How can one detect if someone has meningococcal?

Very ill. Meningococcus is not a minor illness, but patients tend to become very ill very rapidly. If there is an outbreak locally and someone you know may have been exposed, taking prophylaxis is important. Lacking a local outbreak we would do blood cultures, but suspect it in persons with a petechial rash, a headache, muscle aches, and/or high fevers early on. Later, purpora, shock, and unconsciousness.