Investigating persistent measles dynamics in Niger and associations with rainfall

Measles is a major cause of child mortality in sub-Saharan Africa. Current immunization strategies achieve low coverage in areas where transmission drivers differ substantially from those in high-income countries. A better understanding of measles transmission in areas with measles persistence will increase vaccination coverage and reduce ongoing transmission. We analysed weekly reported measles cases at the district level in Niger from 1995 to 2004 to identify underlying transmission mechanisms. We identified dominant periodicities and the associated spatial clustering patterns. We also investigated associations between reported measles cases and environmental drivers associated with human activities, particularly rainfall. The annual and 2-3-year periodicities dominated the reporting data spectrum. The annual periodicity was strong with contiguous spatial clustering, consistent with the latitudinal gradient of population density, and stable over time. The 2-3-year periodicities were weaker, unstable over time and had spatially fragmented clustering. The rainy season was associated with a lower risk of measles case reporting. The annual periodicity likely reflects seasonal agricultural labour migration, whereas the 2-3-year periodicity potentially results from multiple mechanisms such as reintroductions and vaccine coverage heterogeneity. Our findings suggest that improving vaccine coverage in seasonally mobile populations could reduce strong measles seasonality in Niger and across similar settings.

[Epidemiological And Clinical Aspects Of Obesity In The Medicine And Endocrinology Service Of Mali Hospital]

INTRODUCTION

Lifestyle changes have played an important role in increasing the prevalence of obesity. The objectives were to describe the epidemiological, clinical and progressive aspects of obesity in patients of the Mali hospital.

PATIENTS AND METHOD

this is a descriptive study with retrospective collection of data from the medical records of patients hospitalized in the Medicine and Endocrinology department. Our patients benefited from weight gain, height, waist measurement and hip measurement with calculation of the body mass index.

RESULTS

the study concerned 90 obese patients out of 1515 hospitalized (5.94% of frequency). The mean age was 42 ± 5 with extremes 10 and 74. The sex ratio was 0.38. Obesity was mixed: 75.4% of men, 60% of woman; Android in 36% of men, 18% of women and the only child aged 10 had morbid obesity. The reason for hospitalization was complications of obesity in 13.30%. The psychological reactions collected were: anxiety 54.40%, indifference 40% and shame 5.60%. There were 68.90% complications including 37.80% cardio metabolic (hypertension associated in 51.10%). The lipid assessment carried out showed hyper LDLdemia: 70%; HDL hypoemia: 67.80%, hyper triglyceridaemia: 66.70%. Our patients received dietary and dietary advice. No drug or surgical treatment has been initiated despite the indication. We recorded 3.30% of deaths.

CONCLUSION

The epidemiological and clinical description, diagnosis and evaluation of the repercussions of obesity are easy in our daily practice. However, care remains insufficient due to the inadequacy of the technical platform, the lack of financial means and the prejudices of our patients (ignorance of obesity as a disease).

Case-Fatality Rates and Sequelae Resulting from Neisseria meningitidis Serogroup C Epidemic, Niger, 2015

We describe clinical symptoms, case-fatality rates, and prevalence of sequelae during an outbreak of Neisseria meningitidis serogroup C infection in a rural district of Niger. During home visits, we established that household contacts of reported case-patients were at higher risk for developing meningitis than the general population.

Ciprofloxacin for contacts of cases of meningococcal meningitis as an epidemic response: study protocol for a cluster-randomized trial

Background

Epidemics of meningococcal meningitis are common in the “African meningitis belt.” Current response strategies include reactive vaccination campaigns, which are often organized too late to have maximal impact. A novel strain of Neisseria meningitidis serogroup C has been circulating in recent years, and vaccine supplies are limited. An evaluation of chemoprophylaxis with single-dose ciprofloxacin for household contacts of meningitis cases has therefore been recommended.

Methods/design

A three-arm cluster-randomized trial has been designed for implementation during a meningococcal meningitis epidemic in a health district in Niger in which at least two Health Zones (HZs) have met the weekly epidemic threshold. The primary outcome is the incidence (attack rate) of meningitis during the epidemic. Villages will be randomized in a 1:1:1 ratio to one of three different arms: standard care, household-level prophylaxis, or village-wide prophylaxis. After study launch, when a case of meningococcal meningitis is identified in an HZ, the first reported case from a village will trigger the inclusion and randomization of the village. Household-level prophylaxis with single-dose ciprofloxacin will be offered in the home to all household members within 24 hours of the notification of the case, and village-wide distributions will occur within 72 hours of the notification of the case. The sample size necessary to detect differences between each of the two intervention arms and the standard care arm will be set after 4 weeks of data collection, in order to quantify multiple variables that could be particular to a given area. The primary analysis will compare attack rates at the end of the epidemic in each of the three arms. A nested sub-study will assess the effects of ciprofloxacin prophylaxis on the prevalence of ciprofloxacin-resistant enterobacteriaceae. A total of 200 participants in the standard care arm and 200 in the village-wide prophylaxis arm will provide stool samples at days 0, 7, and 28 following their village’s inclusion in the study.

Discussion

An innovative trial is proposed for implementation during an epidemic that will assess the impact of a novel strategy for meningitis outbreak response. In parallel, we will describe potential negative effects of the intervention.

Trial registration

ClinicalTrials.gov, NCT02724046. Registered on 15 March 2016. Last updated on 13 June 2017.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2028-y) contains supplementary material, which is available to authorized users.

Efficacy of a Low-Cost, Heat-Stable Oral Rotavirus Vaccine in Niger

BACKGROUND

Each year, rotavirus gastroenteritis is responsible for about 37% of deaths from diarrhea among children younger than 5 years of age worldwide, with a disproportionate effect in sub-Saharan Africa.

METHODS

We conducted a randomized, placebo-controlled trial in Niger to evaluate the efficacy of a live, oral bovine rotavirus pentavalent vaccine (BRV-PV, Serum Institute of India) to prevent severe rotavirus gastroenteritis. Healthy infants received three doses of the vaccine or placebo at 6, 10, and 14 weeks of age. Episodes of gastroenteritis were assessed through active and passive surveillance and were graded on the basis of the score on the Vesikari scale (which ranges from 0 to 20, with higher scores indicating more severe disease). The primary end point was the efficacy of three doses of vaccine as compared with placebo against a first episode of laboratory-confirmed severe rotavirus gastroenteritis (Vesikari score, ≥11) beginning 28 days after dose 3.

RESULTS

Among the 3508 infants who were included in the per-protocol efficacy analysis, there were 31 cases of severe rotavirus gastroenteritis in the vaccine group and 87 cases in the placebo group (2.14 and 6.44 cases per 100 person-years, respectively), for a vaccine efficacy of 66.7% (95% confidence interval [CI], 49.9 to 77.9). Similar efficacy was seen in the intention-to-treat analyses, which showed a vaccine efficacy of 69.1% (95% CI, 55.0 to 78.7). There was no significant between-group difference in the risk of adverse events, which were reported in 68.7% of the infants in the vaccine group and in 67.2% of those in the placebo group, or in the risk of serious adverse events (in 8.3% in the vaccine group and in 9.1% in the placebo group); there were 27 deaths in the vaccine group and 22 in the placebo group. None of the infants had confirmed intussusception.

CONCLUSIONS

Three doses of BRV-PV, an oral rotavirus vaccine, had an efficacy of 66.7% against severe rotavirus gastroenteritis among infants in Niger. (Funded by Médecins sans Frontières Operational Center and the Kavli Foundation; ClinicalTrials.gov number, NCT02145000 .).

