CESTODES
Presented by Group 2
GENERAL CHARACTERISTICS
CESTODES are classified as under the subkingdom METAZOA,
Phylum Platythelminthes.
Considered as primitive worms
Do not possess a digestive system nor a nervous system.
Commonly known as tapeworms, they are flat and consists of
three distinct regions: head, neck and body (proglottids)
All cestodes are hermaphroditic( self fertilizing)
Grows by adding new proglottids or body from the neck
GENERAL CHARACTERISTICS
THREE REGIONS:
HEAD - contains an organ of attachment called SCHOLEX, In some
species, the scholex has a fleshy extension called a "rostellum"
BODY - divided into multiple segments called "proglottids". A series of
proglottids are called "STROBILLA" ( strobilli -plural).
NECK - serves as the region of growth and connects the head to the
body of the worm.
GENERAL CHARACTERISTICS
LIFE CYCLE
EGG - contains an embryo called ONCOSPHERE which represents the first
larval stage or the motile stage.
LARVAE/ LARVA - acquired through ingestion of under cooked or raw flesh
of the intermediate host.
ADULT WORM - undergoes self impregnation with the gravid segment
rupturing to release the egg in the intestines. These eggs then passed out to
the external environment during defecation.
CESTODES
INTESTINAL
EXTRA-INTESTINAL
TAENIA SAGINATA
(BEEF TAPEWORM)
TAENIA SOLIUM
( PORK TAPEWORM)
HYMENOLEPIS NANA
(DWARF TAPEWORM)
ECHINOCOCCUS
GRANULOSUS
(DOG TAPEWORM OR
HYDATID TAPEWORM)
TAENIA SAGINATA
(BEEF TAPEWORM)
IMPORTANT PROPERTIES AND LIFE
CYCLE
LABORATORY DIAGNOSIS
Task Name
EPIDEMIOLOGY AND PATHOGENESIS
TREATMENT
Task Name
DISEASE: TAENIASIS
PREVENTION AND CONTROL
IMPORTANT PROPERTIES AND
LIFE CYCLE
The intermediate host is cattle where the eggs enter the blood
vessels within the cattle's intestine.
The eggs are transported to the skeletal muscles of the cattle
where they develop into cysticerci (Larvae)
Infection with beef tapeworm is acquired by ingestion of
improperly cooked or raw beef containing the infective larva
called cysticercus.
The larvae then mature into adult worms in the small intestines
within a period of approximately 3 months.
These tapeworms are known to achieve a length of as much as 10
meters.
Humans serves as the definitive hosts.
The eggs are usually indistinguishable from Taenia Solium.
Proglottid is rectangular contains more uterine branches (about 15
to 30)
EPIDEMIOLOGY AND
PATHOGENESIS
Taenia Saginata infection is common in the areas in
the world where beef is routinely eaten, especially
undercooked beef.
Found to be endemic in Eastern Europe, Russia,
Eastern Africa, and Latin America.
The adult worms do not produce significant damage
in the small intestine.
DISEASE: TAENIASIS
Majority of patients are asymptomatic.
Those with high worm burden may
complain of diarrhea, abdominal pain,
loss of appetite with resultant weight
loss and body malaise.
The gravid proglottis may reach the
anus where egg-laying may occur
resulting in the itchiness in anal region.
LABORATORY DIAGNOSIS
Sample: Stool ova and Perianal Swab
Microscopy:
1. 15 to 20 Uterine branches (Gravid Proglottis) of T. Saginata
2. Eggs
TREATMENT
Antihelminth: Praziquantel, Niclosamide
PREVENTION AND CONTROL
Hand hygiene
Improved meat inspection
Ensure that meat products are cooked
at at least 165F (74C)
Freeze meat to 31F (-35C) or below for
at least 7 to 10 days.
