Increase in Meningococcal Serogroup W Disease, Victoria, Australia, 2013-2015

Area of Science:

• Microbiology
• Epidemiology
• Public Health

Background:

• Invasive meningococcal disease (IMD) is a serious infection caused by Neisseria meningitidis.
• Serogroup W (MenW) strains have emerged as a significant cause of IMD globally.
• Monitoring serogroup distribution is crucial for public health interventions.

Purpose of the Study:

• To analyze the epidemiological trends of invasive meningococcal disease in Victoria, Australia.
• To investigate the contribution of Neisseria meningitidis serogroup W to the changing patterns of IMD.
• To identify the specific strains responsible for the increase in MenW cases.

Main Methods:

• Retrospective analysis of invasive meningococcal disease case data from Victoria, Australia.
• Surveillance data from 2013 to 2015 was examined.
• Molecular characterization of Neisseria meningitidis isolates to determine serogroup and sequence type.

Main Results:

• A dramatic increase in invasive meningococcal disease caused by Neisseria meningitidis serogroup W was observed in Victoria.
• The proportion of MenW cases rose from 4% in 2013 to 30% in 2015.
• The increase was primarily attributed to strains belonging to the serogroup W sequence type 11 clonal complex.

Conclusions:

• Neisseria meningitidis serogroup W has become a dominant cause of invasive meningococcal disease in Victoria.
• The emergence of specific MenW strains, previously identified in the UK and South America, is driving this trend.
• Enhanced surveillance and potential vaccination strategies targeting these strains may be warranted.