An elderly patient is recovering after becoming the 11th West Australian diagnosed with meningococcal disease this year.
The WA Health Department said today that it had identified the person's close contacts and provided them with information.
Antibiotics, to minimise the chance that the organism might be passed on to others, will be prescribed where necessary.
Meningococcal disease is an uncommon, life-threatening illness caused by a bacterial infection of the blood or the membranes that line the spinal cord and brain.
There are usually 20 to 25 cases in WA each year, with 16 notified last year, the lowest number in more than 20 years.