Strongyloides stercoralis

8. Strongyloides stercoralis
Strongyl: cylinder oides: like stercoralis: faecal
In the soil
Free-living cycle
Indirect cycle
male female
Mature egg
Hatching
rhabditiform
larva
Infective filariform larva
Optimum
environmental conditions
Unfavorable
environmental conditions
In man
Parasitic cycle
Direct cycle
4 moults
2 moults
In the
soil
Contains
rhabditiform
larva

9. Parasitic Cycle
in Man
Venous
blood
3rd
moult
4th
moult
♂ ♀
Rhabditiform
larvae in stool
On the
groundInfective filariform larva
Free-living adult
Duodenum
& upper
jejunum
Skin
lesion
Larva is
swallowed
Pulmonary
lesion
Intestinal
lesion

10. Diagnostic Stage Infective Stage
Rhabditiform larva Filariform larva
Notched
tail
end
Filariform
oesophagus
fills anterior ½
of larva
250µ long 500-600µ long
Rhabditiform
oesophagus

17. Pathogenesis and Clinical Picture
due to penetration of larvae into the skin.
Itching and dermatitis.
due to migration of larvae.
Verminous pneumonitis,
minute haemorrhage.
(Loeffler’s syndrome)
Fever, cough, dyspnea, haemoptysis
Skin lesion
Lung lesion

18. Duodenitis causing
burning epigastric
pain with tenderness.
Diarrhoea alternates with constipation
Constipation gives enough time for rhabditiform
larvae to develop into infective filariform larvae
Rhabditiform
larvae
Intestinal lesion
Larvae penetrate
mucosa of large
intestine causing
internal autoinfection
Larvae penetrate perianal
skin after coming out of the
anus causing
external autoinfection

23. Larva currens
Larva of S.stercoralis left on skin
of buttock or thigh move in the
skin at a rate of 5-10 cm / hour
causing linear eruption
Long standing heavy infection causes:
Dysentery, malabsorption , steatorrhoea
and weight loss
Autoinfection increases worm burden (( and leads
to persistent infection.
Currens: fast running

24. Disseminated Strongyloidiasis
Venous
blood
Systemic circulation
Strongyloides: an Opportunistic parasite
Larvae penetrate extra
intestinal organs
Occurs
more in
patients
with
impaired
immunity
Aorta

25. Diagnosis
1- Examination of faeces or duodenal contents for
larvae.
2- Examination of sputum
for larvae.
3- Eosinophilia.
4- Serological tests.
Treatment
Thiabendazole OR Ivermectin
Prevention and Control
As in Ancylostoma
250µ

27. Question
Autoinfection :
an infected person re-infects himself by the same
parasite either externally (hand to mouth) or internally.
Enumerate helminths transmitted by autoinfection.
 Enterobius vermicularis
 Strongyloides stercoralis
 Hymenolepis nana
 Taenia solium eggs
Name one that is transmitted through skin penetration.
Strongyloides stercoralis.
Name one that is common among children.
Enterobius vermicularis
Hymenolepis nana

29. Prepared by:
1- Mohamed Fathy Helmy
2- Mohamed Nabil Badawy
3- Mohammd Metwelly
4- Mohamed Mamdouh
5-Mohamed M Elkhabaza