This document summarizes the life cycles and transmission of various intestinal parasites. It discusses nematodes (roundworms) like Ascaris, Enterobius, and Ancylostoma which infect the intestines. It also mentions the tissue-infecting roundworm Trichinella spiralis. For flatworms, it covers trematodes (flukes) like Schistosoma which causes schistosomiasis, and cestodes (tapeworms) such as Taenia and Echinococcus. The document describes the infective stages, symptoms, diagnosis, and transmission routes of these parasites.

2. • Life Stages
– Egg, Larva, Adult;
complex life cycles
– Infective stage: Egg or
Larva
– Definitive host: harbours
adult stage
– Intermediate hosts: may
be more than one

3. Nematodes – Roundworms
Platyhelminthes – Flatworms
Trematodes Cestodes
Flukes
(Non segmented)
Tape worms
(Segmented)

4. • Intestinal roundworms:
– Ascaris (Giant intestinal roundworm)
– Enterobius (Pinworm)
– Necator / Ancylostoma (Hookworm)
• Tissue roundworms
– Trichinella spiralis - trichinosis

5. Ascaris Enterobius Ancylostoma
Trichinella spiralis

6. • Childrens playing in mud.
• Vegetables contaminated with
human faeces containing eggs.
• Contaminated drinking water.

8.  Allergic reactions.
 Ascaris pneumonia.
 Damage to Kidney or Liver due
to larval migration.
 Vitamin A defeciency.
 Eggs are the infective stage.

9.  Wet Mount Preparation.
 Concentration Technique.
Floatation SedimentationUnfertilised
Fertilised
Embryonated

10. SedimentationSedimentation FloatationFloatation
• Heavy eggs (Ascaris egg)Heavy eggs (Ascaris egg)
• Operculated eggs (Trematodes)Operculated eggs (Trematodes)
• Larvae (Strong sterc.)Larvae (Strong sterc.)
• CystsCysts
• Non Operculated eggs
Trematodes
Cestode
Nematode
• Cysts
Concentration Technique

11. • Enterobius is a human pin
worm/ thread worm/ seat worm.
• Source of infection is an
infected person.
• 1000s of eggs are laid on
perianal skin.
• The infection caused by
Enterobius is called as
Enterobiasis.
• Eggs are the infective stage.

12.  Trichinella spiralis is the
only human parasite.
Causes Trichinosis.
 Source of infected is
consumption of inadequately
cooked pork.
 Infective stage is the
larval form.

13. • Trematodes – Flukes -
nonsegmented
– Schistosoma - blood fluke;
Swimmer’s itch
• Cestodes – Tapeworms -
segmented
– Taenia – beef or pork
tapeworm
– Echinococcus – wild dog
tapeworm

14.  Swimming in
Contaminated water.

16.  Infection caused called
as Schistosomiasis.
Causes Swimmers Itch.
 Haematuria.
 Inflammation of
bladder (Stone formation)

17.  Wet Mount
Preparation.
 Cercariae is the
infective stage of the
parasite.
 Eggs can be
demonstrated by
microscopy.

19. Infection occurs when
the person consumes
undercooked pork.

21.  Affects brain, heart, liver,
lung.
 Epilepsy is most common.
 Ocular cysticercosis –
blurrring of vision, uveitis, iritis
and finally blindness.

22.  Wet Mount Preparation.
 Eggs are the infective stage.

23. • Hymenolepis nana, the
dwarf tapeworm, most
common human
tapeworm worldwide.
• Echinococcus
granulosus, the dog
tapeworm, humans are
intermediate hosts
A few other tapeworms also
cause disease