The Cochise County Health Department has the CDC to help investigate the source of the salmonella outbreak in the Sierra Vista area of Arizona.  There have been forty-six cases reported since early Septemeber.  Full story from the Arizona Daily Star

"We have no working theories or leads on where this is coming from," said Karla Jensen, spokeswoman for the Cochise County Health Department.

"We’ve used all our resources and tested everything, but we’ve come to a block on this," she said. "So we needed to bring in the top experts to try to find some answers."

A team of four epidemiologists from the federal Centers for Disease Control and Prevention arrived in Sierra Vista on Friday and began working in the area Tuesday, after the recent storm cleared.

"It is definitely unusual that no source has been found at this point," said Dr. Rebecca Sunenshine, deputy state epidemiologist for infectious diseases, who previously worked for the CDC and was with the CDC team in Sierra Vista over the weekend.

"That indicates this is a complicated outbreak," she said. "Cochise County has never seen this many salmonella cases before, and it is quite concerning that it keeps going. It just means we need to find the source of it, so we can put a stop to it."