TAENIA SOLIUM
(PORK TAPEWORM)
IMPORTANT PROPERTIES AND LIFE CYCLE
LABORATORY DIAGNOSIS
Task Name
EPIDEMIOLOGY AND PATHOGENESIS
Task Name
DISEASE: TAENIASIS-- CYSTICERCOSIS
TREATMENT
PREVENTION AND CONTROL
IMPORTANT PROPERTIES AND
LIFE CYCLE
Infection with the pork tapeworm is acquired
through ingestion of improperly cooked or raw
pork meat.
Taenia Solium infection can also occur following
the ingestion of food or water contaminated with
human feces that contain the eggs of the
parasite.
Has two infective stages: eggs and larvae
Autoinfection may also occur.
Pigs serves as the intermediate host while
humans serves as both intermediate and
definitive hosts.
EPIDEMIOLOGY AND
PATHOGENESIS
T. solium infection is more prevalent in under developed
communities with poor sanitation and where people eat raw or
undercooked pork.
Higher rates of illness have been seen in people in Latin
America, Eastern Europe, sub Saharan Africa, India, and Asia
(Centers for Disease Control and Prevention).
Adult worms produce little damage in the intestines
Encysted larvae may produce damage in the tissues where
they disseminate.
The larvae may encyst in various tissues of the body, they
evoke little inflammatory response.
DISEASE
1. Taeniasis– the disease produced by the adult worm. Most cases are
asymptomatic but in the presence of high worm burden, manifestations
may be similar to beef tapeworm infection.
2. Cysticercosis– the result of larval encystation in various tissues of the
body. The most common involvement is that of the skeletal muscles
where patients may complain of muscle pain. Cyticercosis of the brain
(neurocysticercosis)is the most feared and most severe involvement. It
may present with symptoms associated with increased intracranial
pressure such as seizures, headache, and vomiting. Ocular cysticercosis
may lead to visual disturbancesdue to development of inflammation of
the uvea (uveitis) and retina (retinitis).
LABORATORY DIAGNOSIS
Microscopic examination of stool specimen from
infected persons
The demonstration of the typical morphology of
the scolex can differentiate pork tapeworm from
beef tapeworm.
For cysticercosis, diagnostic procedure depends on
demonstration of the cyst in tissue, through biopsy
or CT scan.
TREATMENT
The drug of choice for treatment of intestinal infection
is praziquantel.
For cysticercosis, praziquantel may also be effective
but it is usually not recommended for ocular and CNS
involvement.
Alternative drugs include albendazole, paromomycin,
and quinacrine hydrochloride.
Surgical removal of the larvae may be necessary.
Anti convulsants may be given in cases of
neurocysticercosis.
PREVENTION AND CONTROL
Important preventive measures for
pork tapeworm infection are the same
as that for beef tapeworm and include
proper waste disposal and sanitary
measures, thorough cooking of pork
meat, and the prompt treatment of
infected persons to prevent the spread
of the parasite.
DIPHYLLOBOTHRIUM LATUM
(BROAD FISH TAPEWORM)
IMPORTANT PROPERTIES AND LIFE CYCLE
LABORATORY DIAGNOSIS
Task Name
EPIDEMIOLOGY AND PATHOGENESIS
Task
Name
DISEASE:
DIPHYLLOBOTHRIASIS
TREATMENT
PREVENTION AND CONTROL
IMPORTANT PROPERTIES AND
LIFE CYCLE
The longest of the tapeworms, the fish tapeworm can reach a
length of about 13 meters. Its eggs consist of ciliated larvae
called coracidia (s. coracidium).
One end of the egg is occupied by a lid structure called an
operculum.
.Its scolex contains a pair of long sucking grooves.
The gravid segments contain a uterine structure that is
centrally located and assumes a rosette formation.
IMPORTANT PROPERTIES AND
LIFE CYCLE
Human infection with D. latum is through ingestion of
improperly cooked or raw fish containing the
plerocercoid(infective stage), the precursor larval stage
After ingestion, the plerocercoid attaches to the intestinal
mucosa and matures into the adult worm.
