Epidemiological patterns of meningococcal meningitis in Niger in 2003 and 2004: under the threat of N. meningitidis serogroup W135

Since the Neisseria meningitidis serogroup W135 epidemic in Burkina Faso in 2002, the neighbouring countries dread undergoing outbreaks. Niger has strongly enhanced the microbiological surveillance, especially by adding the polymerase chain reaction (PCR) assay to the national framework of the surveillance system. During the 2003 epidemic season, 8113 clinically suspected cases of meningitis were notified and nine districts of the 42 crossed the epidemic threshold, while during the 2004 season, the number of cases was 3521 and four districts notified epidemics. In 2003 and 2004, serogroup A was identified in most N. meningitidis from cerebrospinal fluid (CSF) specimens (89.7% of 759 and 87.2% of 406, respectively). Although serogroup W135 represented only 8.3% of the meningococcal meningitis in 2003 and 7.9% in 2004, and was not involved in outbreaks, it was widespread in various areas of the country. In the regions that notified epidemics, the proportion of serogroup W135 was tiny while it exceeded 40% in several non-epidemic regions. Despite the wide distribution of W135 serogroup in Niger and the fears expressed in 2001, the threat of a large epidemic caused by N. meningitidis W135 seems to have been averted in Niger so far. There is no clear indication whether this serogroup will play a lasting role in the epidemiology of meningococcal meningitis or not. As early as in the 1990s, a significant but transient increase in the incidence of N. meningitidis serogroup X was observed. Close microbiological surveillance is crucial for monitoring the threat and for identifying at the earliest the serogroups involved in epidemics.     

Response Strategies against Meningitis Epidemics after Elimination of Serogroup A Meningococci,Niger

To inform epidemic response strategies for the African meningitis belt after a meningococcal serogroup A conjugate vaccine was introduced in 2010, we compared the effectiveness and efficiency of meningitis surveillance and vaccine response strategies at district and health area levels using various thresholds of weekly incidence rates. We analyzed reports of suspected cases from 3 regions in Niger during 2002–2012 (154,392 health area weeks), simulating elimination of serogroup A meningitis by excluding health area years with identification of such cases. Effectiveness was highest for health area surveillance and district vaccination (58–366 cases; thresholds 7–20 cases/100,000 doses), whereas efficiency was optimized with health area vaccination (5.6–7.7 cases/100,000 doses). District-level intervention prevented <6 cases (0.2 cases/100,000 doses). Reducing the delay between epidemic signal and vaccine protection by 2 weeks doubled efficiency. Subdistrict surveillance and response might be most appropriate for meningitis epidemic response after elimination of serogroup A meningitis.     

Outbreaks of serogroup X meningococcal meningitis in Niger 1995-2000

In the African meningitis belt, the recurrent meningococcal meningitis epidemics are generally caused by serogroup A. In the past 20 years, other serogroups have been detected, such as X or W135, which have caused sporadic cases or clusters. We report here 134 meningitis cases caused by Neisseria meningitidis serogroup X that occurred in Niamey between 1995 and 2000. They represented 3.91% of the meningococcal isolates from all CSF samples, whereas 94.4% were of serogroup A. Meningococcal meningitis cases were detected using the framework of the routine surveillance system for reportable diseases organized by the Ministry of Public Health of Niger. The strains were isolated and determined by the reference laboratory for meningitis in Niamey (CERMES) and further typed at the WHO collaborating center of the Pharo in Marseille and at the National Reference Center for the Meningococci at the Institut Pasteur. Reference laboratories in Marseille and Paris characterized 47 isolates having the antigenic formula (serogroup:serotype:sero-subtype) X:NT:P1.5. Meningitis cases due to meningococcus serogroup X did not present any clinical or epidemiological differences to those due to serogroup A. The seasonal incidence was classical; 93.3% of the cases were recorded during the dry season. The mean age of patients was 9.2 years (+/- 6 years). The sex ratio M/F was 1.3. Case fatality rate was 11.9% without any difference related to age or sex. The increasing incidence of the serogroup X was not related to the decrease of serogroup A, but seemed cyclic, and evolved independently of the recurrence of both serogroups A and C.     

