Calculate epidemics and pandemics?

New model for calculating the worldwide spread of disease

13/12/2013

Avian Influenza, Swine Flu, SARS, EHEC - New human pathogens today often harbor the risk of a pandemic in the face of global connectivity. „The global spread of pathogens can have serious health, social and economic consequences and is a major challenge for the health of the population“, report the Robert Koch Institute (RKI) and the Humboldt University of Berlin in a joint press release. To determine possible propagation pathways of such global waves of infection, the researchers led by Dirk Brockmann, professor at the Humboldt University in Berlin and project group leader at the RKI, have developed a new method of epidemiological modeling, which is described in the current issue of the science magazine „Science“ under the title „The hidden geometry of complex, network-driven contagion phenomena“ is presented.

With the support of scientists from ETH Zurich (Swiss Federal Institute of Technology Zurich), a new mathematical theory had been developed, „that improves the understanding of global disease spread“, so the message of the RKI and the Humboldt University. This will be the „hidden geometry of global epidemics“ visible. The model allows both retrospective statements and prognoses of the propagation paths. For example, the origin of diseases can be more accurately determined in the future and at the same time predict when an epidemic is likely to reach certain places in the world. General are computer simulations that predict the spread of disease - similar to modern weather forecasts - „extremely complex and require the exact knowledge of disease-specific properties, which are not yet known, especially in novel pathogens“, report the Humboldt University and the RKI.

Effective removal crucial for disease spread
The current models for the spread of epidemics have a significant weakness, since they usually work with geographical distances, which are no longer relevant today, according to statements by Brockmann and colleagues. „From the perspective of Frankfurt, for example, other major cities such as London or New York are effectively no further away than geographically close places like Bremen or Leipzig“, so the position of the scientists. They therefore have in their model the geographical distance through the „effective distances“ replaced, which results in the example of air traffic directly from the travel flows of the air traffic network. „Traveling many people from A to B, then the effective distance from A to B is small, few people travel, the effective distance is great“, explain the researchers. The global air traffic network links more than 4,000 airports worldwide with more than 25,000 direct connections, according to scientists. Over three billion passengers are transported each year, covering more than 14 billion kilometers per day, according to Brockmann and colleagues.

Predict the spread of epidemics and determine the place of origin
Today's mobility conditions often result in extremely rapid global spread of pathogens. While the plague spread in Europe in the 14th century as a uniform wave front from south to north at a speed of four to five kilometers per day, modern epidemics reach between 100 and 400 kilometers per day, explained Brockmann. The model has shown, however, „that, contrary to all appearances, modern epidemics do not fundamentally differ from historical patterns of dispersal.“ The spread is only obscured by the changed mobility patterns. The study of the geographical dispersion patterns of SARS (2003) and swine flu (H1N1; 2009) with the help of their newly developed theory have shown that „Complex spatiotemporal propagation patterns become regular, circular wavefronts that can be easily described mathematically.“ Disease propagation rates could thus be calculated relatively easily and it could be determined, „when a wave front is likely to reach any place in the world, or where an infection event has started“, so the conclusion of the scientists. (Fp)

Picture: Aka