Weather modeling> climate modeling> malaria

Global distribution of Malaria risk.

Global distribution of Malaria risk. (Photo credit: Wikipedia)

From the University of Liverpool it seems they are confusing seasonal scale weather with climate.

Climate model to predict malaria outbreaks in India

Scientists from the University of Liverpool are working with computer modelling specialists in India to predict areas of the country that are at most risk of malaria outbreaks, following changes in monsoon rainfall.

The number of heavy rainfall events in India has increased over the past 50 years, but research has tended to focus on the impact this has on agriculture rather than the vector-borne diseases, such as malaria and Japanese Encephalitis.

The University’s School of Environmental Sciences is working with the Council of Scientific and Industrial Research’s (CSIR) Centre for Mathematical Modelling and Computer Simulation (C-MMACS), Bangalore, to develop technology that will help decision makers and planners target areas that are prone to large scale climate variability and malaria epidemics.

The number of malaria cases in India has dropped from two million a year to 1.5 million in recent years, but the percentage of the more dangerous form of the disease, P. falciparum infection, has increased in some areas. The model could help inform early intervention methods to prevent the spread of malaria at key points in the seasonal monsoon cycle, reducing the economic and health impacts of the disease.

Dr Andy Morse, from the University’s School of Environmental Sciences, said: “We already know that an anomalous season of heavy rainfall, when heat and humidity are high, allows insects such as mosquitoes to thrive and spread infection to humans. In order to prepare health services and prevent epidemics we must have a way of predicting when these events are likely to occur in areas that are not accustomed to annual outbreaks of malaria.

“Liverpool has developed human and animal disease models that can be integrated into seasonal forecasting systems to give a picture of what the climate impacts on disease risk will be like in four to six months time.”

Dr Prashant Goswami, from C-MMACS, India, said: “We are rapidly developing our computer modelling capabilities using technology that can address the impacts of climate variability on agriculture and water systems. This knowledge, together with the Liverpool models of vector-borne diseases, will help us develop systems to predict when changes in the monsoonal rain may occur and which areas are most likely to see an increase in malaria.

“Health authorities in India are already very successful at controlling malaria cases, but this new research should support decision makers in keeping ahead of the more serious occurrences of the disease, which is starting to increase across the country alongside the changing climate conditions.”

The work, funded by the UK India Education Research Initiative (UKIERI), forms part of the University’s Global Health research theme, which brings together experts in infectious disease, reproductive health, and mental health from across the institution.

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[UPDATE From Willis]  I trust that Anthony won’t mind if I add my own comments. As often happens, I have personal experience with the subject under discussion. In this case the subject is malaria, regarding which I have far too much personal experience, actually. I have lived and worked in countries where malaria is common. I spent eight years in the Solomon Islands, where the malaria rates are among the highest in the world. I had a friend and co-worker who died from malaria at 46.

I have had malaria myself four times. Twice I had the non-recurring type, the one that doesn’t come back. Then I had the recurrent kind, the one that does come back. Finally, about a year after I moved to Fiji and left the malaria mosquitoes behind, I had a a bout of that recurrent malaria. Then I took the medicine that kills the recurring kind, and I haven’t had it since.

In addition, my wife is a Family Nurse Practitioner. In the Solomons she worked with the outlying clinics in the capital. Then she worked for a couple years as the Peace Corps Medical Officer, charged with keeping the Peace Corps Volunteers healthy. Then for three years, she was the only medical person on a very remote island where I ran a shipyard with a couple dozen employees, plus wives and kids. So she is extremely knowledgeable on the subject, and I learned all about malaria from her and from textbooks.

Then in Fiji, she and I ran a three-country health program, which included Vanuatu which is malarious.

As a result, I’ve seem malaria in all its forms and guises. I have participated in a variety of campaigns to prevent and reduce and interfere with the parasite and its mosquito host. I’ve had the trucks with the malathion chug down the street trailing their clouds. I’ve been involved with indoor DDT spraying. I’ve run bed-net programs. I’ve put oil in tanks and ponds to kill the mosquito larvae. It was a constant drain on the crews and staffs I ran in the Solomon Islands. Someone was always sick, someone was always out, someone was always sweating or shivering.

Here’s my take on this study. In India, the malaria is seasonal with the monsoon. Will the timing and location of the monsoon rains change in the future? Well, they always have changed in the past, so why wouldn’t they change?

Will the current generation of climate models help in planning for that? No way. No way at all. Even their promoters admit in private that they are useless, or worse, actively misleading, at a regional level.

