Serogroup distribution (%) in Burkina Faso, Mali and Niger in the period 2004–2010.

<p>In the figure, the few non-groupable isolates were included together with those assigned to a serogroup on the basis of the capsule PCR and/or their molecular profile, except for ST-192 isolates (n = 2) that were likely to harbour a capsule null gene <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0046019#pone.0046019-Findlow1" target="_blank">[36]</a>. Black bars: serogroup A; white bars: serogroup W135; oblique strips: serogroup X; vertical strips: serogroup Y.</p

Distribution of lineages found among 773 <i>N. meningitidis</i> strains isolated in the African meningitis belt between 2004 and 2010.

a<p>NG, Non-groupable as determined by slide agglutination method.</p>b<p>UA, Unassigned to any clonal complex.</p

Serogroup and sequence type (ST) of invasive meningococcal isolates from sub-Saharan Africa in 2004–2010.

a<p>NG, Non-groupable as determined by slide agglutination method.</p>b<p>UA, Unassigned to any clonal complex.</p>c<p>CAR, Central African Republic.</p

Evolution of the ST-5 complex in the meningitis belt in the period 1988–2010.

<p>The ST is shown within the bar, the country where the new ST was first detected is indicated above and the locus changed to the left. The left end of the bar shows when the variant was first detected and the right end shows the last reported isolation. The three dominant STs are marked with grey background.</p

Summary of household data and crowding by country.

§<p>The geometric mean of residents per household is based on the number of individuals resident in the study households, and not the individuals recruited to the study shown in the second column above. (A maximum of 5 residents were recruited to the study).</p

Multivariable analysis comparing frequent mixers to all others by age, sex and area.

<p>*missing data for 67 records.</p