Friday, December 19, 2008

THE MALARIA SCARE DEBUNKED

Malaria today is most common in tropical countries so Greenie "scientists" assume that it is a warm-climate phenomenon and predict that global warming will spread it into Europe and the United States. Below are some excerpts from an academic journal specializing in malaria studies which show that malaria is NOT limited by climate and that epidemics of it have been known as far North as Finland. So it is not climate that limits malaria but public health measures. Climate is irrelevant. Note that what is true of malaria should also be true of other mosquito-borne diseases such as Dengue fever and Ross river virus



Global warming and malaria: knowing the horse before hitching the cart

By Paul Reiter

Abstract

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.

Common misconceptions

There is a widespread misconception that mosquito-borne diseases require tropical temperatures, or at least the temperatures of the warmer temperate regions. A glance at a map of global isotherms reveals that summer temperatures in many temperate regions are at least as high as in the warmest seasons of many regions in the tropics. The crucial difference is that the tropics do not have cold winters. Moreover, if tropical mosquito-borne pathogens are introduced to temperate regions in the right season, they can be transmitted, if suitable vectors are present

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. 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

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.

Conclusion

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.

Malaria Journal 2008, 7(Suppl 1)


Posted by John Ray.

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