Measuring populations to improve vaccination coverage

In low-income settings, vaccination campaigns supplement routine immunization but often fail to achieve coverage goals due to uncertainty about target population size and distribution. Accurate, updated estimates of target populations are rare but critical; short-term fluctuations can greatly impact population size and susceptibility. We use satellite imagery to quantify population fluctuations and the coverage achieved by a measles outbreak response vaccination campaign in urban Niger and compare campaign estimates to measurements from a post-campaign survey. Vaccine coverage was overestimated because the campaign underestimated resident numbers and seasonal migration further increased the target population. We combine satellite-derived measurements of fluctuations in population distribution with high-resolution measles case reports to develop a dynamic model that illustrates the potential improvement in vaccination campaign coverage if planners account for predictable population fluctuations. Satellite imagery can improve retrospective estimates of vaccination campaign impact and future campaign planning by synchronizing interventions with predictable population fluxes.

The actual and potential costs of meningitis surveillance in the African meningitis belt: Results from Chad and Niger

BACKGROUND

The introduction of serogroup A meningococcal conjugate vaccine in the African meningitis belt required strengthened surveillance to assess long-term vaccine impact. The costs of implementing this strengthening had not been assessed.

METHODOLOGY

The ingredients approach was used to retrospectively determine bacterial meningitis surveillance costs in Chad and Niger in 2012. Resource use and unit cost data were collected through interviews with staff at health facilities, laboratories, government offices and international partners, and by reviewing financial reports. Sample costs were extrapolated to national level and costs of upgrading to desired standards were estimated.

RESULTS

Case-based surveillance had been implemented in all 12 surveyed hospitals and 29 of 33 surveyed clinics in Niger, compared to six out of 21 clinics surveyed in Chad. Lumbar punctures were performed in 100% of hospitals and clinics in Niger, compared to 52% of the clinics in Chad. The total costs of meningitis surveillance were US$ 1,951,562 in Niger and US$ 338,056 in Chad, with costs per capita of US$ 0.12 and US$ 0.03, respectively. Laboratory investigation was the largest cost component per surveillance functions, comprising 51% of the total costs in Niger and 40% in Chad. Personnel resources comprised the biggest expense type: 37% of total costs in Niger and 26% in Chad. The estimated annual, incremental costs of upgrading current systems to desired standards were US$ 183,299 in Niger and US$ 605,912 in Chad, which are 9% and 143% of present costs, respectively.

CONCLUSIONS

Niger's more robust meningitis surveillance system costs four times more per capita than the system in Chad. Since Chad spends less per capita, fewer activities are performed, which weakens detection and analysis of cases. Countries in the meningitis belt are diverse, and can use these results to assess local costs for adapting surveillance systems to monitor vaccine impact.

Rotavirus surveillance in urban and rural areas of Niger, April 2010-March 2012

Knowledge of rotavirus epidemiology is necessary to make informed decisions about vaccine introduction and to evaluate vaccine impact. During April 2010–March 2012, rotavirus surveillance was conducted among 9,745 children <5 years of age in 14 hospitals/health centers in Niger, where rotavirus vaccine has not been introduced. Study participants had acute watery diarrhea and moderate to severe dehydration, and 20% of the children were enrolled in a nutrition program. Of the 9,745 children, 30.6% were rotavirus positive. Genotyping of a subset of positive samples showed a variety of genotypes during the first year, although G2P[4] predominated. G12 genotypes, including G12P[8], which has emerged as a predominant strain in western Africa, represented >80% of isolates during the second year. Hospitalization and death rates and severe dehydration among rotavirus case-patients did not differ during the 2 years. The emergence of G12P[8] warrants close attention to the characteristics of associated epidemics and possible prevention measures.

Efficacy and safety of two closely spaced doses of praziquantel against Schistosoma haematobium and S. mansoni and re-infection patterns in school-aged children in Niger

The aim of this study was to assess the efficacy and safety of two closely spaced doses of praziquantel (PZQ) against Schistosoma haematobium and S. mansoni infection in school-aged children, and to characterise re-infection patterns over a 12-month period. The study was carried out in five villages in western Niger: Falmado, Seberi and Libore (single S. haematobium infection foci), and Diambala and Namarigoungou (mixed S. haematobium-S. mansoni infection foci). Parasitological examinations consisted of triplicate urine filtrations and triplicate Kato-Katz thick smears at each visit. Two 40mg/kg oral doses of PZQ were administered 3 weeks apart. Adverse events were monitored within 4h after dosing by the survey team and 24h after treatment using a questionnaire. Our final study cohort comprised 877 children who were infected with either S. haematobium, or S. mansoni, or both species concurrently and received both doses of PZQ. Follow-up visits were conducted 6 weeks, 6 months and 12 months after the first dose of PZQ. At baseline, the geometric mean (GM) infection intensity of S. haematobium ranged from 3.6 (Diambala) to 30.3eggs/10ml of urine (Falmado). The GM infection intensity of S. mansoni ranged from 86.7 (Diambala) to 151.4eggs/g of stool (Namarigoungou). Adverse events were reported by 33.0% and 1.5% of the children after the first and second doses of PZQ, respectively. We found cure rates (CRs) in S. haematobium-infected children 3 weeks after the second dose of PZQ ranging between 49.2% (Falmado) and 98.4% (Namarigoungou) and moderate-to-high egg reduction rates (ERRs) (71.4-100%). Regarding S. mansoni, only moderate CRs and ERRs were found (51.7-58.8% in Diambala, 55.2-60.2% in Namarigoungou). Twelve months post-treatment, prevalence rates approached pre-treatment levels, but infection intensities remained low. In conclusion, PZQ, given in two closely spaced doses, is efficacious against S. haematobium, but the low ERR observed against S. mansoni raises concern about mounting PZQ tolerance.

Safety and efficacy of praziquantel syrup (Epiquantel®) against Schistosoma haematobium and Schistosoma mansoni in preschool-aged children in Niger

Given the characteristic age-prevalence curve of Schistosoma infection, preventive chemotherapy with praziquantel is primarily targeted at school-aged children, whilst, in highly endemic areas, other high-risk groups might be included for regular treatment. Nevertheless, schistosomiasis can affect children well before they reach school-age, but this population group is usually excluded from preventive chemotherapy. We assessed the safety and efficacy of praziquantel syrup (Epiquantel®) in preschool-aged children in three villages of Niger. Children aged ≤72 months provided multiple urine and stool samples that were microscopically examined using standard protocols. Schistosoma-positive children were treated with praziquantel syrup at a dose of 40 mg/kg after a meal of millet porridge. Children remained under medical supervision for 4h and adverse events were recorded. Additionally, a questionnaire was administrated to the mothers/guardians 24h post-treatment for further probing of adverse events. Treatment efficacy was evaluated 3 and 6 weeks post-treatment using multiple stool and urine samples. A third of the 243 treated children reported adverse events within 4h, whilst a further 6.2% reported adverse events upon probing 24h post-treatment. Abdominal pain, bloody diarrhoea and sleepiness were the most common adverse events, but these were transient and self-limiting. Praziquantel syrup showed moderate-to-high efficacy against Schistosoma haematobium with egg reduction rates of 69.4% and 71.2% 3 and 6 weeks post-treatment and cure rates of 85.7% (95% confidence interval (CI) 79.7-90.5%) and 94.9% (95% CI 90.5-97.6%), respectively. Considerably lower cure and egg reduction rates were observed against Schistosoma mansoni (e.g. cure rate at 6-week post-treatment follow-up was only 50.6% (95% CI 39.9-61.2%). Concluding, praziquantel syrup is well tolerated in preschool-aged children with moderate-to-high efficacy against S. haematobium, but considerably lower efficacy against S. mansoni in Niger. A larger study is warranted to investigate the observed differences in species-specific susceptibilities and to assess operational issues and community-effectiveness.

