Warmer Climate Gives Malaria New Hunting Grounds

Malaria spreading to new regions while millions wasted on vaccines that cannot work for more than 2 years [New Article]

By Stephen Leahy

CHICAGO, U.S., Feb 19 (IPS)

Climate change is bringing malaria to regions of Africa where the disease was previously unknown, researchers report from the conference of the American Association for the Advancement of Science in Chicago this week.

Interestingly, the Arctic, where climate change is happening fastest, is the best place to study how warming temperatures are affecting infectious disease transmission.

[Note: Diseases are expected to increase in proportion to the decline/degradation of natural environment experts at Harvard said in my 2008 article “Doctor” Nature in Danger — Stephen]

Insect-transmitted diseases, primarily malaria, kill 3,000 people in Africa each day, said Andy Dobson of Princeton University in the United States.

Understanding how global warming is altering temperatures and the ecology and ranges of the malaria-transmitting Anopheles mosquito is crucial to understanding the dynamics of how insect-transmitted diseases like malaria will change, Dobson told IPS.

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“Ironically, we’re spending huge amounts of money on trying to develop vaccines for malaria but the best possible vaccine we could make wouldn’t last for longer than two years,” he said.

That’s because the natural lifetime of immunity to malaria is perhaps two years and to eradicate malaria using a vaccine would require vaccinating everyone every year because the malaria parasite evolves quickly, he explained.

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“We’re not going to be able to do that,” Dobson added.

Instead scientists need to be able to understand and project how and where malaria outbreaks will occur under the altered conditions of climate change. However, there is very little data or research on disease transmission in the field. Rather, the focus has been on developing vaccines and genetic analysis of the malaria parasite and mosquito genome – and that “tells us nothing about transmission”, he said.

“A sad testimony to how the (U.S.) National Institutes of Health and the Gates Foundation spend their money,” Dobson told IPS.

Malaria epidemics will likely be a new threat to tens of millions of Africans in previously malaria-free highland regions of Ethiopia, Kenya and Tanzania, and Rwanda and Burundi, warned Christopher Thomas of Aberystwyth University in Britain.

“This shift is projected to be already underway,” Thomas said, based on new computer models of temperature increases. “Malaria is expected to respond quickly to a changed climate because mosquito populations will increase in regions previously too cold.”

There is little natural immunity to malaria in most of these regions, he added.

That also means that some regions, like the Sahel, will see less malaria as they are projected to become too dry for mosquitoes. Still, it’s hardly good news since drought conditions would undermine local food security, he said.

Warming temperatures can explain the eight-fold increase in malaria in the highlands of western Kenya since the 1970s, said Mercedes Pascual, an ecologist at the University of Michigan, United States.

“Historically, people have settled in these regions to be protected from malaria, but this makes them more sensitive,” said Pascual.

The lack of previous exposure to the disease means local peoples’ resistance is low and mortality is much higher than average. Measured temperature increases in some cases has only been 0.5 C degrees, but in combination with increased resistance to the anti-malaria drug chloroquine, that has been enough to fuel the substantial increases in the disease, she believes.

“Climate change is a concern right now,” Pascual concluded.

The lack of understanding of basic mosquito and parasite biology in the field is a serious knowledge gap in determining when and where malaria will strike in new regions, said Matthew Thomas, an entomologist at Penn State University in the U.S.

The female Anopheles mosquitoes spread malaria by biting infected humans and ingesting the malaria parasites along with the blood. The parasites grow very slowly in cooler temperatures and faster when it is warmer. Climate change is not only raising the average temperatures but making nighttime temperatures even warmer.

According to Thomas’s research, that that can make all the difference because during the first 12 hours of the parasite’s incubation, it is very vulnerable to cooler temperatures. Since most mosquitoes bite in the evening or at night, warmer nights are good news for parasites, bad news for humans.

However, Thomas has also learned that if mosquitoes that feed in the morning face rapidly rising daytime temperatures then the malaria parasite development can be stopped. To project what will happen, “We need to understand the effects of temperature and environmental change through the eyes of the mosquito,” he said.

