Last data update: Sep 23, 2024. (Total: 47723 publications since 2009)
Records 1-21 (of 21 Records) |
Query Trace: Niang M [original query] |
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Distribution and dynamics of Anopheles gambiae s.l. larval habitats in three Senegalese cities with high urban malaria incidence
Ndiaye F , Diop A , Chabi J , Sturm-Ramirez K , Senghor M , Diouf EH , Samb B , Diedhiou SM , Thiaw O , Zohdy S , Dotson E , Sene D , Diouf MB , Koscelnik V , Gerberg L , Bangoura A , Clark T , Faye O , Dia I , Konate L , Niang EHA . PLoS One 2024 19 (5) e0303473 Urban malaria has become a challenge for most African countries due to urbanization, with increasing population sizes, overcrowding, and movement into cities from rural localities. The rapid expansion of cities with inappropriate water drainage systems, abundance of water storage habitats, coupled with recurrent flooding represents a concern for water-associated vector borne diseases, including malaria. This situation could threaten progress made towards malaria elimination in sub-Saharan countries, including Senegal, where urban malaria has presented as a threat to national elimination gains. To assess drivers of urban malaria in Senegal, a 5-month study was carried out from August to December 2019 in three major urban areas and hotspots for malaria incidence (Diourbel, Touba, and Kaolack) including the rainy season (August-October) and partly dry season (November-December). The aim was to characterize malaria vector larval habitats, vector dynamics across both seasons, and to identify the primary eco- environmental entomological factors contributing to observed urban malaria transmission. A total of 145 Anopheles larval habitats were found, mapped, and monitored monthly. This included 32 in Diourbel, 83 in Touba, and 30 in Kaolack. The number of larval habitats fluctuated seasonally, with a decrease during the dry season. In Diourbel, 22 of the 32 monitored larval habitats (68.75%) were dried out by December and considered temporary, while the remaining 10 (31.25%) were classified as permanent. In the city of Touba 28 (33.73%) were temporary habitats, and of those 57%, 71% and 100% dried up respectively by October, November, and December. However, 55 (66.27%) habitats were permanent water storage basins which persisted throughout the study. In Kaolack, 12 (40%) permanent and 18 (60%) temporary Anopheles larval habitats were found and monitored during the study. Three malaria vectors (An. arabiensis, An. pharoensis and An. funestus s.l.) were found across the surveyed larval habitats, and An. arabiensis was found in all three cities and was the only species found in the city of Diourbel, while An. arabiensis, An. pharoensis, and An. funestus s.l. were detected in the cities of Touba and Kaolack. The spatiotemporal observations of immature malaria vectors in Senegal provide evidence of permanent productive malaria vector larval habitats year-round in three major urban centers in Senegal, which may be driving high urban malaria incidence. This study aimed to assess the presence and type of anopheline larvae habitats in urban areas. The preliminary data will better inform subsequent detailed additional studies and seasonally appropriate, cost-effective, and sustainable larval source management (LSM) strategies by the National Malaria Control Programme (NMCP). |
Urban malaria vector bionomics and human sleeping behavior in three cities in Senegal
Diop A , Ndiaye F , Sturm-Ramirez K , Konate L , Senghor M , Diouf EH , Dia AK , Diedhiou S , Samb B , Sene D , Zohdy S , Dotson E , Diouf MB , Koscelnik V , Gerberg L , Bangoura A , Faye O , Clark T , Niang EHA , Chabi J . Parasit Vectors 2023 16 (1) 331 BACKGROUND: Malaria is endemic in Senegal, with seasonal transmission, and the entire population is at risk. In recent years, high malaria incidence has been reported in urban and peri-urban areas of Senegal. An urban landscape analysis was conducted in three cities to identify the malaria transmission indicators and human behavior that may be driving the increasing malaria incidence occurring in urban environments. Specifically, mosquito vector bionomics and human sleeping behaviors including outdoor sleeping habits were assessed to guide the optimal deployment of targeted vector control interventions. METHODS: Longitudinal entomological monitoring using human landing catches and pyrethrum spray catches was conducted from May to December 2019 in Diourbel, Kaolack, and Touba, the most populous cities in Senegal after the capital Dakar. Additionally, a household survey was conducted in randomly selected houses and residential Koranic schools in the same cities to assess house structures, sleeping spaces, sleeping behavior, and population knowledge about malaria and vector control measures. RESULTS: Of the 8240 Anopheles mosquitoes collected from all the surveyed sites, 99.4% (8,191) were An. gambiae s.l., and predominantly An. arabiensis (99%). A higher number of An. gambiae s.l. were collected in Kaolack (77.7%, n = 6496) than in Diourbel and Touba. The overall mean human biting rate was 14.2 bites per person per night (b/p/n) and was higher outdoors (15.9 b/p/n) than indoors (12.5 b/p/n). The overall mean entomological inoculation rates ranged from 3.7 infectious bites per person per year (ib/p/y) in Diourbel to 40.2 ib/p/y in Kaolack. Low anthropophilic rates were recorded at all sites (average 35.7%). Of the 1202 households surveyed, about 24.3% of household members slept outdoors, except during the short rainy season between July and October, despite understanding how malaria is transmitted and the vector control measures used to prevent it. CONCLUSION: Anopheles arabiensis was the primary malaria vector in the three surveyed cities. The species showed an outdoor biting tendency, which represents a risk for the large proportion of the population sleeping outdoors. As all current vector control measures implemented in the country target endophilic vectors, these data highlight potential gaps in population protection and call for complementary tools and approaches targeting outdoor biting malaria vectors. |
Results from the second WHO external quality assessment for the molecular detection of respiratory syncytial virus, 2019-2020.
