A young adult has become the first person in Western Australia this year to be diagnosed with the potentially deadly meningococcal disease.
The WA Health Department said on Tuesday the person was hospitalised last week but had since been discharged and was recovering at home.
The patient's closest contacts have also been informed and some have been given antibiotics to minimise the chance of the organism spreading.
Meningococcal disease is an uncommon, life-threatening illness caused by a bacterial infection of the blood or membranes that line the spinal cord and brain.
The department said its incidence had dropped in WA over the past decade from a peak of 86 cases in 2000 to about 20 to 25 cases a year.
There were 16 cases last year, the lowest number recorded in more than 20 years. More than half the cases were people aged under 19.
A vaccine to protect against the C type of meningococcal disease, which in the past was responsible for about 15 per cent of cases in WA, is provided free to one-year-old children.