CNN 2011-06-14（在线收听）

Every week this summer, we'll be doing these special web shows. Today, we're talking about a story we covered toward the end of the school year: an outbreak of E. coli. That's a specific kind of bacteria. You can get it from contaminated food or water, and it can cause some pretty serious health problems.

Officials say this outbreak is limited to an area around one city in Germany. So far, more than 20 people have died from the bacteria. Thousands of people have gotten sick from it. One of the big things officials are trying to figure out is where this E. coli came from. Dr. Sanjay Gupta is going to explain how scientists do that and what people can do to avoid getting sick.

It can be difficult sometimes to figure out exactly from where this came. You know, this is sort of a real medical investigation. They literally have to trace back from the farm to the fork all the different steps of these different foods.

So, for example, bean sprouts being looked at right now. So far, 23 of 40 samples have come back negative. All that tells you is that, so far, they haven't found it. It doesn't mean that it wasn't there. And I can also tell you that sometimes you never get a clear answer as to exactly from where this bacteria originated.

About 2,200 people infected; 60% of them women. 600 of them also got a very serious complication of this infection called HUS: hemolytic-uremic syndrome. Your blood doesn't clot as well. Your kidneys can start to fail. 70% of the people that developed that were also women. Unclear why that is. It could be that women are eating more of whatever the contaminated food was.

For most people who get this infection, it's going to be a couple of bad days. Stomach cramping, stomach pains. They're not going to need antibiotics. But obviously, in a few people, as you're hearing about, the complications can be more severe.

For the consumer, obviously, washing your hands, washing your food, not cross-contaminating your food: these are the things a consumer can do. But distributors, the manufacturers, the people who are getting this food to your table, they obviously have to take some responsibility here as well, in terms of making sure this food is free of contamination.