A popular Virginia high school senior who passed away suddenly this week likely died from bacterial meningitis, it has emerged. Madison Small, from Ashburn, left school early on Mondayand, after she woke up in the night with a severe headache, she was rushed to hospital. By Tuesday afternoon, her father, Tim Small, had contacted the Broad Run High School to let staff know that his youngest daughter had passed away that morning. On Friday, the Loudoun County Health Department confirmed she died of meningococcal meningitis, which causes membranes covering the brain and spinal cord to swell, My Fox DC reported. Loss: Eighteen-year-old Madison Small, pictured, passed away suddenly on Tuesday morning after feeling ill on Monday and it has now emerged she died of meningococcal meningitis . The bacteria causes membranes covering the brain and spinal cord to swell. It is the school system's first confirmed case in two years, the Washington Post reported. The last case in Loudoun was in January 2013. Public Health and school district officials said they do not have reason to believe her illness poses a risk to other students, particularly because last week was spring break. Loudoun County schools spokesman Wayde Byard told the Post that lockers at the school have been cleaned twice but there is no indication of an outbreak. 'It's a very tragic case... but there's no reason to panic,' he said. David Goodfriend, director of the Loudoun County Health Department, said a small number of people who had contact with Small would be watched for symptoms. Her close friend Devan Rook told the Washington Post that she had thought nothing of it when her friend went to the school nurse on Monday afternoon. Loved: Madison's family said she was otherwise healthy when her health suddenly declined on Monday . Family: Her father Tim Small, pictured center, spoke at a candle-lit vigil held for the teenager on Tuesday evening. Madison is pictured left with her older siblings and parents . Meningococcal meningitis causes membranes that cover the brain and spinal cord to become inflamed. It is caused by a bacterium that around 10 per cent of people naturally have in the back of their nose or throat with no issue - but sometimes it can invade the body. The bacteria is passed through direct contact with body fluids, such as through kissing or sharing eating utensils or drinks. Symptoms can include fever, headache, stiff neck, nausea, vomiting, sensitivity to light and confusion. It is often diagnosed in infants, adolescents and young adults, and a vaccine is recommended for all children aged 11 to 18. The disease can be treated with effective antibiotics but it is important that treatment be started as soon as possible. Even with antibiotic treatment, people die in about 10 to 15 per cent of cases. And 11 to 19 per cent of survivors will have long-term disabilities, including loss of limbs, deafness, nervous system problems, or brain damage. 'Didn't think anything was wrong with her,' she said. 'In the middle of the night, she woke up complaining of headaches and stuff, and they took her to [Inova] Loudoun Hospital and realized it was pretty serious. 'They couldn't handle it there, so they medevac-ed her over to [Inova Fairfax Hospital]. At that point, she wasn't doing too well, and several of her organs were shutting down.' She passed away on Tuesday morning. Her father, Tim Small, also told WUSA9 that his youngest had seemed the picture of health over the weekend, when they played catch together. On Tuesday night, just hours after news of their her death, hundreds of friends, classmates and family gathered for a candle-lit vigil at the school. Friends remembered Small as a talented softball player who had happily mentored younger members of the team. She was also excited about starting Virginia Tech in the fall, they said. School Principal Dave Spage, who broke the news to parents in an email on Tuesday, said he thought there were as many as 400 or 500 people at the vigil, which he said 'speaks to her circle and her involvement here', NBC reported. Madison's father, who also has an older daughter and son with his wife, spoke to those who had gathered. Remembered: Hundreds of people gathered for a candle-lit vigil following Madison's death on Tuesday . Support: Her varsity softball teammates wear their jerseys and line 2nd base as a tribute to Madison . Vigil: Friends lit candles as they shared memories of the beloved 18-year-old on Tuesday . Memorial: Classmates places flowers on Madison's desk after she was taken fatally ill . 'Life can be short, we found that out today,' he said. 'Make the most of it: love each other. Don't get bogged down in the little nitpicky crap. Put that aside. Life's too short.' In a Facebook post shared widely between Madison's friends online, she wrote a touching post in 2011, quoting Winnie The Pooh. 'If there's a tomorrow when we're not together, there's something you must always remember,' she wrote, beneath a smiling photo of herself. 'You're braver than you believe, stronger than you seem, and smarter than you think. But the most important thing is even if we're apart, I'll always be with you.'
Madison Small woke up feeling ill on Monday night so was rushed to hospital, but her organs began shutting down and she died on Tuesday .
The health department confirmed on Friday that she died of meningococcal meningitis - the school district's first case in two years .
The health department does not believe any one else is at risk but is monitoring people who came into close contact with her just in case .