But even if the models said that at some point in the future you’d get more rain in region X, or that you’d have earlier rains in region Y, how on earth would that help you? The climate models can’t predict what will happen in the oncoming monsoon season, which is what might help.

And even if the models someday could predict the monsoons locations and timing say seven times out of ten, I’m not sure what you’d do. The most cost effective means of preventing malaria are bed nets. But even if the models said this monsoon might be early and might hit hardest in the north, I wouldn’t gamble and put all the bed nets in the north.

Instead, I’d do what I assume they are doing now—watch and monitor and take preventive measures where and as needed, because the real need might end up being in the south.

So I’d see where the rains come, sure, and predict it if I could. But malaria is a disease and it spreads on its own strange timetable. One year you’ll have lots of rain and not much malaria. The next year you’ll have less rain, and more malaria. Who knew? It depends on timing and the life cycle of the mosquito, and the timing and cycle of the malaria parasite, and how many people are in an area, and how well they keep mosquito breeding pools down, and which travelers take the disease where, and a dozen other things.

For example, in the Solomons you could bet that in December and January you’d get an upsurge in the malaria cases. But not because of the weather. The problem was kids coming home from the boarding schools, which the main kind of grade schools there. The boarding schools often didn’t have bed nets and as a consequence had endemic malaria. When they came back to their towns and villages, they brought the malaria with them.

But even knowing that was coming, every year like clockwork, didn’t help in the fight. All you could do is do what you could to protect yourself, and then brace against the inevitable onslaught of malaria-ridden mosquitoes in December.

And anyone who thinks that a climate model could help with that hasn’t thought it through. The reality is you have to fight malaria as, when, and where it develops, not where it’s predicted to develop.

Regards to all,

w.

 

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30 thoughts on “Weather modeling> climate modeling> malaria

  1. Before we start serving up the usual ridicule regarding models and climate change, it’s well to note that there is a worthwhile (IMHO) attempt here to couple a disease vector model with regional climate forecasts to get ahead of malaria outbreaks. There is no mention of AGW or CAGW, and regional climate changes (think PDO and the Pacific Northwest) are certainly worth studying/quantifying when targeting limited resources such as health care dollars (or rupees).

  2. Odd that the researchers state that rainfall has changed in India. These authors found no change….
    Rainfall extremes in India show no trend in number or intensity over the last 50 years. The spatial variablity has increased, but not the number or intensity.
    http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1327.html
    These authors found no change over the last 100 years.
    No significant trend is discernable during the last 10 decades..
    http://www.agu.org/pubs/crossref/2011/2010JD014966.shtml
    These authors looked at 135 years of rain hsitory, and found no trend.
    From the conclusion:
    “”for the whole of India, no significant trend was detected for annual, seasonal, or monthly rainfall.””
    Kumar, V., Jain, S.K. and Singh, Y. 2010. Analysis of long-term rainfall trends in India. Hydrological Sciences Journal 55: 484-496.
    Note that they also stated that the IPCC had suggested that there would a reduction in the amount freshwater, impacting agriculture. The authors decided to use data, not models.

  3. D. J. Hawkins says:
    April 2, 2012 at 9:27 am
    Before coupling two models it would be best to get one at least and both, if possible, right.

  4. @Les,
    “The spatial variablity has increased, …”
    Wouldn’t that be the point of developing a seasonal model to predict malaria outbreaks in India? And if the authors did use data to develop their model – instead of the proxy, adjusted to match the model junk – isn’t that exactly what we’ve been criticizing the CAGW community for not doing?

  5. D. J. Hawkins says:
    Remember, it was these same “environmentalists” and their type of thinking who were responsible for banning DDTand malathion, lack of which is the main cause of the worsening of the incidence of malaria. And I do not believe anyone ever really proved DDT was harmfull in any statistically significant causal manner, only that it accumulated in fat cells over time. Malathion, well at high levels, like anything else at high enough levels, can be harmfull, though I am not sure it is completely banned though I don’t seem to be able to obtain any.

  6. Billy: It will be more than 2 models coupled. They would have to start with one of the IPCC global GCMs, which is based on faulty economic models. How faulty? The high emissions scenario shows North Korea with twice the GDP per capita of the US.
    They would then feed the global model into a regional model, which have been shown to have absolutely no skill what so ever.
    Then the regional model would be fed into into the biological model.
    Of course, they would only use the worst case from each model, to feed into the next.
    As Willis says, its models all the way down….

