Tropical Diseases

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Tropical Diseases

• Global Warming Effects on

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Warming effects on infectious diseases

• Vector borne diseases such as malaria, yellow and
  dengue fever and encephalitis are not necessarily
  related to temperature
• Most vectors prefer a small range of warm
  temperatures

3

• Lab testing of West Nile Virus Transmission with
  mosquitoes and birds.

Reisen, WK. (2006). Effects of temperature on
the transmission of West Nile virus by Culex
tarsalis (Diptera Culicidae). Journal of
Medical Entomology, 43(2), 309-317.
4

• Six villages in the West Usambara Mountains in
  northeast Tanzania,
• Left AxisBiting Rates
• Right Axis Rainfall and
• Temperature

Bodker, R. 2003. Relationship between altitude
and intensity of malaria transmission in the
Usambara Mountains, Tanzania. Journal of Medical
Entomology 40 (5) 706-717.
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Warming Effects on Infectious Diseases

• Humidity increase varies in different locations
  on Earth due to global warming
• Disease increase varies on location for global
  warming
• Temperate zones such as United States might see
  increase in diseases (Texas outbreaks of Malaria
  for example)

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Disruption of an ecosystem

• Vector predators, such as bats or birds that
  consume insects may migrate to new locations to
  avoid hotter climates
• Vector populations could grow due to the missing
  predators and infectious diseases could further
  increase

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Spreading of Infectious Diseases

• If global warming continues, birds or other
  animal reservoirs might have to migrate to new
  habitats, exposing new diseases in new locations
• West Nile virus infects more than 30 North
  American mosquito species, which together
  transmit infection to at least 150 bird species,
  many of which migrate to new and distant
  locations, spreading the virus to rural and urban
  ecosystems throughout North and Central America

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Emerging Diseases

• HIV, SARS, H5N1 (Bird Flu), and other new
  diseases appearing in the last 30 years are
  definitely influenced by global warming but there
  are other greater factors including the ease of
  air travel and population growth for humans

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Morens, DM. (2004). The challenge of emerging and
re-emerging infectious diseases. Nature,
430(6996), 242-249.Red represents newly
emerging diseases blue, re-emerging/resurging
diseases black, a 'deliberately emerging'
disease. Many diseases emerged and re-emerged
because of global warming? Possibly, but there
are certainly other factors.
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Conclusion

• Global warming contributes in introducing and
  spreading more diseases globally, but in the
  short term, it definitely would not cause any an
  epidemic situations by itself