Summary Background To combat Neisseria meningitidis serogroup A epidemics in the meningitis belt of sub-Saharan Africa, a meningococcal serogroup A conjugate vaccine (MACV) has been progressively rolled out since 2010. We report the first meningitis epidemic in Niger since the nationwide introduction of MACV. Methods We compiled and analysed nationwide case-based meningitis surveillance data in Niger. Cases were confirmed by culture or direct real-time PCR, or both, of cerebrospinal fluid specimens, and whole-genome sequencing was used to characterise isolates. Information on vaccination campaigns was collected by the Niger Ministry of Health and WHO. Findings From Jan 1 to June 30, 2015, 9367 suspected meningitis cases and 549 deaths were reported in Niger. Among 4301 cerebrospinal fluid specimens tested, 1603 (37·3%) were positive for a bacterial pathogen, including 1147 (71·5%) that were positive for N meningitidis serogroup C (NmC). Whole-genome sequencing of 77 NmC isolates revealed the strain to be ST-10217. Although vaccination campaigns were limited in scope because of a global vaccine shortage, 1·4 million people were vaccinated from March to June, 2015. Interpretation This epidemic represents the largest global NmC outbreak so far and shows the continued threat of N meningitidis in sub-Saharan Africa. The risk of further regional expansion of this novel clone highlights the need for continued strengthening of case-based surveillance. The availability of an affordable, multivalent conjugate vaccine may be important in future epidemic response.

Rift Valley fever ( RVF ) is a mosquito‐borne viral zoonosis causing abortions and high mortality among animals, whereas in humans, the disease is usually mild or asymptomatic. In September 2016, the Republic of Niger declared the first RVF outbreak in the northern region of Tahoua near the Malian border. This study describes the outbreak and reports the results of serological and molecular investigations of the human and animal samples collected. Serum samples from both human and animal suspected cases have been confirmed at the Centre de Recherche Médicale et Sanitaire ( CERMES ) and the Laboratoire Centrale d'Elevage ( LABOCEL ) public health and animal reference laboratories, respectively. Techniques for biological confirmation were real time reverse transcription polymerase chain reaction ( RT ‐ PCR ) and enzyme linked immunosorbent assay ( ELISA ). Phylogenetic trees were established after genetic sequencing of the small and medium segments of the RVF virus ( RVFV ) genome. Out of the 399 human samples collected, 17 (4.3%) were confirmed positive for RVFV . Overall, 33 (8.3%) deaths occurred out of which five (29%) were among the 17 confirmed cases. Regarding animals, 45 samples were tested, three of which were RT ‐ PCR positive and 24 were IgG positive. The phylogenetic analyses showed that the Niger strains clustered with Senegal 2013 and Mauritania 2015 RVFV strains. This first outbreak of RVF was very challenging for public and animal health laboratories in Niger. Besides resulting in human deaths, important loss of cattle has been reported. Therefore, vigilance has to be strengthened emphasising vector control strategies and active surveillance among animals.

Hepatitis E virus (HEV) infection in developing countries is associated with poor hygiene, lack of clean drinking water, and inadequate sanitation. In this study, we report the first case investigation and describe the present situation of HEV outbreak within displaced persons camps in the Diffa region, Republic of Niger. The investigation showed the outbreak to be closely linked to unclean water supply, low hygiene, and sanitation facility standards. Between January and September 2017, a total of 1,917 HEV suspect cases were recorded from which 736 (38.4%) have been confirmed positive for HEV by reverse transcription polymerase chain reaction and enzyme linked immunosorbent assay. Overall, 38 (1.9%) deaths were recorded, including 17 (44.7%) pregnant women. The ongoing outbreak highlights poor drinking water quality and sanitation conditions in displaced persons camps in the Diffa region. Disease containment and patient care activities, particularly for pregnant women, may have resulted in decreased transmission of infection and deaths.

La Chimioprévention du Paludisme Saisonnier (CPS) est une stratégie recommandée par l'Organisation Mondial de la Santé (OMS) dans les pays du Sahel. Une étude cas témoin a été conduite pour estimer l'impact en santé publique de la phase pilote de la CPS à Magaria au Niger en comparant l'incidence du paludisme de six Centres de Santé Intégrés (CSI) où la CPS est mise en oeuvre à celle de 6 autres CSI sans CPS. Une enquête ménage a permis d'échantillonner 482 enfants dont 241 cas et 241 témoins. La CPS réduit le portage et la charge parasitaire de façon significative. La CPS réduit l'incidence du paludisme simple de 73%. Il existe une corrélation forte entre la CPS et la réduction du nombre d'épisode de paludisme (R = 0,59). La CPS réduit l'incidence du paludisme grave de 26,5%. La CPS réduit les convulsions de 19,9% mais elle n'a pas d'impact sur l'anémie. La CPS réduit significativement le coma de 13,2% et les hospitalisations de 23%. La CPS réduit enfin la mortalité de 48,3%. La CPS est une stratégie prometteuse qui permettra aux pays du sahel de contrôler le paludisme et d'accéder au stade de pré-élimination en réduisant le portage, la morbidité et la mortalité.

Summary. Problem. Transfusional malaria is an accidental transmission of Plasmodium via a blood transfusion. Its magnitude is underestimated and very little data on the assessment of this risk are available in Niger. Objective. This study aimed to determine the prevalence of plasmodial infection of blood bags at the National Blood Transfusion Center of Niamey (NBTC). Methodology. A cross-sectional study to diagnose Plasmodium infection by microscopy and Rapid Diagnostic Test (RDT) was carried out during the rainy season (September to November 2015). Blood grouping was performed by the BETH-VINCENT technique. Results. One thousand three hundred and fifty-seven (1357) blood bags were collected. One hundred and fifty-seven (11.6%) of the donors were infected with Plasmodium by microscopy and 2.4% (9/369) by rapid diagnostic test. All infections were with P. falciparum (100%). The mean parasite density was 197 parasites/μL (SD=281; [80: 2000]). There were no significant differences in infection prevalence between the ABO blood groups (p=0.3) or the rhesus positivity (p=08). There is also no significant difference in temporal (p=0.1) and spatial (p=0.6) distribution. Conclusion. The transmission of transfusional malaria during the rainy season is a fact in Niger. Such risks were independent of the ABO blood type and positivity for the rhesus antigen. Pretransfusion diagnosis or posttransfusion therapy should be instituted to prevent it.