Insect or rodent borne human diseases have recently been reappearing in Europe. These diseases have serious health, ecological and political consequences. (Dec.'07)
These last years, insect or rodent borne human diseases have been reappearing in Europe. These diseases have serious health, ecological and political consequences. The reasons behind these outbreaks are only partially known. The transformation of our land and practices, the evolution of control policies, and local or global eco-climatic changes are all factors that could be affecting the distribution and dynamics of the pathogenic agents responsible for these diseases and how they’re transmitted.
EDEN (Emerging Diseases in a Changing European Environment), a European Commission funded project, aims to understand and catalogue the impact of environmental changes on the risk of introduction, implantation and distribution of these diseases which are emerging on European soil. EDEN’s goal is to identify the ecosystems most likely to harbor the vectors of these diseases. Eventually, EDEN will be able to offer public health decision-makers tools and methods to monitor disease on a local and regional level.
EDEN integrates researchers in 48 institutes from 24 countries, and covers all European ecosystems from the polar circle in the North to the Mediterranean basin in the South, and from Portugal in the West to the Danube delta in the East.
The project focuses on current human diseases that are particularly sensitive to environmental changes, some which are already present in Europe (like tick-borne or rodent-borne diseases, Leishmaniasis, West Nile Fever) and some which could appear or re-emerge (like malaria or Rift Valley Fever).
Remote sensing tools, mathematical epidemiology and ecological and biodiversity science are being used to describe, model and monitor the way these diseases operate. “There are several different fields of research within the EDEN project,” says Guy Hendrickx, secretary of EDEN’s Steering Committee. “That’s its strength, in fact – being multidisciplinary. Not only are we targeting different diseases, but we’re coming at them from different angles. On the one hand by modelling, on the other by remote sensing and biodiversity, and finally by computerized systems that will enable us to gather and analyze all the results to form a support for decision-making.”
In Camargue, the scientists of the EDEN project are particularly looking at West Nile Fever, a bird disease that researchers know well. The virus works in a cycle: it’s transmitted from birds to mosquitoes, then from mosquitoes to birds and other animals. In Camargue, ornithologists with the EDEN project catch several thousand birds per year in the park of Pont du Gau. Their goal: determine what percentage of them have been infected with West Nile Virus and thereby define how urgent the disease is.
Over the course of 2004 in Camargue, mosquitoes that had contracted the virus from infected birds in turn passed it on to thirtysome horses in the region. Even if no human cases of the disease have yet been reported in this area of Europe, researchers with the EDEN project are trying to draw up a profile of the virus as a preventative measure. To do so, they must observe and understand the impact of environmental changes on its ecology. Its main vector, the Culex mosquito, is being caught by scientists in Camargue and studied by virologists with the EDEN project. “West Nile is a very interesting virus, it’s a virus of nature” explains Paul Reiter, head of the “Insects and Infectuous Diseases” department at the Institut Pasteur. “We need to understand the ecology of the virus and all of the factors that go to (provide) the transmission in the field. Once we understand that, then we maybe could understand how that may happen in the future if the world continues to get warm.”