Improving the Quality of Adult Mortality Data Collected in Demographic Surveys: Validation Study of a New Siblings' Survival Questionnaire in Niakhar,Senegal

Background

In countries with limited vital registration, adult mortality is frequently estimated using siblings'' survival histories (SSHs) collected during Demographic and Health Surveys (DHS). These data are affected by reporting errors. We developed a new SSH questionnaire, the siblings'' survival calendar (SSC). It incorporates supplementary interviewing techniques to limit omissions of siblings and uses an event history calendar to improve reports of dates and ages. We hypothesized that the SSC would improve the quality of adult mortality data.

Methods and Findings

We conducted a retrospective validation study among the population of the Niakhar Health and Demographic Surveillance System in Senegal. We randomly assigned men and women aged 15–59 y to an interview with either the DHS questionnaire or the SSC. We compared SSHs collected in each group to prospective data on adult mortality collected in Niakhar. The SSC reduced respondents'' tendency to round reports of dates and ages to the nearest multiple of five or ten (“heaping”). The SSC also had higher sensitivity in recording adult female deaths: among respondents whose sister(s) had died at an adult age in the past 15 y, 89.6% reported an adult female death during SSC interviews versus 75.6% in DHS interviews (p = 0.027). The specificity of the SSC was similar to that of the DHS questionnaire, i.e., it did not increase the number of false reports of deaths. However, the SSC did not improve the reporting of adult deaths among the brothers of respondents. Study limitations include sample selectivity, limited external validity, and multiple testing.

Conclusions

The SSC has the potential to collect more accurate SSHs than the questionnaire used in DHS. Further research is needed to assess the effects of the SSC on estimates of adult mortality rates. Additional validation studies should be conducted in different social and epidemiological settings.

Trial Registration

Controlled-Trials.com ISRCTN06849961 Please see later in the article for the Editors'' Summary     

Genetic diversity and quinolone resistance in Campylobacter jejuni isolates from poultry in Senegal

We used the multilocus sequence typing (MLST) method to evaluate the genetic diversity of 46 Campylobacter jejuni isolates from chickens and to determine the link between quinolone resistance and sequence type (ST). There were a total of 16 ST genotypes, and the majority of them belonged to seven clonal complexes previously identified by using isolates from human disease. The ST-353 complex was the most common complex, whereas the ST-21, ST-42, ST-52, and ST-257 complexes were less well represented. The resistance phenotype varied for each ST, and the Thr-86-Ile substitution in the GyrA protein was the predominant mechanism of resistance to quinolone. Nine of the 14 isolates having the Thr-86-Ile substitution belonged to the ST-353 complex. MLST showed that the emergence of quinolone resistance is not related to the diffusion of a unique clone and that there is no link between ST genotype and quinolone resistance. Based on silent mutations, different variants of the gyrA gene were shown to exist for the same ST. These data provide useful information for understanding the epidemiology of C. jejuni in Senegal.     

Préférence de ponte et niveaux d’adaptation de différentes souches de Caryedon serratus Ol. (Coleoptera: Bruchidae) à l’arachide (Arachis hypogaea L., Fabaceae)

Résumé

La sélection du substrat de ponte par des souches de la bruche de l’arachide, Caryedon serratus, issues d’hôtes différents est étudiée au laboratoire. Des tests de choix sur des gousses de différentes plantes ont été d’abord effectués. Les distributions des oeufs sur les différents substrats de ponte sont comparées. Les niveaux d’adaptation des souches dites sauvages (Bauhinia rufescens, Cassia sieberiana, Piliostigma reticulatum et Tamarindus indica) sur l’arachide et les capacités de développement de la souche ? arachide ? sur les graines des plantes hôtes ? sauvages ? sont aussi testés. Les résultats révèlent que, d’une manière générale, les souches évoluent selon le principe de sélection d’hôtes de Hopkins puisque la ponte se fait de manière privilégiée sur la gousse de la plante d’où est issue la femelle. La souche ? Piliostigma ? dépose ses oeufs de manière indifférenciée sur gousses de P. reticulatum et sur gousses d’arachide. Les résultats des tests sur les niveaux d’adaptation révèlent du point de vue de la durée de développement, qu’on peut considérer les différentes souches comme identiques quant à leurs possibilités intrinsèques de développement sur l’arachide. Le paramètre poids des adultes, montre que la souche ? Bauhinia ? est intrinsèquement moins bien adaptée que les autres souches sur l’arachide. Les taux fécondité révèlent que les différentes souches sont identiques quant à leurs possibilités intrinsèques de développement sur l’arachide mais, ici également, la souche ? Bauhinia ? paraît moins bien adaptée à l’arachide. Le passage de la souche ? arachide ? aux plantes hôtes sauvages est possible mais, élevée sur graines plantes hôtes sauvages, celle-ci se comporte généralement moins bien que sur arachide.     

