Ascaris lumbricoides & Trichuris trichiura
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Transcript of Ascaris lumbricoides & Trichuris trichiura
THE NEMATODESG. Biteno, K.R. Feranil, K.K. Gregorio, K. Medina, C.W.
Mendoza
NEMATODE
Multicellular parasites that appear round in cross
section
Adult nematodes have a tapered, cylindric body with
an esophagus and longitudinal muscles.
Nematodes cause disease associated with the
intestines and the skin.
What’s AheadIn
testi
nal
Sp
ecie
sEnterobius vermicularis –
Pinworm/ Seat worm/ Society worm
Trichuris trichiura –
Whipworm
Ascaris lumbricoides –
Large Intestinal Roundworm
Necator americanus –
New World Hookworm
Ancylostoma duodenale –
Old World Hookworm
Strongyloides stercoralis –Threadworm
Inte
sti
na
l-T
iss
ue
S
pe
cie
s Trichinella spiralis –Trichina worm
Dracunculus medinensis– Guinea Worm
DEFINITION OF TERMS
Copulation Mating of select
worms
Cuticle Surface covering
present on adult
nematodes
Embryonated Fertilized egg
Decorticated Eggs lacking an
outer mammillated
albuminous coating
Larva Juvenile worms
Unembryonated Unfertilized egg
INFECTIVE STAGE Stage in the parasitic
life cycle that is
capable of invading a
definitive host.
AUTOREINFECTION Reinfecting oneself
Buccal capsule Long oral cavity; also
known as a buccal
cavity
Buccal cavity Long oral cavity; also
known as a buccal
capsule
Chitin Shell made up of a
thick nitrogen-
containing
polysaccharide
coating
Corticated Eggs containing a
mammillated
albuminous material
Morphology and Life Cycle
Members of the class Nematoda assume three
basic morphologic forms:
• Vary in size and shape
• Located inside the fertilized eggs; emerge and continue to mature
• Develop from the maturing larvae
• Sexes separate (females larger than males)
• Equipped with a digestive and reproductive system
Morphology and Life Cycle
Life cycles of individual nematodes are similar
but organism specific
Intestinal nematode infection may be initiated in
several ways.
Fertilized adult female nematodes lay their eggs
in the intestine and are then shed in the stool;
they mature in the soil and infect a new host in 2-
4 weeks.
Most members have the ability to exist
independent of a host (free living).
ASCARIS
LUMBRICOIDESG. Biteno, K. Feranil, K.K. Gregorio, K. Medina, C.W.
Mendoza
Ascaris lumbricoides
COMMON NAMES:
Common associated disease and condition
names:
Large Intestinal Roundworm
Roundworm of man
Ascariasis
Roundworm Infection
Ascaris lumbricoides
A soil – transmitted helminth.
Usual infection of 10-20 worms may not cause symptoms.
Causes varying degrees of pathology:
Tissue reaction to the invading larvae
Intestinal irritation to the adult
Other complications due to extraintestinalmigration.
Ascaris lumbricoides
Most common complain of the patient:
VAGUE ABDOMINAL PAIN
Fatal effects of A. lumbricoides are due to
erratic migration of adult worms.
MORPHOLOGY
UNFERTILIZED EGGS
PARAMETER DESCRIPTION
SIZE 85-95 um by 38-45 um;
Size variations possible
SHAPE Varies
EMBRYO Unembryonated;
Amorphous mass of
protoplasm
SHELL Thin
Other
features
Usually corticated
A. lumbricoides, unfertilized egg
Amorphous mass of protoplasm
Heavy Albuminous Coating
Thin Shell
MORPHOLOGY
A. lumbricoides, fertilized egg
PARAMETER DESCRIPTION
SIZE 40-75 um by 30-50 um
SHAPE Rounder than non-fertilized
version
EMBRYO Undeveloped unicellular
embryo
SHELL Thick chitin
Other
features
May be corticated or
decorticated
FERTILIZED EGGS
Undeveloped unicellular embryo
Thick chitin shellCoarse MammilatedAlbuminous Coating(Corticated)
Unfertilized and Fertilized Eggs:
Females will release unfertilized
eggs, which are more elongated
(left) than fertilized eggs (right).
Unfertilized eggs may also lack the
mammillated layer.
Fertilized Egg:
Undeveloped eggs are passed in the
stool.
Stained brown from bile.
Fertilized Egg:
Can be Decorticated.
Developed Egg:
This egg contains an infective larvae
(L2) that could infect a person if
ingested.
