More than 135 people who reported falling sick between July 13 and July 16 after visiting a Chipotle restaurant in Sterling, Virginia have been identified by local authorities. The Loudoun County Health Department reported Monday that its investigation of the reports found two individuals tested positive for the same strain of norovirus following reports from earlier this month.

“Two ill patrons have tested positive for the same strain of norovirus. Based on symptoms reported and these preliminary laboratory results, the cause of the outbreak is believed to be norovirus, though the specific source of the norovirus has not yet been identified,” Dr. David Goodfriend, director of the Loudoun County Health Department, said in a statement. “The Health Department is not aware of any customers becoming ill since the reopening of the facility last Wednesday.”

READ: Chipotle Norovirus Returns? Today's Stock Price After Restaurant Closes From Illness

As International Business Times previously reported, patrons of the fast food chain reported their symptoms — which included violent vomiting, fevers, dizziness and stomach cramps — on the website iwaspoisoned.com. Two of those individuals were reportedly hospitalized.

“I ate at Chipotle Saturday, July 15, around 6 p.m.,” one user wrote in a report. “I had a chicken burrito with black beans, brown rice, corn, salsa, cheese and lettuce. Monday night around 11 p.m. I began having severe stomach pain and by 3 a.m. had non-stop diarrhea. By Tuesday morning I also had a fever. The diarrhea stopped Tuesday evening and the fever broke then as well. Now (Wednesday) I'm weak and tired with no appetite.”

Chipotle's stock prices sank 7.6 percent on July 18, shortly after the incidents were initially reported. The company had reportedly been up 3.9 percent this year after recovering from 2015’s widespread reports of illness after patrons ate at multiple Chipotle restaurants nationwide.

According to the Center for Disease Control (CDC), norovirus symptoms typically appear in an infected person within 12-48 hours after a person is exposed. The most common symptoms experienced by individuals who have contracted the illness are diarrhea, nausea, vomiting and stomach aches.

READ: What Is Norovirus? Chipotle Closes Virginia Restaurant After Outbreak Of Contagious Virus

“We are grateful to the Health Department for working with us to manage this incident,” a Chipotle spokesperson told IBT in a statement. “Norovirus is common and easily transmitted by human contact, and this incident is not suggestive of any supply chain issues. When we learned of this issue, we took immediate and aggressive action to correct it, including proactively notifying local health officials, voluntarily closing our restaurant, deploying our safety support teams and performing a complete sanitization of all surfaces in the restaurant. We appreciate and value our customers and we offer our sincerest apologies to those who may have been affected.”

“We are sorry that individuals reported sickness from one of our locations.” Chipotle’s Chairman and CEO Steve Ells in a separate statement provided to IBT. “The safety and well-being of our customers is always our top priority. Our Sterling, VA, restaurant has reopened for business.”