Meningitis outbreak: Some questions and answers The toll in the nationwide fungal meningitis outbreak has risen to 14 dead and 155 sickened across 11 states, linked to a tainted back pain treatment from a Massachusetts compounding facility. Health officials continue to investigate the cause, with the U.S. Centers for Disease Control and Prevention reporting Thursday that some 14,000 patients in 23 states have been injected with the potentially tainted steroid, which was recalled last week. Here's a closer look at the state of the outbreak. What is meningitis? Meningitis is an infection that causes inflammation of the meninges, the membranes covering the brain and spinal cord. The infection can be viral, bacterial or fungal. Those who have become sick as a result of the recent outbreak are suffering from a fungal variety. Fungal meningitis is extremely rare, though it can be caused by spores commonly found in the environment. Thus far, laboratory testing by the CDC has identified the fungus Exserohilum in 10 infected people and Aspergillus in one other person. Is fungal meningitis contagious? No, the infection can't travel from person to person. The fungus infects people once it's injected into the central nervous system. Other types of meningitis are contagious. According to the CDC, the bacterial variety can be passed through nose and throat fluids (such as during kissing), and the viral variety is often spread by fecal contamination (when people don't wash hands after using the toilet). What are the symptoms of fungal meningitis? They can include weakness, worsened back pain, stiff necks, mild headaches, light sensitivity, fever and slurred speech. The symptoms can be slight, the CDC says. What is the source of the outbreak? Investigators have linked it to a steroid treatment that is injected into the spinal column to alleviate back pain. This is a very common procedure - millions of patients receive injections each year, said Dr. Shaheda Quraishi, a physiatrist at the Cushing Neuroscience Institute on Long Island in New York. The drug in question - preservative-free methylprednisolone acetate - came from the New England Compounding Center in Framingham, Mass. Three tainted batches of the steroid were sent to 75 medical facilities in 23 states, including California. NECC has since shut down and recalled all of its products. Thus far, Tennessee has been hit hardest by the outbreak, with 49 reported sick and six dead. Why was the steroid injection preservative free? Preservatives can cause arachnoiditis, an inflammation of the arachnoid layer of the spinal cord and brain, Quraishi said. Some patients may also have allergies. So it's generally best to avoid putting them in epidural injections. Who is at risk? People who've had an injection and who are experiencing any symptoms should contact a doctor as soon as possible, the CDC said. The incubation period is usually between one and four weeks, but the CDC says infections have been known to surface outside that window, and the contaminated steroid could have been given as early as May 21. What is a compounding facility? These facilities are set up to create medicines that are tailored to a specific patient's needs. They can take a manufacturer's drug and raise or lower the dose or change it from solid to liquid form. They've grown popular with smaller clinics and private practices as a more affordable alternative to buying drugs in bulk straight from manufacturers, Quraishi said. How did the fungus get into the steroid in the first place? It's unclear - the CDC's investigation is ongoing on that point. Experts from the U.S. Food and Drug Administration and the Massachusetts Department of Public Health are assisting. "Something like this should never happen," Quraishi said. That's the bottom line. Who oversees the safety of compounding facilities? Although the FDA regulates drug manufacturers, it does not have the same authority over drug compounders such as NECC. This week, lawmakers in Washington called for a congressional investigation of the outbreak. "This incident raises serious concerns about the scope of the practice of pharmacy compounding in the United States and the current patchwork of federal and state laws and systems that oversee this practice," Rep. Henry A. Waxman (D-Beverly Hills) and others wrote in a letter to the leaders of the House Committee on Energy and Commerce.