Infections in children admitted with complicated severe acute malnutrition in Niger

Background

Although malnutrition affects thousands of children throughout the Sahel each year and predisposes them to infections, there is little data on the etiology of infections in these populations. We present a clinical and biological characterization of infections in hospitalized children with complicated severe acute malnutrition (SAM) in Maradi, Niger.

Methods

Children with complicated SAM hospitalized in the intensive care unit of a therapeutic feeding center, with no antibiotics in the previous 7 days, were included. A clinical examination, blood, urine and stool cultures, and chest radiography were performed systematically on admission.

Results

Among the 311 children included in the study, gastroenteritis was the most frequent clinical diagnosis on admission, followed by respiratory tract infections and malaria. Blood or urine culture was positive in 17% and 16% of cases, respectively, and 36% had abnormal chest radiography. Enterobacteria were sensitive to most antibiotics, except amoxicillin and cotrimoxazole. Twenty-nine (9%) children died, most frequently from sepsis. Clinical signs were poor indicators of infection and initial diagnoses correlated poorly with biologically or radiography-confirmed diagnoses.

Conclusions

These data confirm the high level of infections and poor correlation with clinical signs in children with complicated SAM, and provide antibiotic resistance profiles from an area with limited microbiological data. These results contribute unique data to the ongoing debate on the use and choice of broad-spectrum antibiotics as first-line treatment in children with complicated SAM and reinforce the call for an update of international guidelines on management of complicated SAM based on more recent data.

Removing the regional level from the Niger vaccine supply chain

OBJECTIVE

Since many of the world's vaccine supply chains contain multiple levels, the question remains of whether removing a level could bring efficiencies.

METHODS

We utilized HERMES to generate a detailed discrete-event simulation model of Niger's vaccine supply chain and compared the current four-tier (central, regional, district, and integrated health center levels) with a modified three-tier structure (removing the regional level). Different scenarios explored various accompanying shipping policies and frequencies.

FINDINGS

Removing the regional level and implementing a collection-based shipping policy from the district stores increases vaccine availability from a mean of 70-100% when districts could collect vaccines at least weekly. Alternatively, implementing a delivery-based shipping policy from the central store monthly in three-route and eight-route scenarios only increases vaccine availability to 87%. Restricting central-to district vaccine shipments to a quarterly schedule for three-route and eight-route scenarios reduces vaccine availability to 49%. The collection-based shipping policy from district stores reduces supply chain logistics cost per dose administered from US$0.14 at baseline to US$0.13 after removing the regional level.

CONCLUSION

Removing the regional level from Niger's vaccine supply chain can substantially improve vaccine availability as long as certain concomitant adjustments to shipping policies and frequencies are implemented.

Seasonality of meningitis in Africa and climate forcing: aerosols stand out

Bacterial meningitis is an ongoing threat for the population of the African Meningitis Belt, a region characterized by the highest incidence rates worldwide. The determinants of the disease dynamics are still poorly understood; nevertheless, it is often advocated that climate and mineral dust have a large impact. Over the last decade, several studies have investigated this relationship at a large scale. In this analysis, we scaled down to the district-level weekly scale (which is used for in-year response to emerging epidemics), and used wavelet and phase analysis methods to define and compare the time-varying periodicities of meningitis, climate and dust in Niger. We mostly focused on detecting time-lags between the signals that were consistent across districts. Results highlighted the special case of dust in comparison to wind, humidity or temperature: a strong similarity between districts is noticed in the evolution of the time-lags between the seasonal component of dust and meningitis. This result, together with the assumption of dust damaging the pharyngeal mucosa and easing bacterial invasion, reinforces our confidence in dust forcing on meningitis seasonality. Dust data should now be integrated in epidemiological and forecasting models to make them more realistic and usable in a public health perspective.

Spatial dynamics of meningococcal meningitis in Niger: observed patterns in comparison with measles

Throughout the African meningitis belt, meningococcal meningitis outbreaks occur only during the dry season. Measles in Niger exhibits similar seasonality, where increased population density during the dry season probably escalates measles transmission. Because meningococcal meningitis and measles are both directly transmitted, we propose that host aggregation also impacts the transmission of meningococcal meningitis. Although climate affects broad meningococcal meningitis seasonality, we focus on the less examined role of human density at a finer spatial scale. By analysing spatial patterns of suspected cases of meningococcal meningitis, we show fewer absences of suspected cases in districts along primary roads, similar to measles fadeouts in the same Nigerien metapopulation. We further show that, following periods during no suspected cases, districts with high reappearance rates of meningococcal meningitis also have high measles reintroduction rates. Despite many biological and epidemiological differences, similar seasonal and spatial patterns emerge from the dynamics of both diseases. This analysis enhances our understanding of spatial patterns and disease transmission and suggests hotspots for infection and potential target areas for meningococcal meningitis surveillance and intervention.

The impact of making vaccines thermostable in Niger's vaccine supply chain

OBJECTIVE

Determine the effects on the vaccine cold chain of making different types of World Health Organization (WHO) Expanded Program on Immunizations (EPI) vaccines thermostable.

METHODS

Utilizing a detailed computational, discrete-event simulation model of the Niger vaccine supply chain, we simulated the impact of making different combinations of the six current EPI vaccines thermostable.

FINDINGS

Making any EPI vaccine thermostable relieved existing supply chain bottlenecks (especially at the lowest levels), increased vaccine availability of all EPI vaccines, and decreased cold storage and transport capacity utilization. By far, the most substantial impact came from making the pentavalent vaccine thermostable, increasing its own vaccine availability from 87% to 97% and the vaccine availabilities of all other remaining non-thermostable EPI vaccines to over 93%. By contrast, making each of the other vaccines thermostable had considerably less effect on the remaining vaccines, failing to increase the vaccine availabilities of other vaccines to more than 89%. Making tetanus toxoid vaccine along with the pentavalent thermostable further increased the vaccine availability of all EPI vaccines by at least 1-2%.

CONCLUSION

Our study shows the potential benefits of making any of Niger's EPI vaccines thermostable and therefore supports further development of thermostable vaccines. Eliminating the need for refrigerators and freezers should not necessarily be the only benefit and goal of vaccine thermostability. Rather, making even a single vaccine (or some subset of the vaccines) thermostable could free up significant cold storage space for other vaccines, and thereby help alleviate supply chain bottlenecks that occur throughout the world.

Evaluation and use of surveillance system data toward the identification of high-risk areas for potential cholera vaccination: a case study from Niger

BACKGROUND

In 2008, Africa accounted for 94% of the cholera cases reported worldwide. Although the World Health Organization currently recommends the oral cholera vaccine in endemic areas for high-risk populations, its use in Sub-Saharan Africa has been limited. Here, we provide the principal results of an evaluation of the cholera surveillance system in the region of Maradi in Niger and an analysis of its data towards identifying high-risk areas for cholera.

RESULTS

We evaluated the cholera surveillance data using a standard CDC protocol, through interviews with heads of the system, and a review of cholera data collected between 2006-2009. The surveillance system was found to be sufficiently reliable to be able to utilize the data for the detection of high risk areas for cholera vaccination. Temporal, geographic and socio-demographic analyses of cholera cases indicated that between 2006 and 2009, 433 cholera cases were reported in the Maradi region of Niger. Two deprived neighborhoods of the region's capital city, Bagalam and Yandaka, represented 1% of the regional population and 21% of the cholera cases, reaching a yearly incidence rate of 3 per 1000 in 2006 and 2008, respectively.

CONCLUSIONS

The results of this evaluation suggest that the reporting sensitivity of the surveillance system is sufficient, to appropriately classify the region as cholera endemic. Additionally, two overcrowded neighborhoods in the regional capital met WHO criteria for consideration for cholera vaccination.

