Reference
Childs, D.Z., Cattadori, I.M., Suwonkerd, W., Prajakwong, S. and Boots, M. 2006. Spatiotemporal patterns of malaria incidence in northern Thailand. Transactions of the Royal Society of Tropical Medicine and Hygiene 100: 623-631.
Background
In a recent review article published in the International Journal of Medical Microbiology entitled "Global climate change and the emergence/re-emergence of infectious diseases," Zell (2004) writes that many people "assume a correlation between increasing disease incidence and global warming." However, he goes on to demonstrate that this simplistic association is a far cry from what actually occurs in the real world; and the subsequent study of Childs et al. (2006) provides a good example of this fact.
What was done
The authors of the newer paper present a detailed analysis of long-term time series of malaria incidence in northern Thailand, based on monthly time series (January 1997 through January 2002) of total malaria cases in the country's 13 northern provinces.
What was learned
Over this quarter-century time period, when climate alarmists claim the world warmed at a rate and to a level that were unprecedented over the prior several thousand years, the UK, US and Thai researchers report there was an approximately constant rate of decline in total malaria incidence (from a mean monthly incidence in 1977 of 41.5 cases per 100,000 people to 6.72 cases per 100,000 people in 2001), due primarily to a reduction in cases positive for Plasmodium falciparum (mean monthly incidence in 1977 and 2001 of 28.6 and 3.22 cases per 100,000 people, respectively) and secondarily to a reduction in cases positive for P. vivax (mean monthly incidence in 1977 and 2001 of 12.8 and 3.5 cases per 100,000 people, respectively).
What it means
Noting that "there has been a steady reduction through time of total malaria incidence in northern Thailand, with an average decline of 6.45% per year," Childs et al. say this result "reflects changing agronomic practices and patterns of immigration, as well as the success of interventions such as vector control programmes, improved availability of treatment and changing drug policies," which means that we can't attribute the welcome trend to global warming. Aw, shucks.
Reference
Zell, R. 2004. Global climate change and the emergence/re-emergence of infectious diseases. International Journal of Medical Microbiology 293, Suppl. 37: 16-26.