Poor hygiene and transport of poultry are linked to the spread of avian influenza © Marco Lambertini, BirdLife International
Globalisation has turned the chicken into the world’s number one migratory bird species, says Nirmal Jivan Shah, Chief Executive of Nature Seychelles, echoing the position of the global conservation partnership, BirdLife International (Nature Seychelles is BirdLife in Seychelles). Movements of chickens around the world take place 365 days of the year, unlike the seasonal migrations of wild birds, says BirdLife.
With poor controls already blamed for H5N1 outbreaks in China, South-east Asia and Turkey, the Nigerian outbreak again demonstrates that lapses in bio-security are the major reason for avian influenza’s continuing spread around the world.
Another worrying development in the spread of avian influenza is the first cases of H5N1 in wild birds in the European Union. Over the past week individual wild birds, mostly mute swans, have died of avian influenza in Greece, Italy, Slovenia, Austria, Hungary, France, Germany, Bulgaria, Azerbaijan and Romania. These reports involve death of individual birds and not large-scale die-off. There is to date no evidence that the wild birds have passed it to other birds.
The mute swans are all believed to have come from a localised area in the Black sea region. Their movement into central and western Europe is thought to be in response to freezing weather conditions around the Black Sea. Wild birds normally die within a few days of infection and the appearance of swans in several countries indicates they were likely infected just prior to migrating.
It is possible; though unlikely the swans caught the disease from other wild birds. A more probable route is through contact with infected poultry or their waste products. Mute Swans often feed by grazing on agricultural fields and the practice of spreading poultry manure onto fields as fertilizer is widespread in Eastern Europe. The UN’s Food and Agriculture Organisation (FAO) has warned that viruses can stay alive in the manure for many weeks and can infect birds the swan deaths again highlight the need for major improvements in agricultural practices.
The dead swans will fuel the debate over how H5N1 is spreading. However, it is notable that if wild birds had been spreading the disease across continents there would have been trails of dead birds following migration routes, which is not the case. BirdLife experts believe that globally the major route of spread remains unrestricted movement of poultry and poultry products. Seychelles is fortunate; as an isolated oceanic nation, bio-security measures are not difficult to implement.
Nature Seychelles and the other national organisations in more than 100 countries that make up the BirdLife partnership believe the time has probably come for an independent scientific inquiry into the spread of H5N1. This could help the world learn lessons from the recent outbreaks and help to stop further ones.
Nature Seychelles, 22 February 2006.