Explaining seasonal fluctuations of measles in Niger using nighttime lights imagery

Measles epidemics in West Africa cause a significant proportion of vaccine-preventable childhood mortality. Epidemics are strongly seasonal, but the drivers of these fluctuations are poorly understood, which limits the predictability of outbreaks and the dynamic response to immunization. We show that measles seasonality can be explained by spatiotemporal changes in population density, which we measure by quantifying anthropogenic light from satellite imagery. We find that measles transmission and population density are highly correlated for three cities in Niger. With dynamic epidemic models, we demonstrate that measures of population density are essential for predicting epidemic progression at the city level and improving intervention strategies. In addition to epidemiological applications, the ability to measure fine-scale changes in population density has implications for public health, crisis management, and economic development.

Impact of changing the measles vaccine vial size on Niger's vaccine supply chain: a computational model

Background

Many countries, such as Niger, are considering changing their vaccine vial size presentation and may want to evaluate the subsequent impact on their supply chains, the series of steps required to get vaccines from their manufacturers to patients. The measles vaccine is particularly important in Niger, a country prone to measles outbreaks.

Methods

We developed a detailed discrete event simulation model of the vaccine supply chain representing every vaccine, storage location, refrigerator, freezer, and transport device (e.g., cold trucks, 4 × 4 trucks, and vaccine carriers) in the Niger Expanded Programme on Immunization (EPI). Experiments simulated the impact of replacing the 10-dose measles vial size with 5-dose, 2-dose and 1-dose vial sizes.

Results

Switching from the 10-dose to the 5-dose, 2-dose and 1-dose vial sizes decreased the average availability of EPI vaccines for arriving patients from 83% to 82%, 81% and 78%, respectively for a 100% target population size. The switches also changed transport vehicle's utilization from a mean of 58% (range: 4-164%) to means of 59% (range: 4-164%), 62% (range: 4-175%), and 67% (range: 5-192%), respectively, between the regional and district stores, and from a mean of 160% (range: 83-300%) to means of 161% (range: 82-322%), 175% (range: 78-344%), and 198% (range: 88-402%), respectively, between the district to integrated health centres (IHC). The switch also changed district level storage utilization from a mean of 65% to means of 64%, 66% and 68% (range for all scenarios: 3-100%). Finally, accounting for vaccine administration, wastage, and disposal, replacing the 10-dose vial with the 5 or 1-dose vials would increase the cost per immunized patient from $0.47US to $0.71US and $1.26US, respectively.

Conclusions

The switch from the 10-dose measles vaccines to smaller vial sizes could overwhelm the capacities of many storage facilities and transport vehicles as well as increase the cost per vaccinated child.

Health care seeking behavior for diarrhea in children under 5 in rural Niger: results of a cross-sectional survey

BACKGROUND

Diarrhea remains the second leading cause of death in children under 5 years of age in sub-Saharan Africa. Health care seeking behavior for diarrhea varies by context and has important implications for developing appropriate care strategies and estimating burden of disease. The objective of this study was to determine the proportion of children under five with diarrhea who consulted at a health structure in order to identify the appropriate health care levels to set up surveillance of severe diarrheal diseases.

METHODS

A cluster survey was done on 35 clusters of 21 children under 5 years of age in each of four districts of the Maradi Region, Niger. Caretakers were asked about diarrhea of the child during the recall period and their health seeking behavior in case of diarrhea. A weighted cluster analysis was conducted to determine the prevalence of diarrhea, as well as the proportion of consultations and types of health structures consulted.

RESULTS

In total, the period prevalence of diarrhea and severe diarrhea between April 24th and May 21st 2009 were 36.8% (95% CI: 33.7 - 40.0) and 3.4% (95% CI: 2.2-4.6), respectively. Of those reporting an episode of diarrhea during the recall period, 70.4% (95% CI: 66.6-74.1) reported seeking care at a health structure. The main health structures visited were health centers, followed by health posts both for simple or severe diarrhea. Less than 10% of the children were brought to the hospital. The proportion of consultations was not associated with the level of education of the caretaker, but increased with the number of children in the household.

CONCLUSIONS

The proportion of consultations for diarrhea cases in children under 5 years old was higher than those reported in previous surveys in Niger and elsewhere. Free health care for under 5 years old might have participated in this improvement. In this type of decentralized health systems, the WHO recommended hospital-based surveillance of severe diarrheal diseases would capture only a fraction of severe diarrhea. Lower levels of health structures should be considered to obtain informative data to ensure appropriate care and burden estimates.

Effectiveness of ready-to-use therapeutic food compared to a corn/soy-blend-based pre-mix for the treatment of childhood moderate acute malnutrition in Niger

Standard nutritional treatment of moderate acute malnutrition (MAM) relies on fortified blended flours though their importance to treat this condition is a matter of discussion. With the newly introduced World Health Organization growth standards, more children at an early stage of malnutrition will be treated following the dietary protocols as for severe acute malnutrition, including ready-to-use therapeutic food (RUTF). We compared the effectiveness of RUTF and a corn/soy-blend (CSB)-based pre-mix for the treatment of MAM in the supplementary feeding programmes (SFPs) supported by Médecins Sans Frontières, located in the Zinder region (south of Niger). Children measuring 65 to <110 cm, newly admitted with MAM [weight-for-height (WHM%) between 70% and <80% of the NCHS median] were randomly allocated to receive either RUTF (Plumpy'Nut®, 1000 kcal day(-1)) or a CSB pre-mix (1231 kcal day(-1)). Other interventions were similar in both groups (e.g. weekly family ration and ration at discharge). Children were followed weekly up to recovery (WHM% ≥ 85% for 2 consecutive weeks). In total, 215 children were recruited in the RUTF group and 236 children in the CSB pre-mix group with an overall recovery rate of 79.1 and 64.4%, respectively (p < 0.001). There was no evidence for a difference between death, defaulter and non-responder rates. More transfers to the inpatient Therapeutic Feeding Centre (I-TFC) were observed in the CSB pre-mix group (19.1%) compared to the RUTF group (9.3%) (p = 0.003). The average weight gain up to discharge was 1.08 g kg(-1) day(-1) higher in the RUTF group [95% confidence interval: 0.46-1.70] and the length of stay was 2 weeks shorter in the RUTF group (p < 0.001). For the treatment of childhood MAM in Niger, RUTF resulted in a higher weight gain, a higher recovery rate, a shorter length of stay and a lower transfer rate to the I-TFC compared to a CSB pre-mix. This might have important implications on the efficacy and the quality of SFPs.

Measles hotspots and epidemiological connectivity

Though largely controlled in developed countries, measles remains a major global public health issue. Regional and local transmission patterns are rooted in human mixing behaviour across spatial scales. Identifying spatial interactions that contribute to recurring epidemics helps define and predict outbreak patterns. Using spatially explicit reported cases from measles outbreaks in Niger, we explored how regional variations in movement and contact patterns relate to patterns of measles incidence. Because we expected to see lower rates of re-introductions in small, compared to large, populations, we measured the population-size corrected proportion of weeks with zero cases across districts to understand relative rates of measles re-introductions. We found that critical elements of spatial disease dynamics in Niger are agricultural seasonality, transnational contact clusters, and roads networks that facilitate host movement and connectivity. These results highlight the need to understand local patterns of seasonality, demographic characteristics, and spatial heterogeneities to inform vaccination policy.

Reducing wasting in young children with preventive supplementation: a cohort study in Niger

OBJECTIVE

To compare the incidence of wasting, stunting, and mortality among children aged 6 to 36 months who are receiving preventive supplementation with either ready-to-use supplementary foods (RUSFs) or ready-to-use therapeutic foods (RUTFs).

