Ecologists of the Station Biologique de la Tour du Valat and of the GEMI-CNRS in the Camargue (France), Michel Gauthier-Clerc, Camille Lebarbenchon and Frédéric Thomas conclude that human commercial activities, particularly those associated with poultry, are the major factors that have determined its global dispersal.
Highly pathogenic avian influenza virus subtype H5N1 was first detected in poultry in November 1996 in south-east China. The virus subsequently dispersed throughout most of Asia, and also to Africa and Europe. From mid-2005, migratory wild birds have been widely considered to be the primary source of the dispersal of H5N1 outside Asia. This claim was based on the discovery in May 2005 that hundreds of wild birds had died on Lake Quinghaihu, on the high Asian plateau in China. It is however clear that the trajectory of the virus does not correspond with to the main migration routes of wild birds. The global network of migration routes seemed to hide the globalisation - without strict health control - of the exchanges of poultry, the more likely mechanism for disease spread.
During the previous epizooties of highly pathogenic subtypes of H5 and H7, it was shown that the expansion of these viruses was due to human activities, in particular, movements of poultry or their products. This commercial scenario is the one that explained the expansion and the maintenance of the H5N1 virus in south-east Asia until 2004, via the legal and illegal trade in poultry.
The cases in western Europe in February 2006 after a cold spell on the Black Sea showed that virus can spread through infected wild birds travelling short distances, but no evidence for long distance transmission during seasonal migration has yet been found. The evidence overwhelmingly supports the hypothesis that human movements of domestic poultry have been the main agent of global dispersal of the virus to date. The occurrence of an outbreak at a commercial turkey farm in Suffolk, England, in February 2007 fits this wider pattern.
Wild birds, particularly waterfowl, are a key element of the viral ecology of low pathogenic avian influenza. Very high densities of domestic animals and increased stress factors are particularly favourable for the maintenance and transmission of virulent agents, in particular subtypes of highly pathogenic influenza. Paradoxically, the H5N1 virus coupled with a fear of transmission by wild birds could lead to a reversion to battery farming which increases risk of outbreaks. This would stall the current trend to better animal welfare resulting from free-range agriculture. Maintaining these trends, whilst controlling disease through strong veterinary scrutiny and control of trade, is more likely to be a successful strategy.
Davina Quarterman | alfa
How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)
The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.
The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
29.05.2017 | Life Sciences
29.05.2017 | Physics and Astronomy
29.05.2017 | Statistics