Hookworm infection pathophysiology: Difference between revisions

Jump to navigation Jump to search
(Created page with "__NOTOC__ {{Hookworm infection}} {{CMG}} == Pathophysiology == '''Etiologic agents:''' The human hookworms include two nematode (roundworm) species, Ancylostoma duodenale a...")
 
m (Changes made per Mahshid's request)
 
(4 intermediate revisions by 2 users not shown)
Line 5: Line 5:
== Pathophysiology ==
== Pathophysiology ==


'''Etiologic agents:'''
====Etiologic Agents====


The human hookworms include two nematode (roundworm) species, Ancylostoma duodenale and Necator americanus.  (Adult females: 10 to 13 mm (A. duodenale), 9 to 11 mm (N. americanus); adult males: 8 to 11 mm (A. duodenale), 7 to 9 mm (N. americanus).  A smaller group of hookworms infecting animals can invade and parasitize humans (A. ceylanicum) or can penetrate the human skin (causing cutaneous larva migrans), but do not develop any further (A. braziliense, A. caninum, Uncinaria stenocephala).  Occasionally A. caninum larva may migrate to the human intestine causing eosinophilic enteritis; this may happen when larva is ingested rather than through skin invasion.
The human hookworms include two nematode (roundworm) species, ''Ancylostoma duodenale'' and ''Necator americanus''.  (Adult females: 10 to 13 mm (''A. duodenale''), 9 to 11 mm (''N. americanus''); adult males: 8 to 11 mm (''A. duodenale''), 7 to 9 mm (''N. americanus'').  A smaller group of hookworms infecting animals can invade and parasitize humans (A. ceylanicum) or can penetrate the human skin (causing cutaneous larva migrans), but do not develop any further (''A. braziliense'', ''A. caninum'', ''Uncinaria stenocephala'').  Occasionally ''A. caninum'' larva may migrate to the human intestine causing eosinophilic enteritis; this may happen when larva is ingested rather than through skin invasion.


'''Life cycle:'''
====Life Cycle====
[[Image:Hookworm LifeCycle.gif|left|frame|Life cycle of Hookworm]]
[[Image:Hookworm LifeCycle.gif|left|frame|Life cycle of Hookworm]]
<br clear="left"/>
<br clear="left"/>


Eggs are passed in the stool '''1''', and under favorable conditions (moisture, warmth, shade), larvae hatch in 1 to 2 days.  The released rhabditiform larvae grow in the feces and/or the soil '''2''', and after 5 to 10 days (and two molts) they become become filariform (third-stage) larvae that are infective '''3'''.  These infective larvae can survive 3 to 4 weeks in favorable environmental conditions.  On contact with the human host, the larvae penetrate the skin and are carried through the veins to the heart and then to the lungs.  They penetrate into the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed '''4'''.  The larvae reach the small intestine, where they reside and mature into adults.  Adult worms live in the lumen of the small intestine, where they attach to the intestinal wall with resultant blood loss by the host '''5'''.  Most adult worms are eliminated in 1 to 2 years, but longevity records can reach several years.
Eggs are passed in the stool '''(1)''', and under favorable conditions (moisture, warmth, shade), larvae hatch in 1 to 2 days.  The released rhabditiform larvae grow in the feces and/or the soil '''(2)''', and after 5 to 10 days (and two molts) they become become filariform (third-stage) larvae that are infective '''(3)'''.  These infective larvae can survive 3 to 4 weeks in favorable environmental conditions.  On contact with the human host, the larvae penetrate the skin and are carried through the veins to the heart and then to the lungs.  They penetrate into the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed '''(4)'''.  The larvae reach the small intestine, where they reside and mature into adults.  Adult worms live in the lumen of the small intestine, where they attach to the intestinal wall with resultant blood loss by the host '''(5)'''.  Most adult worms are eliminated in 1 to 2 years, but longevity records can reach several years.
Some A. duodenale larvae, following penetration of the host skin, can become dormant (in the intestine or muscle).  In addition, infection by A. duodenale may probably also occur by the oral and transmammary route.  N. americanus, however, requires a transpulmonary migration phase.
Some A. duodenale larvae, following penetration of the host skin, can become dormant (in the intestine or muscle).  In addition, infection by A. duodenale may probably also occur by the oral and transmammary route.  N. americanus, however, requires a transpulmonary migration phase.