SUBJECTS AND METHODS

Children aged 6 to 36 months in 12 villages of Maradi, Niger, (n = 1645) received a monthly distribution of RUSFs (247 kcal [3 spoons] per day) for 6 months or RUTFs (500-kcal sachet per day) for 4 months. We compared the incidence of wasting, stunting, and mortality among children who received preventive supplementation with RUSFs versus RUTFs.

RESULTS

The effectiveness of RUSF supplementation depended on receipt of a previous preventive intervention. In villages in which a preventive supplementation program was previously implemented, the RUSF strategy was associated with a 46% (95% confidence interval [CI]: 6%-69%) and 59% (95% CI: 17%-80%) reduction in wasting and severe wasting, respectively. In contrast, in villages in which the previous intervention was not implemented, we found no difference in the incidence of wasting or severe wasting according to type of supplementation. Compared with the RUTF strategy, the RUSF strategy was associated with a 19% (95% CI: 0%-34%) reduction in stunting overall.

CONCLUSION

We found that the relative performance of a 6-month RUSF supplementation strategy versus a 4-month RUTF strategy varied with receipt of a previous nutritional intervention. Contextual factors will continue to be important in determining the dose and duration of supplementation that will be most effective, acceptable, and sustainable for a given setting.

Rural-urban gradient in seasonal forcing of measles transmission in Niger

Seasonally driven cycles of incidence have been consistently observed for a range of directly transmitted pathogens. Though frequently observed, the mechanism of seasonality for directly transmitted human pathogens is rarely well understood. Despite significant annual variation in magnitude, measles outbreaks in Niger consistently begin in the dry season and decline at the onset of the seasonal rains. We estimate the seasonal fluctuation in measles transmission rates for the 38 districts and urban centres of Niger, from 11 years of weekly incidence reports. We show that transmission rates are consistently in anti-phase to the rainfall patterns across the country. The strength of the seasonal forcing of transmission is not correlated with the latitudinal rainfall gradient, as would be expected if transmission rates were determined purely by environmental conditions. Rather, seasonal forcing is correlated with the population size, with larger seasonal fluctuation in more populous, urban areas. This pattern is consistent with seasonal variation in human density and contact rates due to agricultural cycles. The stronger seasonality in large cities drives deep inter-epidemic troughs and results in frequent local extinction of measles, which contrasts starkly to the conventional observation that large cities, by virtue of their size, act as reservoirs of measles.

Mortality risk among children admitted in a large-scale nutritional program in Niger, 2006

Background

In 2006, the Médecins sans Frontières nutritional program in the region of Maradi (Niger) included 68,001 children 6–59 months of age with either moderate or severe malnutrition, according to the NCHS reference (weight-for-height<80% of the NCHS median, and/or mid-upper arm circumference<110 mm for children taller than 65 cm and/or presence of bipedal edema). Our objective was to identify baseline risk factors for death among children diagnosed with severe malnutrition using the newly introduced WHO growth standards. As the release of WHO growth standards changed the definition of severe malnutrition, which now includes many children formerly identified as moderately malnourished with the NCHS reference, studying this new category of children is crucial.

Methodology

Program monitoring data were collected from the medical records of all children admitted in the program. Data included age, sex, height, weight, MUAC, clinical signs on admission including edema, and type of discharge (recovery, death, and default/loss to follow up). Additional data included results of a malaria rapid diagnostic test due to Plasmodium falciparum (Paracheck®) and whether the child was a resident of the region of Maradi or came from bordering Nigeria to seek treatment. Multivariate logistic regression was performed on a subset of 27,687 children meeting the new WHO growth standards criteria for severe malnutrition (weight-for-height<−3 Z score, mid-upper arm circumference<110 mm for children taller than 65 cm or presence of bipedal edema). We explored two different models: one with only basic anthropometric data and a second model that included perfunctory clinical signs.

Principal Findings

In the first model including only weight, height, sex and presence of edema, the risk factors retained were the weight/height^1.84 ratio (OR: 5,774; 95% CI: [2,284; 14,594]) and presence of edema (7.51 [5.12; 11.0]). A second model, taking into account supplementary data from perfunctory clinical examination, identified other risk factors for death: apathy (9.71 [6.92; 13.6]), pallor (2.25 [1.25; 4.05]), anorexia (1.89 [1.35; 2.66]), fever>38.5°C (1.83 [1.25; 2.69]), and age below 1 year (1.42 [1.01; 1.99]).

Conclusions

Although clinicians will continue to perform screening using clinical signs and anthropometry, these risk indicators may provide additional criteria for the assessment of absolute and relative risk of death. Better appraisal of the child's risk of death may help orientate the child towards either hospitalization or ambulatory care. As the transition from the NCHS growth reference to the WHO standards will increase the number of children classified as severely malnourished, further studies should explore means to identify children at highest risk of death within this group using simple and standardized indicators.

Effect of preventive supplementation with ready-to-use therapeutic food on the nutritional status, mortality, and morbidity of children aged 6 to 60 months in Niger: a cluster randomized trial

CONTEXT

Ready-to-use therapeutic foods (RUTFs) are an important component of effective outpatient treatment of severe wasting. However, their effectiveness in the population-based prevention of moderate and severe wasting has not been evaluated.

OBJECTIVE

To evaluate the effect of a 3-month distribution of RUTF on the nutritional status, mortality, and morbidity of children aged 6 to 60 months in Niger.

DESIGN, SETTING, AND PARTICIPANTS

A cluster randomized trial of 12 villages in Maradi, Niger. Six villages were randomized to intervention and 6 to no intervention. All children in the study villages aged 6 to 60 months were eligible for recruitment.

INTERVENTION

Children with weight-for-height 80% or more of the National Center for Health Statistics reference median in the 6 intervention villages received a monthly distribution of 1 packet per day of RUTF (92 g [500 kcal/d]) from August to October 2006. Children in the 6 nonintervention villages received no preventive supplementation. Active surveillance for conditions requiring medical or nutritional treatment was conducted monthly in all 12 study villages from August 2006 to March 2007.

MAIN OUTCOME MEASURES

Changes in weight-for-height z score (WHZ) according to the World Health Organization Child Growth Standards and incidence of wasting (WHZ <-2) over 8 months of follow-up.

RESULTS

The number of children with height and weight measurements in August, October, December, and February was 3166, 3110, 2936, and 3026, respectively. The WHZ difference between the intervention and nonintervention groups was -0.10 z (95% confidence interval [CI], -0.23 to 0.03) at baseline and 0.12 z (95% CI, 0.02 to 0.21) after 8 months of follow-up. The adjusted effect of the intervention on WHZ from baseline to the end of follow-up was thus 0.22 z (95% CI, 0.13 to 0.30). The absolute rate of wasting and severe wasting, respectively, was 0.17 events per child-year (140 events/841 child-years) and 0.03 events per child-year (29 events/943 child-years) in the intervention villages, compared with 0.26 events per child-year (233 events/895 child-years) and 0.07 events per child-year (71 events/1029 child-years) in the nonintervention villages. The intervention thus resulted in a 36% (95% CI, 17% to 50%; P < .001) reduction in the incidence of wasting and a 58% (95% CI, 43% to 68%; P < .001) reduction in the incidence of severe wasting. There was no reduction in mortality, with a mortality rate of 0.007 deaths per child-year (7 deaths/986 child-years) in the intervention villages and 0.016 deaths per child-year (18 deaths/1099 child-years) in the nonintervention villages (adjusted hazard ratio, 0.51; 95% CI, 0.25 to 1.05).

CONCLUSION

Short-term supplementation of nonmalnourished children with RUTF reduced the decline in WHZ and the incidence of wasting and severe wasting over 8 months.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00682708.

