Ancylostomiasis overview: Difference between revisions
| Line 13: | Line 13: | ||
==pathophysiology== | ==pathophysiology== | ||
[[Ancylostomiasis]] is a [[hookworm infection]], [[soil-transmitted]] [[helminths]] (STH) | [[Ancylostomiasis]] is a [[hookworm infection]], [[soil-transmitted]] [[helminths]] (STH) occurs predominantly in [[countries]] with [[low socioeconomic]] [[status]] located in [[tropical]] and [[subtropical]] areas of the [[world]]. The [[external]] [[surface]] of [[helminth]] comprises key [[molecules]] [[excretory/secretory]] (ES) products which contain distinct [[molecules]], mostly [[proteins]], and also [[lipids]], and [[carbohydrates]]. These [[molecules]] help the [[parasite]] to [[survive]] and evade the [[host]] [[immunological]] [[response]]. The life cycle of hookworm include: human hookworm and zoonotic hookworm. [[Mature females]] released eggs in the host’s [[small intestine]] and these eggs are passed in the feces, where they hatch [[first stage]] [[rhabditiform]] [[larva]] (L1). L1 feeds on soil [[microbes]] and [[molts]] to the L2 stage, and under appropriate conditions, develops into an [[infective]] [[filariform]] (L3) stage larva. The [[infective-stage]] [[larvae]] (L3) enter the body either through a [[cutaneous route]] or by [[direct]] [[oral ingestion]]. The [[infective larvae]] (L3) [[penetrate]] the [[skin]] and through the [[dermis]], enters the [[bloodstream]], and reach the [[lungs]] and [[ascend]] to the [[pharynx]] and reach the [[small intestine]] where they [[mount]] into [[fourth-stage]] [[larvae]] and [[mature]] into [[blood-feeding]] [[adults]] [[male]] or [[female]]. These [[adult worms]] degrades the [[intestinal mucosa]] and [[erosion]] of [[blood vessels]] which results in [[blood]] [[extravasation]] | ||
==Causes== | ==Causes== | ||
Revision as of 20:10, 30 August 2021
|
Ancylostomiasis Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Ancylostomiasis overview On the Web |
|
American Roentgen Ray Society Images of Ancylostomiasis overview |
|
Risk calculators and risk factors for Ancylostomiasis overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Kalpana Giri, MBBS[2]
Overview
Ancylostomiasis was first discovered by Dubini, an Italian physician, in 1838 who provided the first detailed description of hookworms during an autopsy on a woman who had died in Milan. Ancylostomiasis may be classified according to the species into two groups: Human hookworm: Ancylostoma and Necator Americanus and Zoonotic hookworm: Ancylostoma braziliense, Ancylostoma caninum, Ancylostoma ceylanicum and Uncinaria stenocephala. Ancylostomiasis is a hookworm infection, soil-transmitted helminths (STH) occurs predominantly in countries with low socioeconomic status located in tropical and subtropical areas of the world. The external surface of helminth comprises key molecules excretory/secretory (ES) products which contain a large range of structurally and functionally distinct molecules, mostly proteins, and also lipids, and carbohydrates. These molecules help the parasite to survive and evade the host immunological response. The biological role and molecular nature of hookworm ES products are still unclear. The life cycle of hookworm include: human hookworm and zoonotic hookworm. Mature females released eggs in the host’s small intestine and these eggs are passed in the feces, where they hatch first stage rhabditiform larva (L1) within several days. The L1 feeds on soil microbes and molts to the L2 stage, and under appropriate conditions, each eggs hatch in warm, moist, sandy soil, or in feces and develops into an infective filariform (L3) stage larva. The infective-stage larvae (L3) enter the body either through a cutaneous route or by direct oral ingestion. Human hookworm such as Ancylostoma and Necator americanus enter the body by skin penetration which may cause a local pruritic dermatitis, at the site of penetration whereas the ancylostoma species can also enter the body orally. The infective larvae (L3) migrate through the dermis, enters the bloodstream, and reach the lungs and migrate across the alveoli. Then they ascend from the bronchial tree to the pharynx and reach the small intestine where they mount into fourth-stage larvae and mature into blood-feeding adults male or female. These adult worms degrades the intestinal mucosa and erosion of blood vessels which results in blood extravasation. Hookworms also secrete Ancylostoma ceylanicum anticoagulant peptide-1, which inhibits the blood coagulation in the attachment site and leads to blood loss from the intestine. Zoonotic hookworm (i.e., cat and dog hookworms) include: Ancylostoma braziliense, Ancylostoma caninum, Ancylostoma ceylanicum and Uncinaria stenocephala. Among these most commonly encountered hookwormis Ancylostoma braziliense. It causes cutaneous larva migrans (creeping eruption). Ancylostoma ceylanicum is the only species that develops to adult in humans, and causes