A baby girl is being treated in hospital for an invasive disease she contracted at just six months old.
The child, from Adelaide, is fighting a case of a rare strain of meningococcal, South Australia Health revealed on Monday.
While she is in a stable condition, more than a dozen close contacts may have been infected.
The health department revealed 15 people had been directed to complete a course of “clearance antibiotics”.
The strain has been identified as serogroup W, SA Health said in a statement.
She is one of four cases of invasive meningococcal disease this year, two of which were serogroup W and two serogroup B.
Five cases were recorded last year, including three of serogroup B and two of serogroup Y.
Meningococcal disease usually causes meningitis - inflammation of the lining of the brain and spinal cord and/or septicaemia, which is blood poisoning, according to NSW Health.
Between five and 25 per cent of people carry meningococcal bacteria at the back of their nose and throat without showing any illness or symptoms
The bacteria is passed between people in the secretions from the back of the nose and throat.
Transmission usually requires close and prolonged contact with a person carrying the bacteria who is generally completely well.
An example of 'close and prolonged contact' is living in the same household or intimate and deep kissing.
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