RememberRemember• Autoinfection
• Mode of infection
• Infective stage
• Definitive host
• Intermediate host
•Type of parasites
•Source of infection
•Vector
•transmission
Location in humansLocation in humansTrematodes (flukes)Trematodes (flukes)
BloodBloodSchistosoma hematobiumSchistosoma hematobium
S. mansoniS. mansoni
S. japonicumS. japonicum
S. mekongiS. mekongi
s. intercalatums. intercalatum
LiverLiverClonorchis sinensisClonorchis sinensis
Dicrocoelium dendriticumDicrocoelium dendriticum
Opisthorchis felineusOpisthorchis felineus
O.ViverriniO.Viverrini
Fasciola hepaticaFasciola hepatica
f.giganticaf.gigantica
IntestineIntestineFasciolopsis buskiFasciolopsis buski
Echinostoma sppEchinostoma spp
Heterophyes heterophyesHeterophyes heterophyes
lunglungParagonimus westermaniParagonimus westermani
Infective stage Forked tail cercaria
Diagnostic stage
Egg with lateral spine
Biomephlaria intermeddiat host
Schistosoma mansoni • Is caused by persons passing faces containing eggs of parasite into water which is used for bathing ,washing clothes ,fishing ….
• After mating ,mature S. mansoni flukes migrate to small tributary veins of inferior mesenteric, Which
drain large intestine. flukes can also be found in portal venous system.
Life cycle•Person become infected by
contact with water containing infective cercaria . Cercaria attached to skin and are able to penetrate unbroken skin (can penetrate mucous membranes).
•During penetration cercaria loss their tail and develop into schistosomules which migrate through SC tissue into blood vessels.
•In blood young flukes are carried through right side of heart to lung
•From lung most of schistosomules pass through left side of heart ,enter abdominal aorta, and from there reach the portal (liver ) circulation.
•In blood vessels of the liver ,young flukes reach maturity.
schisto in m. vein.jpg
..
CLINICAL FEATURESCLINICAL FEATURES : :
• Swimmer's itch: may occur at site of Swimmer's itch: may occur at site of cercarial penetration.cercarial penetration.
• In Schistosomiasis it is the eggs not In Schistosomiasis it is the eggs not adult which responsible for pathology.adult which responsible for pathology.
• Eggs acquiring host antigens and Eggs acquiring host antigens and protected from attack by host immune protected from attack by host immune responses.responses.
• Most eggs penetrate intestinal wall Most eggs penetrate intestinal wall and excreted in stool with blood and and excreted in stool with blood and mucus mucus
•Trapped egg mature Trapped egg mature normally normally secreting antigenssecreting antigens that produce strong immune that produce strong immune response.response.
•Egg it self do not damage Egg it self do not damage body,body,
cellular infiltrationcellular infiltration resultant resultant from immune response that from immune response that cause pathology associated cause pathology associated with schistosomiasiswith schistosomiasis
• Eggs lodged in mucosa lead to formation Eggs lodged in mucosa lead to formation of granuloma- ulceration and thickening of granuloma- ulceration and thickening of bowel of bowel
• large granuloma lead to colonic and large granuloma lead to colonic and rectal rectal polyp.polyp.
• Eggs reach liver through portal vein Eggs reach liver through portal vein causing thickening of portal vessels causing thickening of portal vessels ==periportal fibrosisperiportal fibrosis –in heavy infection –in heavy infection lead to enlarged liver with fibrosis-portal lead to enlarged liver with fibrosis-portal hypertension –ascites and splenomegaly.hypertension –ascites and splenomegaly.
• Varicose v. in oesophagus –hematemesisVaricose v. in oesophagus –hematemesis
• Eggs in spinal cord ,lung …..Eggs in spinal cord ,lung …..
pathology & clinical picture of Schistosoma mansoni 1-per patent period. 2-egg deposition and extrusion. 3-tissue proliferation.
1-prepatent period: a-skin penetration: causing skin irritation N.B. from cercarial skin penetration to passage of eggs (adult stage) it take 5-7 weeks.
b- systemic symptoms (slight fever, muscle pain,--)
2-Egg deposition and extrusion: Affect mainly large intestinal wall, liver and spleen. Intestinal wall: schistosomal dysentery (blood and mucus exudates in stool) ,thickening and fibrosis of colon and rectum. Hepatomegaly: due to egg deposition. Splenomegaly: due to congestion Egg deposition: in other organs e.g. kidneys and spinal cord.