Williams T , Jackson S , Barr I , Bi S , Bhiman J , Ellis J , von Gottberg A , Lindstrom S , Peret T , Rughooputh S , Viegas M , Hirve S , Zambon M , Zhang W , Dia N , Razanazatovo N , Al-Nabet Admh , Abubakar A , Tivane A , Barakat A , Naguib A , Aziz A , Vicari A , Moen A , Govindakarnavar A , Hall A , Darmaa B , Nathalie B , Herring B , Caetano BC , Whittaker B , Baumeister E , Nakouné E , Guthrie E , Inbanathan F , Nair H , Campbell H , Kadjo HA , Oumzil H , Heraud JM , Mott JA , Namulondo J , Leite J , Nahapetyan K , Al Ariqi L , Gazo MHI , Chadha M , Pisareva M , Venter M , Siqueira MM , Lumandas M , Niang M , Albuaini M , Salman M , Oberste S , Srikantiah P , Tang P , Couto P , Smith P , Coyle PV , Dussart P , Nguyen PN , Okada PA , Wijesinghe PR , Samuel R , Brown R , Pebody R , Fasce R , Jha R , Lindstrom S , Gerber S , Potdar V , Dong X , Deng YM . Influenza Other Respir Viruses 2023 17 (1) e13073 Background: External quality assessments (EQAs) for the molecular detection of human respiratory syncytial virus (RSV) are necessary to ensure the standardisation of reliable results. The Phase II, 2019–2020 World Health Organization (WHO) RSV EQA included 28 laboratories in 26 countries. The EQA panel evaluated performance in the molecular detection and subtyping of RSV-A and RSV-B. This manuscript describes the preparation, distribution, and analysis of the 2019–2020 WHO RSV EQA. Methods: Panel isolates underwent whole genome sequencing and in silico primer matching. The final panel included nine contemporary, one historical virus and two negative controls. The EQA panel was manufactured and distributed by the UK National External Quality Assessment Service (UK NEQAS). National laboratories used WHO reference assays developed by the United States Centers for Disease Control and Prevention, an RSV subtyping assay developed by the Victorian Infectious Diseases Reference Laboratory (Australia), or other in-house or commercial assays already in use at their laboratories. Results: An in silico analysis of isolates showed a good match to assay primer/probes. The panel was distributed to 28 laboratories. Isolates were correctly identified in 98% of samples for detection and 99.6% for subtyping. Conclusions: The WHO RSV EQA 2019–2020 showed that laboratories performed at high standards. Updating the composition of RSV molecular EQAs with contemporary strains to ensure representation of circulating strains, and ensuring primer matching with EQA panel viruses, is advantageous in assessing diagnostic competencies of laboratories. Ongoing EQAs are recommended because of continued evolution of mismatches between current circulating strains and existing primer sets. © 2023 The Authors. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd. |
Efficacy and safety of artemether-lumefantrine and dihydroartemisinin-piperaquine for the treatment of uncomplicated Plasmodium falciparum malaria and prevalence of molecular markers associated with artemisinin and partner drug resistance in Uganda.
Ebong C , Sserwanga A , Namuganga JF , Kapisi J , Mpimbaza A , Gonahasa S , Asua V , Gudoi S , Kigozi R , Tibenderana J , Bwanika JB , Bosco A , Rubahika D , Kyabayinze D , Opigo J , Rutazana D , Sebikaari G , Belay K , Niang M , Halsey ES , Moriarty LF , Lucchi NW , Souza SSS , Nsobya SL , Kamya MR , Yeka A . Malar J 2021 20 (1) 484 BACKGROUND: In Uganda, artemether-lumefantrine (AL) is first-line therapy and dihydroartemisinin-piperaquine (DP) second-line therapy for the treatment of uncomplicated malaria. This study evaluated the efficacy and safety of AL and DP in the management of uncomplicated falciparum malaria and measured the prevalence of molecular markers of resistance in three sentinel sites in Uganda from 2018 to 2019. METHODS: This was a randomized, open-label, phase IV clinical trial. Children aged 6 months to 10 years with uncomplicated falciparum malaria were randomly assigned to treatment with AL or DP and followed for 28 and 42 days, respectively. Genotyping was used to distinguish recrudescence from new infection, and a Bayesian algorithm was used to assign each treatment failure a posterior probability of recrudescence. For monitoring resistance, Pfk13 and Pfmdr1 genes were Sanger sequenced and plasmepsin-2 copy number was assessed by qPCR. RESULTS: There were no early treatment failures. The uncorrected 28-day cumulative efficacy of AL ranged from 41.2 to 71.2% and the PCR-corrected cumulative 28-day efficacy of AL ranged from 87.2 to 94.4%. The uncorrected 28-day cumulative efficacy of DP ranged from 95.8 to 97.9% and the PCR-corrected cumulative 28-day efficacy of DP ranged from 98.9 to 100%. The uncorrected 42-day efficacy of DP ranged from 73.5 to 87.4% and the PCR-corrected 42-day efficacy of DP ranged from 92.1 to 97.5%. There were no reported serious adverse events associated with any of the regimens. No resistance-associated mutations in the Pfk13 gene were found in the successfully sequenced samples. In the AL arm, the NFD haplotype (N86Y, Y184F, D1246Y) was the predominant Pfmdr1 haplotype, present in 78 of 127 (61%) and 76 of 110 (69%) of the day 0 and day of failure samples, respectively. All the day 0 samples in the DP arm had one copy of the plasmepsin-2 gene. CONCLUSIONS: DP remains highly effective and safe for the treatment of uncomplicated malaria in Uganda. Recurrent infections with AL were common. In Busia and Arua, the 95% confidence interval for PCR-corrected AL efficacy fell below 90%. Further efficacy monitoring for AL, including pharmacokinetic studies, is recommended. Trial registration The trail was also registered with the ISRCTN registry with study Trial No. PACTR201811640750761. |
Determinants of malaria testing at health facilities: the case of Uganda
Kigozi RN , Bwanika J , Goodwin E , Thomas P , Bukoma P , Nabyonga P , Isabirye F , Oboth P , Kyozira C , Niang M , Belay K , Sebikaari G , Tibenderana JK , Gudoi SS . Malar J 2021 20 (1) 456 BACKGROUND: The World Health Organization (WHO) recommends prompt malaria diagnosis with either microscopy or malaria rapid diagnostic tests (RDTs) and treatment with an effective anti-malarial, as key interventions to control malaria. However, in sub-Saharan Africa, malaria diagnosis is still often influenced by clinical symptoms, with patients and care providers often interpreting all fevers as malaria. The Ministry of Health in Uganda defines suspected malaria cases as those with a fever. A target of conducting testing for at least 75% of those suspected to have malaria was established by the National Malaria Reduction Strategic Plan 2014-2020. METHODS: This study investigated factors that affect malaria testing at health facilities in Uganda using data collected in March/April 2017 in a cross-sectional survey of health facilities from the 52 districts that are supported by the US President's Malaria Initiative (PMI). The study assessed health facility capacity to provide quality malaria care and treatment. Data were collected from all 1085 public and private health facilities in the 52 districts. Factors assessed included supportive supervision, availability of malaria management guidelines, laboratory infrastructure, and training health workers in the use of malaria rapid diagnostic test (RDT). Survey data were matched with routinely collected health facility malaria data obtained from the district health information system Version-2 (DHIS2). Associations between testing at least 75% of suspect malaria cases with several factors were examined using multivariate logistic regression. RESULTS: Key malaria commodities were widely available; 92% and 85% of the health facilities reported availability of RDTs and artemether-lumefantrine, respectively. Overall, 933 (86%) of the facilities tested over 75% of patients suspected to have malaria. Predictors of meeting the testing target were: supervision in the last 6 months (OR: 1.72, 95% CI 1.04-2.85) and a health facility having at least one health worker trained in the use of RDTs (OR: 1.62, 95% CI 1.04-2.55). CONCLUSION: The study findings underscore the need for malaria control programmes to provide regular supportive supervision to health facilities and train health workers in the use of RDTs. |
Therapeutic Efficacy of Artemisinin-Based Combination Therapies in Democratic Republic of the Congo and Investigation of Molecular Markers of Antimalarial Resistance.
