Ministry of Higher
Education and Science
Research Sulaimani
Polytechnic University
Kalar Technical Institute
……………..Department
Subject:
Report about
ASCARIASIS IN HUMAN
By
DLNYA
Email:
Phone No.:
Supervised by
DR. HASSAN
2019-2020
LIST OF CONTENTS
1. INTRODUCTION 1
2. SCIENTIFIC CLASSIFICATION
2
3. MORPHOLOGY 3
4. LIFE CYCLE
5. PATHOGENESIS
6. SYMPTOMS
7. DIAGNOSIS
8. TREATMENT
9. PREVENTION
10. CONCLUSIONS 19
11. REFERENCES 21
ii
1. INTRODUCTION
Ascariasis is a helminthic infection in humans caused by the
nematode Ascaris lumbricoides. The infection is acquired by the
ingestion of the embryonated eggs and the larvae pass through
pulmonary migration phase for maturation. It has been estimated
that over 1.4 billion people throughout the world are infected with
A. lumbricoides. Pulmonary disease caused by Ascaris is caused by
larvae during their pulmonary migration and maturation. Ascaris-
induced intestinal obstruction is a frequent complication in children
with heavy worm loads in endemic areas. Prolonged obstruction
may be complicated by intussusception, volvulus, hemorrhagic
infarction of the bowel, and perforation. Hepatobiliary and
pancreatic ascariasis are two of the most common and well-
described entities caused by Ascaris.
2. Scientific classification
Kingdom: Animalia
Phylum: Nematoda
Class: Chromadorea
Order: Ascaridida
Family: Ascarididae
Genus: Ascaris
2
3. Morphology:
Adult:
The round worm resembles to earthworm. It is elongated tapering
to both end, anterior being thinner than posterior. Freshly excreted
worm is yellowish pink in color, which gradually changes to white.
The worm is sexually diamorphic.
3
Adult male: 15-30 cm in length, 3-4 mm in diameter, tail
curved
Adult female; 20-40 cm length, 2-6mm diameter, tail straight
Egg:
Ascaris egg is round or oval, 60*40 µm size, thick brown shell and
have rough surface. It is the infective form of parasite.
i) Un fertilized egg; large, more elongated (38-55*78-105)
µm
ii) fertilized egg; ovoid (35-50*50-70)µm, golden brown
color
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4. Life cycle:
The life cycle of Ascaris completes in single host. Human.
Adult worm lives in small intestine
Stages in life cycle:
Stage I: Eggs in faeces
5
Sexually mature female produces as many as 200,000 eggs
per day, which are shed along with faeces in unembryonated
form. They are non infective.
Stage II: Development in soil
Embryonation occurs in soil as optimum temperature of 20-
25C with sufficient moisture and O2
Infective larva develops within egg in about 3-6 weeks.
Stage III: Human infection and liberation of larvae
Human get infection with ingestion of embryonated egg
contaminated food and water
Within embryonated state inside egg, first stage larvae
develops into second stage larvae. This second stage larvae is
known as Rhabtitiform larvae
Second stage larve is stimulated to hatch out by the presence
of alkaline pH in small intestine and solubilization of its outer
layer by bile.
Stage IV: migration of larvae through lungs
Hatched out larvae penetrates the intestinal wall and carried
to liver through portal circulation
6
It then travels via blood to heart and to lungs by pulmonary
circulation within 4-7 days of infection.
The larvae in lungs molds twice, enlarge and breaks into
alveoli.
Stage V: Re-entry to stomach and small intestine
From alveoli, the Larvae then pass up through bronchi and
into trachea and then swallowed.
The larvae passes down the oesophagus to the stomach and
reached into small intestine once again.
Small intestine is the normal habitat of Ascaris and it
colonises here.
Within intestine parasite molds twice and mature into adult
worm.
Sexual maturation occurs with 6-10 weeks and the mature
female discharges its eggs in intestinal lumen and excreted
along with faeces, continuing the life cycle.
The life span of parasite is 12-18 months
7
5. PATHOGENESIS
The pathogenesis of ascariasis is generally related to organ damage
and host reactions to larval migration as well as the number and
location of adult worm in the body. Ascaris larvae migrating
through the intestinal mucosa, liver and lungs provoke
hypersensitivity reaction in the human host. Some of the larvae
may be immobilised and covered with eosinophils, resulting in the
formation of granulomas. In the lungs, movement of the larvae
from the blood vessels into the air spaces results in haemorrhage.
