Research findings from University of Liverpool update understanding of bird flu epidemiology.

A new study, 'Preventable H5N1 avian influenza epidemics in the British poultry industry network exhibit characteristic scales,' is now available. "Epidemics are frequently simulated on redundantly wired contact networks, which have many more links between sites than are minimally required to connect all. Consequently, the modelled pathogen can travel numerous alternative routes, complicating effective containment strategies," researchers in Liverpool, the United Kingdom report (see also Bird Flu Epidemiology).

"These networks have moreover been found to exhibit 'scale-free' properties and percolation, suggesting resilience to damage. However, realistic H5N1 avian influenza transmission probabilities and containment strategies, here modelled on the British poultry industry network, show that infection dynamics can additionally express characteristic scales. These system-preferred scales constitute small areas within an observed power law distribution that exhibit a lesser slope than the power law itself, indicating a slightly increased relative likelihood. These characteristic scales are here produced by a network-pervading intranet of so-called hotspot sites that propagate large epidemics below the percolation threshold. This intranet is, however, extremely vulnerable; targeted inoculation of a mere 3-6% (depending on incorporated biosecurity measures) of the British poultry industry network prevents large and moderate H5N1 outbreaks completely, offering an order of magnitude improvement over previously advocated strategies affecting the most highly connected 'hub' sites. In other words, hotspots and hubs are separate functional entities that do not necessarily coincide, and hotspots can make more effective inoculation targets," wrote A.R. Jonkers and colleagues, University of Liverpool.

The researchers concluded: "Given the ubiquity and relevance of networks (epidemics, Internet, power grids, protein interaction), recognition of this spreading regime elsewhere would suggest a similar disproportionate sensitivity to such surgical interventions."

Jonkers and colleagues published their study in the Journal of the Royal Society, Interface (Preventable H5N1 avian influenza epidemics in the British poultry industry network exhibit characteristic scales. Journal of the Royal Society, Interface, 2010;7(45):695-701).

For additional information, contact A.R. Jonkers, University of Liverpool, Dept. of Earth and Ocean Sciences, Jane Herdman Laboratories, Liverpool, UK.

Keywords: City:Liverpool, Country:United Kingdom, Bird Flu Epidemiology, Avian Flu, Avian Influenza, Bird Flu, Epidemics, Epidemiology.

This article was prepared by Virus Weekly editors from staff and other reports. Copyright 2010, Virus Weekly via NewsRx.com.