Energy needs in the treatment of uncomplicated severe acute malnutrition: Secondary analysis to optimize delivery of ready‐to‐use therapeutic foods

Outpatient therapeutic feeding protocols for the treatment of uncomplicated severe acute malnutrition in children were initially based on weight gain data from inpatient settings and expert knowledge of the physiological requirements during recovery. However, weight gain and energy requirements from historic inpatient settings may differ from modern outpatient settings and therefore may not be appropriate to guide current therapeutic feeding protocols. We calculated the weight gain and average estimated total daily energy requirement of children successfully treated for uncomplicated severe acute malnutrition as outpatients in Niger (n = 790). Mean energy provided by six therapeutic feeding protocols was calculated and compared with average estimated energy requirements in the study population. Overall weight gain was 5.5 g·kg^?1·day^?1 among recovered children. Average energy requirements ranged from 92 to 110 kcal·kg^?1·day^?1 depending on the estimation approach. Two current therapeutic feeding protocols were found to provide an excess of energy after the first week of treatment in our study population, whereas four research protocols tended to provide less energy than the estimated requirement after the first week of treatment. Alternative feeding protocols have the potential to simplify and lead to important savings for programmes but should be evaluated to show adequacy to meet the energy needs of children under treatment, as well as feasibility and cost efficiency. Our findings rely on theoretical calculations based on several assumptions and should be confirmed in field studies.     

酸氧化电位水对微生物杀灭效果的观察

目的测定酸氧化电位水消毒液对细菌芽胞的杀灭效果和对HBsAg抗原性的破坏作用,了解该消毒液用于医疗器械消毒时的使用剂量.方法采用载体流动浸泡定量杀菌试验、载体浸泡定性HBsAg抗原性的破坏试验和医疗器械模拟现场消毒试验,分别测定酸氧化电位水消毒液对细菌芽胞的杀灭效果、HBsAg抗原性的破坏作用和使用消毒效果.结果酸氧化电位水消毒液在氧化还原电位值(1150±50)mV、pH值2.2±0.2和有效氯含量(55±10)mg/L时,流动浸泡作用15min可杀灭枯草杆菌黑色变种芽胞达消毒要求,载体浸泡作用10min可破坏HBsAg的抗原性,连续流动浸泡消毒45min,对干燥于医疗器械表面的枯草杆菌黑色变种芽胞的杀灭率可达99.90%以上.     

Impact of the shift from NCHS growth reference to WHO2006 growth standards in a therapeutic feeding programme in Niger

Objectives  To describe the implementation of the WHO₂₀₀₆ growth standards in a therapeutic feeding programme.
Methods  Using programme monitoring data from 21 769 children 6–59 months admitted to the Médecins Sans Frontières therapeutic feeding programme during 2007, we compared characteristics at admission, type of care and outcomes for children admitted before and after the shift to the WHO₂₀₀₆ standards. Admission criteria were bipedal oedema, MUAC <110 mm, or weight-for-height (WFH) of <-70% of the median (NCHS) before mid-May 2007, and WFH <-3 z score (WHO₂₀₀₆) after mid-May 2007.
Results  Children admitted with the WHO₂₀₀₆ standards were more likely to be younger, with a higher proportion of males, and less malnourished (mean WFH -3.6 z score vs. mean WFH -4.6 z score). They were less likely to require hospitalization or intensive care (28.4% vs. 77%; 12.8% vs. 36.5%) and more likely to be treated exclusively on an outpatient basis (71.6% vs. 23%). Finally, they experienced better outcomes (cure rate: 89% vs. 71.7%, death rate: 2.7% vs. 6.4%, default rate: 6.7% vs. 12.3%).
Conclusions  In this programme, the WHO₂₀₀₆ standards identify a larger number of malnourished children at an earlier stage of disease facilitating their treatment success.     

Sediment Quality Status of Two Creeks in the Upper Bonny Estuary,Niger Delta,in Relation to Urban/Industrial Activities

Two creeks (Azuabie and Obufe) in the upper Bonny Estuary, Nigeria were studied to determine how industrial and other anthropogenic activities have influenced their relative sediment qualities. Total organic carbon, total hydrocarbons, zinc, lead, cadmium and iron were significantly higher in the Azuabie creek, while phosphate, nitrate, copper and chromium did not show significant differences between the two creeks. Principal component analysis (PCA) ordinations discriminated all locations in the Obufe creek into a cluster along with the less-contaminated sites in the Azuabie creek. The other two sites in the Azuabie creek clustered separately, showing that they were contamination hot-spots.     

