China’s dead pig mystery got a lot worse:  Officials now say 2,00 to 3,300 dead pigs have been pulled out of a river that provides Shanghai with its drinking water.  And residents are getting a little nervous.

The first dead pigs started showing up last week, along the banks of the Huangpu River.  And because there’s a cell phone camera practically everywhere in the world, photos popped up on the Internet, alarming Shanghai’s urban sophisticates.

They still don’t know the source of the dead pigs but suspicion is falling on the possibility of an unscrupulous farmer in an upstream province.

So far, health officials have found no trace of foot and mouth disease, blue-ear pig disease or swine fever.  But they did detect wisps of porcine circovirus, which a disease that affects pigs but is not believed to infect humans.

The mystery is shining new light on the problems in China’s rivers.  In the Huangpu, the dead pigs share the river with tons of industrial and household garbage. 

Chinese environmental officials are slowing owning up to the problem, admitting that 20 percent of rivers are "too toxic for human contact", while 40 percent are severely polluted.