva migrans by Ancylostoma caninum Cutaneous larva migrans due to Uncinaria Diffuse unilateral subacute neuroretinitis Infection by Uncinaria Larva migrans of skin Larva migrans, cutaneous Necatoriasis Strongyloidal cutaneous larva [icd9data.com]
After infection, the first symptom patients notice is a palm or sole irritation, that is pruritic and either vesicular or erythematous, that should be differentiated from cutaneous larva migrans. [symptoma.com]
See separate Cutaneous Larva Migrans article. Life cycle [ 1 ] Eggs are passed in the stool and (with favourable conditions of moisture, warmth and shade) larvae hatch in one to two days. [patient.info]
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Papular Rash
In these areas, repeated exposure to third-stage larvae of Necator americanus or Ancylostoma duodenale results in a local pruritic, erythematous, papular rash known as "ground itch." [ Note: The three main soil-transmitted helminth infections, Ascariasis [histopathology-india.net]
rash known as “ground itch.” [nejm.org]
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Cutaneous Manifestation
manifestations of hookworm infection must be differentiated from cercarial dermatitis (“swimmer's itch”) and creeping eruption from other causes, such as gnathostomiasis, strongyloidiasis, and infection with fly larvae. [nejm.org]
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Papule
This may appear as a localized area of redness and swelling, or papules. [dermnetnz.org]
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Pruritus
In the migratory phase, pruritus, erythema and vesiculation will occur once the filariform larvae have penetrated the skin of the feet or hands. This is known as "ground or dew itch" in people who go barefoot. [isradiology.org]
The vaccine was safe and well-tolerated, with the most frequently observed adverse events being injection site reactions, including mild to moderate pain, swelling, erythema, and pruritus (G. Simon, personal communication). [doi.org]
Neurologic
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Headache
Intestinal hookworms cause persistent blood loss, which might manifest as melena and cause anemia, which may trigger symptoms like a headache, palpitations, fatigue and impaired memory and learning capabilities. [symptoma.com]
Cysts in the brain and spinal cord can produce seizures, confusion, headaches, weakness and paralysis. These cysts can be detected with CAT scans or magnetic resonance imaging. [livestrong.com]
As iron deficiency anemia develops and worsens, the patient may become indolent and have weakness, palpitations, fainting, dizziness, dyspnea, mental apathy and headache. [isradiology.org]
[…] patients report subjective clinical improvement after treatment. 26 A moderate or heavy hookworm burden results in recurrent epigastric pain and tenderness, nausea, exertional dyspnea, pain in the lower extremities, palpitations, joint and sternal pain, headache [nejm.org]
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Dizziness
As iron deficiency anemia develops and worsens, the patient may become indolent and have weakness, palpitations, fainting, dizziness, dyspnea, mental apathy and headache. [isradiology.org]
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Apathy
As iron deficiency anemia develops and worsens, the patient may become indolent and have weakness, palpitations, fainting, dizziness, dyspnea, mental apathy and headache. [isradiology.org]
Workup
The skin might reflect the chronic character of the anemia, as it becomes wax-like and has green-yellow color, typical to tropical chlorosis. Dermatological examination shows the rash described above, that is sometimes accompanied by scratching lesions or typical cutaneous larva migrans, a serpiginous erythematous lesion that appears at the hookworm entrance site [6]. Lung auscultation reveals wheezing and stool inspection may diagnose melena. Signs of heart failure appear if anemia is severe. Patients might also present with peripheral edema or even anasarca, due to hypoproteinemia [7]. Infected children exhibit growth retardation [8].
Blood tests must include a complete cell blood count, that reveals an iron deficiency anemia and eosinophilia, more prominent in eosinophilic enteritis than larva migrans [7]. Serum immunoglobulin E is high, as in other parasite infections. Serum ferritin and protoporphyrin levels are decreased [9].
