WORM

INFESTATION
MR MWAKASHITA
BSc Nur.
INTRODUCTION

• Helminths are worms with many cells.

• Tapeworms, pinworms, and roundworms are among the
most common helminths.
• The study of worms is helminthology
• Worm infestations are common in children and are usually
transmitted through faecal oral route or by skin penetration.
 The Hookworms
(Genera Ancylostoma and Necator)

Hookworms are parasitic roundworms in the nematode family,

Ancylostomatidae.
Species that infect humans, include
Ancylostoma duodenale

Necator americanus

Ancylostoma caninum is a hookworm of dogs but can also infect man.

Hookworms live primarily in the intestines of a host, feeding on blood.

 The hookworms

A larger group of hookworms infecting animals can invade

and parasitize humans E.g (Ancylostoma ceylanicum)

Others can penetrate human skin (causing cutaneous larva

migrans-CLM), but do not develop any further
(A. braziliense, A. caninum, Uncinaria stenocephala).
 Cont…
In susceptible children hookworms cause intellectual,
cognitive and growth retardation, intrauterine growth
retardation, prematurity and low birth weight among new-
borns born to infected mothers.
Hookworm infection is rarely fatal, but anaemia can be
significant in the heavily infected individual.
Ancylostoma spp
 General Life cycle:
Hookworms

The adult hookworm lives in small intestine of its host

attached to the intestinal wall feeding (sucking) on host
blood.

Female worms produce eggs which come out with faeces.

The eggs hatch in environment and develop from a first

stage larva (L1) ( hatchling) to a second stage larva (L2)
and finally a third stage larva (L3) which is infective to
new host.
 General Life cycle II:
Hookworms

The L3 can infect host in several ways:

Penetrate host’s skin directly through the feet or belly
or whatever part of the skin is touching the ground.
Licking and swallowing soil contaminated with L3
(larval ingestion)

Once inside the host, they get to intestine where

some worms simply stay and mature into
adulthood.
 General Life cycle III:
Hookworms

Other species undergo lung migration.

In lungs, the larvae develop into L4 and when they are
ready they break out of the lung, climb up the trachea
(windpipe), get coughed into the throat and swallowed and
mature in intestine.

There in, adults males and females mate and female start
laying eggs thereby completing the life cycle.
The hookworms: Life cycle
 Pathophysiology

Hookworm infection is generally considered to be

asymptomatic, but is an extremely dangerous infection
because its damage is “silent and insidious.”There are general
symptoms that an individual may experience soon after
infection.
Ground-itch, which is an allergic reaction at the site of
parasitic penetration and entry, is common in patients
infected with N. americanus.
Additionally, cough and pneumonitis may result as the larvae
begin to break into the alveoli and travel up the trachea.
Then once the larvae reach the small intestine of the host
and begin to mature, the infected individual will suffer from
diarrhea and other gastrointestinal discomfort.
However, the “silent and insidious” symptoms refer mainly to
chronic, heavy-intensity hookworm infections.
Major morbidity associated with hookworm is caused by
intestinal blood loss, iron deficiency anaemia, and protein
malnutrition.
They result mainly from adult hookworms in the small intestine
ingesting blood, rupturing erythrocytes, and degrading
haemoglobin in the host.
This long-term blood loss can manifest itself physically through
facial and peripheral oedema; eosinophilia and pica caused by
iron deficiency anaemia.
It is widely accepted that children who suffer from chronic
hookworm infection can suffer from growth retardation as well
as intellectual and cognitive impairments.
 Hookworm infections:
Signs and Symptoms
abdominal pain Pica (eating dirt)
colic (cramping and
excessive crying in
infants)
intestinal cramps
nausea
fever
blood in your stool
appetite loss
itchy rash
Diagnosis

