Meningitis is an inflammation of the protective membranes covering the brain and spinal cord, known as the meninges. It can be caused by various infectious agents, including bacteria, viruses, fungi, and parasites. The most common form is viral meningitis, but bacterial meningitis is more severe and can be life-threatening. Understanding meningitis involves recognizing the different types, causes, and how it affects the body.

There are several types of meningitis, with bacterial and viral being the most widely recognized. Bacterial meningitis is often more severe, requiring immediate medical attention, as it can result in brain damage, hearing loss, or even death if left untreated. Viral meningitis, though typically less severe, can still cause significant discomfort and requires treatment to manage symptoms. Fungal and parasitic meningitis are less common but are particularly concerning for individuals with weakened immune systems. Each type has its own set of causes, transmission methods, and severity.

The causes of meningitis are diverse, with bacteria such as Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae being some of the most common culprits in bacterial cases. Viral meningitis is usually caused by enteroviruses, though the herpes simplex virus and HIV can also lead to viral meningitis. Fungal infections, like those caused by Cryptococcus, typically affect individuals with weakened immune systems, such as those living with HIV/AIDS. Meningitis can also result from parasitic infections, although this is extremely rare.