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Growth and development failure (failure

to thrive) due to parasitic infections

Lisawati Susanto & Taniawati Supali

Department of Parasitology, Faculty of Medicine,

University of Indonesia


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Definition

is a description applied to children whose

current weight or rate of weight gain is

significantly below that of other children of

similar age and sex.

height or weight less than the third to fifth

percentiles for age on more than one

occasion.


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Failure to thrive

In general, the rate of change in weight

and height may be more important than

the actual measurements.

It is important to determine whether failure

to thrive results from medical problems or

factors in the environment, such as abuse

or neglect.


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Etiology of failure to

thrive

Chromosome abnormalities, such as Downsyndrome and Turner syndrome

Abnormalities in the gastrointestinal system, whichmay result in malabsorption or absence of digestiveenzyme, resulting inadequate nutrition.

Abnormalities of the endocrine system, such asgrowth hormone deficiency

Damage to the brain or central nervous system,which may cause feeding difficulties

Anemia


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Giardia lamblia

Ascaris lumbricoides

Hookworms

Some parasites within their life cycle pass through

gastrointestinal system
http://en.wikipedia.org/wiki/Image:Digestive_system_diagram.svghttp://en.wikipedia.org/wiki/Image:Digestive_system_diagram.svghttp://en.wikipedia.org/wiki/Image:Digestive_system_diagram.svghttp://en.wikipedia.org/wiki/Image:Digestive_system_diagram.svg


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Parasitic infection and failure to thrive

Chronic parasitic infections may cause

disturbances on food absorption in the GI

tract system effecting the host nutrition.


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Parasitic infection and failure to thrive

In general parasitic infections could be

divided into two classifications: helminthes

(metazoa) and protozoa

Helminthes:Ascaris lumbricoides, hook

worm

Protozoa: Giardia lamblia


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Class Species Infective stage

Nematoda Ascaris lumbricoidesHookworms

Mature egg

Filariform larva

Protozoa Giardia lambia Cyst


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Risk factors

Defecation habits

Geophagia (eating soil)

Cultural differences relating to personal

and food hygiene

Inadequate sanitation

Poor socio-economic conditions

Occupation such as farmer, mining labour


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Ascariasis is a disease caused by Ascarislumbricoides (round worm), which is the mostprevalent intestinal worm infection in the world.

The adult worm lives in the lumen of smallintestine

Eggs are found in the soil, infection occurs whena person accidentally ingests (swallow) infectiveeggs.


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Ascariasis

Route of infection:

Children/Human become infected after

touching their mouth with their hands

contaminated with eggs from soil or othercontaminated surfaces


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Life cycle ofA. lumbricoides

Human ingested embryonatedegg. In the stomach, larvaehatch from the eggs. and arecarried via the hepatic portalvein, then systemic circulationto the lungs, mature in the

lungs (10 -14 days), penetratethe alveolar walls, ascend thebronchial tree to the throat,and are swallowed.

Once swallowed, they reach the

intestines and develop intoadults worms. Adult female

worms lay eggs that are then

passed in feces; this cycle will

take between 2 3 months

Eggs are passed in the stool.

Unfertilized eggsmay be ingested butnot infective.


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Pathogenesis

Heavy infection children with malnutrition

Acute inflammatory response

Proinflammatory Monokines (IL-1, IL-6, TNF-)

Appetite

Loss of protein raise resting energy expenditure


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Pathogenesis

Adult worms in the small intestine

Direct competition with the host for nutrients


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Adult worms

Protease inhibitors & anti-trypsine


secreting

Interfering host digestion Enable to ingest the meal

before host absorption


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Adult worms

Abnormalities of small intestine

Changes in the absorption of fat and xylose



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Symptoms of ascariasis

Commonly infected persons: No symptoms

Immature worms enter the small intestine and

mature into adult worms.

- abdominal symptoms: abdominaldiscomfort-fullness, malabsorption.


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Ascariasis

Complications:

Adult worms move to bile duct and

interfere the lipid digestion.

Heavy infection in children:

loss of appetite and insufficient absorption of

digested foods can occur as a large number

of parasites take nourishment from the hosts

body Nutritional deficiencies


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Treatment

Drug of choice:

Albendazole - 400 mg (single dose)

Mebendazole - 500 mg (single dose)Pyrantel pamoat - 10 mg/kg BW (single

dose)


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Prevention

Sanitary disposal of feces through the

implementation of latrines

Health education: personal hygiene and food

hygiene


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Hookworm

There are two species of hookworm which infect human

Ancylostoma duodenaleAncylostoma duodenale Necator americanusNecator americanus


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Hookworm

Disease:

Ancylostomiasis

Necatoriasis

Route of infection:

Ancylostoma duodenale : oral, percutaneous

Necator americanus : percutaneous

Filariform larva (infective stage)


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Hookworm

Hookworm eggs require warm, moist,

shaded soil to hatch into larvae.These barely visible larvaepenetrate the skin(often throughbare feet), are carried to the lungs,go through the respiratory tract tothe mouth, are swallowed, and

eventually reach the small intestine.This journey takes about a week. Inthe small intestine, the larvaedevelop into half-inch-long worms,attach themselves to the intestinalwall, and suck blood. The adult

worms produce thousands of eggs.These eggs are passed in the feces(stool). If the eggs contaminate soiland conditions are right, they willhatch, molt, and develop intoinfective larvae again after 5 to 10

days.