Moriarty LF , Nkoli PM , Likwela JL , Mulopo PM , Sompwe EM , Rika JM , Mavoko HM , Svigel SS , Jones S , Ntamabyaliro NY , Kaputu AK , Lucchi N , Subramaniam G , Niang M , Sadou A , Ngoyi DM , Muyembe Tamfum JJ , Schmedes SE , Plucinski MM , Chowell-Puente G , Halsey ES , Kahunu GM . Am J Trop Med Hyg 2021 105 (4) 1067-1075 Routine assessment of the efficacy of artemisinin-based combination therapies (ACTs) is critical for the early detection of antimalarial resistance. We evaluated the efficacy of ACTs recommended for treatment of uncomplicated malaria in five sites in Democratic Republic of the Congo (DRC): artemether-lumefantrine (AL), artesunate-amodiaquine (ASAQ), and dihydroartemisinin-piperaquine (DP). Children aged 6-59 months with confirmed Plasmodium falciparum malaria were treated with one of the three ACTs and monitored. The primary endpoints were uncorrected and polymerase chain reaction (PCR)-corrected 28-day (AL and ASAQ) or 42-day (DP) cumulative efficacy. Molecular markers of resistance were investigated. Across the sites, uncorrected efficacy estimates ranged from 63% to 88% for AL, 73% to 100% for ASAQ, and 56% to 91% for DP. PCR-corrected efficacy estimates ranged from 86% to 98% for AL, 91% to 100% for ASAQ, and 84% to 100% for DP. No pfk13 mutations previously found to be associated with ACT resistance were observed. Statistically significant associations were found between certain pfmdr1 and pfcrt genotypes and treatment outcome. There is evidence of efficacy below the 90% cutoff recommended by WHO to consider a change in first-line treatment recommendations of two ACTs in one site not far from a monitoring site in Angola that has shown similar reduced efficacy for AL. Confirmation of these findings in future therapeutic efficacy monitoring in DRC is warranted. |
The genomic epidemiology of multi-drug resistant invasive non-typhoidal Salmonella in selected sub-Saharan African countries.
Park SE , Pham DT , Pak GD , Panzner U , Maria Cruz Espinoza L , von Kalckreuth V , Im J , Mogeni OD , Schütt-Gerowitt H , Crump JA , Breiman RF , Adu-Sarkodie Y , Owusu-Dabo E , Rakotozandrindrainy R , Bassiahi Soura A , Aseffa A , Gasmelseed N , Sooka A , Keddy KH , May J , Aaby P , Biggs HM , Hertz JT , Montgomery JM , Cosmas L , Olack B , Fields B , Sarpong N , Razafindrabe TJL , Raminosoa TM , Kabore LP , Sampo E , Teferi M , Yeshitela B , El Tayeb MA , Krumkamp R , Dekker DM , Jaeger A , Tall A , Gassama A , Niang A , Bjerregaard-Andersen M , Løfberg SV , Deerin JF , Park JK , Konings F , Carey ME , Van Puyvelde S , Ali M , Clemens J , Dougan G , Baker S , Marks F . BMJ Glob Health 2021 6 (8) BACKGROUND: Invasive non-typhoidal Salmonella (iNTS) is one of the leading causes of bacteraemia in sub-Saharan Africa. We aimed to provide a better understanding of the genetic characteristics and transmission patterns associated with multi-drug resistant (MDR) iNTS serovars across the continent. METHODS: A total of 166 iNTS isolates collected from a multi-centre surveillance in 10 African countries (2010-2014) and a fever study in Ghana (2007-2009) were genome sequenced to investigate the geographical distribution, antimicrobial genetic determinants and population structure of iNTS serotypes-genotypes. Phylogenetic analyses were conducted in the context of the existing genomic frameworks for various iNTS serovars. Population-based incidence of MDR-iNTS disease was estimated in each study site. RESULTS: Salmonella Typhimurium sequence-type (ST) 313 and Salmonella Enteritidis ST11 were predominant, and both exhibited high frequencies of MDR; Salmonella Dublin ST10 was identified in West Africa only. Mutations in the gyrA gene (fluoroquinolone resistance) were identified in S. Enteritidis and S. Typhimurium in Ghana; an ST313 isolate carrying bla (CTX-M-15) was found in Kenya. International transmission of MDR ST313 (lineage II) and MDR ST11 (West African clade) was observed between Ghana and neighbouring West African countries. The incidence of MDR-iNTS disease exceeded 100/100 000 person-years-of-observation in children aged <5 years in several West African countries. CONCLUSIONS: We identified the circulation of multiple MDR iNTS serovar STs in the sampled sub-Saharan African countries. Investment in the development and deployment of iNTS vaccines coupled with intensified antimicrobial resistance surveillance are essential to limit the impact of these pathogens in Africa. |
Occupational Exposures to Engineered Nanomaterials: a Review of Workplace Exposure Assessment Methods
McCormick S , Niang M , Dahm MM . Curr Environ Health Rep 2021 8 (3) 223-234 PURPOSE OF REVIEW: The purpose of this review is to consolidate exposure assessment methods for occupational research on engineered nanomaterials (ENMs) published within the past 5 years (2015-2020). RECENT FINDINGS: The three ENMs that generated the highest volume of new research include titanium dioxide, graphene, and aluminum oxide. A multi-metric approach, using both online and offline instruments and analyses, has been found to be a useful method to characterize ENM workplace exposures and was commonly used in the recently published literature. Particle number concentration was the most common online exposure metric used, followed by the metrics of mass and surface area. There are currently no consensus methods for offline analyses of most ENMs. Researchers generally used