Stool evaluation may diagnose infestation by describing eggs or larvae, but may also be negative, in which case disease cannot be excluded. Stool should be processed immediately after emission and look especially for eggs because larvae might be confused with those of Strongyloides stercoralis.
Polymerase chain reaction is another valuable but unfortunately not widely available way to diagnose this disease [10].
Hookworm infection patient may also be susceptible to other diseases, due to the demonstrated down-regulation of the immune system that comes with this condition [11] [12].
Other diagnostic methods include colonoscopy, that describes ulceration and sometimes adult hookworms attached to the colon and thoracic radiography, that might show diffuse infiltrates.
Serum
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Microcytic Anemia
Hookwork disease identification chonic parasitic infection iron deficiency and hypochromic, microcytic anemia, Children w/heavy long term infection may have hypoprteinemia and may be retarded in mental and physical development. [quizlet.com]
Hookworm can cause hypothermia that is severe enough to reduce fever caused by malaria. 25 Other than hypochromic microcytic anemia, the most prominent laboratory finding is eosinophilia. [nejm.org]
Microbiology
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Necator Americanus
The most common hookworm species are Ancylostoma duodenale and Necator americanus. In this report we present a case of overt gastrointestinal bleeding because of hookworm infection. [ncbi.nlm.nih.gov]
Fig. 3 Nucleotide sequence alignment of the ITS-1 gene from Trichostrongylus colubriformis used in this study, Ancylostoma duodenale, and Necator americanus. [doi.org]
In Cohort 2, ten (10) volunteers will receive an inoculum of 50 infectious Necator americanus larvae. In the optional Cohort 3, ten (10) volunteers will receive an inoculum of 75 infectious Necator americanus larvae. [clinicaltrials.gov]
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Ancylostoma Duodenale
The most common hookworm species are Ancylostoma duodenale and Necator americanus. In this report we present a case of overt gastrointestinal bleeding because of hookworm infection. [ncbi.nlm.nih.gov]
Fig. 3 Nucleotide sequence alignment of the ITS-1 gene from Trichostrongylus colubriformis used in this study, Ancylostoma duodenale, and Necator americanus. [doi.org]
Ancylostoma duodenale produces more blood loss than Necator americanus. More anemia comes about with the infection of the Ancylostoma duodenale. [coursera.org]
Treatment
The impact of anthelmintic treatment is greatest when albendazole is co-administered with praziquantel. [ncbi.nlm.nih.gov]
The RCT in Peru found no impact of treatment on Hb or mean birthweight but showed a significant decrease in the prevalence of very low birthweight with anthelmintic treatment [24]. [doi.org]
Prognosis
What Is the Prognosis? Proper treatment of hookworm infections results in a high recovery rate. How Is the Diagnosis Made? Reinfection is common. Wearing shoes prevents the larvae from entering the body through the feet. [healthychildren.org]
Outlook (Prognosis) You will have a complete recovery if you get treated before serious complications develop. Treatment gets rid of the infection. [ufhealth.org]
Prognosis The prognosis for patients with hookworm disease is generally good. However, reinfection rates are extremely high in countries with poor sanitation. [medical-dictionary.thefreedictionary.com]
Etiology
Worldwide, N. americanus is the predominant etiology of human hookworm infection, whereas A. duodenale occurs in more scattered focal environments [ 3 ]. [doi.org]
Since the number of diseases and the etiology are varied, one should additionally consider that autoimmune diseases can affect several parts of the body either isolated or simultaneously. [dovepress.com]