The dynamics of measles in sub-Saharan Africa

Although vaccination has almost eliminated measles in parts of the world, the disease remains a major killer in some high birth rate countries of the Sahel. On the basis of measles dynamics for industrialized countries, high birth rate regions should experience regular annual epidemics. Here, however, we show that measles epidemics in Niger are highly episodic, particularly in the capital Niamey. Models demonstrate that this variability arises from powerful seasonality in transmission-generating high amplitude epidemics-within the chaotic domain of deterministic dynamics. In practice, this leads to frequent stochastic fadeouts, interspersed with irregular, large epidemics. A metapopulation model illustrates how increased vaccine coverage, but still below the local elimination threshold, could lead to increasingly variable major outbreaks in highly seasonally forced contexts. Such erratic dynamics emphasize the importance both of control strategies that address build-up of susceptible individuals and efforts to mitigate the impact of large outbreaks when they occur.

Time is of the essence: exploring a measles outbreak response vaccination in Niamey, Niger

The current World Health Organization recommendations for response during measles epidemics focus on case management rather than outbreak response vaccination (ORV) campaigns, which may occur too late to impact morbidity and mortality and have a high cost per case prevented. Here, we explore the potential impact of an ORV campaign conducted during the 2003-2004 measles epidemic in Niamey, Niger. We measured the impact of this intervention and also the potential impact of alternative strategies. Using a unique geographical, epidemiologic and demographic dataset collected during the epidemic, we developed an individual-based simulation model. We estimate that a median of 7.6% [4.9-8.9] of cases were potentially averted as a result of the outbreak response, which vaccinated approximately 57% (84563 of an estimated 148600) of children in the target age range (6-59 months), 23 weeks after the epidemic started. We found that intervening early (up to 60 days after the start of the epidemic) and expanding the age range to all children aged 6 months to 15 years may lead to a much larger (up to 90%) reduction in the number of cases in a West African urban setting like Niamey. Our results suggest that intervening earlier even with lower target coverage (approx. 60%), but a wider age range, may be more effective than intervening later with high coverage (more than 90%) in similar settings. This has important implications for the implementation of reactive vaccination interventions as they can be highly effective if the response is fast with respect to the spread of the epidemic.

Unacceptably high mortality related to measles epidemics in Niger, Nigeria, and Chad

BACKGROUND

Despite the comprehensive World Health Organization (WHO)/United Nations Children's Fund (UNICEF) measles mortality-reduction strategy and the Measles Initiative, a partnership of international organizations supporting measles mortality reduction in Africa, certain high-burden countries continue to face recurrent epidemics. To our knowledge, few recent studies have documented measles mortality in sub-Saharan Africa. The objective of our study was to investigate measles mortality in three recent epidemics in Niamey (Niger), N'Djamena (Chad), and Adamawa State (Nigeria).

METHODS AND FINDINGS

We conducted three exhaustive household retrospective mortality surveys in one neighbourhood of each of the three affected areas: Boukoki, Niamey, Niger (April 2004, n = 26,795); Moursal, N'Djamena, Chad (June 2005, n = 21,812); and Dong District, Adamawa State, Nigeria (April 2005, n = 16,249), where n is the total surveyed population in each of the respective areas. Study populations included all persons resident for at least 2 wk prior to the study, a duration encompassing the measles incubation period. Heads of households provided information on measles cases, clinical outcomes up to 30 d after rash onset, and health-seeking behaviour during the epidemic. Measles cases and deaths were ascertained using standard WHO surveillance-case definitions. Our main outcome measures were measles attack rates (ARs) and case fatality ratios (CFRs) by age group, and descriptions of measles complications and health-seeking behaviour. Measles ARs were the highest in children under 5 y old (under 5 y): 17.1% in Boukoki, 17.2% in Moursal, and 24.3% in Dong District. CFRs in under 5-y-olds were 4.6%, 4.0%, and 10.8% in Boukoki, Moursal, and Dong District, respectively. In all sites, more than half of measles cases in children aged under 5 y experienced acute respiratory infection and/or diarrhoea in the 30 d following rash onset. Of measles cases, it was reported that 85.7% (979/1,142) of patients visited a health-care facility within 30 d after rash onset in Boukoki, 73.5% (519/706) in Moursal, and 52.8% (603/1,142) in Dong District.

CONCLUSIONS

Children in these countries still face unacceptably high mortality from a completely preventable disease. While the successes of measles mortality-reduction strategies and progress observed in measles control in other countries of the region are laudable and evident, they should not overshadow the need for intensive efforts in countries that have just begun implementation of the WHO/UNICEF comprehensive strategy.

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.

Estimating transmission intensity for a measles epidemic in Niamey, Niger: lessons for intervention

The objective of this study is to estimate the effective reproductive ratio for the 2003-2004 measles epidemic in Niamey, Niger. Using the results of a retrospective and prospective study of reported cases within Niamey during the 2003-2004 epidemic, we estimate the basic reproductive ratio, effective reproductive ratio (RE) and minimal vaccination coverage necessary to avert future epidemics using a recent method allowing for estimation based on the epidemic case series. We provide these estimates for geographic areas within Niamey, thereby identifying neighbourhoods at high risk. The estimated citywide RE was 2.8, considerably lower than previous estimates, which may help explain the long duration of the epidemic. Transmission intensity varied during the course of the epidemic and within different neighbourhoods (RE range: 1.4-4.7). Our results indicate that vaccination coverage in currently susceptible children should be increased by at least 67% (vaccine efficacy 90%) to produce a citywide vaccine coverage of 90%. This research highlights the importance of local differences in vaccination coverage on the potential impact of epidemic control measures. The spatial-temporal spread of the epidemic from district to district in Niamey over 30 weeks suggests that targeted interventions within the city could have an impact.

Late vaccination reinforcement during a measles epidemic in Niamey, Niger (2003-2004)

Low measles vaccination coverage (VC) leads to recurrent epidemics in many African countries. We describe VC before and after late reinforcement of vaccination activities during a measles epidemic in Niamey, Niger (2003-2004) assessed by Lot Quality Assurance Sampling (LQAS). Neighborhoods of Niamey were grouped into 46 lots based on geographic proximity and population homogeneity. Before reinforcement activities, 96% of lots had a VC below 70%. After reinforcement, this proportion fell to 78%. During the intervention 50% of children who had no previous record of measles vaccination received their first dose (vaccination card or parental recall). Our results highlight the benefits and limitations of vaccine reinforcement activities performed late in the epidemic.

Ceftriaxone as effective as long-acting chloramphenicol in short-course treatment of meningococcal meningitis during epidemics: a randomised non-inferiority study

BACKGROUND

In sub-Saharan Africa in the 1990s, more than 600,000 people had epidemic meningococcal meningitis, of whom 10% died. The current recommended treatment by WHO is short-course long-acting oily chloramphenicol. Continuation of the production of this drug is uncertain, so simple alternatives need to be found. We assessed whether the efficacy of single-dose treatment of ceftriaxone was non-inferior to that of oily chloramphenicol for epidemic meningococcal meningitis.

METHODS

In 2003, we undertook a randomised, open-label, non-inferiority trial in nine health-care facilities in Niger. Participants with suspected disease who were older than 2 months were randomly assigned to receive either chloramphenicol or ceftriaxone. Primary outcome was treatment failure (defined as death or clinical failure) at 72 h, measured with intention-to-treat and per-protocol analyses.

FINDINGS

Of 510 individuals with suspected disease, 247 received ceftriaxone, 256 received chloramphenicol, and seven were lost to follow-up. The treatment failure rate at 72 h for the intention-to-treat analysis was 9% (22 patients) for both drug groups (risk difference 0.3%, 90% CI -3.8 to 4.5). Case fatality rates and clinical failure rates were equivalent in both treatment groups (14 [6%] ceftriaxone vs 12 [5%] chloramphenicol). Results were also similar for both treatment groups in individuals with confirmed meningitis caused by Neisseria meningitidis. No adverse side-effects were reported.

