By Debra Goldschmidt

CNN

(CNN) -- Four more people have become ill with E. coli linked to contaminated soy nut butter, the Centers for Disease Control and Prevention said Tuesday, bringing the total number of reported cases to 16.

Eight of the ill individuals have been hospitalized. Five of those hospitalized have suffered hemolytic uremic syndrome, a type of kidney failure that can be life-threatening, although most people recover within a few weeks.

"Ill people range in age from 2 to 48 years, with a median age of 10. Fourteen (88%) of the 16 ill people are younger than 18 years old," the CDC said in a report on the outbreak investigation.

The most recently reported symptoms began on February 21 and took an average of two or three weeks to be reported. Symptoms of E. coli illness usually begin two to eight days after consuming the bacteria. They include severe stomach cramps, diarrhea and vomiting. Most people recover in five to seven days, although 5% to 10% of individuals diagnosed with this type of E. coli illness develop hemolytic uremic syndrome, according to the CDC.

The newly reported illnesses were in Missouri, Virginia, Washington and Wisconsin, bringing the total number of states involved in the outbreak to nine. Previous cases were reported in Arizona, California, Maryland, New Jersey and Oregon.

I.M. Healthy expanded its recall Tuesday to include all its soy nut butter varieties as well as all its granola products, regardless of "best by" dates marked on the packaging. The company initially recalled only its original creamy SoyNut Butter with specific "best by" dates.

As part of the ongoing investigation, health officials have spoken with all but one of the ill individuals. All reported consuming these products within the week before their symptoms began.

The products are sold nationwide online and at stores. Consumers are advised to discard any of the products and not to consume them.

On Monday a lawsuit was filed against the Illinois-based company on behalf of Mosby and Erin Simmons, whose child started having abdominal pain on January 25. According to the lawsuit he was admitted to Good Samaritan Hospital in San Jose, California, five days later and then transferred to Lucile Packard Stanford Children's Hospital for advanced care.

There, he was diagnosed with an E. coli infection and was treated with "dialysis and blood transfusions for life-threatening hemolytic uremic syndrome," the lawsuit said. He spent 24 days in the hospital before being discharged. The child "continues to recover at home and faces uncertain future medical complications," said the family's lawyer, William Marler, in a statement.

Marler said he is also representing three other individuals: two children who are hospitalized in Seattle and an adult in California.