Schistosoma- an insight by Priyam Nath

morphology and geographical distribution of the worm as well as epidemology, its lifecycle , its definitive and intermediate host,various life stages egg, cercarie ,adult worm, the disease schistosomiasis, its symptoms and control medication,diagnostic stages,management, bilharziasis

1. NAME -PRIYAM NATH 3 rd SEMESTER 017 SCHISTOSOMA -an insight

2. INTRODUCTION Schistosoma is the only trematode that invades through the skin. Five species of schistomes infect humans Schistosome haematobium causes urinary tract disease the other species causes intestinal disease GEOGRAPHIC DISTRIBUTION Schistosoma haematobium -Africa, some in Middle East, Turkey, and India Schistosoma mansoni -Africa and America Schistosoma japonicum -Far east Asia, Some parts of Africa Schistosoma mekongi - Southeast Asia Schistosoma intercalatum - central and west Africa

3. EPIDEMIOLOGY AND MORPHOLOGY Approximately 250 million people are infected with schistosomes and 600 million people are at risk Adult worms are 10 to 20mm long Schistosomes have separate sexes The male has a canal in which the slender female worm resides

4. THE EGG Eggs penetrate the intestinal or bladder mucosa and are passed in stool or urine Other eggs remain within the host organ or are transported through the portal system to the liver Excreted eggs hatch in freshwater, releasing miracidia , the first larval stage Miracidia enters snails

5. THE CERCARIE Infective stage Cercarie penetrate human skin within a few minutes after exposure When they penetrate they lose their forked tail and transform into schistosomula Schistosomula mature and reach mesentric veins( S.mansoni i , S.japonicum . ) ,bladder vessels ( S.haematobium )where they live and ovulate for duration of hosts life

6. ADULT WORM Schistosoma mansoni Schistosoma japonicum

7. INTERMEDIATE HOST Schistosoma haematobolium - Bulinus truncatus Schistosoma mansoni - Biomphalaria alexandria Schistosomia japonicum - O ncomelania sp. Schistosomia mekongi - N eotricula aperta

8. LIFE CYCLE

9. SCHISTOSOMA COUPLE Schistosoma japonicum Schistosoma mansoni

10. PERIOD OF COMMUNICABILITY Life span-5to 10 years, so infected human can excrete eggs up to 10 years An infected snail can release cercarie from several weeks to 3 months of its life An infected snail can lay eggs 300-3000/day

11. SCHISTOSOMIASIS SCHISTOSOMIASIS OR BILHARZIA Disease affecting many people in developing countries. ‘Acute schistosomiasis '- snail fever and cutaneous schistosomiasis Low mortality rate, schistosomiasis can also be very debilitating Bilharzia or bilharziosis , named after Theodor Bilharz , who first described the cause of urinary schistosomiasis in 1851.

12. SYMPTOMS Hepatosplenomegaly Muscle atrophy Anaemia Diarrhea Haemorrhage from the gastrointestinal tract

13. DIAGNOSTIC STAGE Schistosoma haematobolium Eggs found in urine of urinary Schistosomiasis patients Oval egg with terminal spine Schistosoma mansoni Eggs found in stool of intestinal Schistosomiasis patients Oval egg with lateral spine

14. MANAGEMENT Contaminated water should be avoided Sanitary disposal of sewage Prevent contamination of water by feces and urine Destruction of snails Treat the patients No vaccine is available Praziquantel is effective against all species

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