INTERPRETATION

Single-dose ceftriaxone provides an alternative treatment for epidemic meningococcal meningitis--its efficacy, ease of use, and low cost favour its use. National and international health partners should consider ceftriaxone as an alternative first-line treatment to chloramphenicol for epidemic meningococcal meningitis.

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.

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.

Polymerase chain reaction assay and bacterial meningitis surveillance in remote areas, Niger

To compensate for the lack of laboratories in remote areas, the national reference laboratory for meningitis in Niger used polymerase chain reaction (PCR) to enhance the surveillance of meningitis caused by Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae. PCR effectively documented the wide geographic spread of N. meningitidis serogroup W135.

Are anti-Chlamydia pneumoniae antibodies prognosis indicators for peripartum cardiomyopathy?

BACKGROUND

The authors recently pointed out an epidemiological relation between specific anti-Chlamydia pneumoniae antibodies and peripartum cardiomyopathy in Niamey (Republic of Niger).

DESIGN

In this work, they studied the prognosis value of such specific antibodies.

METHODS

The serological status for specific IgG, IgA and IgM anti-C. pneumoniae antibodies of 50 African women (age, mean+/-SD = 30.2 +/- 7 years) hospitalized in Niamey, with peripartum cardiomyopathy, was determined at the time of diagnosis. The diagnosis was categorized as 'complete remission' (13 patients, age = 29.3 +/- 6.5 years, observation delay = 27 months), 'incomplete remission' (27 patients, age = 30.7 +/- 7.6 years, observation delay = 14 months) and 'deceased' (10 patients, age = 30.3 +/- 6.2 years, observation delay = 13 months). The control group comprised 27 African women (age = 25.2 +/- 4.6 years), living in the same area. The Mann-Whitney and Fisher's exact tests were used for the statistical comparison.

RESULTS

The dilution of IgG specific anti-C. pneumoniae antibodies was higher (P = 0.047) in the 'incomplete remission' compared with 'complete remission'. The dilution of IgA specific anti-C. pneumoniae antibodies was higher (P = 0.033) in the patients with a severe evolution ('deceased' + 'incomplete remission') compared with 'complete remission'. There was no significant difference between patients in 'complete remission' compared with 'controls'.

CONCLUSIONS

At the time of peripartum cardiomyopathy diagnosis the specific IgG and IgA anti-C. pneumoniae antibodies are of prognosis value: a high dilution is more often associated with a poor prognosis. This is the first identified prognosis factor during the precocious evolution of peripartum cardiomyopathy.

Emergence of complex and diverse CRF02-AG/CRF06-cpx recombinant HIV type 1 strains in Niger, West Africa

On the basis of partial env and gag subtyping, we documented that the majority of HIV-1 strains circulating in Niger were CRF02-AG (54.3%) or CRF06-cpx (18.1%) and that 9% of the samples were possible recombinants between CRF02 and CRF06. To determine in more detail the precise structure of these viruses we sequenced the full-length genomes for three such strains (97NE-003, 00NE-036, and 00NE-095). From the bootscan and phylogenetic tree analysis it is evident that the new viruses are the result of recombination events between CRF02-AG and CRF06-cpx strains. Importantly, each virus had a different complex recombinant structure with multiple breakpoints, leading to viruses with complex mosaic patterns.

Predominance of CRF02-AG and CRF06-cpx in Niger, West Africa

A total of 110 HIV-1-positive samples obtained in 1997 (n = 44) and 2000 (n = 66) were genetically characterized in the V3-V5 envelope region and the p24 gag region. The majority of the strains were CRF02-AG (54.3%) or CRF06-cpx (18.1%) in env and gag. More than 9% of the samples were recombinants between CRF02 and CRF06; 9 were CRF06 in env but CRF02 in gag, and for one sample the opposite was seen. Overall for 23 (20.9%) samples, the subtype designation was different between env and gag, and in 20 of these 23 samples a CRF was involved in the recombination event. No significant differences were seen between subtype distributions in 1997 and 2000, except that the proportion of recombinants increased from 13.6% in 1997 to 27.2% in 2000.

[Chlamydia pneumoniae and acute respiratory tract infections in breast-feeding infants: simultaneous mother-child serological study in Niamey (Niger)]

The age and the origin of Chlamydia pneumoniae primary infection in Sahelian areas are unknown. To evaluate the prevalence of C. pneumoniae antibodies, the authors studied the serological status of C. pneumoniae-, C. psittaci- and C. trachomatis-specific antibodies of 50 mother-child couples using the microimmunofluorescence technique. Children were 10 to 34 month-old (18,1 6,2, mean SD), breast-fed and hospitalized with acute respiratory tract infections in Niamey (republic of Niger). Specific C. pneumoniae IgG antibodies were present in 46/48 (95.8%) children, IgA in 32/48 (66.6%). In the mothers, specific C. pneumoniae IgG antibodies were present in 40/48 (83.3%), IgA in 31/48 (64.6%). The specific IgM antibodies were steadily absent in mothers and children. In the mother-child couples, 38/46 (79.2%) had specific C. pneumoniae IgG antibodies and 23/47 (48.9%) had IgA. The prevalence of specific C. pneumoniae IgG and IgA antibodies is very high in this population. These results point out that C. pneumoniae primary infection is very precocious in this paediatric population and is very different from American, Asian and European reports. A mother-child direct contamination during the first months of life in this breast-feeding pediatric population is discussed.

[Value of malaria prophylaxis in surgical intervention in a malaria endemic zone , Niamey, Niger]

One hundred patients were included in a randomised trial to identify surgical factors inducing malaria and assess the impact of chloroquine prophylaxis in Niamey where resistance to the drug is moderate. Thick smears were positive in 19 patients without prophylaxis (37%) versus 7 under chloroquine (15%). Factors influencing malaria were surgical intervention lasting more than 1 hour and general anaesthesia. Chloroquine prophylaxis was significantly efficient under such circumstances.

[Behavioral disorders after treatment with isoniazid]

Isoniazid, efficient antituberculosis drug, can provoke neuropsychiatric manifestations at certain patients. Two mechanisms of action for isoniazid-related psychosis are kept by the majority of authors: pyridoxin deficiency isoniazid toxicity, molecule near chemically to iproniazid, powerful IMAO (monoamine oxydase inhibitor). The predisposing factors are: slow acetylator, diabetes, hepatic insufficiency, old age, alcoholism. Family and personal history of mental illness are also predisposing factors. We report here the observation of a 53-year-old man presented with psychotic symptoms suspected to be relation with isoniazid. The favorable evolution after the definitive stop of isoniazid therapy is in favor of this hypothesis. Although rare, the neuropsychiatric symptoms during tuberculosis treatment by isoniazid, the possibility of iatrogenic etiology must be evoked. Isoniazid, antituberculosis very used in Africa, is mentioned by several authors like the cause of psychiatric disorders. Pyridoxin deficiency seems to play a role of trigger. Supplementation with vitamin B6 during the treatment by isoniazid must be therefore systematic to warm these unrests.

[Blackwater fever in adults with sickle cell anemia. Two fatal cases]

Blackwater fever is characterized by severe intravascular hemolysis with renal failure caused by recurrent use of quinine for prophylaxis. Once described in European patients, sporadic cases have been reported more and more often in autochthonous Africans and Asians. Newer antimalarials including aminoalchohol mefloquine, and halofantrine have also been implicated in Blackwater fever. In this report we describe two cases of blackwater fever involving patients with sickle cell anemia (HbSS). Symptoms including fever, acute hemolytic anemia, emesis, back pain, and hemoglobinuria were characteristic of blackwater fever. Both patients died. Although the underlying mechanism of blackwater fever remains unclear, a likely explanation is an immunoallergic reaction to quinine. Association with glucose-6-phosphate dehydrogenase deficiency has often been reported. Our cases suggest that blackwater fever may also be correlated with hemoglobinopathy such as HbSS.

