1. gastrointestinal block week 3 schistosomiasis & Fasciolopsiasis trematode parasites

2. Objective know the global distribution of schistosomiasis
describe the life cycle of schistosomiasis
compare relation between chronic schistosomiasis and portal hypertension
know pathology, diagnosis and treatment of schistosomiasis
know life cycle of Fasciola hepatica
know pathology , diagnosis and treatment of Fasciola hepatica
compare between true infection and sheep liver infected with Fasciola hepatica which lead to false infection

3. Definition
Schistosomiasis is a chronic, parasitic disease caused by blood flukes Blood trematodes (trematode worms) of the genus Schistosoma also known as bilharzia,
ETIOLOGY
a. Schistosoma haematobium
b. Schistosoma mansoni
c. S. japonicum
Two forms of schistosomiasis exist
Intestinal schistosomiasis and
2. Urogenital schistosomiasis

4. Epidemiology
The disease is found in Africa, South America, East Asia and Middle East Over 230 million people require treatment for schistosomiasis yearly 90% of those requiring treatment for schistosomiasis live in Africa. More than 200,000 deaths per year are due to schistosomiasis in sub-Saharan Africa

5. Mode of transmission
Infection occurs when your skin comes in contact with contaminated freshwater in which certain types of snails that carry schistosomes are living. Freshwater becomes contaminated by Schistosoma eggs when infected people urinate or defecate in the water. If you live in or travel to areas where schistosomiasis occurs and your skin comes in contact with freshwater from canals, rivers, streams, ponds, or lakes, you are at risk of getting schistosomiasis.
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6. Life cycle of schistosomiasis

7. Life cycle (Eggs  larvae  into snail)
Parasite eggs released into freshwater (from human urine, feces)
Eggs hatch  ciliated miracidia, free swimming
Miracidia find & infect snail host (different species prefer diff’t snail sp.)
Each miracidia transforms into many fork-tailed, free swimming forms called cercariae within 4-6 weeks of entering snail.
Cercariae leave snail and move into water up to 18 days.
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8. Life cycle (Into human  lymphatics  lungs  liver)
6. Cercariae find a human host,
penetrate skin, and differentiate into
larval forms called schistosomulae.
7. Migrate through the host’s skin,
gain access to the lymphatic system.
8. Travel to the lungs (stay 3-8 days and ~70% are eliminated)
9. Migrate to liver portal system, mature into male & female adults
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9. Life cycle (maturation  movement to target organs  egg production)
10. In liver, m & f pair up  female inserts herself into the gynecophoral canal of male  they are now ‘paired’. 11. Migrate to favoured sites: S. mansoni – mesenteric venules of large bowel & rectum S. japonicum – mesenteric veins of the small intestine S. haematobium – perivesical venous plexus surrounding the bladder Egg lyes 50% comes out 50%trapped in tissues, carried away by blood circulation, lymph. causing an immune reaction and progressive damage to organs.

10. SIGNS & SYMPTOMS
Clinical picture: low grade fever. Fatigue, weight loss and anemia
Intestinal schistosomiasis
Abdominal pain
2. Diarrhea 3. Blood in stool, fresh or melena 4. Hematemesis 5. Liver enlargement
Urogenital schistosomiasis
1. Hematuria (terminal)
2. dysuria
3. Frequent need to urinate (polyuria)
4. In females; genital lesions, vaginal bleeding, pain during sexual intercourse and nodules on the vulva, irregular menstruation
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11. Schistosoma dermatitis or “swimmers itch (Early) acute infection Katayama fever fever urticaria malaise diarrhea
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12. Chronic Infection (Late)
Symptoms of chronic infection caused by eggs that travel to various parts of body
Eggs remain trapped in host tissues  secrete Ags  granulomatous inflammatory immune response
Granuloma
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13. Chronic Infection When eggs meet the liver/spleen)
Hepatosplenic schistosomiasis
Eggs carried by portal circulation  liver
Granulomatous response
Granulomas are walled off with fibrous tissue  fibrosis obstructs portal veins  portal hypertension
Esophageal varices (dilated esophageal veins, which drain the liver bursting can cause bleeding to death. Hypovolemic shock Caused directly by portal hypertension.)
Splenomegaly (enlarged spleen, due to fibrosis)

14. Portal hypertension is an increase in the blood pressure within a system of veins called the portal venous system. Veins coming from the stomach, intestine, spleen, and pancreas merge into the portal vein 

