"The classical idea has been that people working or living close to the forest were at risk for the disease, but that view failed to consider such factors as quality of life and general level of health," said co-author Luis Fernando Chaves of the University of Michigan. "Contrary to what was previously believed, the more forest you have, even in a marginal population, the more protected you are against the disease."
The researchers examined county-level ACL case data from 1996 through 2000 for Costa Rica, a country in which approximately 20,000 acres of land are deforested annually to make way for cattle ranching and banana, mango and citrus fruit plantations. In addition to examining such factors as forest cover, rainfall, elevation, and percent of the population living less than five kilometers from the forest edge, the researchers also incorporated an index of social marginalization into their analysis. This index, which takes into account income, literacy, level of education, average distance to health centers, health insurance coverage and other indicators of life at the margins of mainstream society, provides a single measure of quality of life.
The researchers found a strong geographic overlap between disease incidence and social marginalization that was not found between disease incidence and the other ecological variables.
"When we looked just at factors such as climate and the physical environment, we found no specific patterns with respect to the disease," Chaves said. "But when we looked at the social data, we found clear patterns according to marginality."
Putting everything together, the researchers discovered that in fact there is a relationship between ACL and deforestation, but it's not the simple, "less forest, less disease" relationship that previously was believed to exist. Instead, there's a complex connection with El Niño Southern Oscillation (ENSO), a periodic ocean-atmosphere fluctuation in the Pacific Ocean that is an important cause of inter-annual climate variability around the world and also influences disease cycles. In highly deforested counties, socially marginalized human populations are more vulnerable to ENSO's effects, and disease incidence actually is higher, the analysis suggests.
Dr. Chaves concluded that the “study calls for control efforts targeted to socially excluded populations and for more localized ecological studies of transmission in vectors and reservoirs in order to understand the role of biodiversity changes in driving the emergence of this disease.”
The researchers are now planning on conducting similar analyses for other diseases, such as malaria, paying close attention to how climatic fluctuations, ecological factors, and patterns of biodiversity relate to human disease patterns.
CITATION: Chaves LF, Cohen JM, Pascual M, Wilson ML (2008) Social Exclusion Modifies Climate and Deforestation Impacts on a Vector-Borne Disease. PLoS Negl Trop Dis 2(2): e176. doi:10.1371/journal.pntd.0000176
CONTACT:Luis Fernando Chaves
Andrew Hyde | alfa
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy