The recent appearance of the H5N1 bird flu in pigs does raise viral reassortment concerns. Here's what we know about this highly pathogenic avian influenza virus so far.

A World Health Organization official on Thursday called for stronger surveillance in animals for evidence of infection with H5N1 bird flu in order to curb its spread. The official also urged stronger efforts to reduce the risk of transmission of the virus to new species of animals and to humans.

WHO along with the partnership of World Organization for Animal Health and Food and Agriculture Organization has decided to step up the surveillance of H5N1 virus after a human case was reported in the US earlier this month.

Australia's surveillance of bird flu has been described as a possible "model" to follow globally, with the spread of the H5N1 strain of the virus causing concerns for international health authorities.

The developing avian influenza panzootic and the growing possibility of a pandemic bring to the fore the existential questions for humanity of climate change and the destruction of public health, both of which must be stopped in order to control the growing threats.

Britain has secured five million doses of H5 bird flu vaccine to prepare for a possible global pandemic, the UK Health Security Agency (UKHSA) announced today.

A recent study shows a mild increase in the H4N1 strain of bird flu transmissibility through air compared to older variants.