The global burden of cholera outbreaks in Niger: an analysis of the national surveillance data, 2003-2015.

Background: Niger has experienced multiple cholera outbreaks since the occurrence of cholera in West Africa in 1970-1971. Understanding the origins of these geographic variations at different scales in the region and in health districts is an essential step in the rational and operational fight against this disease.

Methods: We conducted a retrospective review of all suspected cholera cases in Niger from 2003 to 2015. Data from 2010 to 2015 were reviewed to determine the number and percentage of stool specimens tested, with distribution by serotype. We also determined the time between sampling and sending to a laboratory.

Results: From 2003 through 2015 a total of 16 328 cases of cholera, including 578 deaths, were reported to the National Surveillance Database (overall case fatality rate 3.5%). The number of cases was greater among males (63.29%). Patients >15 y of age accounted for 69.80% of cases. All regions recorded cholera cases throughout the period 2003 to 2015, except in 2009, when no outbreak was reported. All epidemics recorded were due to the subtype serogroup O1 serotype Ogawa and all strains confirmed the presence of the ctxB, rstR, tcpA, zot, ace and ctxA genes encoding the toxin of this serotype.

Conclusions: The global burden of cholera remains high in Niger. To successfully prevent and control outbreaks, adapted guidelines and strategies should be reviewed to provide more focused information and assign clear roles and responsibilities.