The best place to understand mosquito biology is the Arctic, suggests Andy Dobson, even if there are no malarial parasites. The primary reason is that climate change is already in fast-forward in the Arctic, well ahead of Africa. The life cycles of local parasites have accelerated with the warming temperatures by a factor of three or four, he said.

“Mosquito populations have boomed and the caribou are getting hammered,” Dobson said.

The Arctic also is simpler ecologically, with far less biodiversity than Africa, making it easier to tease out the details of host-parasite interactions. It is a kind of giant disease-transmission lab that could provide early insights into what may happen in the Mediterranean and tropical regions in the future, he explained.

It is also important to remember that malaria is a disease of the poor. The southeastern U.S. and the northern portions of Australia have perfect conditions for the disease but are malaria-free, noted Matthew Thomas.

“We could make serious inroads in understanding the biology in three to five years, but lack funding,” said Thomas.

First published as HEALTH Warmer Climate Gives Malaria New Hunting Grounds.

Related articles by Stephen Leahy

New Diagnostic Tool Could Slash Malaria Deaths in Children

Vitamin A and Zinc Supplements Cuts Malaria in Africa

Junk Food and Smoking to Kill 100s of Millions in Poor Countries

22 thoughts on “Warmer Climate Gives Malaria New Hunting Grounds

  1. Nice article. I have difficulty seeing how they view the Arctic as a “giant disease-transmission lab” useful to study the impact of climate on Malaria. As said, the region may have mosquito-borne diseases but not malaria. The mosquito species are also not the same I suspect, and the simplicity of arctic system may not be an advantage per say, when it comes to studying the dynamic of Malaria infections.

    Relative to a given vector-borne disease, different species can have different competency to act as reservoirs of the disease. The parasite has to survive in the animals’ body and some species have better defense mechanisms than others. Also, the parasite has to be retransmitted effectively from infected populations back to more mosquitoes (reservoirs : warm-blooded animals, including humans) to pose a threat of transmission to humans not yet infected. I remember reading about ticks and lyme disease, and how some animals constituted incompetent reservoirs, unable to infect ticks with the disease, while other species constituted highly competent reservoirs. I wonder if that is relevant to the dynamic of Malaria transmission as well?

    If specific species have different competency to act as reservoirs for Malaria and mediate the level of risk that malaria poses to humans in an area, then it may be important to understand that complex dynamic with precisely the species involved in the “malaria ecosystem”. That Arctic ecosystems are simple does not seem much helpful regarding this issue, neither does a caribou-mosqito or moose-mosquito link.

    In the end, maybe the Arctic can be useful for studying the impact of climate change on mosquitoes in general, but I am not sure how the “disease” part gets integrated in an effective way, if what is studied is diseases other than malaria, with other types of mammals in an area with extremely low population density (as I understand it, humans themselves may even be the most important reservoir of malaria?).

    There are also, supposedly, at least five different species that can cause Malaria and they may not have the exact same cycle, which potentially further complicates the task of projecting how the dynamic of infection will respond as a result of climate change.

    Note that I don’t know much about Malaria in particular, that’s just my two cents on the questions, I have really enjoyed reading your article.

    • Thanks and some interesting points. I believe Dobson’s thought on this was since temperatures are changing so quickly in the Arctic it offers a window in the future for rest of the planet regarding how temperature changes may affect disease transmission. So it is the dynamic of CC induced changes that are his focus.

  2. What a lot of baloney!
    Malaria is not a disease of climate, it is a disease of poverty.
    How can even a modest historian not be aware that malaria was once endemic in the USA, Britain, New Zealand as well as other temperate countries, and is only eradicated through efforts of the respective governments funded by their fortunately sufficiently wealthy tax payers.



    • Roger you really should read the story to the end before you declare it “baloney”. It plainly says malaria is a disease of poverty and that is why it is no longer endemic in USA NZ etc. All the experts interviewed in the story are… well experts on malaria and they know the history of the disease. Why would you assume they don’t?

