| agro-ecological features of the introduction and spread of the highly pathogenic avian influenza (hpai) h5n1 in northern nigeria. | nigeria was the first african country to report highly pathogenic avian influenza (hpai) h5n1 virus outbreaks in february 2006 and has since been the most severely hit country in sub-saharan africa. a retrospective survey carried out towards the end of 2007, coupled with follow-up spatial analysis, support the notion that the h5n1 virus may have spread from rural areas of northern nigeria near wetlands frequented by palaearctic migratory birds. possibly, this could have happened already during n ... | 2008 | 19021104 |