Thursday, August 4, 2011

Much fuss about nothing

In recent years, there has been much hue and cry about the spread of avian influenza by wild birds, fuelled in part by the related deaths of nearly 300 people. These deaths caused people to speculate that there could be a new pandemic in the human population, with the virus being spread rapidly by migratory birds which circumnavigate the globe annually. As always, rumours are fuelled by lack of factual information, and in Southern Africa in particular, there has been little information available on the Avian Influenza Virus and its prevalence in the region.

These fears have been shown to be unfounded by work done by Dr Graeme Cumming and colleagues working in Botswana, Mocambique, South Africa and Zimbabwe. They counted, captured and sampled birds at five sites in the four countries, one of which was Lake Ngami, and did not positively identify any highly pathogenic H5N1. They also found that the annual influx of Palaearctic migrants had no detectable influence on this situation i.e. the migrants did not bring the virus into Southern Africa as had been speculated.

Other avian influenza viruses were found at a low frequency in some waterbirds, especially dendrocygnid (whistling) ducks. The White-faced Duck (shown above) and the Fulvous Duck, both have an extensive range across Africa, and individuals from populations north of the equator may mix with Palaearctic duck species, such as the Garganey, that migrate annually to western Europe. However, these two species had no trace of the lethal H5N1 strain.

For more information, read the original paper (see reference below).

Reference: Cumming GS, Caron A, Abolnik C, Cattoli G, Bruinzeel LW, Burger CE, Cecchettin K, Chiweshe N, Mochotlhoane B, Mutumi GL and Ndlovu M. 2011. The Ecology of Influenza A Viruses in Wild Birds in Southern Africa. EcoHealth Journal.





1 comment:

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