  7. John W: your
    Wouldn’t that be the point of developing a seasonal model to predict malaria outbreaks in India?
    Regional models have very little skill. Regional biological models based on regional climate models based on global climate models based on poor economic models would have even less skill.
    And if the authors did use data to develop their model – instead of the proxy, adjusted to match the model junk – isn’t that exactly what we’ve been criticizing the CAGW community for not doing?
    Yes, which was my point. Data trumps models.

  8. Wouldn’t it be easier to just map where the mosquito is likely to occur, them erase all of that area where DDT is not used?

  9. as per an earlier comment – using a model and coupling with another (and another..and another..etc) is somewhat futile if one or any of the models are inherently incorrect – or indeed downright inaccurate.
    As for predictive rainfall forecasts – well, what can one say? – in the monsoon period it rains and the area it covers likely varies by ‘a bit’ as no doubt the historical records will show. This is no doubt of importance in respect of health issues, and modelling malarial spread may well be worthwhile BUT not as a ‘linked on’ model to some uselessly predictive long term weather forecast! This is not a subject about which I know very much, but I would presume that for malaria to spread there needs to be standing water and mozzies aplenty? Given that monsoon rainfall is largely generically ‘predicted’ rather than specifically predicted (i.e. monsoon period equals high chance of heavy rain!) surely any predictive capacity for malarial spread is similarly more ‘generic’?
    Old adages are hard to beat – we are in April and in the UK this equals ‘April showers’ – it’s a generic term, but is based on many years of observations – the odd dry or wet April is not really predictable, and thus I find myself asking – is monsoon rainfall any different?

  10. Arnt the climate models known to be really poor at replicating the moonsoon patterns? I am sure I saw a paper published on the matter? All seems like a waste of time and money (again)

  11. To cut this Gordian Knot, use DDT. The increased – or not – mosquito population will not spread any diseases if it is severely cut back byuse of a powerful insecticide.

  12. Interesting to note that the Wiki map alongside shows how sharply malaria risk corresponds to political boundaries.
    The tropical issue is obvious, but look at the political boundaries.
    It is notable here in South Africa how lack of attention and the ban on DDT have allowed malaria to encroach, where once it had been eradicated. Some sanity seems to have prevailed and I believe that DDT spraying has started again and malaria is being pushed back into Mozambique, where they do nothing.
    Look at Mozambique and Namibea on the map.

  13. Why is it that malaria is now considered to be a tropical disease? Historically it’s been found all the way up into Scandinavia. It was brought to the New World *by Columbus* and the source of it on the Mainland USA is thought to be *Southeastern England.”
    I note in the map provided in the link that the “green” countries where malaria is rare-to-gone that they’re all more or less “1st world” countries, with the notable exceptions being the North African countries that are primarily desert. Seems to me is a poor-person’s disease, not a tropical disease, and has absolutely nothing to do with climate.

  14. sometimes, when things get a bit abstract, I think of my own kid.
    Would I trust my kids life to the models ?
    No.
    Would I take the DDT risk ?
    Yes

  15. Please see:
    P. Reiter (2000) From Shakespeare to Defoe: malaria in England in the Little Ice Age. Emerg Infect Dis. 2000 Jan-Feb; 6(1): 1–11.
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2627969/?tool=pmcentrez
    Abstract: Present global temperatures are in a warming phase that began 200 to 300 years ago. Some climate models suggest that human activities may have exacerbated this phase by raising the atmospheric concentration of carbon dioxide and other greenhouse gases. Discussions of the potential effects of the weather include predictions that malaria will emerge from the tropics and become established in Europe and North America. The complex ecology and transmission dynamics of the disease, as well as accounts of its early history, refute such predictions. Until the second half of the 20th century, malaria was endemic and widespread in many temperate regions, with major epidemics as far north as the Arctic Circle. From 1564 to the 1730s the coldest period of the Little Ice Age malaria was an important cause of illness and death in several parts of England. Transmission began to decline only in the 19th century, when the present warming trend was well under way. The history of the disease in England underscores the role of factors other than temperature in malaria transmission.

  16. The number of malaria cases in India has dropped from two million a year to 1.5 million in recent years, but the percentage of the more dangerous form of the disease, P. falciparum infection, has increased in some areas.

    Yes, but has it decreased in other areas?

    This knowledge, together with the Liverpool models of vector-borne diseases, will help us develop systems to predict when changes in the monsoonal rain may occur and which areas are most likely to see an increase in malaria.

