SchistosomiasisBlood and Lymphatic
System
Schistosomiasis (bilharziasis)• Schistosomiasis transmission has
been reported from 78 countries (WHO, 2015).
• In 2013 : > 40 million people, were treated for schistosomiasis.
• at least 90% of those requiring treatment live in Africa.
Schistosomiasis (bilharziasis)
• >>> School-age children are often most at risk tend to spend time swimming or bathing in water
• >>> in tropical and sub-tropical areas; in poor communities with poor sanitation, no adequate water resources
Species Geographic DistributionS. japonicum Southeast Asia , Japan, parts of
China and Indonesia (Central of Sulawesi).
S. mansoni Africa, Nile River valley in Sudan and Egypt, South America, Caribbean
S. mekongi Cambodia and Laos
S. intercalatum Central and West Africa.
S. haematobium Africa, Middle East
Species Intermediate host
Reservoir host
S. japonicum Onchomelania Various animals, such as dogs, cats, rodents, pigs, cow, horse and goats
S. mansoni Biomphalaria baboons
S. mekongi Neotricula aperta.
dogs
S. intercalatum Bulinus
Morphology• S.j. : ♀ : 26mm x 0.3 mm
♂: 12-20 mm x 0.5 mm
Source: http://neglecteddiseases.wordpress.com/schistosomiasas/
Eggs of Schistosoma
S. japonicumS.mekongi
S.mansoni
S.intercalatum
S.haematobium
http://www.dpd.cdc.gov/dpdx/HTML/Frames/morphologytables/body_morph_figure6.htm
Life Cycle
Intermediate host
Source: http://www.infectionlandscapes.org/2012/06/schistosomiasis.html
Oncomelania snail
Biomphalaria snail
Bulinus snail
Transmission :
• contaminate freshwater sources with their excreta containing parasite eggs which hatch in water.
• People become infected when larval forms of the parasite (cercaria) penetrate the skin during contact with infested water.
Pathogenesis & Clinical Symptom
1. The incubation period • usually 14-84 days;• Penetration of cercariae causes transient
dermatitis (swimmer’s itch)• Fever, chills, • urticaria, angio-neurotic edema• cough, and muscle aches
Pathogenesis & Clinical (cont’d)
2. Acute stage• Hyperemia in the wall of intestine (adult
worm arrive in the venules• Trauma with hemorrhage ( eggs escape
from the venules intestinal mucosaintestinal canal
• Diarrhea and dysentry syndrome (severe infection)
Pathogenesis & Clinical (cont’d)• Eggs secreted by adult worm pairs enter the
circulation and lodge in organs ( >>> liver)
• immune responses to schistosome eggs commonly lodge in the liver granulomatous reactions cirrhosis of the liver.
Pathogenesis & Clinical (cont’d)
3. Tissue proliferation &repair• The liver decreased in size : parenchyma
replaced by the scar tissue• Splenomegaly• enlarged liver, • abdominal pain,• blood in the stool
Pathogenesis & Clinical (cont’d)
• Portal hypertension• Cirrhosis ("Pipe stem Portal Fibrosis)• Ascites• Central nervous system lesions have
been reported, but are rare.
http://www.themonsterguide.com/MGWFSwimmersItch.html
Source:http://neglecteddiseases.wordpress.com/schistosomiasas/
Biopsy of liver,lung and colon
Diagnosis
• Microscopic:–Examination of stool for eggs
• Serologic testing: for antischistosomal antibody
Treatment
• The goal : reduction of worm load
reduction of egg production
reduces morbidity and mortality
Treatment
• Praziquantel (drug of choice)• Dose : 40 - 60 mg/kg per day orally in 2 – 3 divided doses for one day
Epidemiology & Control• The WHO strategy on use of anthelminthic
drugs now makes it possible to control schistosomiasis in poor and marginalized community
• Mass drugs administration / regular treatment with praziquantel (twice in a year)
• Eradication of snail with molluscacide• Health education is a must
Epidemiology & control
• In 2006, the prevalence of schistosomiasis in Danau Lindu : 0.49% and 1.08% in Napu Valley (1973: 73 %)
Prevention• Avoid swimming or wading in freshwater
when you are in endemic areas• Drink safe water.• Vigorous towel drying after an accidental,
very brief water exposure
Thank you
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