In the Nature issue of 6 July, Ducatez et al revealed the detection of three very different strains of Avian Influenza (HPAI) in poultry farms in two different parts in Nigeria. These strains of Avian Influenza were sequenced at the Erasmus Medical Centre in Rotterdam, the Netherlands.
One of them appeared to be very similar to H5N1 found in a buzzard in Denmark and swans in Germany, where it is only known in wild birds. The two others are closest to strains detected in poultry in Egypt and Central Asia.
From this, McKenzie concluded in the New Scientist, that transmission took place by wild birds. This conclusion is too quick and simplistic.
Ducatez et al in Nature just say that spread within Nigeria does not in itself explain the variety of strains found in that country and that there must have been multiple introductions. About how this happens they are uncertain: ‘perhaps at inland waters and key bird areas or through unprotected trade’. They also state that the virus has further spread in Nigeria and that surveillance is necessary in combination with control measures.
Wetlands International and CIRAD are intending to perform surveillance in Nigeria this year in wild birds in the context of a FAO program. Earlier work in this context did not find any HPAI H5N1 in wild birds in Africa.
Even against the background of this new information, firm conclusions on the source of these infections, with too much emphasis on wild birds would be premature. More field research is urgently needed to see whether wild birds are also are carrying the highly pathogenic strain in Africa. There is a pressing need to build a scientifically sound knowledge-base on wild bird movements and wetlands in Africa and in the flyways that link Europe and Asia. This information needs to be more readily provided to governments to develop proper and timely risk assessments and contingency plans to respond to future outbreaks of this growing problem of highly pathogenic avian influenza.
Wetlands International continues work with CIRAD, FAO, and Wildlife Conservation Society to step up surveillance of wild birds during the forthcoming southward migration (September-November) in Africa, Europe and West Asia with plans to establish similar surveillance programmes further east in Central, South and Southeast Asia.
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