physical factors infl. prevalence of disease

• outline how patterns of avg annual temp affects patterns of disease

  • close to equator = higher temps
  • higher temps in Africa and south america
  • lower temps in north Europe and North America
  • anomaly = cooler temps in western china
• outline how patterns of annual total rainfall affects patterns of disease

  • dry areas are North Africa and Middle East = desert
  • wet areas are central Africa , South America , south east Asia = all rainforests
• outline how patterns of global relief affects patterns of disease

  • relief features such as mountains act as physical barriers
  • example: himalayas or the alps
• outline how patterns of water stress affects patterns of disease

  • high demand and low supply = water stress
  • high water stress in areas such as India and china where there are high populations and low availability
  • low water stress in areas of rainforests and low populations
• temp and rainfall are important influences of vector borne diseases

  (link between physical factors and disease diffusion)

  • temperature influences rate of vector reproduction and viral replication
  • rainfall creates marine habitats for vector reproduction
  • example: malaria mosquitos thrive in warm and humid conditions
• outline how seasonal variations affect disease outbreaks

  • vector borne diseases often peak during rainy season
  • example: Bilharzia is caused by flatworms and hosted by freshwater snails = linked closely to seasonal precipitation and temps
• West Nile virus

  • first identified in Uganda
  • transmitted by mosquitos
  • birds are the main host
  • spread to humans = zoonotic disease
  • in 2012 = 5500 cases reported in the USA = highest in Texas where there's the highest temps