A seven-month-old girl from metropolitan Adelaide is in hospital in a critical condition after being diagnosed with invasive meningococcal.
SA Health has identified several close contacts of the infant, and has directed seven people to take antibiotics to prevent further infection.
Symptoms of the disease include rash, fever, headache, diarrhoea, and nausea or vomiting.
SA Health said the baby had contracted the serogroup W strain of the disease.
Serogroup B is the most common cause of invasive meningococcal in Australia, followed by serogroups W, and Y.
In Australia, a free meningococcal vaccine effective against the A, C, W and Y strains is provided for children at 12 months of age, then again in year 10, or between the ages of 15 to 19.
There have been 11 cases of invasive meningococcal reported in South Australia this year, more than double last year's case numbers.
Of this year's cases, six were diagnosed as serogroup W and five were serogroup B.
