Diphyllobothrium latum Quiz

• Cestodes are parasites of the small intestine.
• Lecture pertains to Cestode parasites affecting small intestine

General Characteristics of Cestodes

• Cestodes, also known as tapeworms, are flat and segmented.
• Size can vary from millimeters to meters
• Cestodes lack a body cavity and alimentary canal.
• They have a hermaphroditic genital system
• Excretory system consists of flame cells draining into collecting tubes.
• The cestode body comprises of the scolex (head), neck, and strobila (segments or proglottids).
• The scolex contains fixation organs, such as suckers or bothria.
• The neck is the worm's actively dividing portion.
• The strobila consists of immature segments, mature segments, and gravid segments.
• Immature segments contain immature sex organs; mature segments contain mature male and female sex organs; gravid segments contain the gravid uterus.

Classification of Cestodes

• Cestodes are classified based on their organ of fixation: Bothria (Pseudophyllidea), or Suckers (Cyclophyllidea).

Cestodes Impact on Human Health

• As a Definitive Host (DH):
  • Cestodes carry the adult worm in the small intestine.
  • Infection occurs via ingestion of eggs.
  • Symptoms include diarrhea, abdominal pain, vomiting, and indigestion.
  • Diagnosis involves detecting eggs or gravid segments in stool.
  • Examples include Taenia saginata, Taenia solium, and Hymenolepis spp.
• As an Intermediate Host (IH):
  • Cestodes carry the larva in tissues such as the liver, lung, brain, or bones.
  • Infection stems from ingesting eggs.
  • Clinical manifestations are pressure symptoms at the affected site.
  • Diagnosis is by antibody detection.
  • Examples include Taenia solium(Cysticercosis) and Sparganosis.

Pseudophyllidea: Diphyllobothrium latum

• Commonly called the "Fish Tapeworm;" infection leads to Diphyllobothriasis.
• Found in Finland, Siberia, lake regions of Europe, Japan, Chile, and America.
• The habitat is in the small intestine

Hosts

• DH: Humans
• IH: Requires two intermediate hosts: Cyclops (water flea) and freshwater salmon/cyprinoid fish
• RH: Fish-eating animals like dogs, cats, and foxes

Morphology of Diphyllobothrium latum

• It is a long tapeworm, measuring 3-10 meters with 3000 segments.
• Scolex: Elongated almond-shaped, 2.5x1 mm, featuring 2 slit-like bothria
• Mature Segment: Broader than long, measuring approximately 20x3 mm
• Does not have Gravid segments

Life Cycle of Diphyllobothrium latum

• Unembryonated eggs are passed in feces and embryonate in water
• Coracidia hatch from the eggs and are ingested by crustaceans
• Procercoid larvae develop in the crustacean's body cavity
• Infected crustaceans are consumed by small freshwater fish; procercoid larva develops into the plerocercoid larva
• Predator fish consume the infected small fish
• Humans become infected by consuming raw or undercooked infected fish

Diphyllobothrium latum Egg

-Oval -Thick shelled -Yellowish blown -Immature

• Operculated- 70 um x 50 um

Plerocercoid

• Solid
• Elongated, 1-2 cm with invaginated anterior end
• Body is striated but not segmented

Infection Details

• Infective Stage: Plerocercoid in fish muscles.
• Infection occurs through ingestion of insufficiently cooked, pickled, or smoked fish.
• Diagnostic Stage: Detection of eggs in stool.

Disease Pathogenesis and Clinical Manifestation

• Light infections are typically asymptomatic.
• Heavy infections cause intestinal mucosa inflammation, resulting in appetite loss, hunger pains, nausea, vomiting, and diarrhea.
• Complications include pernicious anemia, neurological issues from B12 deficiencies, and intestinal obstruction.

Diphyllobothriasis Diagnosis & Treatment

• Diagnosis involves clinical evaluation of abdominal pain and diarrhea
• Lab identification of eggs via stool examination and smear testing
• Treatment includes Praziquantel and treatment for anemia
• Prevention includes fish freezing and diagnosis of patients

Pseudophyllidea - Diphyllobothrium mansoni

• Also known as Spirometra mansoni that causes Sparganosis
• Distribution is common in Far East, Africa, and USA
• Commonly found in the small intestine

Hosts

• DH: Dogs and Cats
• IH: Cyclops (water flea), Frogs, snakes, birds and occasionally man (blind intermediate host)
• Life cycle resembles Diphyllobothrium latum
• Morphology resembles D. latum; Sparganum larva is solid and elongated.

Sparganosis

• Invasion of human tissue by the larval stage of Spirometra mansoni or Sparganum mansoni in subcutaneous tissue, eye, and lymph nodes.
• Infection occurs by drinking water containing infected cyclops, eating flesh of infected frogs, birds, or snakes, or applying infected animal flesh as poultices.