Ultrastructure of the spermatozoon of Anomotaenia quelea (Mettrick, 1961) (Cestoda,Cyclophyllidea, Dilepididae), an intestinal parasite of Quelea quelea (Aves,Ploceidae) in Senegal

The mature spermatozoon of Anomotaenia quelea exhibits an apical cone of electron-dense material and two helicoidal crest-like bodies. The apical cone near its base is surrounded by a lucent cytoplasm and a spiraled layer of cortical microtubules. The crest-like bodies are of different lengths, spiraled and make an angle of 30–40° to the hypothetical spermatozoon axis. The axoneme is of the 9 + ‘1’ trepaxonematan pattern and is surrounded by a periaxonemal sheath of electron-dense material. The cytoplasm contains in regions III and IV numerous electron-dense granules situated between the periaxonemal sheath and the cortical microtubules. The posterior extremity of the spermatozoon of A. quelea exhibits a nucleus and a disorganized axoneme and cortical microtubules. This type of posterior extremity of the mature spermatozoon has never been described previously in a Dilepididae. Similarly, two crest-like bodies have not been observed before in a dilepidid cestode.     

Cryptococcal Meningitis in Senegal: Epidemiology, Laboratory Findings, Therapeutic and Outcome of Cases Diagnosed from 2004 to 2011

Background

Cryptococcal meningitis is one of the most important opportunistic infection and a major contributor to early mortality. In sub-Saharan Africa, particularly in Senegal, prevalence of cryptococcal meningitis remains high. This study aimed to describe the epidemiology, laboratory profile, therapeutic and outcome of cases diagnosed in Dakar.

Methods

We analyzed the cryptococcosis cases diagnosed at the department of parasitology–mycology in Fann Teaching Hospital in Dakar from 2004 to 2011. The diagnosis was confirmed by culture on Sabouraud’s dextrose agar and/or by India ink preparation and/or by cryptococcal antigen detection. The diagnosis methods were assessed by using culture as reference.

Results

A total of 106 cases of cryptococcal meningitis were diagnosed. The prevalence of cryptococcal meningitis was 7.8 %. The mean age of the patients was 40.17 ± 9.89 years. There were slightly more male (53.8 %) than female (46.2 %) patients; 89.6 % were found to be infected with HIV, and the median CD4+ count was 27/mm³. Approximately 79.5 % of the patients had <100 CD4+ lymphocytes/mm³. India ink staining presented sensitivity at 94.11 % and specificity at 100 %. Sensitivity and specificity of cryptococcal antigen detection in cerebrospinal fluid were, respectively, 96.96 and 15.78 %. The most frequently used antifungal drug was fluconazole (86.7 %), and the mortality rate was 62.2 % (66 deaths).

Conclusion

Early diagnosis is essential to control cryptococcosis, and countries should prioritize widespread and reliable access to rapid diagnostic cryptococcus antigen assays. But it is important to make available conventional methods (India ink and culture) in the maximum of laboratory in regional health facilities.     

Regulation of Eukaryotic Initiation Factor 4AII by MyoD during Murine Myogenic Cell Differentiation

Gene expression during muscle cell differentiation is tightly regulated at multiple levels, including translation initiation. The PI3K/mTOR signalling pathway exerts control over protein synthesis by regulating assembly of eukaryotic initiation factor (eIF) 4F, a heterotrimeric complex that stimulates recruitment of ribosomes to mRNA templates. One of the subunits of eIF4F, eIF4A, supplies essential helicase function during this phase of translation. The presence of two cellular eIF4A isoforms, eIF4AI and eIF4AII, has long thought to impart equivalent functions to eIF4F. However, recent experiments have alluded to distinct activities between them. Herein, we characterize distinct regulatory mechanisms between the eIF4A isoforms during muscle cell differentiation. We find that eIF4AI levels decrease during differentiation whereas eIF4AII levels increase during myofiber formation in a MyoD-dependent manner. This study characterizes a previously undefined mechanism for eIF4AII regulation in differentiation and highlights functional differences between eIF4AI and eIF4AII. Finally, RNAi-mediated alterations in eIF4AI and eIF4AII levels indicate that the myogenic process can tolerate short term reductions in eIF4AI or eIF4AII levels, but not both.     