The major etiology of Hookworm infection is N. Americanus which is found the Americas, sub-Saharan Africa, and Asia [29]. A. duodenale is found in more scattered focal environments, namely Europe and the Mediterranean [30]. [web.stanford.edu]
Epidemiology
Our epidemiological understanding of hookworm has improved through the development of mathematical models of transmission dynamics, which coupled with decades of field research across multiple epidemiological settings, have shown that certain population [ncbi.nlm.nih.gov]
Pathophysiology
University Tropical Parasitology: Protozoans, Worms, Vectors and Human Diseases This course provides students an understanding of important human parasitic diseases, including their life cycles, vectors of transmission, distribution and epidemiology, pathophysiology [coursera.org]
Trichostrongyles are related to hookworms in terms of transmission mode, morphology, and pathophysiology. [doi.org]
Heterogeneity of autoimmune diseases: pathophysiologic insights from genetics and implications for new therapies. Nat Med. 2015;21(7):730–738. 9. Jacobson DL, Gange SJ, Rose NR, Graham NM. [dovepress.com]
Pathophysiology and Clinical Disease Larval Invasion of Tissue Figure 1. Figure 1. Cutaneous Larva Migrans Caused by Ancylostoma braziliense. Reprinted from Despommier et al., 8 with the permission of the publisher. [nejm.org]
Prevention
Treating in this way is called preventive treatment (or "preventive chemotherapy"). [web.archive.org]
Specifically, we found that while preventive chemotherapy appeared to dramatically reduce hookworm infection, WASH was associated with infection intensity. [ncbi.nlm.nih.gov]
(Image courtesy of the Centers for Disease Control and Prevention.) Hookworm - Ancylostoma caninum illustration Hookworm egg - illustration This is a hookworm egg. Hookworms hatch in damp vegetation. [leehealth.org]
(Image courtesy of the Centers for Disease Control and Prevention.) This is a photograph of a hookworm on the lining of the intestine. (Image courtesy of the Centers for Disease Control and Prevention.) This is a hookworm egg. [mountsinai.org]
Treating in this way is called preventive treatment (or “preventive chemotherapy”). [cdc.gov]
References
- Hotez PJ, Brooker S, Bethony JM, et al. Hookworm infection. N Engl J Med. 2004 Aug 19. 351(8):799-807.
- Nacher M, Singhasivanon P, Traore B, et al. Short report: hookworm infection is associated with decreased body temperature during mild Plasmodium falciparum malaria. Am J Trop Med Hyg 2001;65:136-7
- Anyaeze CM. Reducing burden of hookworm disease in the management of upper abdominal pain in the tropics. Trop Doct 2003;33:174-5.
- Hotez PJ, Brooker S, Bethony JM, et al. Hookworm infection. N Engl J Med. 2004 Aug 19. 351(8):799-807.
- Gilles HM, Williams EJ, Ball PA. Hookworm infection and anaemia: an epidemiological, clinical, and laboratory study. Q J Med 1964;331:1-24.
- Heukelbach J, Feldmeier H. Epidemiological and clinical characteristics of hookworm-related cutaneous larva migrans. Lancet Infect Dis. 2008 May. 8(5):302-9.
- Brooker S, Bundy DAP. Soil-transmitted Helminths (Geohelminths). Cook GC, Zumla AI, eds. Manson’s Tropical Diseases. 22nd ed. Philadelphia, PA: WB Saunders; 2009. 1515-48.
- Stoltzfus RJ, Albonico M, Tielsch JM, Chwaya HM, Savioli L. Linear growth retardation in Zanzibari school children. J Nutr. 1997 Jun. 127(6):1099-105.
- Stoltzfus RJ, Chwaya HM, Tielsch JM, Schulze KJ, Albonico M, Savioli L. Epidemiology of iron deficiency anemia in Zanzibari schoolchildren: the importance of hookworms. Am J Clin Nutr 1997;65:153-9.
- Gasser RB, Cantacessi C, Loukas A. DNA technological progress toward advanced diagnostic tools to support human hookworm control. Biotechnol Adv. 2008;26(1):35-45.
- Olatunde BO, Onyemelukwe GC. Immunosuppression in Nigerians with hookworm infection. Afr J Med Med Sci 1994;23:221-5.
- Loukas A, Prociv P. Immune responses in hookworm infections. Clin Microbiol Rev 2001;14:689-703.