3-Tissue proliferation & repair: Intestine:
fibrosis, thickening and development of papillomata, loss of tone , fibrous
constriction diarrhea fistulae. Periportal fibrosis ,esophageal varices
haematemesis ,ascitis . Pulmonary complications:
bronchopulmonary and cardiopulmonary (obstructive vascular disease ) cor pulmonale. CNS involvement.
Schistosoma hematobium
PathologyPathology::• Swimmer's itchSwimmer's itch
• Hematouria–eggs penetrate wall of Hematouria–eggs penetrate wall of
bladder (bladder (blood in urineblood in urine).).
• Eggs trapped in wall of bladder Eggs trapped in wall of bladder causing causing
granulomagranuloma..
• Many eggs calcified (sandy patch)Many eggs calcified (sandy patch)
• Urinary infection–kidney damage – Urinary infection–kidney damage –
squamous cell carcinoma.squamous cell carcinoma.
• Stones , nephrotic syndrome.Stones , nephrotic syndrome.
pathology& clinical picture of Schistosoma hematobium
1. Pre-patent period. 2. egg deposition and extrusion. 3. tissue proliferation.
1-Prepatent period a.Skin penetrations : cause skin irritation N.B. From cercarial penetration to passage of eggs (adult stage) it take 10- 12 weeks. b.Systemic symptoms (slight fever, muscle pain…)
2-Egg deposition and extrusion
Most eggs traped in sucbmucosa and muscularis of bladder. Initially painless terminal haematuria for months to years, then burning micturition.
Cystoscopy shows hyperplasia and inflammation of lower bladder, initial papillomata.
3 -Tissue proliferation& repair: a- Generalized hyperplasia and
fibrosis of bladder, lower ureter, sandy patches, squamous cell carcinoma. b- Calaculi: obstructive uropathy leading to: -retrograde infection. -hydronephrosis and renal failure.
c- periportal fibrosis (eggs from v. of rectum and colon… portal vein …liver (PPF)
d- lung involvement (eggs from hypogastric vein to- common iliac vein to –heart to lung )
Diagnosis of schistosomiasisDiagnosis of schistosomiasis::
• Is by finding eggs depending on Is by finding eggs depending on species in urine ,feces, or rectal species in urine ,feces, or rectal scrapingscraping..
Parasitological diagnosisParasitological diagnosis : :
• Urinary schistosomiasisUrinary schistosomiasis1.1. urineurine : sedmentation, : sedmentation,
centrifugation,and filtrationcentrifugation,and filtration
2.2. AspirateAspirate :: bladder cystoscopy.bladder cystoscopy.
3.3. BiopsyBiopsy : rectum protoscopy : rectum protoscopy
• Intestinal schistosomiasisIntestinal schistosomiasis::
Stool examination Stool examination
1.1. Direct smearDirect smear
2.2. Thick smear (kato method)Thick smear (kato method)
3.3. Concentration methodsConcentration methods..
Rectal mucosa :Rectal mucosa :
swab, aspirate and biopsyswab, aspirate and biopsy..
Ancillary investigation inAncillary investigation in
schistosomiasis:schistosomiasis:• EndoscopyEndoscopy:: papillomta papillomta• RadiologicalRadiological - Ultrasound for liver periportal - Ultrasound for liver periportal
fibrosis.fibrosis. - X-ray - X-ray calcification ,obstructive uropathycalcification ,obstructive uropathy Pulmonary changes e.g. cor Pulmonary changes e.g. cor
pulmonalepulmonale• Serological tests:Serological tests: ELISA mainly survey method to detect:ELISA mainly survey method to detect: Ab :light or old infection Ab :light or old infection Ag :in active infection.Ag :in active infection.
Chemotherapy of Chemotherapy of schistosomiasisschistosomiasis
praziquantel.praziquantel.
Fasciola hepatica
• Large fluke, 3x1.5cm• Causing fascioliasis• Common parasites of herbivores, cosmopolitan, mostly in sheep
raising areas.
Immature egg
•_Fasciola-hepatica-_Fasciola-hepatica-EggEgg
Life cycle of Fasciola heptica
Life cycle Adult egg (in water) miracidium (pierce snail soft tissue multiply give sporocyst rediacercaria metacercaria (infective stage on water plant), Upon ingestion metacercaria burrows through duodenal wall liver parenchyma bile duct where it becomes adult.
Pathology Invasion of adult to biliary tree producing biliary obstruction and fibrosis. Eating raw liver infected with Faciola, adult worm attaches to pharyngeal mucosa causing pain, bleeding and edema.
Diagnosis Eggs in duodenal aspirate and stools. (Exclude spurious infection.) Treatment : Bithionol Control: Avoid ingestion of infected plants.
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