    I love models. (The computing kind) 😉
    Indian monsoons to be drier
    http://journals.ametsoc.org/doi/full/10.1175/JCLI3820.1
    Indian monsoons to be wetter
    http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10s10-3-5-2.html
    Malaria may increase
    http://dx.doi.org/10.1016/S0959-3780%2899%2900020-5
    Malaria may continue decreasing
    http://dx.doi.org/10.1038/nature09098

    Another alarming climate myth bites the dust – mosquito borne malaria does NOT increase with temperature
    http://wattsupwiththat.com/2011/12/20/another-climate-myth-bites-the-dust-mosquito-born-malaria-does-not-increase-with-temperature/

    “…..sometimes common throughout Europe as far north as the Baltic and northern Russia….
    In fact, the most catastrophic epidemic on record anywhere in the world occurred in the Soviet Union in the 1920s, with a peak incidence of 13 million cases per year, and 600,000 deaths. Transmission was high in many parts of Siberia, and there were 30,000 cases and 10,000 deaths due to falciparum infection (the most deadly malaria parasite) in Archangel, close to the Arctic circle. Malaria persisted in many parts of Europe until the advent of DDT.”
    Professor Paul Reiter, Institut Pasteur
    http://www.publications.parliament.uk/pa/ld200506/ldselect/ldeconaf/12/12we21.htm

    and so on………….

  17. I know you’re under a lot of pressure to get these posts out quickly, but a little formatting would make authorship much clearer, e.g.:
    From the University of Liverpool it seems they are confusing seasonal scale weather with climate. From a University of Liverpool press release:
    [quote]
    “Climate model to predict malaria outbreaks in India”
    “Scientists from the University of Liverpool are working with computer modelling specialists in India to predict areas of the country that are at most risk of malaria outbreaks, following changes in monsoon rainfall. . . ”
    Similarly for the confusing post about the New Scientist review, above, where it’s totally unclear who is speaking at any point.
    /Mr Lynn

  18. A little global cooling and we’ll be safe for sure. / sarc

    A total of 1,803 persons died of malaria in the western parts of Finland and in the south-western archipelago during the years 1751–1773 [23]. Haartman [21] reports severe epidemics in the region of Turku in the years 1774–1777 and the physician F.W. Radloff mentioned that malaria was very common in the Aland Islands in 1795 [39].”
    Huldén et al – 2005 Malaria Journal
    http://www.malariajournal.com/content/4/1/19

    http://www.ingentaconnect.com/content/esa/jme/1986/00000023/00000001/art00009

  19. the more serious occurrences of the disease, which is starting to increase across the country alongside the changing climate conditions.”
    Note the implied causal relationship. Climate change is causing the spread of the more serious form of malaria. I very much doubt they have any evidence for this.
    A predictive model of malaria outbreaks would be a valuable thing, but this reads more like a grant application. Which says to me that they haven’t had much success to date.

  20. Oh, ff’s sake. Malaria and other mosquito-borne diseases need two things: water (for the mozzies to breed in) and infected people (to supply the bug that the mozzies transmit). As PPs have pointed out, the incidence of mosquito vector diseases correlates most closely with wealth, not rainfall. If 1,000 people with malaria were transplanted into currently malaria-free northern Canada or the Russian steppes in summer – guess what – there would be a malaria outbreak in the wider population.
    There is certainly a role for insecticides, draining of swamps near population centres etc in combating this awful disease. I shuddered when I read that ‘only’ 1.5 million cases in India is considered to be an improvement. But the main determinant of whether or not a person gets malaria in this day and age is their income, and the prosperity of the society they live in. That is why there is no malaria to speak of in northern Europe, or Canada, or Australia – all of which have plenty of water and plenty of hungry anopheles over large areas in summer.
    This dumb piece of research assumes that water is the critical variable. If they looked at patterns of malaria infection in parts of Africa, they might find that the critical variable is poor people who have malaria already, even in non monsoonal or even quite dry locations.

  21. I’ve added an update to the head post. Reading johanna’s post above, I can only agree. Weather and water is not the critical variable.
    w.

  22. johanna,
    No prosperity= no swamp draining & no DDT or malathion. Intercorrelated variables. Drain the swamps and spray for mosquitos, particularly where there is an infected population. Unfortunately, there are places that could afford to take these steps but due to their misguided “green” thinking will not allow for use of the pesticides or damaging “wetlands”. This also gives a perfect excuse to those in charge to not do anything to help and more money with which they can abscond &/or give to their friends and relatives (supporters), same thing.