gravimetric or elemental analyses for carbonaceous nanomaterials, titanium dioxide, and other nanometals, but there was little overlap between other ENM materials reviewed. Using biological markers of exposure, such as urinary oxidative stress biomarkers, as an indication of chronic exposure may also be useful for some ENMs and should be further researched. Generally, similar online instrumentation and offline electron microscopy methods were used for all ENMs. However, this consistency was not observed for offline mass analysis methods within specific ENMs. Consolidation of the most recent methods and results of exposure assessments within this broad material category can guide researchers toward future areas of study. Establishing consensus methods of exposure assessment for each individual ENM is crucial to characterizing workplace exposures, pooling data to fully understand their associated risks, and developing useful occupational exposure limits. |
Estimates of inactivated influenza vaccine effectiveness among children in Senegal: results from two consecutive cluster-randomized controlled trials in 2010 and 2011
Niang MN , Sugimoto JD , Diallo A , Diarra B , Ortiz JR , Lewis KDC , Lafond KE , Halloran ME , Widdowson MA , Neuzil KM , Victor JC . Clin Infect Dis 2020 72 (12) e959-e969 BACKGROUND: We report results of Years 2 and 3 of consecutive cluster-randomized controlled trials of trivalent inactivated influenza vaccine (IIV3) in Senegal. METHODS: We cluster-randomized (1:1) 20 villages to annual vaccination with IIV3 or inactivated poliovirus vaccine (IPV) of age-eligible residents (6 months - 10 years). The primary outcome was total vaccine effectiveness against laboratory-confirmed influenza illness (LCI) among age-eligible children (modified-intention-to-treat population [mITT]). Secondary outcomes were indirect (herd protection) and population (overall community) vaccine effectiveness. RESULTS: We vaccinated 74% of 12,408 age-eligible children in Year 2 (June 2010-April 11) and 74% of 11,988 age-eligible children in Year 3 (April 2011-December 2011) with study vaccines. Annual cumulative incidence of LCI was 4.7 (Year 2) and 4.2 (Year 3) per 100 mITT child vaccinees of IPV villages. In Year 2, IIV3 matched circulating influenza strains. The total effectiveness was 52.8% (95% CI: 32.3%-67.0%), and the population effectiveness was 36.0% (95% CI: 10.2%-54.4%) against LCI caused by any influenza strain. The indirect effectiveness against LCI by A/H3N2 was 56.4% (95% CI: 39.0%-68.9%). In Year 3, 74% of influenza detections were vaccine-mismatched to circulating B/Yamagata and 24% were vaccine-matched to circulating A/H3N2. The Year 3 total effectiveness against LCI was -14.5% (95% CI: -81.2%-27.6%). Vaccine effectiveness varied by type/subtype of influenza in both years. CONCLUSION: IIV3 was variably effective against influenza illness in Senegalese children, with total and indirect vaccine effectiveness present during the year when all circulating strains matched the IIV3 formulation. |
Immunogenicity of seasonal inactivated influenza and inactivated polio vaccines among children in Senegal: Results from a cluster-randomized trial
Niang M , Deming ME , Goudiaby D , Diop OM , Dia N , Diallo A , Ortiz JR , Diop D , Lewis KDC , Lafond KE , Widdowson MA , Victor JC , Neuzil KM . Vaccine 2020 38 (47) 7526-7532 Data on influenza vaccine immunogenicity in children are limited from tropical developing countries. We recently reported significant, moderate effectiveness of a trivalent inactivated influenza vaccine (IIV) in a controlled, cluster-randomized trial in children in rural Senegal during 2009, a year of H3N2 vaccine mismatch (NCT00893906). We report immunogenicity of IIV3 and inactivated polio vaccine (IPV) from that trial. We evaluated hemagglutination inhibition (HAI) and polio antibody titers in response to vaccination of three age groups (6 through 35 months, 3 through 5 years, and 6 through 8 years). As all children were IIV naïve, each received two vaccine doses, although titers were assessed after only the first dose for subjects aged 6 through 8 years. Seroconversion rates (4-fold titer rise or increase from <1:10 to ≥1:40) were 74-87% for A/H1N1, 76-87% for A/H3N2, and 54-79% for B/Yamagata. Seroprotection rates (HAI titer ≥ 1:40) were 79-88% for A/H1N1, 88-96% for A/H3N2, and 52-74% for B/Yamagata. IIV responses were lowest in the youngest age group, and they were comparable between ages 3 through 5 years after two doses and 6 through 8 years after one dose. We found that baseline seropositivity (HAI titer ≥ 1:10) was an effect modifier of IIV response. Using a seroprotective titer (HAI titer ≥ 1:160) recommended for IIV evaluation in children, we found that among subjects who were seropositive at baseline, 69% achieved seroprotection for both A/H1N1 and A/H3N2, while among those who were seronegative at baseline, seroprotection was achieved in 11% for A/H1N1 and 22% for A/H3N2. The IPV group had high baseline polio antibody seropositivity and appropriate responses to vaccination. Our data emphasize the importance of a two-dose IIV3 series in vaccine naïve children. IIV and IPV vaccines were immunogenic in Senegalese children. |
Intensity of pyrethroid resistance in Anopheles gambiae before and after a mass distribution of insecticide-treated nets in Kinshasa and in 11 provinces of the Democratic Republic of Congo.
