There has been an outbreak of a new form of Swine Flu in Mexico with several cases also reported in California and Texas.

According to the World Health Organization, the strain of the virus has the potential to become a pandemic. And the WHO is thinking of declaring the outbreak an issue of "international concern" since the unusually potent virus has killed 68 people so far and infected more than 1,000.

That level of mortality is extremely troubling. The normal rate of death in average flu outbreaks is 2-3% - 20 or 30 deaths per 1,000. A particularly virulent strain could kill millions and infect tens of millions more.

According to Jason Gale of Bloomberg News, the Mexican government has closed theaters and taken other measures to try and stop the spread of the virus and reports on the origins of the bug:

The new influenza strain, a conglomeration of genes from swine, bird and human viruses, poses the biggest threat of a large-scale flu pandemic since the emergence of the H5N1 strain that has killed millions of birds and hundreds of people, said William Schaffner, an influenza expert at Vanderbilt University School of Medicine in Nashville, Tennessee.

"It re-combined to create something totally new," David Butler-Jones, Canada's chief public health minister, told reporters yesterday. "How, when, or where it did that I don't think we know. What it will lead to is impossible to predict."

WHO's alert level is at level 3, meaning there is no, or very limited, human-to-human transmission of a potential pandemic virus. Officials at the agency have said the global spread of the H5N1 bird flu virus since 2003 has put the world closer to another influenza pandemic than at any time since 1968, when the last of the previous century's three pandemics occurred.