Acquisition of virulence genes by a carrier strain gave rise to the ongoing epidemics of meningococcal disease in West Africa

Abstract

SignificanceHistorically, Neisseria meningitidis serogroup A strains have caused large epidemics of meningitis across sub-Saharan Africa. Following mass vaccination from 2010, serogroup A outbreaks have been mostly eliminated. Starting in 2013 however, yearly epidemics of a previously unknown serogroup C strain have led to tens of thousands of cases in Nigeria and Niger. We show how this new strain evolved from a benign ancestor through the acquisition of virulence genes encoding the serogroup C capsule and a phage linked to invasiveness, illustrating that minor genetic changes in a microbe can have major public health consequences. Our reconstruction of the spatiotemporal outbreak dynamics in the Niger–Nigeria border region suggests direct epidemiological consequences of contrasting outbreak responses in the two countries.

The Global Meningococcal Initiative meeting on prevention of meningococcal disease worldwide: Epidemiology, surveillance, hypervirulent strains, antibiotic resistance and high-risk populations

“…The outbreak was associated with atypical symptoms (diarrhea, vomiting, and mental confusion) and metagenomic analysis revealed the presence of a strain with 91-98% similarity to ST-10217 in six of the 10 specimens analyzed, the remaining four specimens were inconclusive [73,74]. This strain appears to be evolved and likely has the epidemic potential [75]. Outbreaks have also been reported among military personnel.…”

Meningococcus serogroup C clonal complex ST-10217 outbreak in Zamfara State, Northern Nigeria

“…Prior to the recent outbreaks, the last NmC outbreak in sub-Saharan Africa was reported in 1979 in Burkina Faso 10 . The emergence and expansion of NmC ST-10217 CC with the propensity to cause large outbreaks threatens the public health gains made by the MenAfriVac campaigns 7 , 16 . This reinforces the need for strategic vision and action towards controlling meningitis epidemics in the meningitis belt.…”

“…These outbreaks were followed by a larger outbreak in Niger in 2015 13 . All the recent outbreaks were attributed to a novel strain of NmC sequence type (ST)-10217 whose emergence threatens the public health gains made by the MenAfriVac 14 – 16 .…”

The sudden emergence of aNeisseria gonorrhoeaestrain with reduced susceptibility to extended-spectrum cephalosporins, Norway

“…To generate a high-quality reference genome for comparative genomic analyses, long read data were generated on the Oxford Nanopore GridION platform for one of the Norwegian isolates (641189). DNA was extracted and sequences generated as described previously (17) . For assembly we employed a hybrid approach implemented in Unicycler v0.4.7 (18) , leveraging both long Oxford Nanopore reads and short accurate Illumina reads.…”