Wat'senga F , Agossa F , Manzambi EZ , Illombe G , Mapangulu T , Muyembe T , Clark T , Niang M , Ntoya F , Sadou A , Plucinski M , Li Y , Messenger LA , Fornadel C , Oxborough RM , Irish SR . Malar J 2020 19 (1) 169 BACKGROUND: Between 2011 and 2018, an estimated 134.8 million pyrethroid-treated long-lasting insecticidal nets (LLINs) were distributed nationwide in the Democratic Republic of Congo (DRC) for malaria control. Pyrethroid resistance has developed in DRC in recent years, but the intensity of resistance and impact on LLIN efficacy was not known. Therefore, the intensity of resistance of Anopheles gambiae sensu lato (s.l.) to permethrin and deltamethrin was monitored before and after a mass distribution of LLINs in Kinshasa in December 2016, and in 6 other sites across the country in 2017 and 11 sites in 2018. METHODS: In Kinshasa, CDC bottle bioassays using 1, 2, 5, and 10 times the diagnostic dose of permethrin and deltamethrin were conducted using An. gambiae s.l. collected as larvae and reared to adults. Bioassays were conducted in four sites in Kinshasa province 6 months before a mass distribution of deltamethrin-treated LLINs and then two, six, and 10 months after the distribution. One site in neighbouring Kongo Central province was used as a control (no mass campaign of LLIN distribution during the study). Nationwide intensity assays were conducted in six sites in 2017 using CDC bottle bioassays and in 11 sites in 2018 using WHO intensity assays. A sub-sample of An. gambiae s.l. was tested by PCR to determine species composition and frequency of kdr-1014F and 1014S alleles. RESULTS: In June 2016, before LLIN distribution, permethrin resistance intensity was high in Kinshasa; the mean mortality rate was 43% at the 5x concentration and 73% at the 10x concentration. Bioassays at 3 time points after LLIN distribution showed considerable variation by site and time and there was no consistent evidence for an increase in pyrethroid resistance intensity compared to the neighbouring control site. Tests of An. gambiae s.l. in 6 sites across the country in 2017 and 11 sites in 2018 showed all populations were resistant to the diagnostic doses of 3 pyrethroids. In 2018, the intensity of resistance varied by site, but was generally moderate for all three pyrethroids, with survivors at x5 the diagnostic dose. Anopheles gambiae sensu stricto (s.s.) was the most common species identified across 11 sites in DRC, but in Kinshasa, An. gambiae s.s. (91%) and Anopheles coluzzii (8%) were sympatric. CONCLUSIONS: Moderate or high intensity pyrethroid resistance was detected nationwide in DRC and is a serious threat to sustained malaria control with pyrethroid LLINs. Next generation nets (PBO nets or bi-treated nets) should be considered for mass distribution. |
Multicountry distribution and characterization of extended-spectrum beta-lactamase-associated gram-negative bacteria from bloodstream infections in sub-Saharan Africa
Toy T , Pak GD , Duc TP , Campbell JI , El Tayeb MA , Von Kalckreuth V , Im J , Panzner U , Cruz Espinoza LM , Eibach D , Dekker DM , Park SE , Jeon HJ , Konings F , Mogeni OD , Cosmas L , Bjerregaard-Andersen M , Gasmelseed N , Hertz JT , Jaeger A , Krumkamp R , Ley B , Thriemer K , Kabore LP , Niang A , Raminosoa TM , Sampo E , Sarpong N , Soura A , Owusu-Dabo E , Teferi M , Yeshitela B , Poppert S , May J , Kim JH , Chon Y , Park JK , Aseffa A , Breiman RF , Schutt-Gerowitt H , Aaby P , Adu-Sarkodie Y , Crump JA , Rakotozandrindrainy R , Meyer CG , Sow AG , Clemens JD , Wierzba TF , Baker S , Marks F . Clin Infect Dis 2019 69 S449-s458 BACKGROUND: Antimicrobial resistance (AMR) is a major global health concern, yet, there are noticeable gaps in AMR surveillance data in regions such as sub-Saharan Africa. We aimed to measure the prevalence of extended-spectrum beta-lactamase (ESBL) producing Gram-negative bacteria in bloodstream infections from 12 sentinel sites in sub-Saharan Africa. METHODS: Data were generated during the Typhoid Fever Surveillance in Africa Program (TSAP), in which standardized blood cultures were performed on febrile patients attending 12 health facilities in 9 sub-Saharan African countries between 2010 and 2014. Pathogenic bloodstream isolates were identified at the sites and then subsequently confirmed at a central reference laboratory. Antimicrobial susceptibility testing, detection of ESBL production, and conventional multiplex polymerase chain reaction (PCR) testing for genes encoding for beta-lactamase were performed on all pathogens. RESULTS: Five hundred and five pathogenic Gram-negative bloodstream isolates were isolated during the study period and available for further characterization. This included 423 Enterobacteriaceae. Phenotypically, 61 (12.1%) isolates exhibited ESBL activity, and genotypically, 47 (9.3%) yielded a PCR amplicon for at least one of the screened ESBL genes. Among specific Gram-negative isolates, 40 (45.5%) of 88 Klebsiella spp., 7 (5.7%) of 122 Escherichia coli, 6 (16.2%) of 37 Acinetobacter spp., and 2 (1.3%) of 159 of nontyphoidal Salmonella (NTS) showed phenotypic ESBL activity. CONCLUSIONS: Our findings confirm the presence of ESBL production among pathogens causing bloodstream infections in sub-Saharan Africa. With few alternatives for managing ESBL-producing pathogens in the African setting, measures to control the development and proliferation of AMR organisms are urgently needed. |
Effectiveness of seasonal influenza vaccination of children in Senegal during a year of vaccine mismatch: a cluster-randomized trial