'''Can animals transmit hookworm infection to me?'''
====Can Animals Transmit Hookworm Infection to Me?====


Yes, but not directly. Puppies and kittens are especially likely to have hookworm infections. Animals that are infected pass hookworm eggs in their stools. The eggs can hatch into larvae, and both eggs and larvae may be found in dirt where animals have been. Eggs or larvae can get into your body when you accidentally eat or have direct contact with contaminated dirt. For example, this can happen if a child is walking barefoot or playing in an area where dogs or cats have been (especially puppies or kittens).
Yes, but not directly. Puppies and kittens are especially likely to have hookworm infections. Animals that are infected pass hookworm eggs in their stools. The eggs can hatch into larvae, and both eggs and larvae may be found in dirt where animals have been. Eggs or larvae can get into your body when you accidentally eat or have direct contact with contaminated dirt. For example, this can happen if a child is walking barefoot or playing in an area where dogs or cats have been (especially puppies or kittens).
Line 24: Line 24:
{{Reflist|2}}
{{Reflist|2}}
[[Category:Disease]]
[[Category:Disease]]
[[Category:Infectious disease]]
 
[[Category:Parasitic diseases]]
[[Category:Needs overview]]

Latest revision as of 18:02, 18 September 2017

Hookworm infection Microchapters

Home

Patient Information

Overview

Pathophysiology

Epidemiology and Demographics

Risk Factors

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms

Laboratory Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Hookworm infection pathophysiology On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Hookworm infection pathophysiology

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Hookworm infection pathophysiology

CDC on Hookworm infection pathophysiology

Hookworm infection pathophysiology in the news

Blogs on Hookworm infection pathophysiology

Directions to Hospitals Treating Hookworm infection

Risk calculators and risk factors for Hookworm infection pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Pathophysiology

Etiologic Agents

The human hookworms include two nematode (roundworm) species, Ancylostoma duodenale and Necator americanus. (Adult females: 10 to 13 mm (A. duodenale), 9 to 11 mm (N. americanus); adult males: 8 to 11 mm (A. duodenale), 7 to 9 mm (N. americanus). A smaller group of hookworms infecting animals can invade and parasitize humans (A. ceylanicum) or can penetrate the human skin (causing cutaneous larva migrans), but do not develop any further (A. braziliense, A. caninum, Uncinaria stenocephala). Occasionally A. caninum larva may migrate to the human intestine causing eosinophilic enteritis; this may happen when larva is ingested rather than through skin invasion.

Life Cycle

Life cycle of Hookworm


Eggs are passed in the stool (1), and under favorable conditions (moisture, warmth, shade), larvae hatch in 1 to 2 days. The released rhabditiform larvae grow in the feces and/or the soil (2), and after 5 to 10 days (and two molts) they become become filariform (third-stage) larvae that are infective (3). These infective larvae can survive 3 to 4 weeks in favorable environmental conditions. On contact with the human host, the larvae penetrate the skin and are carried through the veins to the heart and then to the lungs. They penetrate into the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed (4). The larvae reach the small intestine, where they reside and mature into adults. Adult worms live in the lumen of the small intestine, where they attach to the intestinal wall with resultant blood loss by the host (5). Most adult worms are eliminated in 1 to 2 years, but longevity records can reach several years. Some A. duodenale larvae, following penetration of the host skin, can become dormant (in the intestine or muscle). In addition, infection by A. duodenale may probably also occur by the oral and transmammary route. N. americanus, however, requires a transpulmonary migration phase.

Can Animals Transmit Hookworm Infection to Me?

Yes, but not directly. Puppies and kittens are especially likely to have hookworm infections. Animals that are infected pass hookworm eggs in their stools. The eggs can hatch into larvae, and both eggs and larvae may be found in dirt where animals have been. Eggs or larvae can get into your body when you accidentally eat or have direct contact with contaminated dirt. For example, this can happen if a child is walking barefoot or playing in an area where dogs or cats have been (especially puppies or kittens).

References