There is oedema of the alveoli. Alveolar sacs are filled with a
serous exudate, the peribronchial tissues becoming infiltrated with
eosinophils and neutrophils, and mucus production in the bronchi
is increased. Known as Loeffler's syndrome, it gives rise to dry
cough, high fever and bronchial asthma. The effect is severe when
the number of larvae is large or when transmission is seasonal.
The presence of adult A. lumbricoides in the intestine induces
disordered changes in the jejunal mucosa and intestinal muscle
layers. There is a coarsening of mucosal folds, shortening of the
crypt depth, reduced mucus production and hypertrophy of the
intestinal muscle layers. Protein energy malnutrition, reduced food
intake and impaired cognitive function in children are associated
with these problems of ascariasis .
Due to its large size and aggregating and migratory activities,
adult Ascaris frequently precipitates severe complications. Fever,
ingestion of some drugs or food by the host, and surgical
8
anaesthesia have been suggested as predisposing factors for worm
migration from their usual location. Worms may move toward the
upper gastrointestinal tract and become vomited . In heavy
infections, several worms may ball up and cause intestinal
obstruction . This may be accompanied by such complications as
intussusceptions, volvulus, haemorrhagic infarction and perforation
of the intestine. Invasion of the biliary duct, hepatic abscesses,
acute pancreatitis, acute appendicitis, peritonitis and obstruction of
the upper respiratory tract are also reported . Allergic reactions
such as asthma, eosinophilia and urticaria have been reported in
laboratory workers who have had previous exposure to materials
from Ascaris worms
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6. Symptoms
Ascariasis may not cause symptoms at first. However, as the
infestation inside the small intestine grows, a person may start to
notice symptoms, including:
abdominal pain or discomfort
loss of appetite
worms visible in stool
vomiting
impaired growth in children
weight loss
nausea
diarrhea
irregular bowel movements
In more advanced infestations, the worms can travel to the lungs. If
this occurs, a person may also experience symptoms, including:
fever
discomfort in the chest
gagging cough
bloody mucus
10
shortness of breath
wheezing
In rare cases, a person may experience a complication
known as aspiration pneumonia.
11
7. Diagnosis
In heavy infestations, it's possible to find worms after cough or
vomit. The worms can come out of other body openings, such as
mouth or nostrils.
Stool tests
Mature female ascariasis worms in intestine begin laying eggs.
These eggs travel through digestive system and eventually can be
found in stool.
Examination of stool for the tiny (microscopic) eggs and larvae.
But eggs won't appear in stool until at least 40 days after infected.
Blood tests
blood can be tested for the presence of an increased number of a
certain type of white blood cell, called eosinophils. Ascariasis can
elevate eosinophils, but so can other types of health problems.
Imaging tests
X-rays. The mass of worms may be visible in an X-ray of
the abdomen. In some cases, a chest X-ray can reveal the
larvae in the lungs.
12
Ultrasound. An ultrasound may show worms in the
pancreas or liver.
CT scans or MRIs. Both types of tests create detailed
images of the internal structures, which detect worms that are
blocking ducts in the liver or pancreas. CT scans combine X-
ray images taken from many angles.
13
8. TREATMENT
Typically, only infections that cause symptoms need to be treated.
In some cases, ascariasis will resolve on its own.
Medications
Anti-parasite medications are the first line of treatment against
ascariasis. The most common are:
Albendazole (Albenza)
Ivermectin (Stromectol)
Mebendazole
14
9. PREVENTION
Avoid contact with soil that may be contaminated with
human feces, including with human fecal matter (“night
soil”) used to fertilize crops.
Washing hands with soap and warm water before handling
food.
Teach children the importance of washing hands to prevent
infection.
Wash, peel, or cook all raw vegetables and fruits before
eating, particularly those that have been grown in soil that
has been fertilized with manure.
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10. CONCLOSION
As the most prevalent helminth infection, Ascaris is important
from both health and economic perspectives. Despite the wide
range of impacts on the health of hosts, Ascaris remains a
neglected tropical disease. Furthermore, the parasite’s persistence
and prevalence present difficulties regarding control strategies for
the worm itself and concurrent infectious diseases.
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12. REFERENCES
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