The main cause of meningitis is typically an infection, with viral infections being the most common cause, followed by bacterial infections, and, more rarely, fungal and parasitic infections. Bacterial causes include species such as Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae, and group B streptococcus. Other less common causes can include injuries, cancer, certain drugs, and autoimmune disorders