enteric hookworm infection. Ancylostoma caninum occasionally reaches adulthood in humans, and causes eosinophilic enteritis.Common causes of Ancylostomiasis include: Ancylostoma duodenale, Necator americanus, Ancylostoma ceylanicum, and less common organisms include: Ancylostoma braziliense, Ancylostoma caninum, Ancylostoma ceylanicum, and Uncinaria stenocephala. Ancylostomiasis differentiated from ascariasis, trichuriasis, and Strongyloides species. The incidence rate of hookworm infection was 7.5/100 person-years, prevalence is approximately 1 billion people worldwide, and mortality rate in the tropics is approximately 50-60,000 deaths per year. It commonly affects children and women of childbearing age. Common risk factors of ancylostomiasis include: exposure to soil where filariform larvae, the infective stage, live in and penetrate human skin, Poor sanitation, low socioeconomic status, low educational attainment. The majority of the infected patients remain asymptomatic. The symptoms of ancylostomiasis typically develop by direct contact of the skin with contaminated soil and the fecal-oral route. The most common complications include: Iron deficiency anemia, in child: intellectual and cognitive development, in pregnant women: severe anemia, impaired growth, severe anemia, premature birth, neonatal anemia.Prognosis is generally excellent with proper treatment. The diagnostic test of ancylostomiasis is the microscopic detection of hookworms eggs in stool. The majority of patients with ancylostomiasis are asymptomatic. Common symptoms of ancylostomiasis include: anorexia, flatulence, diarrhea, weight loss, pallor, dyspnea, weakness, generalized edema, melena, hematemesis, dizziness, syncope, cough, sneezing, hemoptysis, nausea, vomiting, pharyngeal irritation, itchy, erythematous, serpiginous skin lesions. Physical examination include: pallor, fatigue, dizziness, serpiginous, erythematous, and palpable plaque, abdominal distension. Lab findings include: decreased hemoglobin, eosinophilia, presence of several live and motile worms in upper gastrointestinal endoscopy. For treatment anti-helminthic therapies are recommended among patients with ancylostomiasis. Efficacy of treatment varies according to the severity of infection, geographical distribution, and age groups. Multiple blood transfusion, iron supplements are also be given in severe cases. Effective measures for the primary prevention of ancylostomiasis include periodic mass anthelminthic treatment of at-risk populations, avoid Gardening barefooted, Patient Education on proper hygiene and sanitation.
Historical Perspective
Ancylostomiasis was first discovered by Dubini, an Italian physician, in 1838 who provided the first detailed description of hookworms during an autopsy on a woman who had died in Milan. Necator americanus and Ancylostoma duodenale were responsible for all human hookworm infections mentioned by Bethony et al ( 2006), de Silva et al.(2003), however Bradbury & Traub (2016) and Traub et al. (2008) mentioned Ancylostoma ceylanicum is also an important hookworm of humans, especially in South East Asia.
Classification
Ancylostomiasis may be classified according to the species into two groups: Human hookworm: Ancylostoma and Necator Americanus and Zoonotic hookworm: Ancylostoma braziliense, Ancylostoma caninum, Ancylostoma ceylanicum and Uncinaria stenocephala.
pathophysiology
Ancylostomiasis is a hookworm infection, soil-transmitted helminths (STH) occurs predominantly in countries with low socioeconomic status located in tropical and subtropical areas of the world. The external surface of helminth comprises key molecules excretory/secretory (ES) products which contain distinct molecules, mostly proteins, and also lipids, and carbohydrates. These molecules help the parasite to survive and evade the host immunological response. The life cycle of hookworm include: human hookworm and zoonotic hookworm. Mature females released eggs in the host’s small intestine and these eggs are passed in the feces, where they hatch first stage rhabditiform larva (L1). L1 feeds on soil microbes and molts to the L2 stage, and under appropriate conditions, develops into an infective filariform (L3) stage larva. The infective-stage larvae (L3) enter the body either through a cutaneous route or by direct oral ingestion. The infective larvae (L3) penetrate the skin and through the dermis, enters the bloodstream, and reach the lungs and ascend to the pharynx and reach the small intestine where they mount into fourth-stage larvae and mature into blood-feeding adults male or female. These adult worms degrades the intestinal mucosa and erosion of blood vessels which results in blood extravasation
Causes
Common causes of Ancylostomiasis include: Ancylostoma duodenale, Necator americanus, Ancylostoma ceylanicum, and less common organisms include: Ancylostoma braziliense, Ancylostoma caninum, Ancylostoma ceylanicum, and Uncinaria stenocephala.
