Cyclospora sickens more than 500, CDC calls for better technology

More cases of cyclospora infections continue to be reported by the Centers for Disease Control and Prevention .

As of the evening of Aug. 7, 504 cases of cyclosporiasis have been reported in Arkansas, Connecticut, Florida, Georgia, Iowa, Illinois, Kansas, Louisiana, Minnesota, Missouri, Nebraska, New Jersey, New York (including New York City), Ohio, Texas and Wisconsin. Investigators are still struggling to pinpoint sources of the outbreaks in most of the 16 affected states.

At least 30 people have been hospitalized and no one has died.

Cyclosporiasis is caused by a cyclospora parasite found in contaminated food or drinking water.

Symptoms include nausea, diarrhea -- which health officials have said can last up to 57 days -- abdominal pain, cramping, flu-like aches and pains and low-grade fever.

Texas, with 190 cases, leaped ahead of Iowa (153) and Nebraska (85) this week to have the most reported infections.

In Iowa and Nebraska, the outbreak was traced to salads served at Darden Restaurant-owned Olive Garden and Red Lobster establishments in those states. The restaurants received the salads from Taylor Farms de Mexico, a North American supplier of produce to the food service industry.

But, government health officials still have not definitively linked the cases in other states to these restaurant chains or salads.

"We don't know that all the parasites are the same," CDC director Dr. Thomas Frieden, told CBS News chief medical correspondent Dr. Jon LaPook Wednesday.

He pointed out the last time there was a big cyclospora outbreak in the U.S. -- in 1997, when more than 1,000 illnesses were reported -- was traced to at least four different sources, including fresh fruits, vegetables and spices.

"Unless we can really track it down and understand it better, we can't figure out where it's coming from, and we may not be able to prevent as well as we could otherwise," said the CDC chief.

Frieden said more technological advances are needed to sequence a genome in real time, and mesh that information with patient interviews and other resources to quickly find the source of an outbreak and stop it.

"Not being able to analyze the genomic sequence of a microbe in real time is like trying to solve a crime without using fingerprints," he said.

But the CDC does not have this technology despite it existing, according to LaPook. He pointed out during the 2010 cholera outbreak, the CDC had to send samples to Canada to get analyzed and interpreted.

"Unfortunately we've been falling behind," said Frieden. "Microbes are evolving constantly, the technology to sequence genomes has been evolving rapidly -- and while we've made some progress, we haven't kept pace."

LaPook reports the CDC requested $40 million from Congress for a upgraded hardware and software. This could not only help determine future foodborne disease outbreaks, but find the sources of other outbreaks, such as hospital-acquired infections from beds or cooling systems, more rapidly.

"If we're not able to use next generation or whole genome sequencing, we may miss things that are happening," said Frieden.