Diallo A , Diop OM , Diop D , Niang MN , Sugimoto JD , Ortiz JR , Faye EHA , Diarra B , Goudiaby D , Lewis KDC , Emery SL , Zangeneh SZ , Lafond KE , Sokhna C , Halloran ME , Widdowson MA , Neuzil KM , Victor JC . Clin Infect Dis 2019 69 (10) 1780-1788 Background: Population effects of influenza vaccination of children have not been extensively studied, especially in tropical developing countries. In rural Senegal, we assessed the total (primary objective) and indirect effectiveness of inactivated influenza vaccine, trivalent (IIV3). Methods: In this double-blind, cluster-randomized trial, villages were randomly allocated (1:1) for high-coverage vaccination of children aged 6 months through 10 years with 2008-09 northern hemisphere IIV3 or inactivated polio vaccine (IPV). Vaccinees were monitored for serious adverse events. All village residents, vaccinated and unvaccinated, were monitored for signs and symptoms of influenza illness using weekly home visits and surveillance in designated clinics. The primary outcome was all laboratory-confirmed symptomatic influenza. Results: Between May 23 and July 11, 2009, 20 villages were randomized, and 66.5% of age-eligible children were enrolled (3918 in IIV3 villages and 3848 in IPV villages). Follow-up continued until May 28, 2010. Four unrelated serious adverse events were identified. Among vaccinees, total effectiveness against illness caused by seasonal influenza virus (presumed all drifted A/H3N2 based on antigenic characterization data) circulating at high rates among children was 43.6% (95% CI, 18.6% to 60.9%). Indirect effectiveness against seasonal A/H3N2 was 15.4% (95% CI, -22.0% to 41.3%). Total effectiveness against illness caused by pandemic influenza virus (A/H1N1pdm09) was -52.1% (95% CI, -177.2% to 16.6%). Conclusions: IIV3 provided statistically significant, moderate protection to children in Senegal against circulating pre-2010 seasonal influenza strains but not against A/H1N1pdm09 not included in the vaccine. No indirect effects were measured. Further study in low resource populations is warranted. |
Current state of knowledge on the health effects of engineered nanomaterials in workers: a systematic review of human studies and epidemiological investigations
Schulte PA , Leso V , Niang M , Iavicoli I . Scand J Work Environ Health 2019 45 (3) 217-238 Objectives The widespread application of nano-enabled products and the increasing likelihood for workplace exposures make understanding engineered nanomaterial (ENM) effects in exposed workers a public and occupational health priority. The aim of this study was to report on the current state of knowledge on possible adverse effects induced by ENM in humans to determine the toxicological profile of each type of ENM and potential biomarkers for early detection of such effects in workers. Methods A systematic review of human studies and epidemiological investigations of exposed workers relative to the possible adverse effects for the most widely used ENM was performed through searches of major scientific databases including Web of Science, Scopus, and PubMed. Results Twenty-seven studies were identified. Most of the epidemiological investigations were cross-sectional. The review found limited evidence of adverse effects in workers exposed to the most commonly used ENM. However, some biological alterations are suggestive for possible adverse impacts. The primary targets of some ENM exposures were the respiratory and cardiovascular systems. Changes in biomarker levels compared with controls were also observed; however, limited exposure data and the relatively short period since the first exposure may have influenced the incidence of adverse effects found in epidemiological studies. Conclusions There is a need for longitudinal epidemiologic investigations with clear exposure characterizations for various ENM to discover potential adverse health effects and identify possible indicators of early biological alterations. In this state of uncertainty, precautionary controls for each ENM are warranted while further study of potential health effects continues. |
The phylogeography and incidence of multi-drug resistant typhoid fever in sub-Saharan Africa.
Park SE , Pham DT , Boinett C , Wong VK , Pak GD , Panzner U , Espinoza LMC , von Kalckreuth V , Im J , Schutt-Gerowitt H , Crump JA , Breiman RF , Adu-Sarkodie Y , Owusu-Dabo E , Rakotozandrindrainy R , Soura AB , Aseffa A , Gasmelseed N , Keddy KH , May J , Sow AG , Aaby P , Biggs HM , Hertz JT , Montgomery JM , Cosmas L , Fields B , Sarpong N , Razafindrabe TJL , Raminosoa TM , Kabore LP , Sampo E , Teferi M , Yeshitela B , El Tayeb MA , Sooka A , Meyer CG , Krumkamp R , Dekker DM , Jaeger A , Poppert S , Tall A , Niang A , Bjerregaard-Andersen M , Valborg Løfberg S , Seo HJ , Jeon HJ , Deerin JF , Park J , Konings F , Ali M , Clemens JD , Hughes P , Sendagala JN , Vudriko T , Downing R , Ikumapayi UN , Mackenzie GA , Obaro S , Argimon S , Aanensen DM , Page A , Keane JA , Duchene S , Dyson Z , Holt KE , Dougan G , Marks F , Baker S . Nat Commun 2018 9 (1) 5094 There is paucity of data regarding the geographical distribution, incidence, and phylogenetics of multi-drug resistant (MDR) Salmonella Typhi in sub-Saharan Africa. Here we present a phylogenetic reconstruction of whole genome sequenced 249 contemporaneous S. Typhi isolated between 2008-2015 in 11 sub-Saharan African countries, in context of the 2,057 global S. Typhi genomic framework. Despite the broad genetic diversity, the majority of organisms (225/249; 90%) belong to only three genotypes, 4.3.1 (H58) (99/249; 40%), 3.1.1 (97/249; 39%), and 2.3.2 (29/249; 12%). Genotypes 4.3.1 and 3.1.1 are confined within East and West Africa, respectively. MDR phenotype is found in over 50% of organisms restricted within these dominant genotypes. High incidences of MDR S. Typhi are calculated in locations with a high burden of typhoid, specifically in children aged <15 years. Antimicrobial stewardship, MDR surveillance, and the introduction of typhoid conjugate vaccines will be critical for the control of MDR typhoid in Africa. |
Biological monitoring of workers exposed to engineered nanomaterials
Schulte P , Leso V , Niang M , Iavicoli I . Toxicol Lett 2018 298 112-124 As the number of nanomaterial workers increases, there is need to consider whether biomonitoring of exposure should be used as a routine risk management tool. Currently no biomonitoring of nanomaterials is mandated by authoritative or regulatory agencies. However, there is a growing knowledge base to support such biomonitoring, but further research is needed, as are investigations of priorities for biomonitoring. That research is focused on validation of biomarkers of exposure and effect. Additionally, there is the possibility of using biomarkers of effect as indicators of early adverse effects in biomonitoring of nanomaterial workers. However, these biomarkers of effect are generally nonspecific. These biomarkers also need validation before they should be used. Overall biomonitoring of nanomaterial workers can be an important supplement to the exposure and risk assessment and risk management practices, although additional research is needed. |
