Schistosomiasis
description
Transcript of Schistosomiasis
Overview Epidemiology Pathogenesis Diagnosis and treatment Vaccination Control Prevention
Theodor Bilharz (1851)
Pirajá da Silva (1908)
2nd most socioeconomically devastating parasitic disease.
3 species that infect humans
Origin› Africa› New World
Intermediate host› Human waste in water› Survival of these parasites depends on
human habits of polluting water with their own feces.
Most Vulnerable people:› Farmers› Fishermen› Children
Moslem countries› They perform ablution
Factors that influence transmission› Economic level› Education level› Sex
Males have the highest rates of infection and are the most intense
› Age
Protective immunity to super infection is elicited› By repeated exposure to cercaria› Presence of adult worms
Resistance to re-infection › Adults (most apparent)› Children (least resistant)
During the age of 8 to 18 years of age
Is unusual › Due to eggs and not to adult worms
Has three phases› Migratory
From the time of penetration until maturity egg production
Symptom less› Acute› Chronic
Acute Phase › Katayama Fever› Schtistosome being producing eggs› Symptoms include
Chills and fever Fatigue Lymphadenopathy
› Many eggs are carried by the hepatic portal circulation back to the liver.
Chronic Phase › Endemic areas
Asymptomatic› Intestinal
Mild, chronic, bloody diarrhea Abdominal pain Lethargy
› Schistosomiasis haematobia Pain on urination and blood in urine
8% of cases of infection S. japonicum and S. mansoni development of egg granulomas and fibrosis in the liver seriously impedes portal blood flow. › Enlargement of the spleen
S. japonicum tend to involve the small intestinal › Eggs of S. japonicum reach the brain more
often › Of the other 60% of all neurological diseases
of Schistosomiasis all brain lesions are due to S. japonicum
S. haematobium is the least seroius › Pain is most intense at the end of urination › Strong evidence nmj mnb that it cause bladder
cancer.
Identification of eggs un stools or urine
› Kato-Katz technique Tissue biopsy Antibody detection
Schistosomiasis is readily treated using a single oral dose of the drug Praziquantel annually
Education
Control by Chemotherapy› Lowered from 60.3% to Helling-Giese
1996.8% one after treatment with parziquantel
Vector Control
Control of snails Environmental management measures
› Stream channelization› Seepage control› Canal lining › Canal relocation with deep burial of snails,
can prevent increase in transmission Procambarus clarkii
Would have great potential value
Protection can be conferred by irradiated cercariae
A number of parasite-derived antigens confer partial protection against re-infection when used to immunize mice, rate, and other animals.
Avoid Swimming
Drink Safe Water
Heat bath water for 5 minutes at 150 F
Vigorously towel down after accidental contact with water.
Audibert, M., R. Josseran, R. Josse, and A. Adjidji.1990. Irrigation, Schistosomiasis, and malaria in the Logone Valley, Camerron. Am. J. Trop. Hyg. 42:550-560.
Bergquist, N. 1995. Controlling schistosomiasis by vaccination: A realistic option? Parasitol. Today 11:191-193.
Bickle, Q. D., M. G. Taylor, M. J. Doenhoff, and G. S. Nelson. 1979. Immunization of
Mice with gamma-irradiated intramuscularly injected Schistosoma mansoni. Parasitology. 79:209-222.
Brand, K. G. 1979. Schistosomiasis- Cancer: Etiological consideration. Acta Tropic 36:203-214.
Capron, A. 1998. Schistosomiasis: Forty years’ war on the worm. Parasitol. Today 14:379-384.
Grassi, L., M. T. Jorda, Z. Andrade, and S. M. G. Cappa.2001. Shortreport: Schistosoma mansoni mirabilis are killed by the defense system of an Argentine Strain of Biomphalaria straminea. Am. J. Trop. Med. Hyg. 65:290-292.
Gryseels, B. 1994. Human resistance to Schistosoma infections. Parasitol. Today 10:380- 384.
Hagan, P., and H. A. Wilkins. 1993. Concomitant immunity in schistosomiasis. Parasitol. Today 9:3-6.
Helling-Giese, G., E. F .Kjetland, S. G. Gundersen, G. Poggensee, J. Richter, I. Krantz, and H. Feldmeier. 1996. Schistomiasis in women: Manifestation in the upper reproductive tract. Acta Tropia 62:225-238.
Hofkin, B.V., G. M. Mkoji, D. K. Koech, and E. S. Loker. 1991. Control of Schistosome-transmitting snails in Kenya by the North American crayfish Procambarus clarkii. Am. J. Trop. Med Hyg. 45:339-344.
Loker, E.S. 1983. A comparative study of the life histories of mammalian schistosomiasis. Parasitology.87:373-369.
Madsen, H. 1990. Biological methods for the control of freshwater snails. Parasitol. Today 6:237-Helling-Giese 19961.
Osmundsen, J.A. 1965, August 22. Science Battle is on against a dread crippler. The New York Times, p.8E.
Pointier,J.P., and J. Jourdane. 2000. Biological control of the snail hosts of schistosomiasis in areas of low transmission; The example of the Caribbean are. Acta. Tropica. 77:53-60.
Roberts, L., J. Janovy, 2005. Foundations of Parasitology. 7th Edition. McGraw-Hill. New York, NY.
Spencer, H. C., E. Ruiz-Tiben, N.S. Mansour, and B. L. Cline. 1990. Evaluation of UNICEF/Arab Republic of Egypt/WHO Schistosomiasis Control project in Beheira Governorate. Am. J. Trop. Med. Hyg. 42:441-448.
Strickland, G. T., and M. F. Abdel-Wahab.1991.Schistosomiasis. In G.T. Strickland (Ed.) Hunter’s Tropical Medicine, 7th ed. 81 Philadelphia: W. B. Saunders Co., pp.781-809.