Schistosoma and Global Warming

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Schistosoma

• Prof Dr Kamran Ashraf
• Shifa-ul-haq

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Biology

• Schistosomes are blood flukes and belong to the
• Class Trematode
• Order Digenea
• Family Schistosomatidae

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Family Schistosomatidae

• Bilharziella
• Ornithobilharzia
• Schistosoma
• Trichobilharzia
• Minor Genra
• Austrobilharzia
• Dendrobilharzia
• Gigantobilharzia
• Heterobilharzia
• Microbilharzia
• Schistosomatium

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Genus Schistosoma

• S mansoni
• S hematobium
• S japonicum
• S intercalatum
• S mekongi
• Currently, 21 species of this genus have been
  recognized

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Host Range

• Digenetic
• Wide host range in case of S. japonicum
• S. bovis
• S. mattheei
• S. rodhaini

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Dogs, cats, rodents, pigs, horse and goats,
serve as reservoirs
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Intermediate Hosts

• S. hematobium and S. intercalatum by Bulinus
• S. mansoni by Biomphalaria
• S. japonicum by Oncomelania
• S. mekongi by Neotricula

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Right-Bulinus Left-Oncomelania
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Flash Video of Life Cycle about 2.30 Seconds ??
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Period of communicability

• Life span 5-10 years( up to 30), so infected
  human can excrete eggs up to 10 years.
• An infected snail can release cercariae from
  several weeks to 3 months of its life.
• An infected snail can lay eggs 300-3000/day

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Schistosomiasis

• Bilhaziasis
• Snail Fever
• Urinary Schistosomiasis
• Katayama Fever (Acute Type)
• Swimmers Itch or Orientobilharziasis
  (Orientobilharzia, Trichobilharzia , Schistosoma
  spindale )

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• Theodor Bilharz 1st describe the cause of urinary
  Schistosoma.

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• In ancient Egyptian Papyri symptoms of chronic
  haematobium was described as a Dripping Penis
  Disease
• Schistosoma eggs have been recovered from
  Egyptian and Chinese mummies

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Distribution

• 2nd most prevalent parasitic disease in the
  world, only behind the Malaria

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• More than 250 million people are infected (WHO,
  2013)
• 120 million people are symptomatic.
• Another 700 million people are at risk of
  infection.

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Geographic Distribution

• 78 countries
• The endemic areas Africa, the CaribbeanSouth
  America, East Asia, and the Middle East

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• 200 000 mortality
• 1.7-4.5 million DALYs
• DALY (Disability Adjusted Life Years)?
• One lost year of "healthy" life.

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What, if its a huge problem
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Vaccination

• The administration of radiation-attenuated
  cercariae
• Antigens from Schistosomules by P-I Lille, France
• Schistosoma paramyosin
• Target the fecundity of the female Schistosomes

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Treatment

• Praziquantel
• Somehow Artemether

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• At least 243 million people required treatment
  for Schistosomiasis in 2011 (WHO)

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• The number of people reported to have been
  treated for Schistosomiasis in 2011 was 28.1
  million
• Reasons
• Shortage of medicine
• High cost of Praziquantel
• No other proven alternative
• Patent competition

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Concluding

• More than 250 million affected
• 700 million at risk
• No vaccine possibility in near future
• 243 million required treatment, but only 28
  million got it
• But the problem not halted here

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Global Warming

• An Average increase in the temperature of the
  atmosphere which can contribute to changes in
  global climate patterns.

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How Global Warming Works?
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Causes of Global Warming

• Burning of Fossil Fuels (coal/crude oil)

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Causes of Global Warming

• Population Increase

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Causes of Global Warming

• Deforestation

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Causes of Global Warming

• Transportation- Fuels (LPG, Kerosine, Fuel, Jet
  Oil)

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Causes of Global Warming

• Industrial Process, manufacturing of steel, cement

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Causes of Global Warming

• Agriculture and Farming
• Methane is 20 responsible for global warming and
  2/3 of methane is produced by animals
• Ruminants produce 80 million metric tons of
  methane annually
• Methane is more potent green house gas than co2

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• Interestingly Ciliate Protozoa are more
  responsible for methane production (Isotricha,
  Eudiplodinium, Epidinium  Entodinium)

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Causes of Global Warming

• Waste Management
• Landfills are also major source of methane

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Causes of Global Warming

• Use of Natural Gas for Cooking

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Environmental and Human Effects of Global Warming

• Increase in average temperature More extreme
  heat waves, less cold spell of winter
• Increase in frequency of extreme events
  tornados, floods, heat waves, snow fall
• Rising in temperature and variable precipitation
  decrease production of staple food Increase in
  Malnutrition

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Environmental and Human Effects of Global Warming

• Population Displacement
• Flooding
• Sea level rising
• More than half of the world's population is now
  living within 60km of the sea

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Environmental and Human Effects of Global Warming

• UV Exposure
• Skin Cancer
• Premature Aging
• Cataracts
• Suppression of Immunity

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Environmental and Human Effects of Global Warming

• Climate-Sensitive Diseases

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• Development of cold-blooded animals is positively
  related to temperature.
• Development will arrest when temp. drops below
  acritical threshold
• Lowest developing temp. or biological zero
• The higher the temperature, the higher
• the possibility that the host snail will shed
  cercariae of S. japonicum

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• According to available temperature data for 1960
  and 2000, the median January temperature,
  averaged across the 193 observing stations in
  China, increased by 0.9C.
• The mean temperature will continue to rise
  indeed at an accelerated pace with predicted
  increases by 2030 and 2050 of 1.7 and 2.2C,
  respectively

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• Biologic model and experiments identified a
  temperature threshold of 15.4C for development
  of Schistosoma japonicum within Oncomelania
  hupensis, and a temperature of 5.8C at which
  half the snail sample investigated was In
  hibernation
• Historical data suggest that the geographic range
  of O. hupensis is cold tolerant and restricted by
  the mean January temperature of 0C
• So, the increasing average temperatures
  associated with global warming are hypothesized
  to increase the ranges of O. hupensis habitat

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• At the same time, longer seasonal periods of mean
  temperatures gt 15.4C (the minimum temperature
  needed for parasite development) mean that the
  accumulated degree-days necessary for parasite
  development and transmission will occur in
  progressively more regions than before

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• Ultimately, as global warming progresses, more
  areas currently deemed as marginal for snail and
  schistosome habitat are expected to become
  recognized transmission zones