Tang Jiaqi, author of the study and a researcher at the Research Institute for Medicine of Nanjing Command, said this development could possibly lead to a pandemic.

The microbe Streptococcus suis is present in pigs and usually only affects piglets. Occasionally, it infects farm workers who come into close contact.

For the past 35 years, only 200 human cases had been reported in China, and fewer than ten percent of the cases were fatal.

Last year alone, more than 200 people were infected in an outbreak in China's Sichuan province, one-fifth of the victims died.

No evidence has been found of direct transmission between humans. In past cases, those infected have had meningitis or blood poisoning. In Sichuan, most victims displayed symptoms of streptococcal toxic shock syndrome (STSS), which is usually caused by a different strain of Streptococcus bacteria.

According to Tang, most Streptococcus infections can be treated with antibiotics, but STSS is hard to treat.

Through genetic sequencing, Chinese researchers have ascertained that the Chinese strains have some genes not found in other strains, indicating that the virus could have possibly mutated into a more lethal form.

Sichuan province in China is also believed to be the origin for SARS, an infectious human respiratory disease. Some animal health experts have also pointed to southern China as the source of bird flu.