Diagnosis depends on finding characteristic worm eggs

on microscopic examination of the stools.
 Cutaneous larval migrans
Cutaneous larva migrans ("CLM") is a skin disease in
humans, caused by the larvae of various nematode
parasites, the most common of which is Ancylostoma spp.
Sometimes referred to as "creeping eruption" or "ground
itch“
Animal passes faeces that are infested with hookworm eggs
Eggs hatch into infective larvae able to penetrate human
skin (even through solid material, such as a beach towel).
The larvae commonly found in shaded, moist, or sandy
areas (such as beaches, a child's sandbox, or areas
underneath a house),
Life Cycle (cutaneous larval
migrans)
Cutaneous Larval Migrans
 Treatment
Albendazole is effective both in the intestinal stage and during the
stage the parasite is still migrating under the skin.
In case of anaemia, iron supplementation can cause relief symptoms
of iron deficiency anaemia.
However, as red blood cell levels are restored, shortage of other
essentials such as folic acidor vitamin B12may develop, so this might
also be supplemented.
The most common treatment for Hookworm are Benzimidazoles
(BZAs), specifically albendazole and mebendazole. BZAs kill adult
worms by binding to the nematode’s β- tubulin and subsequently
inhibiting microtubule polymerization within the parasite.
In certain circumstances, levamisole and pyrantel pamoate may be
used.
 Treatment
Albendazole/mebendazole

200-500mg Mebendazole once a day (OD) for

3 days
400mg Albendazole once a day (OD) for 3
days
 Nursing Diagnosis
Altered growth and
development
Altered nutrition; less than
body requirements
Diarrhoea
Fatigue
High risk for fluid volume
deficit
High risk for infection
Knowledge deficit
Ineffective breathing
pattern
Prevention

The infective larvae develop and survive in an

environment of damp dirt, particularly sandy and loamy
soil. The main lines of precaution are those dictated by
sanitary science:
a.Do not defecate in places other than latrines, toilets
etc.
b.Do not use human excrement or raw sewage or
untreated 'night soil' as manure/fertilizer in agriculture
c.Deworm
d.Hand washing
ASCARIASIS (Round worm
infestation)

Ascariasis is an infection by the nematode Ascaris

Lumbricoides (intestinal roundworm).
 Most common worm parasitizing human intestine,
with an estimated 1 billion infections worldwide.
Cont’

 Usually found in overcrowded areas with poor

sanitation.
 Contamination of the soil by human faeces is a factor
in its spread.
 Humans are infected by the ingestion of the eggs in
contaminated raw vegetables and drinking water.
 eating raw vegetables when night soil is used for
fertilizer.
 Water pollution may cause water transmission.
Life cycle and clinical features

 The eggs are swallowed and passed in to the intestines,

where they hatch as larvae.
 Larvae enter the blood stream and pass through the
pulmonary circulation, migrate through the lungs and
return to the gastrointestinal tract
 They grow, mature and mate. Large numbers of worms
may migrate into various organs of the body and cause
obstruction to the trachea, bronchi, bile duct, appendix,
and pancreatic duct.
 Signs and symptoms

• Coughing • Weight loss

• Shortness of breath • Fatigue
• Abdominal pain • Presence of worm in vomit
• Abdominal distension or stool
• Disturbed sleep
• Restlessness
• Impaired growth
• Nausea and diarrhea
• Blood in the stool
Cont’

 Masses of worms in the intestine cause gastrointestinal

discomfort, severe abdominal pain, and vomiting.
 May cause acute intestinal obstruction due to load of
worms.
 Fever, chills, dyspea, cough and pneumonia may develop
from inversion of the lungs by large numbers of larvae
Cont’

 Adult worms may migrate into the ampulla of vater

and then to the pancreatic or biliary ducts, causing
acute and agonizing pain.
Ascariasis is diagnosed by detecting ova or worms in
the faeces.
Cont’

Management
Mebendazole
Dose: 500mg once off or100mg orally BD for 3 days
Side Effects: Abdominal pain, diarrhoea.
 Prevetion
Preventive measures include providing adequate toilet
facilities and teaching the importance of personal
hygiene.
All patients with the infestation should be treated.
Cont…