[Chlamydia infection and peripartum dilated cardiomyopathy in Niger]

Peripartum cardiac failure due to cardiomyopathy is common in sub-saharan Africa. The etiology is unknown. This study was performed in Niger to assess a possible relationship between peripartum cardiomyopathy and Chlamydia. A total of 50 African women presenting peripartum cardiomyopathy underwent testing for infection by Chlamydia pneumoniae, Chlamydia trachomatis, and Chlamydia psittaci. The inclusion criteria were cardiac failure during the last three months of pregnancy or first 6 months postpartum with echocardiographic evidence of dilated cardiomyopathy. Similar testing was carried out in a control group of 25 African women from the same geographical location without cardiac disease. Detection of specific IgG, IgA and IgM antibodies was performed using the microimmunofluorescence technique. The cut-off values were > or = 1/32 for specific IgG antibody and > or = 1/16 for specific IgA and IgM antibody. Statistical comparison of the patient and control groups was achieved using the chi 2 test. For Chlamydia pneumoniae, 48 patients (96 p. 100) versus 20 controls (80 p. 100) controls were positive for IgG antibodies (p < 0.025) and 39 patients (80 p. 100) versus 14 controls (56 p. 100) were positive for IgA antibodies (p < 0.05). No patient or control demonstrated IgM antibodies for Chlamydia pneumoniae. For Chlamydia trachomatis and Chlamydia psittaci, differences in positive rates were not statistically significant. This is the first study demonstrating infection in patients with peripartum cardiomyopathy. The possible role of Chlamydia pneumoniae is discussed.

[Acute intoxication with "sobi-lobi" (Datura). Four cases in Niger]

The datura (Datura stramonium, Datura metel) belongs to a group of plants from the solanacies variety and can be the cause of voluntary intoxication. In Nigher, its flowers and seeds are used for their hallucinogenic properties. Its alcaloïds have an atropine-like effect. We are reporting here the first four cases of voluntary intoxication among teenagers in Niamey (Republic of Niger). The symptoms, which happened to be identical for the four patients, lead us quickly towards the possibility of a collective intoxication. During the questioning, the patients admitted they had smoked the plant's dried flowers, but also they drunk an herbal tea mixed with datura seeds. Symptoms are comparable to that of intoxications caused by atropine. Neurological signs are the main symptoms (agitation, delirium, disorientation, hallucination, mydriasis, retention of urine...). The others noticeable signs are: fever, dry mouth, tachycardia, thirstiness. The evolution was favourable as the patients left the hospital between D2 and D4. Those clinical features are compared to the literature items, which are inexistent in western Africa. The prognosis may be fatal, especially for the child and during massive intoxications meant to be autolystic or toxicomaniac. The recovery when possible leads usually to no sequels however sever the clinical picture is. The consultation of the population enabled us to comprehend that datura is known and consumed for its hallucinogenic proprieties. The therapeutic guidance is described and prevention suggested.

[Congenital malaria. Parasitological and serological studies in Niamey (Niger)]

Congenital malaria is defined as the presence of Plasmodium parasites in the erythrocytes of newborns less than seven days old. The aim of this study was to determine the incidence of congenital malaria and its possible clinical consequences. We carried out a prospective survey in Niamey, the capital of Niger (600,000 inhabitants) from July to September 1993. Niamey is in an area of mesoendemic malaria and this period of the year corresponds to the rainy season, when malaria transmission is maximal. Ninety mothers and their newborns were included. We assessed the clinical status of the mother and child at the time of the delivery, and took blood smears to check for parasitemia and blood samples to check for antimalaria antibodies by indirect immunofluorescence (IIF). The placenta was not examined. Clinical signs of malaria (fever, splenomegaly, anemia and jaundice) were absent in all mothers and children and 88 of the 90 children had normal birth weights. Plasmodium falciparum was the only parasite detected, with 49 of the 90 mothers and 12 of the 90 newborns having positive blood smears. Serological tests detected the presence of antimalaria antibodies in 73 of the 90 mothers (81.1%) and 68 of the 90 newborns (75.5%). Thus, we found no cases of congenital malaria with clinical signs in this study, despite the high frequency of parasites and antimalaria antibodies. The reasons for this absence of cases of congenital malaria with symptoms are discussed.

Postpartum cardiac failure in Sudanese-Sahelian Africa: clinical prevalence in western Niger

Postpartum cardiac failure (PPCF) is the most frequent clinical form of heart failure in hospitalized women in Sudanese-Sahelian Africa. We have previously studied this disease in a hospital setting. Although the incidence is relatively high in rural areas, no systematic field study has been carried out. In this report, we describe a retrospective study conducted in the western part of Niger in July-August 1991. Sixty-two villages were visited and a thorough search for patients was initiated (from a population of 79,941 inhabitants, 19,941 females 14-40 years of age, corrected census of 1988). Twenty-eight patients from 27 villages were included. The subject patients were those presenting with predefined symptoms (dyspnea and cough) and physical signs (edema of the legs) of congestive heart failure during the six-month period following delivery. Apart from arterial hypertension and previous PPCF, diagnosis of another cardiac disease was an exclusion criterion. The prevalence of PPCF was 1.40 per 1,000 females of child-bearing age. The clinical profiles of these cases were in accordance with those of a previous study in 1989 carried out at Niamey Hospital. These results were a mean +/- SD age of 28 +/- 7 years, multiparity (mean = 4 children), poor socioeconomic status, postpartum ablutions with hot water, and a high sodium intake. This is the first study on the clinical prevalence of PPCF in a Sudanese/Sahelian population living in a rural area.

Nutritional status and plasma trace elements in peripartum cardiomyopathy. A comparative study in Niger

BACKGROUND

Peripartum cardiomyopathy is a frequent condition of unknown origin in Sahelian West Africa.

OBJECTIVE

To identify the nutritional and trace-elements status, plasma concentrations of albumin, pre-albumin (trans-thyretin), retinol binding protein, copper, selenium and zinc were assayed in 35 African women living in a Sahelian area, hospitalized in the Hôpital national, Niamey (Republic of Niger) with peripartum cardiac failure due to peripartum cardiomyopathy.

METHODS

Plasma albumin was assayed by an automatic method; pre-albumin and retinol binding protein by radial immunodiffusion (Mancini's method); and plasma copper, selenium and zinc by neutron activation and particle-induced X-ray emission. The results were compared with those for a control group of African women living under the same conditions but without peripartum cardiac failure.

RESULTS

Plasma albumin and pre-albumin were lower in patients with peripartum cardiomyopathy than they were in controls (P < 0.001). For retinol binding protein, the difference was not statistically significant. The plasma concentrations of selenium and zinc were lower in patients than they were in controls (48 +/- 25 versus 77 +/- 16 ng/ml and 0.90 +/- 0.21 versus 1.17 +/- 0.25 micrograms/ml, respectively, P < 0.001) whereas that of copper was higher (2.03 +/- 0.37 versus 1.23 +/- 0.20 micrograms/ml, P < 0.001). The mean zinc: copper ratio was lower in patients than it was in controls (0.44 versus 0.95).

CONCLUSION

Such differences may be aetiological factors or biological consequences of the peripartum cardiac failure due to cardiomyopathy. Nutritional abnormalities may play a role in the pathophysiology of the disease.