MORPHOLOGY
ADULTS
CHARACTERIS
TIC
FEMALE
ADULT
MALE
ADULT
SIZE (LENGTH) 22-35 cm Up to 30
cm
COLOR Creamy white
pink tint
Creamy
white pink
tint
Other features Pencil lead
thickness;
Paired
reproductive
organs
Prominent
incurved
tail with 2
spicules
200,000
eggs/female/day
A pair of female and male worms of A. lumbricoides. Notice the vulvarwaist(arrow)of the female worm and the coiled end of the male worm.
Adult male
Adult female
LABORATORY DIAGNOSIS
Specimen of choice for A. lumbricoides eggs:
Stool
Adult worms: may be recovered in several
specimen types, depending on the severity of
infection. (Intestine, Gallbladdder, Liver and
Appendix)
Sto
ol Tests • DFS
• Kato-katzTechnique
• Kato technique or cellophane thick methoda
• BEAVER DIRECT SMEAR METHOD (semi-quantitative)
• STOLL’S EGG COUNTING TECHNIQUE
Blo
od
Tests • CBC
• ELISA
Ima
gin
g T
ests • X-Ray
• CT Scan
• Ultasound
LABORATORY DIAGNOSIS
LIFE CYCLE
1. Adult worms live in the lumen of the small intestine.
* A female may produce up to 240,000 eggs per day, which are
passed with the feces.
LIFE CYCLE
2.-3. Fertile eggs embryonate and become infective after
18 days to several weeks depending on the
environmental conditions (optimum: moist, warm,
shaded soil).
LIFE CYCLE
Infective Stage: FULLY EMBRYONATED (with 2nd
stage
Larvae or Rhabditiform Larvae) EGG
LIFE CYCLE
3
.
4-5. After infective eggs are swallowed , the larvae hatch
in
the lumen of the SI and penetrate the intestine wall.
LIFE CYCLE
Larvae enters the venule to go to the liver (through the portal vein) or
to
the heart and pulmonary vessels (7-10 days), where they break out
the capillaries and enter the air sacs, ascend the bronchial tree.
LIFE CYCLE
6.
In the lungs, larvae undergo molting before migrating to
the larynx and oropharynx to be swallowed in the
digestive tract.
LIFE CYCLE
6.
LIFE CYCLE
During the lung migration, the larvae may cause host sensitization resulting in allergic manifestations such as
Eosinophilia and Loeffler’s syndrome may also be present during lung migration.
Lung infiltration
Asthmatic attacks
Edema of the lips
Upon reaching the small intestine, they develop into adult
worms.
*Between 2 and 3 months are required from ingestion of the infective
eggs to oviposition by the adult female. Adult worms can live 1 to 2 years.
LIFE CYCLE
7.
EPIDEMIOLOGY
Estimated worldwide prevalence of 25% (0.8-1.22 billion people).
Most common intestinal helminth infection in the world.
Children are particularly vulnerable.
Risk infection exists wherever fecal disposal is improper.
EPIDEMIOLOGY
Remains endemic in Africa, South and Central America.
The global prevalence in 2010:
Estimated at 464.6 million people.
In tropical countries, it ranges from 60 to 85%.
DISEASE PREVALENCE
Philippines: 31 million
East Asia and the Pacific: 204 million
Sub-Saharan Africa: 173 million
India: 140 million
South Asia: 97 million
China: 86 million
Latin America and Carrabean: 84 million
Middle East and North Africa: 23 million
TREATMENT
Anti – helminthic drugs:
Albendazole
– drug of choice
Mebenazole
Pyrantel pamoate
Piperazine citrate
PREVENTION AND CONTROL
Prevention and control measures involve the ff:
Sanitary disposal of
human feces
Health education (personal, family, and community hygiene)
Mass chemotherapy
done periodically
TRICHURIS TRICHIURA
Trichuris trichiura
COMMON NAME:
Common associated disesase and condition names:
A soil – transmitted helminth frequently observed occuring with A. lumbricoides.
Trichuriasis
Whipworm infection
Whipworm
HISTORY
(1740)Morgani –.
discovered the
residence of adult T.
Trichuria worms in
colon
(1761) Roedere –
gave a report of the exact
morphologic description
and provided accurate
drawings of the parasite
MORPHOLOGY
EGGS
PARAMETER DESCRIPTION
SIZE 50 – 55 um by 25 um
SHAPE Barrel-shaped / Lemon
shaped/ Football-
shaped;
Translucent hyaline
polar plug at each end.
SHELL Smooth; yellow-brown
color because of host
bile contact
Smooth
shell
surface
Hyaline polar plug
NICE TO KNOW
Can you identify??
MORPHOLOGY
• Less resistant to desiccation than A. lumbricoides
EGGS
• the larvae escape and penetrate the intestinal villi where they remain for 3 to 10 days.
LARVA
MORPHOLOGY
ADULTS
PARAMETE
R
DESCRIPTION
SIZE Male – 30-45 mm
Female – 35-50 mm
A female lays approximately
3000 to 10000 eggs per day.
