Schistosomiasis

pvrireview.org/articles/2009/1/1

Largely Neglected Tropical Disease 200 million infected WW 20 million, severely 280,000 deaths annually

wga.hu

Quick Background/Terminology

• Class: Trematode• Genus: Schistosoma• Species: 3 infect humans

– S. mansoni– S. haematobium– S. Japonicum

• Terminology of lifecycle– Miracidia– Cercariae– Schistosomulae– eggsX 3500/day

path.cam.ac.uk

path.cam.ac.uk

treehugger.com

dpd.cdc.gov

path.cam.ac.uk

X 3500/day

Lifecycle

First rash, then flu-like symptomsInitial Infection Dermatitis

Severe Infections/Without Treatment Anemia Human G&D Impairment Cognitive Dysfunction Delayed Growth and Stunting Hepatomegaly Splenomegaly Bladder Cancer Death

emedicine.medscape.com/

path.cam.ac.uk

Fever Chills Cough Muscle Aches

6-10 weeks later

path.cam.ac.uk

path.cam.ac.uk

treehugger.com

dpd.cdc.gov

path.cam.ac.uk

X 3500/day

path.cam.ac.uk

6-10 weeks after rash…

• CBC: eosinophils

Definitive: MicroscopySeriologiesPCR

Is schistosomiasis really a curse?• Population density, movements, and growth:

Paradox of success?

Humans’ altering of their environment …

… Anthropogenic Land Use

The Volta Project in Ghana that trashed the Volta:

…. and the Aswan High Dam scheme in Egypt:

thecommonwealth.org

geogonline.org.uk

books.google.com

Treatment isn’t as simple as a pill

• Anti-helminths:

Praziquantel: 10 cents

• Vaccine in development but will be expensive

• Plants/Herbs—problem

discount-pet-superstore.com

thesynapticleap.org

dragonmoon.ca

We really need a better approach… instead of a pill-centric ideology

• “people’s war against the snail”

Education campaigns

Manpower

fecal exams /stern sanitation

Drugs

books.google.com

This effective measure used conservation medicine

“Unprecedented levels of disease and ill health in many species, driven by increasing burden of anthropogenic environmental change.” (conservationmedicine.org)

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Program based solely on drug delivery

tufts.edu/vet/ccm

drugsdirectory.net

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References• Hewlett BS & Cline BL (1997) Anthropological contributions to a community-based schistosomiasis control

project in northern Cameroon. Tropical Medicine and International Health 2, A25–36. 

• http://emedicine.medscape.com/article/999469-media

• King, C.H., Muchiri, E.M. and Ouma, J.H., 2000. Evidence against rapid emergence of praziquantel resistance in Schistosoma haematobium, Kenya. Emerg. Infect. Dis. 6, pp. 585–594.

• Clennon JA, King CH, Muchiri EM, Curtis Kariuki H, Ouma JH, Mungai P, Kitron U, 2004. Spatial patterns of urinary schistosomiasis infection in a highly endemic area of coastal Kenya. Am J Trop Med Hyg 70: 443–448

• http://www.case.edu/med/epidbio/mphp439/Schistosomiasis.htm

• Madsen H, Bloch P, Phiri H, Kristensen TK, Furu P. 2001. Bulinus nyassanus is an intermediatehost for Schistosoma haematobium in Lake Malawi. Ann Trop Med Parasitol 95:353-360.

• http://www.path.cam.ac.uk/~schisto/schistosoma/schisto_lifecycle_cercaria.html

• http://journals.cambridge.org/action/displayFulltext?type=1&fid=69804&jid=JBS&volumeId=29&issueId=01&aid=69803

• Dezowitz, Robert. New Guinea Tapeworms and Jewish Grandmothers: Tales of Parasits and People.