The reasons for this dramatic resurgence in WNV infections are not clear; however, several factors could be involved ranging from increased enzootic bird-mosquito-bird circulation, resulting in more human spillover infections, to increased human virulence.
In 1996, WNV infection was reported in a human in Morocco (3 ), and in 2008, a serosurvey of wild birds confirmed the circulation of WNV in native birds (4 ).
High WNV prevalence among juvenile birds suggests local virus circulation among resident birds.
Seroconversion of birds suggests local circulation of the virus.
In addition, high titers (640) in 2 adult birds suggest recent circulation of WNV in the area.
The spread of HPAI (H5N1) west across the globe has caused serious debates on the roles of migratory birds in virus circulation (2, 5, 7 ).
One serologic study in the U.K. identified WNV-seropositive wild birds, although subsequent studies have not found evidence of WNV circulation in birds [ 266– 266].
That raises concerns that birds which have survived the disease may act as a reservoir and that if migratory wildfowl caught it, they could carry it out of South-East Asia.The British government, meanwhile, announced it would stockpile 2m doses of a vaccine against the strain of bird flu currently in circulation.
Many scientists now believe that another influenza pandemic is inevitable some time soon.These concerns might be little more than another background worry if it were not for the fact that there is currently a strain of bird flu in widespread circulation to which humans have no natural immunity.
Following 10 minutes of its circulation, the bird was killed by injection of 5 ml of thiopentone sodium into the right brachial vein.
In recognition of the potential benefits of surveillance, the OIE Food and Agriculture Organization global network of expertise on animal influenza (OFFLU) established a working group on wildlife influenzas in October 2014; this group has highlighted the need for wild bird surveillance to understand circulation dynamics of avian influenza virus and recommends full-genome sequencing (15 ).
