An outbreak of meningitis has been reported in six Nigerian states, infecting over a thousand and killing 140. Meningitis causes acute inflammation of the brain and spinal cord. The current outbreak is the worst since 2009, when over 150 people died. The disease is spreading; it could become out of control if refugee camps, prisons and police cells become affected through crowds. Vaccination is a way of preventing meningitis. However a new strain imported from a neighbouring country is now prevalent and requires a different vaccine. The outbreak, attributed to cold nights / dusty winds / dry weather, is aggravated by traditional beliefs, poor hygiene, and overpopulation.