A new study conducted by researchers from Korea and Tennessee has found a strain of the swine flu that, in only two mutations and ten days, kills ferrets.
The strain is currently infecting pigs in South Korea, who do not appear to have any symptoms. The flu virus, called Sw-1204, caused death ten days after ferrets were infected. It is highly contagious and transmitted through respiratory droplets, like those that come from coughing and sneezing.
Ferrets are studied because they have similar responses to flu infection as humans have and are susceptible to the same viruses as humans are.
Pigs are considered "genetic mixing vessels" because they are great at breeding new, potentially potent diseases. Swine flu can be transmitted among humans, birds and pigs.
Researchers say that the study's results indicate the potential of the TRSw viruses that researchers isolated from a Korean slaughterhouse. TRSw viruses are H1N2 and H3N2, both of which are related to the swine flus that are found in North America. These "triple" viruses have genetic components from swine, bird and human viruses.
The researchers identified the mutations by using a process called reverse genetics, which allows scientists to manipulate the virus' genome. The study found two mutations that were responsible for creating the pandemic.
Should humans be worried? Not necessarily. Though ferrets are susceptible to the same illnesses as we are, humans have antibodies in their systems that experimental ferrets do not have. In addition, only three ferrets were studied, and the mutated virus is not likely to leave the Korean laboratory.
Still, the study shows that swine flu certainly has the potential to reach pandemic proportions, similar to the 2009 H1N1 virus. That virus has confirmed to have killed 18,500 people, but the death toll is estimated to be as high as 285,000. The 2009 virus began to circulate among pigs as early as the 1990s.
These new strains of swine flu, a cross between the H3N2 and the H1N1, have reportedly infected nearly 300 people so far. One woman died from the illness, but most people have mild symptoms of the disease, like fever, sore throat, chills, and fatigue. Last week, the CDC reported that three people were infected with H1N2 at the Minnesota State Fair.
There has been a rash of infections of swine flu from state fairs this year, mainly affecting farmers, their families and fairgoers. Swine flus can be particularly troublesome for children. Recent research on the deadly flu virus of 1918, which killed 50 million people, found that the structure of the 2009 virus resembled very closely that of the 1918 flu. Researchers said that H1N1 was particularly deadly for young people, who were not alive in 1918 and would not have built up a resistance to it. Elderly people, who are usually considered at high risk during pandemics, were relatively safe.
The Korean study was published in the Proceedings of the National Academy of Sciences.