      Let me sum up the story for you: There are plenty of poor areas like the highlands of Kenya that didn’t have malaria because it was too cold. Now the region is getting warmer due to climate change and the disease is spreading.

      • “There are plenty of poor areas like the highlands of Kenya that didn’t have malaria because it was too cold. Now the region is getting warmer due to climate change and the disease is spreading.”

        Sorry, I think it is still baloney. For your information, neither Gt Britain nor New Zealand are warmer than the highlands of Kenya neither summer or winter, yet the disease was endemic until eradication measures were taken. History even records that Henry VIII exhibited symptoms of malaria.

        Your article, or your interpretation of the facts does not simply meet the known facts.

        You should be running around figuring out ways to boost the Kenyan Highland economies instead of blaming anything else.



  3. Roger there are no Anopheles gambiae sensu lato mosquitos (the prime malarial vector in Africa) in the UK or NZ because it is indeed too cold. They are very sensitive to cold. Endemic malaria in the UK was transmitted by another kind of mozzie. So your comparison is invalid.

    • What absolute nonsense,

      You are confirming what was is already obvious that malaria can be spread by more than one type of mosquito.

      We are talking about the disease malaria here not the habitat of Anopheles gambiae sensu lato.



  4. Roger you are not making any sense. Of course there are many species of mosquitoes that transmit malaria. And of course the expanding habitat of the Anopheles gambiae sensu lato — the main vector of malaria in Africa — is directly related to the spread of the disease. That habitat expansion is due to warming temps scientists determined. Read the studies.

    • Yes but the cooler climates could just as easily be invaded by the mosquito species that survives in cooler climates. Which is how malaria historically spread around the world anyway as traders apparently carried that mosquito with them.
      What I object to is your contortions of the truth by your claim that global warming is the cause.



  5. If what you suggest was true wouldn’t the cool-loving mozzies have been there long ago?

    The experts who spent years studying this do think global warming is behind it. That is their conclusion not mine and your objection looks a little foolish in the face of their facts & evidence.

    • I read their evidence and it looks like alarmist propaganda to me.

      The highlands of Kenya were probably isolated enough to not have the “cool-loving” mozzies introduced, but still it is only a matter of time.

      The claim that malaria is on the increase because of global warming is still fallacious.

      Without preventative measures it is and always will be a world wide disease; global warming or no global warming.



      • The highlands are not isolated, I just there a while ago. You’re grasping at straws. I believe you would read anything that hints of climate change and reject it as “alarmist propaganda”. Reject away but that doesn’t change reality. Climate change is here.

  6. Lets not forget that it is not just a matter of “cold & warm”. mosquitoes need still-fresh water places to breed. So the increased rainfall in eastern Africa probably has a lot to do with worsening of the malaria situation there, and the long-term lack of rains has alleviated the situation of malaria in places like Senegal.

    Note that rainfall patterns are part of what we call climate-change also.

    I guess this aspect only works for the eastern African situation if it is reasonable to assume that breeding spaces for mosquitoes were limited in the past (still freshwater).

    • I don’t know that eastern Kenya has experienced an increase in rainfall. Most of the country has experienced drought through much of the last decade. Changes in rainfall would have been part of the analysis in any event and the researchers concluded that climate change is a factor in the spread of malaria into new regions.

      • I don’t know about Kenya, but I think there has been a long-term trend of increased precipitation of places like Rwanda and Tanzania, but I am not sure.

  7. Global Warming could not possibly effect mosquito breeding in terms of rainfall. We are going to get eithr drought conditions or flood conditions, neither of which favour the conditions need for mosquito larvae.
    How do I know the conditions will be extreme like that? Will the IPCC says it will be! http://www.ipcc.ch/pdf/assessment-report/ar4/wg2/ar4-wg2-spm.pdf

    Really you guys will be blaming global warming for the earthquake, I have just been through, next.



    • That’s a misunderstanding of the IPCC reports. There will be (and already are) increases in extremes due to climate change (look at all the records that have broken this year alone).. But there will also be shifts, minor changes in rainfall patterns.