A Listeria monocytogenes clone in human breast milk associated with severe acute malnutrition in West Africa: A multicentric case-controlled study

BackgroundSevere acute malnutrition (SAM) is a major public health problem affecting children under the age of five in many low- and middle-income countries, and its resolution would contribute towards achieving the several sustainable development goals. The etiology of SAM is pluri-factorial, including delayed maturation of the gut microbiota, suboptimal feeding practices and dysfunctional breastfeeding. The recent serendipitous detection of Listeria monocytogenes in the breast milk of Malian women, in contrast to French women, suggests a possible association with SAM.Methodology/ Principal findingsTo investigate the possible association of L. monocytogenes carriage in breast milk and SAM, a case-control study was performed in Senegal, with subjects recruited from two areas. Using 16S amplicon sequencing, a culture independent method, 100% (152/152) of the mothers were positive for L. monocytogenes in their breast milk while qPCR analysis gave lower recovery rates. Interestingly, after enrichment in Fraser broth and seeding on PALCALM agar, all 10 isolated strains were isolated from the milk of 10 mothers who had SAM children which also had a significantly increased relative abundance of L. monocytogenes (0.34 (SD 0.35) vs 0.05 (SD 0.07) in controls, p<0.0001). The high genomic similarity between these strains and Malian breast milk strains from a previous study supports the hypothesis of endemic clone carriage in West Africa. Moreover, the in vitro growth inhibition of L. monocytogenes using breast milk samples was obtained from only 50% of the milk of mothers who had SAM children, in contrast to control samples which systematically inhibited the growth of L. monocytogenes with a higher inhibition diameter (15.7 mm (SD 2.3) in controls versus 3.5 mm (SD 4.6) in SAM, p = 0.0001). Lactobacillus and Streptococcus isolated from the breast milk of controls inhibit L. monocytogenes in a species-dependent manner.Conclusions/SignificanceOur study reveals a previously unsuspected carriage of L. monocytogenes in the breast milk of West African women, which is associated with SAM. The inhibitory effect of human selected lactic acid bacterial species against L. monocytogenes might provide new therapeutic and inexpensive options to prevent and treat this neglected public health issue.     

Risk Mapping of Anopheles gambiae s.l. Densities Using Remotely-Sensed Environmental and Meteorological Data in an Urban Area: Dakar,Senegal

Introduction

High malaria transmission heterogeneity in an urban environment is basically due to the complex distribution of Anopheles larval habitats, sources of vectors. Understanding 1) the meteorological and ecological factors associated with differential larvae spatio-temporal distribution and 2) the vectors dynamic, both may lead to improving malaria control measures with remote sensing and high resolution data as key components. In this study a robust operational methodology for entomological malaria predictive risk maps in urban settings is developed.

Methods

The Tele-epidemiology approach, i.e., 1) intensive ground measurements (Anopheles larval habitats and Human Biting Rate, or HBR), 2) selection of the most appropriate satellite data (for mapping and extracting environmental and meteorological information), and 3) use of statistical models taking into account the spatio-temporal data variability has been applied in Dakar, Senegal.

Results

First step was to detect all water bodies in Dakar. Secondly, environmental and meteorological conditions in the vicinity of water bodies favoring the presence of Anopheles gambiae s.l. larvae were added. Then relationship between the predicted larval production and the field measured HBR was identified, in order to generate An. gambiae s.l. HBR high resolution maps (daily, 10-m pixel in space).

Discussion and Conclusion

A robust operational methodology for dynamic entomological malaria predictive risk maps in an urban setting includes spatio-temporal variability of An. gambiae s.l. larval habitats and An. gambiae s.l. HBR. The resulting risk maps are first examples of high resolution products which can be included in an operational warning and targeting system for the implementation of vector control measures.     

Ultrastructure of the spermatozoon of Bothriocotyle sp. (Cestoda: Bothriocephalidea), a parasite of Schedophilus velaini (Sauvage, 1879) (Perciformes: Centrolophidae) in Senegal

The mature spermatozoon of Bothriocotyle sp. is filiform and tapered at both extremities. It possesses 2 axonemes of unequal length, showing the 9 + "1" pattern of Trepaxonemata. The anterior extremity exhibits a crest-like body. Thereafter, the crest-like body disappears, and the first axoneme is surrounded by a ring of cortical microtubules (about 27 units) that persist until the appearance of the second axoneme. This ring of cortical microtubules is characteristic only for species of Bothriocephalidea and represents a very useful phylogenetic character. The spermatozoon cytoplasm is slightly electron-dense and contains numerous electron-dense granules of glycogen in several regions. The anterior and posterior extremities of the spermatozoon lack cortical microtubules. The posterior extremity of the spermatozoon of Bothriocotyle sp. possesses a nucleus and a disorganized axoneme, which also characterizes spermatozoa of the Echinophallidae studied to date.