Nationwide insecticide resistance status and biting behaviour of malaria vector species in the Democratic Republic of Congo
Wat'senga F , Manzambi EZ , Lunkula A , Mulumbu R , Mampangulu T , Lobo N , Hendershot A , Fornadel C , Jacob D , Niang M , Ntoya F , Muyembe T , Likwela J , Irish SR , Oxborough RM . Malar J 2018 17 (1) 129 BACKGROUND: Globally, the Democratic Republic of Congo (DRC) accounted for 9% of malaria cases and 10% of malaria deaths in 2015. As part of control efforts, more than 40 million long-lasting insecticidal nets (LLINs) were distributed between 2008 and 2013, resulting in 70% of households owning one or more LLINs in 2014. To optimize vector control efforts, it is critical to monitor vector behaviour and insecticide resistance trends. Entomological data was collected from eight sentinel sites throughout DRC between 2013 and 2016 in Kingasani, Mikalayi, Lodja, Kabondo, Katana, Kapolowe, Tshikaji and Kalemie. Mosquito species present, relative densities and biting times were monitored using human landing catches (HLC) conducted in eight houses, three times per year. HLC was conducted monthly in Lodja and Kapolowe during 2016 to assess seasonal dynamics. Laboratory data included resistance mechanism frequency and sporozoite rates. Insecticide susceptibility testing was conducted with commonly used insecticides including deltamethrin and permethrin. Synergist bioassays were conducted with PBO to determine the role of oxidases in permethrin resistance. RESULTS: In Lodja, monthly Anopheles gambiae s.l. biting rates were consistently high at > 10 bites/person/night indoors and outdoors. In Kapolowe, An. gambiae s.l. dominated during the rainy season, and Anopheles funestus s.l. during the dry season. In all sites, An. gambiae and An. funestus biting occurred mostly late at night. In Kapolowe, significant biting of both species started around 19:00, typically before householders use nets. Sporozoite rates were high, with a mean of 4.3% (95% CI 3.4-5.2) for An. gambiae and 3.3% (95% CI 1.3-5.3) for An. funestus. Anopheles gambiae were resistant to permethrin in six out of seven sites in 2016. In three sites, susceptibility to deltamethrin was observed despite high frequency permethrin resistance, indicating the presence of pyrethroid-specific resistance mechanisms. Pre-exposure to PBO increased absolute permethrin-associated mortality by 24%, indicating that resistance was partly due to metabolic mechanisms. The kdr-1014F mutation in An. gambiae was present at high frequency (> 70%) in three sites (Kabondo, Kingasani and Tshikaji), and lower frequency (< 20%) in two sites (Lodja and Kapolowe). CONCLUSION: The finding of widespread resistance to permethrin in DRC is concerning and alternative insecticides should be evaluated. |
Incidence of invasive salmonella disease in sub-Saharan Africa: a multicentre population-based surveillance study
Marks F , von Kalckreuth V , Aaby P , Adu-Sarkodie Y , El Tayeb MA , Ali M , Aseffa A , Baker S , Biggs HM , Bjerregaard-Andersen M , Breiman RF , Campbell JI , Cosmas L , Crump JA , Espinoza LM , Deerin JF , Dekker DM , Fields BS , Gasmelseed N , Hertz JT , Van Minh Hoang N , Im J , Jaeger A , Jeon HJ , Kabore LP , Keddy KH , Konings F , Krumkamp R , Ley B , Lofberg SV , May J , Meyer CG , Mintz ED , Montgomery JM , Niang AA , Nichols C , Olack B , Pak GD , Panzner U , Park JK , Park SE , Rabezanahary H , Rakotozandrindrainy R , Raminosoa TM , Razafindrabe TJL , Sampo E , Schütt-Gerowitt H , Sow AG , Sarpong N , Seo HJ , Sooka A , Soura AB , Tall A , Teferi M , Thriemer K , Warren MR , Yeshitela B , Clemens JD , Wierzba TF . Lancet Glob Health 2017 5 (3) e310-e323 BACKGROUND: Available incidence data for invasive salmonella disease in sub-Saharan Africa are scarce. Standardised, multicountry data are required to better understand the nature and burden of disease in Africa. We aimed to measure the adjusted incidence estimates of typhoid fever and invasive non-typhoidal salmonella (iNTS) disease in sub-Saharan Africa, and the antimicrobial susceptibility profiles of the causative agents. METHODS: We established a systematic, standardised surveillance of blood culture-based febrile illness in 13 African sentinel sites with previous reports of typhoid fever: Burkina Faso (two sites), Ethiopia, Ghana, Guinea-Bissau, Kenya, Madagascar (two sites), Senegal, South Africa, Sudan, and Tanzania (two sites). We used census data and health-care records to define study catchment areas and populations. Eligible participants were either inpatients or outpatients who resided within the catchment area and presented with tympanic (≥38.0 degrees C) or axillary temperature (≥37.5 degrees C). Inpatients with a reported history of fever for 72 h or longer were excluded. We also implemented a health-care utilisation survey in a sample of households randomly selected from each study area to investigate health-seeking behaviour in cases of self-reported fever lasting less than 3 days. Typhoid fever and iNTS disease incidences were corrected for health-care-seeking behaviour and recruitment. FINDINGS: Between March 1, 2010, and Jan 31, 2014, 135 Salmonella enterica serotype Typhi (S Typhi) and 94 iNTS isolates were cultured from the blood of 13 431 febrile patients. Salmonella spp accounted for 33% or more of all bacterial pathogens at nine sites. The adjusted incidence rate (AIR) of S Typhi per 100 000 person-years of observation ranged from 0 (95% CI 0-0) in Sudan to 383 (274-535) at one site in Burkina Faso; the AIR of iNTS ranged from 0 in Sudan, Ethiopia, Madagascar (Isotry site), and South Africa to 237 (178-316) at the second site in Burkina Faso. The AIR of iNTS and typhoid fever in individuals younger than 15 years old was typically higher than in those aged 15 years or older. Multidrug-resistant S Typhi was isolated in Ghana, Kenya, and Tanzania (both sites combined), and multidrug-resistant iNTS was isolated in Burkina Faso (both sites combined), Ghana, Kenya, and Guinea-Bissau. INTERPRETATION: Typhoid fever and iNTS disease are major causes of invasive bacterial febrile illness in the sampled locations, most commonly affecting children in both low and high population density settings. The development of iNTS vaccines and the introduction of S Typhi conjugate vaccines should be considered for high-incidence settings, such as those identified in this study. FUNDING: Bill & Melinda Gates Foundation. |
