Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study pins factors behind geography of human disease

16.04.2010
If your home region has a hot, wet climate and a lot of different kinds of birds and mammals living in it, there's a really good chance the region will also contain numerous kinds of pathogens that cause human diseases.

A new study examining the geography of human disease, led by Dr. Rob Dunn at North Carolina State University alongside an international team of biologists and social scientists, shows that that one can predict the number of kinds of disease-causing pathogens in a region just by knowing its climate or the number of birds and mammals found there.

Multiple things, Dunn says, might influence the diversity of pathogens in a region: human population size and density, the amount of time people have lived there or expenditures on disease control. Each of these undoubtedly has some influence, but the environment is dominant.

"We imagine that we have nature under control, but nobody seems to have told nature," Dunn says. "The environment and, in its broadest sense, nature determines the number of kinds of diseases in different regions of the world in much the way that it has influenced the number of kinds of birds, mammals, ants or bees."

But while the environment determines how many diseases one finds in a region, it does not determine how common they are. The researchers also examined the factors correlated to the prevalence, or commonness, of human pathogens across the globe and discovered that the most important factor is health-care spending, specifically expenditures on disease control.

"On the one hand, we are not very effective at altering the numbers of kinds of pathogens present, as those numbers are strongly correlated with environmental conditions. The vagaries of climate and life over which we have little control determine which diseases you are at risk of contracting in any given place," Dunn says. "But on the other hand, we can control the prevalence of pathogens by spending money on disease-control efforts. It is that prevalence that influences human health and well-being."

A paper describing the research appears online in Proceedings of the Royal Society of London: B, a leading peer-reviewed biology journal.

The study examined a host of factors thought to be involved in the global distribution of disease-carrying organisms. Climate and geographic variables, population data, disease-control data, pathogen data and human history data were all factored into statistical models that attempted to show which factors had stronger correlations to disease.

Geographic regions with lots of different kinds of birds and mammals are correlated with the presence of lots of pathogens. The most likely explanation for this relationship is simply that the same environmental factors have influenced patterns in diversity of human pathogens that have patterns in the diversity of the rest of life, including the birds and mammals. Reducing bird and mammal diversity will not remove the diseases, Dunn asserts. In fact, making wild birds and mammals more rare seems likely to increase the diversity of human diseases, with diseases on rare mammals and birds all too eager to jump from their sinking ships.

But all is not lost if you live in hotter and wetter climes with lots of birds and mammals around. Dunn points to life in the United States as one example. Malaria is present but is rare and relatively insignificant because of the country's historic effort at controlling disease. In short, the United States has a large number of different kinds of pathogens, Dunn says, but pathogen prevalence is low because of a strong history of disease-control and health-care spending.

The researchers also suggest ways to optimize future spending. In particular, places where current spending is low and populations are large are likely to be places where the most people will be saved by additional efforts – notably India, Pakistan and East African nations along the equator. "Current health-care spending is quite low, prevalence of pathogens is quite high, and human populations are large in these areas, so it makes sense to target efforts there," Dunn says.

NC State's Department of Biology is part of the university's College of Agriculture and Life Sciences.

Note: An abstract of the paper follows.

"Global Drivers of Human Pathogen Richness and Prevalence"
Authors: Robert R. Dunn and Nyeema C. Harris, North Carolina State University; T. Jonathan Davies, University of California, Santa Barbara and McGill University; Michael C. Garvin, Victoria University of WellingtonPublished: April 15, 2010, online in Proceedings of the Royal Society: B

Abstract: The differences in the richness and prevalence of human pathogens among different geographic locations have ramifying consequences for societies and individuals. The relative contributions of different factors to these patterns, however, have not been fully resolved. We conduct a global analysis of the relative influence of climate, alternative host diversity, and spending on disease prevention on modern patterns in the richness and prevalence of human pathogens. Pathogen richness (number of kinds) is largely explained by the number of birds and mammals in a region. The most diverse countries with respect to birds and mammals are also the most diverse with respect to pathogens. Importantly for human health, prevalence of key human pathogens (number of cases) is strongly influenced by disease control efforts. As a consequence, even where disease richness is high, we might still control prevalence, particularly if we spend money in those regions where current spending are low, prevalence is high, and populations are large.

Mick Kulikowski | EurekAlert!
Further information:
http://www.ncsu.edu

More articles from Studies and Analyses:

nachricht Physics of bubbles could explain language patterns
25.07.2017 | University of Portsmouth

nachricht Obstructing the ‘inner eye’
07.07.2017 | Friedrich-Schiller-Universität Jena

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

 
Latest News

CCNY physicists master unexplored electron property

26.07.2017 | Physics and Astronomy

Molecular microscopy illuminates molecular motor motion

26.07.2017 | Life Sciences

Large-Mouthed Fish Was Top Predator After Mass Extinction

26.07.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>