UPDATED: 04/19/2016, 3:00 PM

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NORTH TEXAS (CBSDFW.COM) – The Alvarado Independent School District is dealing with a contagious bacterium at one of its schools.

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“In the last week and a half we’ve had three confirmed cases of students having Shigella at one of our elementary schools,” said Alvarado ISD spokesman Tommy Brown.

During that time Brown said that out of an abundance of caution, Alvarado Elementary North has sent home an average of two students a day after they showed symptoms of having Shigella.

Last Monday, administrators with the Alvarado ISD sent a letter home with students (see below) saying one youngster at Alvarado Elementary School North had a confirmed case of Shigella, but that number has now increased despite efforts by the school.

“We sent notification home to parents so that they’re aware and so that they can help us and partner with us to make sure that kiddos are doing necessary things to keep their hands clean,” said Alvarado ISD Superintendent, Dr. Kenneth Estes. “They also have things in the room hand sanitizer wipes to wipe down things that are commonly used like door handles and computer keyboards those kinds of things.”

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Shigella is a bacterium that generally infects the digestive tract. Symptoms of the disease include digestive problems, fever, nausea and vomiting.

Brown said the ISD janitorial staff has been increasing efforts to disinfect, focusing on high-touch areas like desks, doorknobs and counters.

“We’ve also had our transportation department… they’ve stepped up their efforts and a little more stringent cleaning process on the buses to make sure it doesn’t spread from campus to campus as well,” he said.

As far as how the number of infections went from one to three, Brown said, “They [students] may have gotten it before we were notified about the original case, before we started cleaning real good and making sure we were taking the proper steps in getting rid of it at the campus.”

Shigella is a bacteria closely related to Salmonella.

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