​An increase in the number of cases of a bacterial disease has worried health experts in the US. A total of 143 cases of the disease have been reported so far. The disease, caused by the bacterium Neisseria meningitidis commonly affects the brain, spinal cord and bloodstream. Meningococcal disease as it is referred to is a serious bacterial infection that affects people aged 30–60 years, African American people, and people with HIV, the US CDC has warned. In this disease, the meninges, or the membrane that covers the brain and spinal cord is infected. The bacterium can multiply aggressively and lead to septicemia. ​