From the Guardian, of course …..
Leading health experts are urging the government to take action against the growing threat that mosquito-borne diseases, including potentially fatal malaria, could soon arrive in the UK.
The disturbing recommendation to “act now before it is too late” is being made as a growing body of evidence indicates that what were once thought of as tropical diseases are being found ever closer to the UK. ….
“With predicted changes to climate in the UK, characterised by warming and wetter summers providing perfect breeding grounds for a number of pest-borne diseases, we need to consider some robust public health measures to minimise the potential outbreaks,” said Julie Barratt, director of the CIEH.
Good heavens! These are experts? Malaria is not a tropical disease. It occurs in all sorts of locations on earth. Malaria was quite common in Alaska during the gold rush.
I am relieved that climate change has decided to spare our British friends of the dreaded droughts it will impose on the rest of us. Still, malaria has nothing to do with the temperature of an area if it thaws at all.
But, let’s not take my word for all of this. Let’s have a look at what real experts have to say about this.
This is from the Malaria Journal. Who knew?
Speculations on the potential impact of climate change on human health frequently focus on malaria. Predictions are common that in the coming decades, tens – even hundreds – of millions more cases will occur in regions where the disease is already present, and that transmission will extend to higher latitudes and altitudes. Such predictions, sometimes supported by simple models, are persuasive because they are intuitive, but they sidestep factors that are key to the transmission and epidemiology of the disease: the ecology and behaviour of both humans and vectors, and the immunity of the human population. A holistic view of the natural history of the disease, in the context of these factors and in the precise setting where it is transmitted, is the only valid starting point for assessing the likely significance of future changes in climate.
Going on into the paper…..
Numerous review publications [2–34] and substantial media attention have had a major impact on public perceptions of the issue. In most cases, these publications make brief mention of where malaria occurs and how it is transmitted, followed by a succession of statements on the action of temperature, rainfall and other climate variables on specific components of the transmission cycle. These statements – often valid in themselves – are used to justify disquieting predictions that are persuasive because they are intuitive. Some are based on mathematical models that select a climate variable (usually temperature), propose a direct interaction with a transmission parameter (e.g. multiplication of the parasite, survival of the vector), and inevitably arrive at the same conclusions. Many focus on the vulnerability of people in poorer countries and place the blame squarely on the activities of the industrial nations. A deplorable trend in the scientific press is the inclusion of a political message, much as in the popular media. ……..
This is not to say that such models are inappropriate. On the contrary, they have become a central component of infectious disease epidemiology, mathematical representations that can be used to explore the dynamics of transmission and the fit of such models to field data. Nevertheless, an inescapable constraint in the case of vector-borne diseases is that the natural history and ecology, of both vector and host, are so complex that it is facile to predict future prevalence and incidence on the basis of temperature. ……
There is a widespread misconception that mosquito-borne diseases require tropical temperatures, or at least the temperatures of the warmer temperate regions. …….
There is also a misconception that mosquitoes die in winter, and that more die in colder winters, but it is obvious that mosquitoes – and indeed all life-forms that are native to temperate regions – have evolved strategies to survive low temperatures.
The physical environment is an important modifier of local climate. Anopheles arabiensis, an important vector of malaria in Africa, can survive in the Sudan when outdoor temperatures are above 55°C by hiding in the thatch of buildings in the daytime, feeding after mid-night, and ovipositing at dawn or dusk . In Lapland, in the past, anopheline species survived the winter in houses and stables, feeding occasionally, and transmitting malaria when outdoor temperatures were below -40°C .
These examples underline the limited value of meteorological variables as a guide to the behaviour and geographic range of vector species, and of the pathogens they transmit.
Malaria in temperate regions
Few people are aware that it is less than forty years since the final eradication of malaria in Europe and the United States. Indeed, the disease was common in the period from the 16th to 18th centuries that climatologists term the Little Ice Age , and data from burial records around the Thames estuary reveal that mortality in “marsh parishes” of England was comparable to that in areas of transmission in sub-Saharan Africa today [40,41].
Until the mid-19th century, the northern limit of transmission was roughly defined by the present 15°C July isotherm. Denmark and parts of Sweden suffered devastating epidemics until the 1860s. Incidence diminished thereafter and the disease had essentially disappeared around the turn of the 20th Century. The same was true in Finland, except for a brief recrudescence in 1941, during the Russo-Finnish war. Figure 1 shows the distribution of malaria cases in Norway between 1860 and 1920. In England, there was a gradual decrease in transmission until the 1880s, after which it dropped precipitously and became relatively rare, except in a short period following World War I. In Germany, transmission also diminished rapidly. After World War I it was mainly confined to a few marshy localities .
There’s a lot more in this very interesting paper. But, I’ve already gone on too long quoting the paper so I’ll just post the conclusions.
Simplistic reasoning on the future prevalence of malaria is ill-founded; malaria is not limited by climate in most temperate regions, nor in the tropics, and in nearly all cases, “new” malaria at high altitudes is well below the maximum altitudinal limits for transmission. Future changes in climate may alter the prevalence and incidence of the disease, but obsessive emphasis on “global warming” as a dominant parameter is indefensible; the principal determinants are linked to ecological and societal change, politics and economics. There is a critical need for cheap, effective control campaigns, as were implemented during the DDT era. A creative and organized search for new strategies, perhaps based on new technologies, is urgently required, irrespective of future climate change.
Ill-founded simplistic reasoning and indefensible obsessive emphasis…… just about sums up all the climate nutters. I don’t know how many times and how many ways they have to be told that their bizarre association of malaria with global warming stems from their mental health issues and nothing else.
One of the people who beclowned themselves is Julie Barratt, director of the CIEH. Would it be too much to ask of the health “experts” to brush up on the diseases they’re trying to scare the public with? A warmer Britain means nothing in terms of malaria.