Malaria: Visually charting our progress

When I was looking up something for last week’s rant, I discovered this map, which shows the progress that has been made in fighting Malaria.  Sometimes, I think it’s easy to forget that while a lot remains to be done, there also has been a lot of success.  The top map (a) is the extent of malaria in 1900, reconstructed from historic records; the bottom map (b) is the extent of malaria in 2007.

1900-2007 malaria rates

Of course, because this is from a scientific paper, there has to be jargon.  To translate:  the different colors relate to the level of infection in the general population (PR, or Parasite rate).  “Endemic” means that the infection is maintained in a community at a more or less steady state.

  • Epidemic/Unstable means that infections break out periodically in these regions
  • Hypoendemic:  less than 10% of the population is infected with malaria
  • Mesoendemic:   between 10% and <50% is infected with malaria
  • Hyperendemic:  Between 50% and75% is infected with malaria
  • Holoendemic: over 75% of the population is infected with malaria

In all but 2% of areas around the globe, malaria infections have declined since the rates before 1968.  This graph helps visually show where the difficult to control hot spots are, and also the range of different countries and environments in which malaria can occur.

I rant often about how malaria is not a monolithic organism, and how it’s transmitted by many different mosquito species in many different environments.  Now you can see what I’m talking about!

ResearchBlogging.org
Full Citation of the paper that is the source of this graphic:
Gething, P., Smith, D., Patil, A., Tatem, A., Snow, R., & Hay, S. (2010). Climate change and the global malaria recession. Nature, 465 (7296), 342-345 DOI: 10.1038/nature09098

3 thoughts on “Malaria: Visually charting our progress

  1. Nice to see a historical perspective on malaria. I’m amazed by how many educated people seem to think that malaria and most arthropod borne diseases are strictly tropical and ‘it can’t happen here’.

    ‘Risk free’ was a poor choice for a category name, though. Low risk would have been better. I remember an outbreak of a dozen cases of malaria a few years ago that were all traced back to a campground in ‘Risk free’ northern Queensland. The first case was a German tourist who had been to Africa and India before coming to Australia. Apparently he was one of those people who don’t use mosquito nets or DEET, and he fed enough Anopheles to infect the rest of the victims over the next month or so. Seems to me that I’ve read of small outbreaks in the eastern US too. Much of the ‘Risk free’ areas on the map have all the needed ingredients for an outbreak of malaria, including human reservoirs: people who have picked up one of the four human malaria protozoans on their travels or brought the disease with them when they migrated.

  2. This is a beatiful example of progress, but a sad picture for the affected areas in Africa where less has changed. The picture is worth a thousand words arguing for continued efforts to meet the needs of people where those needs are now greatest. Thanks for sharing the discussion and citation of the important paper.

  3. Two things:
    I just came back from Costa Rica, and the wildlife is amazing there. Flora and fauna never looked so good.
    Two…I haven’t pollinated in weeks. =/

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