romaine lettuce
A water jet harvester works rows of romaine lettuce near Soledad, California, May 3, 2017. REUTERS/Michael Fiala

The latest E. Coli outbreak linked to contaminated romaine lettuce continues and has affected nearly 100 people in 22 states, health officials said Friday. Forty-six people have been hospitalized, including 10 with kidney failure.

Chopped romaine lettuce from Yuma, Arizona, has been blamed for the E. coli outbreak, with the latest illness beginning on April 20. According to the Centers for Disease Control and Prevention (CDC), laboratory testing confirmed the strain of deadly E. coli O157:H7 bacteria, causing this outbreak, produces a type of toxin that tends to cause more severe illness than previous bacteria, leading to the high hospitalization rate.

The source of the contaminated romaine lettuce remains unknown, but, health officials continue their investigation into the latest outbreak. The Food and Drug Administration identified one farm in Yuma as the source of whole-head romaine that sickened eight inmates in Alaska. Officials said that as the growing season was over, the farm was not growing any more lettuce.

Health officials are examining about two dozen farms in the Yuma region along with the business where the romaine lettuces are supplied.

“We haven’t been able to guarantee that there’s no product coming out of Yuma at this point,” added Stic Harris of the U.S. Food and Drug Administration during a briefing for reporters. "We are investigating dozens of other fields as potential sources of the [tainted] chopped Romaine lettuce."

On April 20, the CDC warned people to throw away any chopped lettuce that they may have in their homes.

The previous E. coli outbreak on such a large scale was with spinach grown in California in 2016. Last year, an outbreak of 17 E. coli infections were reported in 13 states across the United States linked to romaine lettuce, all of which occurred from Nov. 15, 2017, through to Dec. 8, 2017.

E. coli, or Escherichia coli, is a bacteria that normally occurs in the environment as well as in the guts of animals and humans, the CDC says. Some of its types are pathogenic that can cause illness through exposure to contaminated food or water, or contact with animals or other people.

Symptoms usually vary from person to person. In most cases, symptoms appear three to four days after the bacteria is ingested. The symptoms include loss of appetite, fatigue, severe abdominal cramping, diarrhea and fever. More adverse cases would lead to bloody diarrhea, dehydration and even kidney failure.