Dallas County officials think they have figured out what illness has caused approximately 1,400 absences at Richardson High School in the last seven days; the common and highly contagious norovirus.
Officials with Dallas County Health and Human Services made the announcement Tuesday that preliminary laboratory results supported previous suspicions that the illnesses were caused by the same bug that sickened 600 on a recent Caribbean cruise out of New Jersey and prompted the early return of a second vessel out of Galveston.
According to the Centers for Disease Control and Prevention, "Norovirus is a very contagious virus. You can get norovirus from an infected person, contaminated food or water, or by touching contaminated surfaces. The virus causes your stomach or intestines or both to get inflamed (acute gastroenteritis). This leads you to have stomach pain, nausea, and diarrhea and to throw up."
Norovirus typically resolves itself after 1-3 days.
The source of the outbreak at the school has not been revealed.
On Monday, the RISD released attendance data that significantly changed previously released numbers by the district. Tim Clark, with the RISD, said the change in figures were due to the district being able to remove students that were originally only missing specific class periods, but were able to otherwise remain in school. Additionally, the district was able to specify how many students were sent home early due to GI illness currently plaguing the school.
School officials said 214 students were absent Tuesday and 23 of those were sent home due to the GI illness. On Monday, the district reported 239 students were absent and 48 of those were sent home due to the illness.
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On Wednesday, Jan. 29, 96 students were absent, a figure that Clark said was a "typical number" of absences. By Thursday, Jan. 30, the number of absences jumped to 282 students, including 70 students that were sent home from school with the GI illness. The peak of the illness appears to be on Friday, Jan. 31, when 602 students were absent, including 107 who were sent home with the illness.
Clark said the school has approximately 2,550 students enrolled and that last Friday 25 percent of the school population was ill.
Cleaning to Continue After Norovirus Diagnosis
Before determining the illnesses were caused by norovirus, Richardson High School administrators said the mystery illness wasn't the flu and that it wasn't coming from the cafeteria food. While officials worked to identify what was behind the illness, the district was working hard to disinfect surfaces throughout the campus.
"The deep cleans began last Thursday, so every evening from Thursday through last evening, the school has been deep cleaned," Clark said on Monday. "We use antiviral cleaners effective against a wide range of pathogens."
Clark said the district has added additional custodians and cleaning crews and is disinfecting every surface. Clark said the cleaners "will go the extra mile and make sure they're hitting every surface the person can touch."
With numbers of absences falling since last week, the district is hoping for continued progress.
"We are headed in the right direction, so we are guardedly optimistic," Clark said.
#RHSPlague is No Laughing Matter
Students started up a Twitter hashtag about the mysterious virus, called "#RHSPlague," and are trying to make light of the situation with jokes like, "More Plague = Better Parking."
But for school administrators and affected students, it's no laughing matter. Hundreds of students were violently ill over the weekend — symptoms included vomiting, dehydration and exhaustion.
"It is scary, it really is, for that many kids to get sick at one time," said Demetrius Price, who had to pick up his freshman son from the nurse's office at lunchtime Friday.
Price said the nurse's office was "overrun" with hundreds of sick students.
"My son had a cold a few weeks ago, during that cold snap. But nothing serious. This right here was so different," Price said. "It put him on the couch. His energy was low. His appetite was gone. He kept feeling like he had to throw up. I don't know what it is. I was worried he was going to get real dehydrated."
More than 675 students, about a quarter of the school's total student population of 2,500, missed class Friday along with 28 staff members.
"It was just really weird. It was like a ghost town," said high school senior Jenny Watson.
NBC 5's Kendra Lyn, Jeff Smith and Greg Janda contributed to this report.