• Albendazole: for children 2-5 years a single dose of

200mg. for older children and adult’s one dose of
400mg.
• Parantel pamoate ( Combantrin) a single dose of
10mg/kg body weight
• Levamisole: a single dose of 2.5mg/kg body weight
Prevention of Ascaris lumbricoides

• Teach the community on the importance of eating properly washed

vegetables when improperly processed human feces of infected people
are used as fertilizer for food crops.
• Properly hand washing as Infection may occur when food is handled
without removing or killing the eggs on the hands, clothes, hair, raw
vegetables/fruit, or cooked food that is infected by handlers.
• Advise women especially pregnant women to avoid eating soil
• Proper fecal disposal
• Educate the community not to defecate in places other than the toilets
• Advise the farmers not to use human excreta as manure in agriculture
 Complications

1. Intestinal obstruction
2. Inflammation of the intestines or gall bladder
3. Kidney disease
4. Perforation
5. Peritonitis this is the inflammation of the peritoneum
following perforation
6. Anaemia
7. Jaundice due to billiary obstruction by the worm
8. Appendicitis if the appendix gets obstructed by the worm
Pin worms (Enterobiasis)

 General Information
• Parasite Name: Enterobius vermicularis (formerly Oxyuris vermicularis
)
• Synonyms: Pinworm, threadworm, seatworm
• Classification: Helminth (nematode)
Cont’

Females also possess a long, pin-shaped posterior

end from which the parasite's name is derived.
 They dwell primarily in the caecum of the large
intestine, from where the gravid females migrate at
night to lay up to 15,000 eggs on the perineum.
Cont’

 Pinworm eggs are flattened asymmetrically on one side, elongated,

ovoid, approximately 55 mm x 25 mm in size and embryonate in six
hours.
 Eggs can remain viable for about twenty days in a moist environment
 viable eggs and larvae were can be found in the sludge of sewage
treatment plants .
 The eggs are resistance to disinfection
 Life cycle
• The life cycle begins with eggs being ingested. The eggs
hatch in the duodenum .
• The male and female pinworms mate in the ileum where
after the male pinworms usually die, and are passed out
with stool.
• The gravid female pinworms settle in the ileum, caecum,
appendix and ascending colon, where they attach
themselves to the mucosa and ingest colonic contents.
 Cont…

• Almost the entire body of a gravid female becomes filled with

eggs. The estimations of the number of eggs in a gravid female
pinworm range from about 11,000 to 16,000.
• The egg-laying process begins approximately five weeks after
initial ingestion of pinworm eggs by the human host. The gravid
female pinworms migrate through the colon towards the
rectum at a rate of 12 to 14 centimeters per hour.
 Cont…

• They come out from the anus, and while moving on the skin near
the anus, the female pinworms deposit eggs either through (1)
contracting and expelling the eggs, (2) dying and then
disintegrating, or (3) bodily rupture due to the host scratching the
worm.
• After depositing the eggs, the female becomes opaque and dies.
The reason the female emerges from the anus is to obtain the
oxygen necessary for the maturation of the eggs. Gravid female
worms migrate nocturnally outside the anus and oviposit while
crawling on the skin of the perianal area.
Life Cycle:
Reservoir

 Humans are the only natural host of pinworms, and there currently
is no confirmed pinworm reservoir.
TRANSMISSION

 Pinworms do not need to rely on a vector for transmission.