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Hookworm

Worms live in the small intestine by attaching to

the mucose via the buccal capsule.

Worms feed on host mucosa and blood.

Worms change position of attachment site every

4 6 hours in response to tissue depletion andor the onset of local inflammation.

(The blood is still coming out from the old attachment site for

several day)


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Pathogenesis

The adult worms move several times a day to different

attachment sites in the intestinal mucosa.

The worms eat villous tissue and also suck blood

directly from their site of attachment to the intestinal

mucosa and submucosa.

The worms secrete an anticoagulant that blocks the

action of host factor Xa and VII a/tissue factors. Blood

loss continues after the worms move to a new location.


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Pathogenesis

The combination of constant blood loss due tohookworm infection and poor iron intake in thediet results in iron deficiency anaemia.

The severity of iron-deficiency anemia

depends upon the species of hookworms inthe intestine (A. duodenale ingests 4-5 timesmore blood each day than N. americanus)


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Adult worms

Suck host blood Secrete anti-coagulant

from the capillaries of blocking factorsIntestinal mucosa Xa dan VII a

Loss of blood plasma & Blood lost

Its constituents

Hypoproteinemia Anaemia

Pathogenesis


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Hookworm

Heavy infection with hookworm can create

serious health problems for newborns,

children, pregnant women, and persons

who are malnourished.

Head ofA. duodenale Head of N. americanus


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Symptoms

Heavy infection can cause anemia, abdominalpain, diarrhea, loss of appetite, and weight loss.

When children are continuously infected by manyworms, the loss of iron and protein can retardgrowth and mental development, sometimesirreversibly.

Anaemia in Children can impair their educationalperformance.

a

Hookworms on the bowel mucosa


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Diagnosis

The examination of stool sample for the

presence of eggs is the most reliable

means of diagnosis.

The recommended procedure is the Kato-

Katz technique which is able to count the

number of eggs to determine intensity

of infection

Egg counts express as EPG (eggs per gram

of faeces)

Rhabditiform larva

Egg


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Treatment

Drug of choice:Albendazole 400 mg (single dose)

Mebendazole -100 mg (twice a day for 3consecutive days)


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Prevention

Sanitary disposal of feces through the

implementation of latrines

Health education: personal hygiene and food

hygiene Encouraging use of shoes or other footwear

(hookworms).


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Giardia lamblia(Giardiasis)

Zoonosis

Host: animal and human

Trophozoite Cyst


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Life cycle ofG.lamblia

Giardia lamblia exists in two forms, an

active form called a trophozoite, andan inactive form called a cyst. Theactive trophozoite attaches to thelining of the small intestine with asucker and is responsible forcausing the signs and symptoms ofgiardiasis. The trophozoite cannot live

long outside of the body, therefore itcannot spread the infection to others.The inactive cyst, on the other hand,can exist for prolonged periodsoutside the body. When it is ingested,stomach acid activates the cyst, andthe cyst develops into the disease-causing trophozoite. It takes ingestionof only ten cysts to cause infection.Trophozoites are important not onlybecause they cause disease, theyalso produce cysts that exit the bodyin faeces and spread infection toothers.
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Pathogenesis

The mucosal factors :

The intestinal mucosa isdamaged by the attachment oftrophozoites on the epithelialbrush border.

Absorptive activities areblocked due to thetrophozoites "blanketing" theintestinal mucosa and causingfunctional mucosal obstruction

and interference in absorptionof fats and fat-soluble vitamins.

The mucosal and luminal factors involved in the pathogenesis.

The luminal factors : The increased number of anaerobic

& aerobic bacteria in the smallintestine leads to the deconjugationof bile salts. The bile salts are then

taken up by the trophozoitesstimulating parasite growth.

The consumption of host bile salts inchronic infection deplete the bile saltpool and thus contribute to fatmalabsorption.


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Clinical presentation

The clinical presentation of the disease is

influenced by the host's immune response to

the parasite and the parasite load in the

small intestine.


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Symptoms

10-25 cysts are capable of causing clinical

disease.

Symptoms of giardiasis normally begin 1

to 2 weeks (average 7 days) after

becoming infected.


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Symptoms

Commonly no symptoms at all.

Diarrhea: Stools become malodorous, mushy, and greasy.

Watery diarrhea may alternate with soft stools or evenconstipation.

Flatulence

Steatorrhea

Stomach cramps

Nausea. These symptoms may lead to weight loss and

dehydration.


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Symptoms

These symptoms may lead to weight loss.

Weight loss occurs in more than 50% of

patients and averages 10 pounds per person. Chronic illness may occur with adults

presenting with long-standing malabsorptionsyndrome and children with failure to thrive.


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Symptoms

The disease is more prevalent in children.

The symptoms of giardiasis causedehydration due to diarrhea, therefore

drink plenty of fluids .


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Laboratory examination

Stool examination

Trophozoites may be found in fresh, watery

stools.

Cysts are passed in soft and formed stools.


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Laboratory examinations

Stool antigen detection ELISA to detect giardia specific antigen 65

kDa (GSA-65)


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ELISA Results


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Other tests

Detection of trophozoites in duodenalfluid can be done by String test /Entero test.


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Treatment

Metronidazole 3 x 250 750 mg for 7 10

days

Tinidazole: 2 g- single dose


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Prevention

Washing hand after defecation.

Chlorination, sedimentation, and filtrationmethods to purify public water supplies.

Drinking water can be purified by usingfiltration (pore size,


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