Spatio‐temporal patterns of foot‐and‐mouth disease transmission in cattle between 2007 and 2015 and quantitative assessment of the economic impact of the disease in Niger

Foot‐and‐mouth disease (FMD ) is endemic in Niger, with outbreaks occurring every year. Recently, there was an increasing interest from veterinary authorities to implement preventive and control measures against FMD . However, for an efficient control, improving the current knowledge on the disease dynamics and factors related to FMD occurrence is a prerequisite. The objective of this study was therefore to obtain insights into the incidence and the spatio‐temporal patterns of transmission of FMD outbreaks in Niger based on the retrospective analysis of 9‐year outbreak data. A regression tree analysis model was used to identify statistically significant predictors associated with FMD incidence, including the period (year and month), the location (region), the animal‐contact density and the animal‐contact frequency. This study provided also a first report on economic losses associated with FMD . From 2007 to 2015, 791 clinical FMD outbreaks were reported from the eight regions of Niger, with the number of outbreaks per region ranging from 5 to 309. The statistical analysis revealed that three regions (Dosso, Tillabery and Zinder), the months (September, corresponding to the end of rainy season, to December and January, i.e., during the dry and cold season), the years (2007 and 2015) and the density of contact were the main predictors of FMD occurrence. The quantitative assessment of the economic impacts showed that the average total cost of FMD at outbreak level was 499 euros, while the average price for FMD vaccination of one outbreak was estimated to be more than 314 euros. Despite some limitations of the clinical data used, this study will guide further research into the epidemiology of FMD in Niger and will promote a better understanding of the disease as well as an efficient control and prevention of FMD .     

Monitoring adverse events following immunization with a new conjugate vaccine against group A meningococcus in Niger, September 2010

Introduction

MenAfriVac is a new conjugate vaccine against Neisseria meningitidis serogroup A, the major cause of meningitis outbreaks in sub-Saharan Africa. In Niger, the MenAfriVac introduction campaign was conducted in the District of Filingue, during September 2010, targeting 392,211 individuals aged 1–29 years. We set up an enhanced spontaneous surveillance system to monitor adverse events following immunization (AEFI) during the campaign period and 42 days thereafter.

Methods

All the 33 health centres of the district have been designated as surveillance units, which reported AEFIs on a daily basis to the health district headquarters. Health care workers were instructed to screen patients presenting with predefined conditions of interest and patients spontaneously presenting at units or at vaccination posts with complaints after vaccination. Cases were classified as serious (resulting in death, hospitalization or long-term disability) or minor. A National Expert Committee was established to determine if serious cases were causally associated with the vaccine.

Results

In total, 356,532 vaccine doses were administered. During 61 days of monitoring, 82 suspected AEFIs were reported: 16 severe and 66 minor. The cumulative incidence was of 23.0 per 100,000 doses. Among severe cases, 14 were classified as coincidences, one urticaria complicated by respiratory distress was classified as a probable vaccine reaction, and one death was unclassifiable because post-mortem information was unavailable. The number of units that reported at least one case was 19/33 (57.6%).

Conclusions

Although these results are limited by underreporting of cases, we did not identify safety concerns with MenAfriVac. The lessons learned from this experience should be used to reinforce the national pharmacovigilance system in Niger to make it complaint with international standards. In order to do so, we recommend using a lighter system for routine; and conducting regular training and supervisory activities to increase its acceptance among local health workers.     

High sensitivity and specificity of the Pastorex latex agglutination test for Neisseria meningitidis serogroup A during a clinical trial in Niger

There is a great need for a rapid diagnostic test to guide vaccine choice during outbreaks of meningococcal meningitis in resource-poor countries. During a randomised clinical trial conducted during an epidemic of Neisseria meningitidis serogroup A in Niger in 2003, the sensitivity and specificity of the Pastorex latex agglutination test for this serogroup under optimal field conditions were assessed, using culture and/or PCR as the gold standard. Results from 484 samples showed a sensitivity of 88% (95% CI 85-91%) and a specificity of 93% (95% CI 90-95%). Pastorex could be a good alternative to current methods, as it can be performed in a local laboratory with rapid results and is highly specific. Sensitivity can be improved with prior microscopy where feasible. A study specifically to evaluate the Pastorex test under epidemic conditions, using laboratories with limited resources, is recommended.