Differentiating ancylostomiasis from Other Diseases
Ancylostomiasis manifests in a variety of clinical forms, differentiation must be established in accordance with the particular sign and symptoms. Such as abdominal symptoms differentiated from ascariasis and trichuriasis, and parasites associated with pneumonitis and peripheral eosinophilia are Aascaris and Strongyloides species. Cutaneous manifestations are differentiated from contact dermatitis, scabies infection, migratory myiasis, and cercarial dermatitis. In infants gastrointestinal bleeding must be differentiated from other diseases that cause melena, pallor, anorexia, listlessness, and edema such as portal hypertension, Meckel’s diverticulum, or AV malformation. In adults gastrointestinal bleeding must be differentiated from other diseases such as Meckel’s diverticulum and Dieulafoy’s lesions, inflammatory bowel disease and nonsteroidal anti-inflammatory drug-induced small bowel disease. In older patient (>50 years old) are prone to gastrointestinal bleeding from angiectasias, adenocarcinoma, leiomyoma, and lymphoma.
Epidemiology and Demographics
The incidence rate of hookworm infection was 7.5/100 person-years. Prevalence of Ancylostomiasis is approximately 1 billion people worldwide. People of all ages are susceptible to Ancylostomiasis, commonly affects children and women of childbearing age. Mortality rate of Hookworms in the tropics is approximately 50-60,000 deaths per year. Men are more commonly affected by Ancylostomiasis than women. Ancylostomiasis is a common disease that tends to affect cooler, drier regions.
Risk Factors
Common risk factors of ancylostomiasis include: exposure to soil where filariform larvae, the infective stage, live in and penetrate human skin, Poor sanitation, low socioeconomic status, low educational attainment.
Natural History, Complications, and Prognosis
The majority of the infected patients remain asymptomatic. The symptoms of ancylostomiasis typically develop by direct contact of the skin with contaminated soil and the fecal-oral route. The most common complications include: Iron deficiency anemia, in child: intellectual and cognitive development, in pregnant women: severe anemia, impaired growth, severe anemia, premature birth, neonatal anemia. Prognosis is generally excellent with proper treatment.
Diagnosis
Diagnostic Study of Choice
The diagnostic test of ancylostomiasis is the microscopic detection of hookworms eggs in stool.
History and Symptoms
The majority of patients with ancylostomiasis are asymptomatic. Common symptoms of ancylostomiasis include: anorexia, flatulence, Diarrhea, Weight loss, Pallor, Dyspnea, Weakness, Generalized edema, Melena, Hematemesis, Dizziness, Syncope, Cough, Sneezing, Hemoptysis, Nausea, Vomiting, Pharyngeal irritation, Itchy, erythematous, serpiginous skin lesions.
Physical examination
Physical examination include: Pallor, fatigue, Dizziness, serpiginous, erythematous, and palpable plaque associated with edema, abdominal distension.
Lab Findings
Lab findings include: decreased hemoglobin, eosinophilia, Presence of several live and motile worms in upper gastrointestinal endoscopy.
X Ray
There are no x-ray findings associated with ancylostomiasis.
CT
There are no CT findings associated with ancylostomiasis.
Other Diagnostic Studies
Other diagnostic studies for ancylostomiasis include upper gastrointestinal endoscopy, which demonstrates live and motile worms in GI tract.
Treatment
Medical Therapy
Anti-helminthic therapies are recommended among patients with ancylostomiasis. Efficacy of treatment varies according to the severity of infection, geographical distribution, and age groups. Multiple blood transfusion, Iron supplements are also be given in severe cases.
Surgery
Surgical intervention is not recommended for the management of ancylostomiasis.
Primary Prevention
Effective measures for the primary prevention of ancylostomiasis include periodic mass anthelminthic treatment of at-risk populations, avoid Gardening barefooted, Patient Education on proper hygiene and sanitation.