 Infection usually occurs via ingestion of infectious eggs by direct
anus-to-mouth transfer by fingers.
 This is facilitated by the perianal itch (pruritis ani) induced by the
presence of pinworm eggs in the perianal folds, and commonly
occurs as a result of nail biting, poor hygiene, or inadequate hand-
washing.
Cont’

 Retroinfection is also possible, where some of the pinworm larvae

which hatch on the anus return to the gastrointestinal tract of the
original host, leading to a very high parasitic load as well as ensuring
continued infestation.
 Dust containing eggs can become airborne and widely dispersed
when dislodged from surfaces, for instance when shaking out bed
clothes and linen. Consequently the eggs can enter the mouth and
nose through inhalation, and be swallowed later.
Cont’

 Other modes of transfer include:

touching contaminated surfaces, such as clothing, bed linen, and
bathroom fixtures followed by ingestion.
 Pinworm infections are easily spread among young children with the
habits of nail biting and or poor hygiene, and infected children can
easily spread the infection to others
Pathogenicity and Clinical
Manifestations

 Crawling sensation in the rectum and anal regions, from migrating

females,
 pruritus ani, scratching, excoriation and bacterial super infection and
scarification of the anus. This is caused by the migration of female
pinworms to the anus to lay eggs
 Oesinophilia and appendicitis due to the worms which cause
irritation
Cont’

 Nervousness,
 Insomnia
 Nightmares,
 Being bitten at the anus complaint
 Irritability
 Bed wetting
Diagnosis

 Eggs - Perianal swab , scrapings from fingernails

 Adult worms after enemas
 Scotch tape- at night
Treatment

For typical pinworm infections,

 Mebendazole
• Dose: 100mg OD x3 days or 500mg single dose by mouth, repeated
for two weeks to prevent reinfection are the safest and most
efficient.
• The drug targets adult worms, blocking glucose uptake and
subsequently causing death.
• Side Effects: Abdominal pain, diarrhoea.
Cont’

 Albendazole
• Dose: 100 mg doses for patients under two years old, or in doses of
400 mg for older patients.
• Repeated for two weeks.
• Side effects includes; diarrhoea, headache, dizziness
Cont’

 Pyrantel Pamoate
• Dose: 11 mg/kg, not to exceed 1 g.
• Side effects: include GI distress, neurotoxicity, and transient increases
in liver enzymes.
• To relieve itching, warm bath with table salt and application of
ointment with zinc oxide or regular petroleum
Preventive Strategies

• Bathe when you wake up to help reduce the egg contamination.

• Change and wash your underwear each day (avoid sharing
underwear). Frequent changing of night clothes are recommended.
• Change underwear, night clothes, and sheets after each treatment.
Because the eggs are sensitive to sunlight, open blinds or curtains in
bedrooms during the day.
Cont’

• Personal hygiene should include washing hands

after going to the toilet, before eating and after
changing diapers.
• Trim fingernails short.
• Discourage thumb sucking, nail-biting and
scratching bare anal areas. These practices help
reduce the risk of continuous self re-infection.
• De worm regularly or as directed by your primary
physician
complications

• Inflammation of the intestines or gall bladder

• Pus accumulation in the liver
• Inflammation of the pancreas
• Appendicitis
• Peritonitis, inflammation of the sac surrounding the
abdomen
 TAPE WORM INFECTION
(taeniosis and cysticercosis)

 Tape worm infection is an intestinal disease caused by one of several

species of tape worms including:
 Taenia saginata (beef tape worm)
 Taenia solium (pork tape worm)
 Diphyllobothrium latum (fish tape worm).
Cont’

 Tape worms are large flat worms that live in the intestines and grow
15 to 30 feet in length (Byrne, and Bennet, pp 129).
 Egg-bearing sections of the worms (proglottids) are passed in stool.
T. solium life cycle
PM findings in pigs
Taenia saginata:-Life cycle
T. Saginata and T. solium:-Life cycles
Cont’

 If untreated human waste is released in the environment, the eggs

may be ingested by intermediate hosts such pigs, cattle or in case of
fish tape worm small crustaceans, which are in turn ingested by fish.
64
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Cont’

