Beijing ? Experts on a strep germ that’s sickening people and pigs in China are baffled by reports of 37 farmers suddenly falling ill, bleeding under the skin and dying – all previously unheard of with the disease.

While not uncommon in pigs, Streptococcus suis is seldom seen in people and never dozens of cases all at once – raising bigger questions about whether the germ has mixed with some other bacteria or virus.

“Something is different,” Marcelo Gottschalk, one of the world’s leading experts on the disease, told The Associated Press on Wednesday. “We are worried and we wonder what’s happening. We would like to have the strain to identify.”

So few people have studied this disease, Gottschalk is unsure how the Chinese have been able to identify it.