About 20 students at Ritter Elementary in Watts felt ill at school. Eight students had similar symptoms at Huerta Elementary. Sara Welch reports from Downtown L.A. on Nov. 19, 2013.

This post has been corrected. See the note at the bottom for details.

An illness that caused flu-like symptoms among roughly 20 students at an elementary school in Watts last week has spread to another school, sickening about 10 others, Los Angeles Unified officials said.

At least eight students Monday at Dolores Huerta Elementary School in South Los Angeles reported symptoms that included upset stomach, nausea, vomiting and diarrhea around 12:50 p.m. That episode came after about 20 students at Ritter Elementary School in Watts also fell ill with flu-like symptoms on Friday.

Officials were still investigating what caused the illnesses and how it had spread with more than seven miles between the two schools. So far, the illness has been “short and self-resolving” with some of the affected students from Ritter Elementary back in class this week, said Kimberly Uyeda, a doctor who serves as director of medical services and community partnerships for L.A. Unified. 

The sickened students at Ritter were in first-grade and fourth-fifth grade combination classrooms. Those affected at Dolores Huerta were in first- and third-grade classrooms, according to Ellen Morgan, a spokeswoman for the district.

With each new case, school officials say they've been keeping close tabs. L.A. County health officials are also assisting.

“We dispatched a school nurse, we question and assess the students on symptoms and exposures, and then follow up when they go home or return to school,” Uyeda said.

Meanwhile, the investigation did not appear to point to tainted food. Samples from Ritter Elementary tested negative over the weekend for contaminants, and a separate investigation by the district found that not all of the sick children consumed the same meals that day.

Test results from food served at Dolores Huerta were expected later in the week. David Binkle, director of food services for L.A. Unified, said more than 650,000 school meals served districtwide each day are pre-cooked. Each meal is tested at a third-party lab for various food-borne illnesses, parasites and other screenings before it is served.

“In my six years here, I can’t recall a major outbreak linked back to food served at the school,” Binkle said.

In the meantime, school officials were providing parents and guardians with prevention tips, such as thorough hand-washing, to halt the spread of cold and flu-like illness. Officials also urged parents to keep sick children at home if they experience any fever or flu-like symptoms.

[For the record, 3:30 p.m. Nov. 19: An earlier version of this post stated that more than 65,000 pre-cooked meals are served districtwide each day; the correct number is 650,000.] 

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