 The eggs hatch in the intermediate host, the larvae invade the
intestinal wall and are carried through the blood stream to skeletal
muscles and other tissues, where they form cysts.
 People acquire the parasites by eating the cysts in raw or under
cooked meat or fish.
 Cysts hatch and develop into adult worms which hatch onto the
person’s intestinal wall. The worms then grow in length.
Cont’

 People may also act an intermediate host for the pork tape worm,
Taenia solium.
 Pork tape worm eggs reach the stomach when a person swallows
them in food or water contaminated with human excreta or from
contact with the unclean hands of a person infected with adult
worms.
Cont’

 The eggs may also reach the stomach when the proglottids are
regurgitated from the intestine.
 Once the larvae are released, they penetrate the intestinal wall and
travel to muscles, internal organs, the brain or tissue under the skin,
where they form cysts (cysticera).
 This form of the disease is called cysticercosis.
Symptoms

 Although tape worms in the intestines usually cause no symptoms,

some people experience upper abdominal discomfort, diarrhea, and
loss of appetite.
 Occasionally, a person with tape worms may feel a piece of the
worm move out through the anus. Rarely, tape worms acquired from
fish cause anaemia.
Cont’

 Cysts in the brain and meninges,( the tissues covering the brain) in
people with cysticercosis may cause inflammation, resulting in
headache, confusion, other neurologic symptoms and commonly
seizures (Beers, 2003:1136).
Diagnosis

 Diagnosis of intestinal tape worm infection is by finding worm

segments or eggs in a stool sample.
 Cysticercosis is more difficult to diagnose, however cystis in the brain
can be seen with computed tomography (CT) or magnatic resonance
imaging (MRI) scanning.
 Blood tests for antibodies to the pork tape worm also are helpful.
Treatment

 Praziquantel
Dose: 40 mg/kg body weight as a single dose.
Side Effects: Headache, dizziness, loss of appetite, nausea
 Cysticercosis is usually not treated unless it involves the brain, in
which case antiparastic drugs such albendazole or praziquantel may
be given along with corticosteroids.
Prevention

 The first line of defense against tape worms is carefully evaluation of

meat and fish by trained inspectors.
 Cysts are visible in infected meat.
 Thorough cooking (such that all meat reaches more than 135
degrees ferhein height) and prolonged freezing will kill cysts. For this
reason, fresh water fish should be thoroughly cooked. Smoking and
drying do not kill cysts.
 Human cysticercosis

• Human cysticercosis is due to infection of man by larvae of

Taenia solium

• Cysticercosis in humans
• Eggs ingested by humans, or eggs produced by adult worm in gut
hatch in gut (auto-infection, common in people with taeniosis)
• Oncosphere crosses gut, enters other tissues throughout body
• Cysticerci form in humans (brain, eyes, spinal cord and muscles)
similar to that in pigs
• Thus man becomes a dead-end host

76
Human cysticercosis-Signs and Symptoms

• Signs and symptoms will depend on the size and location

of the cysticercus(ci) in the body

• Cysticercosis in muscles
• Lumps under the skin may be felt (subcutaneous cysticercosis)
• Mild myositis

• Cysticercosis in the eyes

• Blurry or disturbed vision
• Swelling or detachment of the retina
Human cysticercosis-Signs and Symptoms

• Cysticerci in the brain (Neurocysticercosis)

• Symptoms of NCC depend upon the location and number
of cysticerci
• Chronic headache
• Seizures
• Hydrocephalus
• Confusion
• Lack of attention to people and surroundings
• Difficult with balance
• Death
Cysticercosis: Treatment

• Praziquantel
• (25mg/kg BW) per day for 3 to 6 days in cutaneous
cysticercosis
• 50mg/kg b.w per day for 2 weeks in Neurocysticercosis
• Give the above in combination with corticosteroids
Albendazole
400mg twice a day for 2 weeks (Note: if taken for longer than 2 wks without 1 wk
break may lead to alopecia or liver impairment or parasite drug resistance)

79
 Brain tissue
showing (NCC)
Cysticerci
THE END

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