      And maybe there is a connection to earthquakes — everything is connected to everything else on this planet. Hope all is well in NZ

  8. Inuit (Inuvialuit) elders and trappers have told me that spring thaw/ice breakup is occuring practucaly a month earlier now compared to 30-40 years ago in the Northern Yukon (Herschel Island area).

    That is quite a telling change.

    • I have spoken to many in the North as well and been in the high Arctic. It is a very serious issue for them and for us as well. You can read more in my articles
      just google: “Stephen Leahy” + arctic.

      I have been covering this for years. We should also understand that a warmer Arctic is changing the weather in the entire northern hemisphere.

  9. Well I think you should take a look at the title of your blog “Warmer Climate Gives Malaria New Hunting Grounds” and bearing in mind that malaria could have established itself in those “new” places if the right mosquito had been accidently introduced, (as it was in New Zealand by the european settler I understand), and just ponder on your standard of journalism




    • Roger you’re simply offering up standard global warming denial talking points, that’s not proof of anything other than an all-too human wish to believe climate change isn’t happening. I wish that were true too. But I have actually read hundreds of climate science studies, talked to hundreds of experts and been to many places like the Arctic where climate change is real and present danger.

      Your libellous nonsense about Pachauri is a pathetic pastiche of assumptions and lies cut’n pasted from other bloggers. I have removed your link. I have met and interviewed Pachauri a few times. FYI here’s a real verifiable fact: he was appointed to the IPCC at George W Bush’s insistence after the US forced a real climate scientist out of the job.

      I have been on this climate denial bus too many times to continue this conversation with someone who is happy to post lies about other people. Give yourself a shake.

  10. Evidence for global warming????

    What the science says…(from Skeptical Science)

    All the indicators show that global warming is still happening.

    The 2009 State of the Climate report of the US National Oceanic and Atmospheric Administration (NOAA), released in mid-2010, brings together many different series of data “from the top of the atmosphere to the depths of the ocean”. The conclusion? All of these independent lines of evidence tell us unequivocally that the Earth is warming.

    The very accessible 10-page summary examines the trends for 10 key climate indicators using a total of 47 different sets of data. All of the indicators expected to increase in a warming world, are in fact increasing, and all that are expected to decrease, are decreasing.

    The 10 indicators are:

    1. Land surface air temperature as measured by weather stations. You know all those skeptic arguments about how the temperature record is biased by the urban heat island effect, badly-sited weather stations, dropped stations, and so on? This is the only indicator which suffers from all those problems. So if you’re arguing with somebody who tries to frame the discussion as being about land surface air temperature, just remind them about the other nine indicators.
    2. Sea surface temperature. As with land temperatures, the longest record goes back to 1850 and the last decade is warmest.
    3. Air temperature over the oceans.
    4. Lower troposphere temperature as measured by satellites for around 50 years. By any of these measures, the 2000s was the warmest decade and each of the last three decades has been much warmer than the previous one.
    5. Ocean heat content, for which records go back over half a century. More than 90% of the extra heat from global warming is going into the oceans – contributing to a rise in…
    6. Sea level. Tide gauge records go back to 1870, and sea level has risen at an accelerating rate.
    7. Specific humidity, which has risen in tandem with temperatures.
    8. Glaciers. 2009 was the 19th consecutive year in which there was a net loss of ice from glaciers worldwide.
    9. Northern Hemisphere snow cover, which has also decreased in recent decades.
    10. Perhaps the most dramatic change of all has been in Arctic sea ice. Satellite measurements are available back to 1979 and reliable shipping records back to 1953. September sea ice extent has shrunk by 35% since 1979.

    Science isn’t like a house of cards, in that removing one line of evidence (eg. land surface air temperature) wouldn’t cause the whole edifice of anthropogenic global warming to collapse. Rather, “land surface warming” is one of more than ten bricks supporting “global warming”; and with global warming established, there is a whole other set of bricks supporting “anthropogenic global warming”. To undermine these conclusions, you’d need to remove most or all of the bricks supporting them – but as the evidence continues to pile up, that is becoming less and less likely.

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