The adult Cestodes worm self fertilizes and the eggs are
passed out with the stool
If the eggs come to contact with fresh water, the coracidium
hatches and is ingested by the first intermediate host, a tiny
crustacean called a copepod (Cyclopssp.).
IMPORTANT PROPERTIES AND
LIFE CYCLE
After ingestion, the coracidiumdevelops into the larval
stage called the procercoid.
The copepod is then eaten by a freshwaterfish (second
intermediate host) where the procercoid develops into
the plerocercoid.
Definitive hosts for the parasitesare humans and other
fish eating mammalssuch as dogs, cats, bears, and
seals.
EPIDEMIOLOGY AND
PATHOGENESIS
D. latum infection occurs in countries
where raw freshwater fish is
consumed.
Little damage is produced in the small
intestines of the human hosts.
In some individuals, the parasite may
compete with the host for vitamin B12,
leading to a deficiency of this vitamin.
DISEASE:
DIPHYLLOBOTHRIASIS
1.Asymptomatic disease – the most common presentation
among most individuals infected with the parasite.
2.Diphyllobothriasis– may manifest with symptoms of
gastrointestinal involvement, which may include diarrhea
and abdominal discomfort. When the adult worm attaches
itself to the jejunum and ileum, the patient may develop
deficiency of vitamin B12, leading to anemia similar to
pernicious anemia and is characterized as megaloblastic
anemia resulting from lack of maturation of red blood cells.
LABORATORY DIAGNOSIS
Diagnosis is based on finding of the
characteristic eggs and/or the
proglottids (less frequent)in a stool
specimen.
TREATMENT
The drug of choice for the treatment
of diphyllobothriasis is praziquantel.
An alternative drug is niclosamide.
PREVENTION AND CONTROL
Preventive measures include proper
sanitary procedures, thorough cooking
of fish prior to consumption, and the
prompt treatment of infected individuals
to prevent spread of the parasite.
Freezing of the fish for 24–48 hours at –
18 °C can kill all larvae.
1
H. nana is different from the other tapeworms because it
does not require an obligatory intermediate animal host.
2
The eggs are directly infectious and humans get the
infection after the accidental ingestion of the eggs of the
parasite.
3
Rodents serve as additional source of infection.
4
Once the eggs gain entrance into the human host after
ingestion of contaminated food and water, the eggs
transform into cysticeroid larvae.
5
Eggs are released after disintegration of the gravid
segments.
01
Eggs may be passed to
the outside environment
through the feces.
02
Some of the eggs may remain
inside the human host. Those
that remain inside hatch into
larvae and mature into adult
worms, thereby starting a new
cycle within the human host.
This type of re-infection is
called autoinfection.
Dwarf tapeworm is the most common
tapeworm recovered in the United States. It
has a worldwide distribution and is also
found in the East Asia and the Philippines. It
is common in areas with inadequate
sanitation and hygiene.
DISEASE: HYMENOLEPIASIS
Most patients are asymptomatic.
In cases of high worm burden, patients may
complain of nausea, weakness, loss of appetite,
diarrhea, and abdominal pain.
In young children with heavy infection, anal
itchiness(pruritus ani) may occur leading to
headaches due to difficulty sleeping.
It can be confused with a pinworm infection.
Autoinfection may lead to hyper infection syndrome
which can result in secondary bacterial infection and
spread of the worms to other tissues of the body.
LABORATORY DIAGNOSIS
Diagnosis is established by finding of the
characteristic eggs in stool specimen.
TREATMENT
Praziquantel is the drug of choice.
Niclosamide can be an alternative
drug.
PREVENTION AND CONTROL
Important preventive measures include proper
hygiene and waste disposal, control of transport
host population, and rodent control.
Proper storage of grains and flour must be
observed to prevent infestation with flour and
grain beetles.
Prompt treatment of infected individuals must be
instituted to prevent the spread of the parasite.
