Schistosomiasis, also known as bilharzia, is caused by several species of the genus Schistosoma and infects over 200 million people worldwide. It is transmitted through contact with fresh water contaminated with infected snails. Symptoms range from a rash upon initial infection to long term complications affecting the gastrointestinal tract, urinary system, liver and other organs. Diagnosis is made through microscopic examination of stool or urine samples or serological tests. Praziquantel is the recommended treatment, with prevention focusing on improved sanitation, access to clean water, and mass drug administration of praziquantel.
3. Introduction
• Schistosomiasis or Bilharzia is a Trematode infection caused by the species of
the genus Schistosoma.
• People are infected during routine agricultural, domestic, occupational, and
recreational activities, which expose them to infested water.
• Lack of hygiene and certain play habits of school-aged children such as
swimming or fishing in infested water make them especially vulnerable to
infection.
• Estimates show that at least 290.8 million people required preventive
treatment for schistosomiasis in 2018, out of which more than 97.2 million
people were reported to have been treated.
• Fresh water snails are the intermediate host
• Urogenital schistosomiasis or intestinal schistosomiasis
4. EPIDEMIOLOGY
• Second to Malaria on human Impact among tropical diseases
• 200 Million people infected Worldwide
• 700 Million at Risk in 74 endemic countries
• 80% in Sub-Saharan Africa
• 14,00 deaths Annually
• Major Health risk in Egypt and Central China
• S. haematobium- Urinary schistomiasis- Most prevalent and widespread in middle East and Africa
• S. intercalatum- 10 countries of Central Africa.
• S. mansoni- found in 52 countries in Africa, Middle East, Caribbean and latin America
• S. japonicum- found in China, Indonesia and Phillipines
• S. mekongi- found in Cambodia and Laos
6. Intermediate Hosts- Fresh
Water Snails
s. japonicum-
Oncomelania sp
S. haematobium, S.
intercalatum, S.
guineensis Bulinus sp.
S. mansoni-Biomphalaria
sp
7.
8. SIGNS AND SYMPTOMS
Clinical syndromes:
• Cercarial dermatitis or Swimmers Itch-penetration of cercarie
• Katayama Fever- 3-6 weeks later characterized by Fever, cough, sweating, abdominal pain, malaise, arthralgia,
hepatosplenomegaly, eosinophilia
-due to sudden release of highly antigen eggs
• Chronic Schistosomiasis- occurs many months to years
-Bloody diarrhoea, abdominal pain, haematemesis, haematuria, dysuria
-Portal hypertension- dyspnoes, fatigue, chest pain
-hepatosplenomegaly, ascites
-CNS symptoms-seizures/altered mental state etc.
9. DIAGNOSIS
• Microscopic Examination of stool and urine for Ova- Gold standard
-S. mansoni & S. japonicum- stool, S. haematobium – urine
-need repeated samples or concentration technique (Kato-Katz technique)
• Serological- Antigen Detection ELISA
- Antibody Detection
• PCR
• Tissue biopsy- rectal biopsy for S. mansoni
11. TREATMENT
• Praziquantel- WHO recommendation as drug of Choice- 40mg/kg OD for
1-2 days
-Paralyses Adult worms, No effect on eggs and Immature worms
• Oxamniquine- Intestinal infections in Africa and South America
-Limitations due to cost.
• Metrifonate-10mg/kg OD each night, 3 courses, 2 weeks interval
-Urinary schistosomiasis-?? Withdrawn from market
• Artemisinin Derivatives- Under Investigations
• Corticosteroids, NSAIDS and Anticonvulsants as adjuvants
S. haematobium are ellipsoidal with a terminal spine.
S. mansoni eggs are also ellipsoidal but with a lateral spine.
S. japonicum eggs are spheroidal with a small knob.
In endemic areas:
Avoid paddling, wading or swimming in fresh water
Avoid untreated tap water or unchlorinated swimming pools.
Heating bathing water or drinking water kills cercariae or Chlorine Treatment
Filtering water with paper coffee filters removes cercariae.