  23. johanna says in part: “But the main determinant of whether or not a person gets malaria in this day and age is their income, and the prosperity of the society they live in. That is why there is no malaria to speak of in northern Europe, or Canada, or Australia …” Not exactly. The reason why there is no malaria to speak of in norther Europe, Canada or Australia – or the U.S. I would add – is because those places sprayed DDT in quanties that supressed the mosquito populations carrying the disease(s). The other nations, to their great misfortune, depended upon money and DDT from those nations in order to supress their own malaria. After the disgusting ban on DDT in the U.S. in 1972 by the EPA – whose director admitted he didn’t read the evidence! – those nations whose DDT programs were incomplete lost funding for it and stopped using it (benighted as they were, in those days they believed whatever was published in America and Western Europe as being true and accurate) and thereby retained the mosquitoes and the malaria – and dengue and black fly blindness and …. The efforts of upper class, well-educated, liberals in America and in Europe caused the deaths of millions of men, women and children and crippled milions more in those societies. I would point out that any efforts which attempt to reduce or have the effect of reducing the prosperity of those nations today – regardless of the asserted intention or purpose of such efforts – merely continues that history of the murders of those who live in such societies.

  24. 15 miles from my home town there was a Malaria case. Then 2 others inside 30 miles.
    When I was a kid, we had the ‘smoke trucks’ going through town in summer to kill mosquitoes. In school we learned to dump any standing water and stock mosquito fish.
    This was in California. NORTHERN California. 30 miles from Chico (which is also in Malaria Country). Why is California not red? Because it’s risk map and the risk is low because we do things to kill mosquitoes. During the Gold Rush, the ’49ers got malaria from mosquitoes up in snow country in the Sierra Nevada mountains. The involved mosquito has been found at 7000 foot elevation. It’s cold there.
    The notion that malaria is related to the tropics is dumb and ignorant. The reason we don’t have malaria in California has nothing to do with weather, it has a lot to do with the things that show up on a web search of malaria control in California:
    http://duckduckgo.com/?t=ous&q=california+malaria+control
    (“duckduckgo” is a search engine that does not snoop on you like Google does. Chrome also snoops on you. )
    Look again at that risk map. As already pointed out; places with money and places with modern societies that kill mosquitoes have low malaria risk. Don’t kill the mosquitoes, you will get malaria even in Alaska and Canada:
    http://www.mysteriesofcanada.com/Canada/malaria_in_canada.htm

    Malaria is an infamous killer throughout much of our world’s tropical areas; it kills or debilitates millions each year, and its economic impact is devastating. But most Canadians might have difficulty imagining malaria outbreaks in Canada.
    But, in the 1800s, particularly along the Rideau and Cataraqui Rivers, malaria was rampant.
    The Rideau and Cataraqui Rivers flow through Eastern Ontario; the Rideau flows North from the Rideau Lakes to the Ottawa River, the Cataraqui flows south into Lake Ontario, near Kingston. They both flow through a rugged, post-glacial landscape, dotted with isolated lakes, ponds, wetlands, swamps, fens, bogs, and so forth. These sluggish and stagnant wetlands were ideal breeding grounds for the Anopheles mosquito, which transmits malaria.

    http://en.wikipedia.org/wiki/Alaska_Gold_Rush

    Dysentery and malaria were also common in Dawson, and an epidemic of typhoid broke out in July and ran rampant throughout the summer.

    So here’s the deal: Don’t control the mosquitoes and have some folks with unmedicated malaria walking around, you WILL get Malaria reestablished in Canada, Alaska, Siberia, Europe, New York, etc.
    It has NOTHING to do with warming (global or otherwise) and has everything to do with summer and rains.

  25. Malaria is usually restricted to tropical and subtropical areas (see map) and altitudes below 1,500 m
    Significant portions of the Red Zone on that map lie *well* above the 1.500 meter line.
    Johanna pegged it.

  26. Just looked back at this after a few days.
    Willis, thanks for providing a few more variables that the authors of this stupid study missed. I didn’t know that there are successful treatments for malaria these days. My old man caught it in Korea in the 1950s and suffered decades of recurrences, complete with sweats, terrible nightmares and general inability to function. And he was one of the lucky ones – he didn’t die.
    The money that paid for this crap ‘research’ might have been used to actually help (in proven ways) people who have, or are at risk of, malaria. It is disgraceful that when we know how to fix at least most of this dreadful problem, money is being wasted on computer models.

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