ANTERIOR
END
Colorless; resembles a whip
handle; contains a slender
esophagus resembling a
string of beads
Female worm
Male worm
MORPHOLOGY
PARAMETER DESCRIPTION
POSTERIOR END Pinkish-gray;
resembles whip
itself;
contains digestive
and reproductive
systems;
Male- possess
prominent curled
tail with a single
spicule and
retractile sheath.
Female -has a
bluntly rounded
posterior end.
•ADULTS
Posterior part of male T.
trichuria
Posterior part of female T.
trichuria
LABORATORY DIAGNOSIS
Specimen of choice for T. trichiura eggs: Stool
Adult worms may be visible on macroscopic examination of the intestinal mucosa.
Adults may also be seen in the rectum in heavy infections.
LABORATORY DIAGNOSIS
– highly recommended in diagnosis
of trichuriases
– used for egg counting to
determine cure rate (CR), egg
reduction rate (ERR), and intensity
of infection.
The T. trichiura eggs are particularly
prominent in infected samples
processed using ZSFMethod.
DFS
Kato thick smear method
Kato-Katz technique
Zinc Sulfate Floatation Method
- Oval with transparent bipolar plugs
LIFE CYCLE
LIFE CYCLE
The unembryonated eggs
are passed with the
stool.
LIFE CYCLE
The unembryonated eggs
are passed with the
stool.
In the soil, the eggs develop
into a 2-cell stage , an
advanced cleavage stage
and then they
embryonate
The unembryonated eggs
are passed with the
stool.
Eggs become infective in 15 to 30 days. After
ingestion (soil-contaminated hands or food), the
eggs hatch in the small intestine, and release
larvae
IS: EMBRYONATED EGG
In the soil, the eggs
develop into a 2-cell
stage , an advanced
cleavage stage and then
they embryonate
The unembryonated eggs
are passed with the
stool.
Eggs become infective in 15 to 30 days. After
ingestion (soil-contaminated hands or food), the
eggs hatch in the small intestine, and release
larvae
In the soil, the eggs
develop into a 2-cell
stage , an advanced
cleavage stage and then
they embryonate
Larva mature and
establish
themselves as
adults in the colon
The unembryonated eggs
are passed with the
stool.
Eggs become infective in 15 to 30 days. After
ingestion (soil-contaminated hands or food), the
eggs hatch in the small intestine, and release
larvae
In the soil, the eggs
develop into a 2-cell
stage , an advanced
cleavage stage and then
they embryonate
Larva mature and
establish
themselves as
adults in the colon
The adult worms live in
the cecum and
ascending colon.
LIFE CYCLE
Each female worm can produce a total of over
60 million eggs over an average lifespan of 2
years.
Unlike A. lumbricoides, there is no heart to
lung migration.
PATHOGENESIS AND CLINICAL
MANIFESTATIONS
The anterior portion of the worms (embedded
in the mucosa) cause petechial haemorrhage
which predispose amebic dysentery presumably
because the ulcers provide suitable site for tissue
invasion of E. histolytica
Mucosa is hyperemic and edematous
Enterorrhagia is common
PATHOGENESIS AND CLINICAL
MANIFESTATIONS
RECTAL PROLAPSE may occur if heavily infected
Lumen of the appendix may be filled with worms and consequent irritation and inflammation may lead to appendicitis or granulomas
Infection with 5,000 eggs/gram of feces is symptomatic.
Infection with 20,000 eggs/gram of feces often develop severe diarrhea or dysenteric volume.
EPIDEMIOLOGY
Considered as the 3rd
most common helminth.
Found primarily in warm climates of the world where poor sanitation practices are common, such as defecating directly into the soil or using human feces as fertilizer.
EPIDEMIOLOGY
Estimated that 902 million are infested (as compare to 355 million in 1947).
The global prevalence in 2010:
Estimated at 464.6 million people.
In tropical countries, it ranges from 60 to 85%.
DISEASE PREVALENCE
Philippines:Prevalence is from 80 to 84%.
Sub-Saharan Africa: Estimated at 20.9% (100million cases).
Oceania: Estimated 1.2million infested persons, accounting for <1% of the global burden of Trichuriasis.
South America: Estimated prevalence rates of 12.5%
TREATMENT
Mebendazole –drug of choice
Abendazole
PREVENTION AND CONTROL
Infection in highly endemic areas may be
prevented by:
Treatment of infected individuals
Sanitary disposal of human feces by construction of toilets and their proper use.
Washing of hands with soap and water before and after meals
Health education on sanitation and personal hygiene
Through washing and scalding of uncooked vegetables especially in areas where night soil is used as fertilizer.
THANK YOU!