Vector Control Module 1D

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Vector ControlModule 1D

• Schistosomiasis

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Schistosomiasis distribution
Worldwide 200 million people infected
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Life cycle
Schistosome eggs
Cercariae
Miracidia
Snails
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• Worms swim to peoples feet and burrow in!

Intermediate host snails A Bulinus transmits
Schistosoma haematobium
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Schisto exposure

• Washing clothes in a pond containing intermediate
  host snails, a source of schisto infection.

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Water project dangers

• After the Navrongo irrigation dam (Ghana) was
  built, the incidence of schistosomiasis increased
  dramatically up to 87 prevalence.

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Symptoms of Schistosomiasis

• abdominal pain
• diarrhoea
• blood in the stool or urine
• liver enlargement is common in advanced cases
• In women, urogenital schistosomiasis may present
  with genital lesions, vaginal bleeding, pain
  during sexual intercourse and nodules in the
  vulva. In men, urogenital schistosomiasis can
  induce pathology of the seminal vesicles,
  prostate and other organs.
• In sub-Saharan Africa, more than 200 000 deaths
  per year are due to schistosomiasis.

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Control measures (1)

• Drugs to reduce number of eggs in infected person
• Reduce snail population
• Reduce release of eggs from snails
• Engineer ways to reduce the need for contact with
  water

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Control measures (2)

• Hygienic disposal of faeces
• Molluscocides can be used to control schito
• Grass cutting on river edges can be effective for
  controlling schistosomiasis snails

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Control

• Environmental control
• Mollusciciding