ECHINOCOCCUS GRANULOSUS
(DOG TAPEWORM OR HYDATID TAPEWORM)
IMPORTANT PROPERTIES AND LIFE CYCLE
LABORATORY DIAGNOSIS
Task Name
EPIDEMIOLOGY AND PATHOGENESIS
Task Name
DISEASE: ECHINOCOCCOSIS,HYDATID CYST
DISEASE, HYDATID DISEASE, HYDATIDOSIS
TREATMENT
PREVENTION AND CONTROL
IMPORTANT PROPERTIES
AND LIFE CYCLE
Infection with E. granulosusis primarily a zoonotic
type of infection.
Dogs are the most important definitive hosts while
sheep are usually the intermediate hosts.
Humans are considered as accidental and dead end
hosts.
The eggs of E. granulosus are identical to those of
Taenia spp. and are thus not diagnostic.
The diagnostic stage of the parasite is its larval
form, which is encased in a cyst wall and is called the
hydatid cyst.
IMPORTANT PROPERTIES
AND LIFE CYCLE
Infection is acquired after ingestion of eggs (infective
stage)from food and water contaminated by dog
feces or through contact with contaminated dog feces.
Eggs transform into larvae in the intestines, penetrate
the intestines, and migrate through the bloodstream to
different tissues in the body, particularlythe liver and
the lungs
The hydatid cyst (pathogenic stage) then develops in
the infected tissues.
Dogs acquire the parasite by eating the visceral
organs of the intermediate host.
EPIDEMIOLOGY AND
PATHOGENESIS
E. granulosus infection is common in Africa, Europe,
Asia, the Middle East, Central and South America, and
in rare cases, North America (Center for Disease
Control and Prevention).
The embryos develop into large, fluid filled hydatid
cysts, which act as space occupying lesions.
In addition, the cyst fluid contains antigens that can
sensitize the host.
Rupture of the cyst, either spontaneously or during
trauma or surgical removal, may lead to the release
of these antigens leading to anaphylaxis and
widespread dissemination of the parasite.
DISEASE: ECHINOCOCCOSIS,HYDATID CYST
DISEASE, HYDATID DISEASE, HYDATIDOSIS
Most patients are asymptomatic during the early stages of the
disease.
As the cysts enlarge, necrosis of the infected tissues occur.
Involvement of the liver may result in obstructive jaundice.
Patients with lung involvement may manifest with cough, chest
pain, and shortness of breath.
Other organs that may be infected include the spleen, kidneys,
heart, bone, and central nervous system, including the brain and
eyes(Center for Disease Control and Prevention).
Cyst rupture may lead to anaphylactic shock leading to death of
the patient.
LABORATORY DIAGNOSIS
There are several ways by which E.
granulosusinfection can be diagnosed.These
include
1. Examination of biopsy specimen;
2. Serologic tests (e.g.,ELISAor indirect
hemagglutination test);
3. Radiography to demonstrate the hydatid cysts
(e.g.,CT scan or ultrasound).
Care should be exercised when doing biopsy to
prevent rupture of the cyst.
TREATMENT
In cases when surgery is
possible, removal of the cyst
has been considered as the
treatment of choice.
If the cyst is located in
inaccessible areas medical
management alone may
prove effective
Drugs that have been proven
effective include
mebendazole, albendazole
and praziquantel.
PREVENTION AND
CONTROL
Improve personal hygiene practices
Prevent food and water from being contaminated with
dog feces.
Avoid feeding pet dogs with contaminated viscera.
The prompt treatment of infected canines and humans
Chemoprophylaxis should be given to dogs in endemic
areas.
Health education
THANK YOU
Group 2
ARCEGA, LUIGI DAX
BONDAD, SHIELA MAE
BRIGALA, KIM ELFA
BRUSAS, SHIEN
DELUANA, JOYCE
FLORIANO, BARBIE ANNE
JARON, EDRIAN
PALCON, DESIREE
PEREZ, ANGELA
RIVAREZ, JOHN REYMOND
ROZAL, ELAINE
SACUEZA, VIA DYNICA
SALCEDO, ANGELYKA
SARMIENTO, JANE
SAVEDRA, JENNY
TOMENIO, JOHN DENNIS