Clinical Manifestations of Sparganosis

• Ocular infection causes painful inflammation
• Painful migratory subcutaneous swelling leads to abscess formation
• Eosinophilia is present
• Larval death causes intense local reactions and urticaria
• Diagnosis: via swelling biopsy that reveals sparganum larvae
• Treatment: via surgical removal
• Prevention: by drinking purified water, cooking meats thoroughly, and avoiding flesh from intermediate hosts as poultices

Cyclophyllidea

• Includes Taenia solium, Taenia saginata ("Intestinal taeniasis"), Cysticercosis,

Taenia saginata and Taenia solium

• Taenia saginata or beef tapeworm, is prevalent worldwide.
• Taenia solium or pork tapeworm, is more common in pork-raising countries.
• Located in the small intestine

Hosts

• DH for both species: Humans
• IH of Taenia saginata: Cattle
• IH of Taenia solium: Pigs (Pork), Man

Morphology

• Taenia saginata: measures 4-10 meters with 1,000-2,000 segments.
• Taenia solium: measures 2-4 meters with 800-900 segments.
• Taenia saginata scolex is 1-2 mm, rhomboid with 4 cup-shaped suckers, lacks rostellum and hooks
• Taenia solium scolex is similar to saginata, has a protruded rostellum with two rows of hooks
• Taenia saginata mature segments are squarish, measuring 1x1.2 cm with alternating genital pore
• Taenia saginata gravid segments measure 15-20 mm x 7 mm, with 15-30 lateral branches and detach singly
• Taenia solium gravid segments measure 10-12 mm x 5 mm, with 7-12 lateral branches and detach in groups

Eggs

• Both Taenia saginata and Taenia solium have eggs that measure 30-40 µm, are spherical with a thick shell.
• T. saginata eggs stain acid fast and are not infectious to humans
• T. solium eggs do not stain acid fast and are infective to humans, and are often associated with cysticercosis.

Larvae:

• Cysticercus bovis: With invaginated inverted scolex, carrying four suckers with no hooks
• Cysticercus cellulosae: With invaginated inverted scolex, carrying four suckers with hooks

Life Cycle

• Humans become infected by ingesting undercooked infected meat
• Cattle and pigs become infected by ingesting vegetation contaminated by eggs or gravid proglottids
• Oncospheres spread in cysticerci in muscle tissue
• Scolex attaches in the small intestine

Disease Details

• The infective stage for T. saginata is Cysticercus bovis in beef muscles
• The infective stage for T. solium is Cysticercus cellulosae in pig muscles.
• Infection occurs via ingestion of improperly cooked or raw beef or pork
• Diagnosis is achieved by finding eggs and gravid segments in stool.

Disease Pathogenesis

• Most people are asymptomatic
• Some experience dizziness, loss of appetite, abdominal pain, and diarrhea
• Passage of gravid segments through the anus, obstruction of intestine/bile/pancreatic ducts, or reaction to worm allergens.
• Clinical diagnosis involves the passage of gravid segments.
• Identifications of eggs and proglottids are very reliable
• Light infection detection can be raised from a repeated exam.

Treatment

• Taeniicides have been developed
• Niclosamide and praziquantel are the drugs of choice.
• Praziquantel causes worm paralysis
• Yomesan causes worm disintegration

Control

• Proper hygiene
• Avoidance of raw meat
• Cooking all meat products

Cysticercosis

• Cysticercosis results from invasion of the tissue of man
• Infection occurs via contaminated food
• Can occur through autoinfection
• Cystierci can be found in connective tissue

Clinical Manifestations of Cysticercosis

• Nodules will form in most regions
• Damage to eyes
• Occurs commonly in the brain

Dangerous symtoms

• Most dangerous symptoms result from encystment in the CNS (Neurocysticercosis)
• Convulsions, epilepsy; Intracranial hypertension
• Psychiatric manifestations

Testing and Diagnosis

• ELISA serum test
• Imaging to find cysticer in tissue
• Albendazole
• Surgical

Prevention and contrl

• Treat all cases
• Avoid medicine that cause nauesa
• Proper hygiene
• Dont use human feces as fertilizer

Hymenolepis nana

• Also know as dwarf tapeworm
• Mostly affects children

Hymenolepis nana

• Located worldwide and is the most common
• Small intestine (ileum)

Host

• Adult worms located in small intestines
• Larvel in submuscusa

Morphology

• 2-4 cm, between 150-200 segments

Life Cycle

• Eggs pass with stool
• Human become infected by ingesting fecas
• Eggs release into the intestines
• Eggs change into cerca cystic for 3 to 4 days
• The cercra hatches and develops in the intestines after 2 to 3 weeks

Infective and Mode

• Egg

_Pathogenesis and clinical manifestations of hymenolepiasis nana

• Light infections are asymptomatic
• Heavy infections cause irritation, inflammation, ulceration of the intestinal mucosa, this leads to abdominal pain, vomiting, mucous diarrhoea
• Absorption of the toxic metabolites of the worm may result in headache, dizziness, nervous irritability and convulsions.
• Some children may suffer anaemia, eosinophilia and allergic manifestations

Diagnosos

• Clincal: children complain of diareah
• Lab: Stool exam
• Size: 40 by 60
• Morph: Sphericle

Treatment

• Oral doses given
• Nicloasemide needs to be retreated

Hymenolepis diminuta

• Rat tapworm
• Most common in rats but can occur in man
• Located in small intestines

###Dipylidium caninum (Dog Tapeworm)

• Dogs, cats, especially children
• larva is most common among fleas
• 20-40 c, 100 segmented
• Ingestion of fleas

Test your understanding of Diphyllobothrium latum, the fish tapeworm. This quiz covers the lifecycle, identification, symptoms, and diagnosis of diphyllobothriasis. Questions cover topics such as microscopic identification, infective stages, and potential complications.