The Department of Health reported Friday that a young child is currently recovery in hospital after being diagnosed with serogroup W meningococcal disease.

Meningococcal disease is an uncommon, life-threatening illness caused by a bacterial infection of the blood and/or the membranes that line the spinal cord and brain, and occasionally of other sites, such as large joints.

Public domain Image/Richard Russell, Dominic Dwyer
Public domain Image/Richard Russell, Dominic Dwyer

The Department of Health has identified the close contacts of the case and provided them with information, and, where appropriate, antibiotics and a vaccine. This is to minimize the chance of further spread of the organism to others, should one or more of the contacts be carrying the strain that caused disease.

The incidence of meningococcal disease has decreased significantly in WA over the past two decades, with around 20 cases now reported each year – down from a peak of 86 cases in 2000.

Twenty-three cases were reported in 2016, and there have now been five cases with disease onset during 2017. The disease occurs more commonly in winter and spring.

Meningococcal bacteria are carried harmlessly in the back of the nose and throat by about 10-20 per cent of the population at any one time. Very rarely, the bacteria invade the bloodstream and cause serious infections.

Meningococcal bacteria are not easily spread from person-to-person. The bacterium is present in droplets discharged from the nose and throat when coughing or sneezing, but is not spread by saliva and does not survive more than a few seconds in the environment.

Invasive meningococcal infection is most common in babies and young children, and older teenagers and young adults, but infection can occur at any age.

Symptoms may include high fever, chills, headache, neck stiffness, nausea and vomiting, drowsiness, confusion, and severe muscle and joint pains. Young children may not complain of symptoms, so fever, pale or blotchy complexion, vomiting, lethargy (blank staring, floppiness, inactivity, being hard to wake, or poor feeding) and rash are important signs.

Sometimes – but not always – symptoms may be accompanied by the appearance of a spotty red-purple rash that looks like small bleeding points beneath the skin or bruises.

Although treatable with antibiotics, meningococcal infection can progress very rapidly, so it is important that anyone experiencing these symptoms seeks medical attention promptly.

With appropriate treatment, most people with the disease recover, although around 5 per cent will die and around 15 per cent may experience complications such as hearing loss, or gangrene requiring skin grafts or amputations.

There are several types of meningococcal bacteria, but internationally disease is most commonly caused by what are known as serogroups A, B, C, W and Y organisms.

A vaccine to protect against the serogroup C type of meningococcal disease, which in the past was responsible for around 15 per cent of cases in WA, is provided free to children at 12 months of age. A vaccine against serogroup B meningococcal infection, historically the most common type in WA, is available on prescription. Combination vaccines are also available that protect against four types of the organism (serogroups A, W and Y, in addition to serogroup C) that occur more commonly overseas.

Serogroups W and (to a lesser extent) Y meningococcal disease have increased significantly in frequency in some parts of Australia, including in WA, over the past three years.

Of the 23 cases reported in WA in 2016, six were serogroup B (the lowest number since 1990), two were serogroup Y and fourteen were serogroup W, up from the long term average of around one serogroup W case per year. Three of the five cases reported to date in 2017 have had serogroup W infection, one was serogroup B, and type could not be determined in one case.

Although the overall incidence of meningococcal disease remains at historically low levels, WA and national health authorities are continuing to closely monitor changes in the incidence of specific serogroups.