HELMINTHIASIS INFECTION

1. SEMEY STATE MEDICAL
UNIVERSITY
NAME : SHARMA HAMENT
GROUP : 438
TOPIC : HELMINTHIASIS
CHECKED BY : VAULIN STANISLAV SERGEEVICH SIR

2. CONTENTS
• INTRODUCTION
• MODE OF ENTRY
• SPREAD AND MECHANISM
• CLASSIFICATION
• CLINICAL FEATURES
• TREATMENT
• REFERENCE

3. INTRODUCTION
Helminth is a general term meaning worm.
The helminths are invertebrates characterized by elongated,
flat or round bodies.
In medically oriented schemes the flatworms or platyhelminths
(platy from the Greek root meaning "flat") include flukes and
tapeworms.
Roundworms are nematodes (nemato from the Greek root
meaning "thread"). These groups are subdivided for
convenience according to the host organ in which they reside,
e.g., lung flukes, extraintestinal tapeworms, and intestinal
roundworms.

4. Parasite modes of entryParasite modes of entry
• Ingestion
• Arthropod bites
• Penetration of intact skin or
mucous membranes

5. Spread and tropisms
• Some parasites must migrate to
certain locations within the host in
order to complete their life cycle
• Non-human parasites, in humans,
often fail to migrate properly and
become “dead-end infections”

6. Mechanisms for evading the
host response
• antigenic variation - trypanosomes
• intracellular infection - plasmodia
• encystation* - amoebae, cestodes
• camouflage - schistosomes

7. • direct destruction of tissue
• hypersensitivity reactions
• eosinophilia
–occurs with helminths, not protozoa
–results from tissue migration
Tissue damage and host response

8. Nematodes (roundworms)
Platyhelminthes (flatworms):
-Trematodes (“flukes”)
- Cestodes (“tapeworms”)
Classification of helminths

9. Helminthic diseases
Intestinal
Others
Strongyloides
 Invasive
Trichinosis
Filaria
Schistosomiasis
Cysticercosis
Echinococcus
(autoinfection cycle)
(muscle pain, uncooked carnivores)
(worms in lymphatics or under skin)
(liver or urinary tract granulomas
and fibrosis)
(cysts in brain, seizures)
(massive cysts in liver or lung)
roundworms
flukes
tapeworms

10. Roundworms (Nematodes)
• In contrast to platyhelminths, nematodes are
cylindrical rather than flattened; hence the
common name roundworm.
• The body wall is composed of an outer cuticle
that has a noncellular, chemically complex
structure, a thin hypodermis, and musculature.
The cuticle in some species has longitudinal
ridges called alae. The bursa, a flaplike
extension of the cuticle on the posterior end of
some species of male nematodes, is used to
grasp the female during copulation.

11. Generalized life cycle of
intestinal nematodes.
•
• острица
• хлыстовик
• аскарида
• анкилостома
•

14. • uncomplicated
– GI upset
• autoinfection
• hyperinfection
– rash
– bronchspasm, infiltrates
– diarrhea
– profound eosinophilia
– recurrent Gram-negative bacteremia
Strongyloides - clinical features

15. Arthropod
vector
Adult
worm pairs
Larvae
(microfilariae)
Lymph- mosquitoes peripheral circulate
dwelling lymphatics in bloodstream
(e.g, Wuchereria
bancroftii )
Skin- biting flies skin nodules migrate through
dwelling or migratory dermis
Life cycles of two types of filaria

18. O. volvulus microfilaria in skin snip

19. Trichinella spiralis

20. • Most common:
– muscle pain and tenderness
– fever +/- chills
– edema (often periorbital)
• >10% eosinophilia (often ~50%)
• elevated CPK
• +/- chronic neurologic/myocardial
• self-limited (2% mortality)
Clinical features of trichinosis

21. Treatment of trichinosis
• antihelminthic (albendazole) to kill
any intestinal adults
• steroids to relieve inflammatory
reactions
• antipyretics

22. Flukes (Trematodes)
• Adult flukes are leaf-shaped flatworms. Prominent oral and
ventral suckers help maintain position in situ. Flukes are
hermaphroditic except for blood flukes, which are bisexual.
The life-cycle includes a snail intermediate host.
• A dorsoventrally flattened body, bilateral symmetry, and a
definite anterior end are features of platyhelminths in general
and of trematodes specifically.
• Flukes are leaf-shaped, ranging in length from a few
millimeters to 7 to 8 cm.

23. Structure of flukes. (A) Hermaphroditic fluke. (B) Bisexual fluke.

24. The life cycle of blood fluke, Schistosoma japonicum. This organism causes
chistosomiasis. Unlikesome flukes, S. japonicum does not have a redia stage, nor does it
enter an arthropod host.

25. Schistosomiasis - pathogenesis
• egg granuloma (type IV reaction)--> fibrosis
• morbidity ~ worm (egg) burden
• adult worms: invisible to the immune system
(survive for years)

26. Drug treatment of schistosomiasis
• Praziquantel increases permeability
of adult parasite to Ca++
.
• Tetanospasm --> death

27. Control of Schistosomiasis
REDUCE CARRIERS mass rx program
ELIMINATE SNAILS molluscicides
destroy snail habitats
snail-eating fish
PREVENT WATER
CONTAMINATION latrines, toilets
public health education
PREVENT HUMAN
EXPOSURE water systems

28. Tapeworms (Cestodes)
• Adult tapeworms are elongated, segmented,
hermaphroditic flatworms that inhabit the
intestinal lumen.
• Larval forms, which are cystic or solid, inhabit
extraintestinal tissues.

29. Structure of
tapeworms• Structure of tapeworms

30. • Generalized
life cycle of
tapeworms

32. CysticerciCysticerci Hydatid CystHydatid Cyst

33. Isolated cysticerci Hydatid cyst

34. Cystic Hydatid Disease
contact
with
dogs
ingestion of
entrails
ingestion of
eggs in
pasturesEchinococcosis

36. Treatment of cysticercosis and
echinococcosis
• Antihelminthic therapy (e.g.,
albendazole, praziquantel)
• (Echinococcus only)
– Surgical removal
– Irrigation-evacuation of cysts

37. REFERENCE
• "Neglected Tropical Diseases". cdc.gov. 6 June 2011.
Retrieved 28 November 2014.
• Jump up^ London Declaration (30 January 2012).
"London Declaration on Neglected Tropical Diseases"
(PDF). Retrieved 26 March 2013.
• ^ Jump up to:a
b
c
d
e
f
g
h
i
Report of a WHO Expert
Committee (1987). Prevention and Control of Intestinal
Parasitic Infections. World Health Organization,
Technical Report Series 749.
• GOOGLE
• WIKIPEDIA

38. The END