The Northland District Health Board says it will carry out a clinical review of the care of a man who died of meningococcal disease.
Ben Brown, 18, died on Saturday, two days after being admitted to Whangerei Hospital's intensive care unit with probable meningococcal disease - a bacterial infection that can cause blood poisoning and meningitis.
The DHB says laboratory tests have confirmed the meningococcal C strain, which can be vaccinated against.
Chief medical adviser Gloria Johnson says Mr Brown's death shows how serious the disease is and the case has now been referred to the coroner.
Dr Johnson says the findings from a clinical review of Mr Brown's care can be shared with his family and the coroner.
It is the fourth case of the disease in Northland in August.
Northland DHB spokesperson Fleur King says a one-year-old boy died earlier in the month, after he was transferred from Whangerei Hospital to Starship Children's Hospital in Auckland.
Ms King says a 45-year-old is in Whangarei Hospital with the disease, and one other person has since been discharged.
Six people died of meningococcal disease last year, and five in 2009.
The Meningitis Foundation says it has been busy fielding calls from concerned people.