15. Chronic Infection When eggs meet the genitourinary areas & CNS
Genitourinary complications
Eggs lodge themselves in wall of bladder & can develop into polyps
Polyps can erode, ulcerate & cause hematuria (blood cells in urine)
Eggs lodge in ureters and urethra, cause lumps and lesions  kidney failure
Eggs lodge into ovaries, the uterus, cervix, fallopian tubes  lumps  complications incl. infertility
(For the men: eggs can also lodge into the testes and the prostate )
CNS complications
S. haematobium and S. mansoni can migrate to the spine
S. japonicum found in the brain and causes encephalopathy (general brain dysfunction)

16. Diagnosis Microscopic Detection Take stool or urine
sample to detect eggs
S. haematobium eggs s.haematobium
are oval and have a spike at the tip
S. japonicum eggs small
and almost spherical with tiny spine
S. mansoni eggs have
a spike on the side (spine)
s.mansoni

17. Treatment Metrifonate  against S. haematobium
Niridazole  against S. japonicum
Oxamniquine  against S. mansoni
WHO recently approved use of combo of 3 drugs at once (rule is always no more than 2) to cure a few related diseases (incl. Schistosomiasis) in hopes that eradication will be faster.
Complications
Drugs ineffective when fibrosis has developed - treatment is then focused on managing the complications (e.g. portal hypertension)
Anticonvulsants may be needed in patients with CNS complications (S. japonicum).

18. Fasciola hepatica is known as Common/ Sheep Liver Fluke(trematodes)
causes the disease fascioliasis
is one of the largest flukes of the world (30 mm by13 mm)
is leaf-shape, pointed at the end
has small but powerful oral sucker
The acetabulum is larger than the oral sucker

19. The life cycle

20. Life cycle
Fasciola hepatica: Sheep liver fluke, causes disease primarily in sheep and other domestic animals • Humans are infected by eating watercress (or other aquatic plants) contaminated by larvae (metacercariae) that excyst in the duodenum, penetrate the gut wall, and reach the liver, where they mature into adults • Hermaphroditic adults in the bile ducts produce eggs, which are excreted in the feces • The eggs hatch in fresh water, and miracidia enter the snails

21. Life cycle
Miracidia develop into cercariae, which then encyst on aquatic vegetation
• Sheep and humans eat the plants, thus completing the life cycle
• Symptoms are due primarily to the presence of the adult worm in the biliary tract
• In early infection, right-upper-quadrant pain, fever, and hepatomegaly can
occur, but most infections are asymptomatic
• Months or years later, obstructive jaundice can occur
• Diagnosis is made by identification of eggs in the feces

22. Signs and symptoms
Incubation phase: from the ingestion of metacercariae to the appearance of the first symptoms; time period: few days
Invasive or acute phase: fluke migration up to the bile ducts
This phase is a result of mechanical destruction of the hepatic tissue and the peritoneum
The major symptoms of this phase are:
Fever: usually the first symptom of the disease; 40–42 °C Abdominal pain
Gastrointestinal disturbances: loss of appetite, flatulence, nausea, diarrhea
Urticaria
Respiratory symptoms (very rare): cough, dyspnoea, chest pain, hemoptysis
Hepatomegaly and splenomegaly
Ascites
Anaemia
Jaundice
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23. Pathogenesis
The development of infection in definitive host is divided into two phases: the parenchymal (migratory) phase and the biliary phase During the migration of flukes, tissues are mechanically destroyed and inflammation appears around migratory tracks of flukes In biliary ducts, flukes mature, feed on blood, and produce eggs. Hypertrophy of biliar ducts associated with obstruction of the lumen occurs as a result of tissue damage. Hypertrophia of bile ducts in liver caused by F. hepatica (liver section of an infested goat)

24. Lab diagnosis Treatment
Most immunodiagnostic tests will detect infection and have a sensitivity above 90% during all stages of the diseases
diagnosis of fasciolosis is usually achieved parasitologically by findings the fluke eggs in stool,
Treatment
A medication called triclabendazole is commonly used to treat a liver fluke infection, as this effectively kills the liver flukes and their eggs.
Other drugs, such as pain relievers, may be used to treat some of the symptoms such as pain and diarrhea.
Surgery may be necessary in rare cases where cholangitis, an infection of the bile ducts in the liver, has developed.

25. End
Thank you four your attention
Any question