Efficacy of a Russian-backbone live attenuated influenza vaccine among children in Senegal: A randomised, double-blind, placebo-controlled trial
Victor JC , Lewis KD , Diallo A , Niang MN , Diarra B , Dia N , Ortiz JR , Widdowson MA , Feser J , Hoagland R , Emery SL , Lafond KE , Neuzil KM . Lancet Glob Health 2016 4 (12) e955-e965 BACKGROUND: Live attenuated influenza vaccines have been shown to significantly reduce influenza in diverse populations of children, but no efficacy studies have been done in resource-poor tropical settings. In Senegal, we assessed the efficacy and safety of a live attenuated influenza vaccine based on Russian-derived master donor viruses and licensed as a single dose. METHODS: In this double-blind, placebo-controlled, parallel group, single-centre trial done near Niakhar, Senegal, generally healthy children aged 2-5 years were randomly allocated (2:1) to receive a single intranasal dose of masked trivalent live attenuated influenza vaccine or placebo. The allocation sequence was computer-generated by PATH with block sizes of three. The manufacturer provided vaccine and placebo in coded vials to preserve blinding. Participants were monitored through the predictable influenza season in Senegal for adverse events and signs and symptoms of influenza using weekly home visits and surveillance in clinics. The primary outcome was symptomatic laboratory-confirmed influenza caused by any strain and occurring from 15 days post-vaccination to the end of the study. The primary analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT01854632. FINDINGS: Between May 23, and July 1, 2013, 1761 children were randomly assigned, 1174 to receive live attenuated influenza vaccine and 587 to receive placebo. The per-protocol set included 1173 vaccinees and 584 placebo recipients followed up to Dec 20, 2013. Symptomatic influenza was laboratory-confirmed in 210 (18%) of 1173 recipients of live attenuated influenza vaccine and 105 (18%) of placebo recipients, giving a vaccine efficacy of 0.0% (95% CI -26.4 to 20.9). Adverse events were balanced between the study groups. Two girls who had received live attenuated influenza vaccine died, one due to anasarca 12 days postvaccination and one due to malnutrition 70 days postvaccination. INTERPRETATION: Live attenuated influenza vaccine was well tolerated in young children in Senegal, but did not provide protection against influenza. Further study in such populations, which might experience extended periods of influenza circulation, is warranted. FUNDING: US Centers for Disease Control and Prevention and Bill & Melinda Gates Foundation. |
The relationship between invasive nontyphoidal Salmonella disease, other bacterial bloodstream infections, and malaria in sub-Saharan Africa
Park SE , Pak GD , Aaby P , Adu-Sarkodie Y , Ali M , Aseffa A , Biggs HM , Bjerregaard-Andersen M , Breiman RF , Crump JA , Cruz Espinoza LM , Eltayeb MA , Gasmelseed N , Hertz JT , Im J , Jaeger A , Parfait Kabore L , von Kalckreuth V , Keddy KH , Konings F , Krumkamp R , MacLennan CA , Meyer CG , Montgomery JM , Ahmet Niang A , Nichols C , Olack B , Panzner U , Park JK , Rabezanahary H , Rakotozandrindrainy R , Sampo E , Sarpong N , Schutt-Gerowitt H , Sooka A , Soura AB , Sow AG , Tall A , Teferi M , Yeshitela B , May J , Wierzba TF , Clemens JD , Baker S , Marks F . Clin Infect Dis 2016 62 Suppl 1 S23-31 BACKGROUND: Country-specific studies in Africa have indicated that Plasmodium falciparum is associated with invasive nontyphoidal Salmonella (iNTS) disease. We conducted a multicenter study in 13 sites in Burkina Faso, Ethiopia, Ghana, Guinea-Bissau, Kenya, Madagascar, Senegal, South Africa, Sudan, and Tanzania to investigate the relationship between the occurrence of iNTS disease, other systemic bacterial infections, and malaria. METHODS: Febrile patients received a blood culture and a malaria test. Isolated bacteria underwent antimicrobial susceptibility testing, and the association between iNTS disease and malaria was assessed. RESULTS: A positive correlation between frequency proportions of malaria and iNTS was observed (P = .01; r = 0.70). Areas with higher burden of malaria exhibited higher odds of iNTS disease compared to other bacterial infections (odds ratio [OR], 4.89; 95% CI, 1.61-14.90; P = .005) than areas with lower malaria burden. Malaria parasite positivity was associated with iNTS disease (OR, 2.44; P = .031) and gram-positive bacteremias, particularly Staphylococcus aureus, exhibited a high proportion of coinfection with Plasmodium malaria. Salmonella Typhimurium and Salmonella Enteritidis were the predominant NTS serovars (53/73; 73%). Both moderate (OR, 6.05; P = .0001) and severe (OR, 14.62; P < .0001) anemia were associated with iNTS disease. CONCLUSIONS: A positive correlation between iNTS disease and malaria endemicity, and the association between Plasmodium parasite positivity and iNTS disease across sub-Saharan Africa, indicates the necessity to consider iNTS as a major cause of febrile illness in malaria-holoendemic areas. Prevention of iNTS disease through iNTS vaccines for areas of high malaria endemicity, targeting high-risk groups for Plasmodium parasitic infection, should be considered. |
Delayed 2009 pandemic influenza A virus subtype H1N1 circulation in West Africa, May 2009-April 2010
Nzussouo NT , Michalove J , Diop OM , Njouom R , Monteiro Mde L , Adje HK , Manoncourt S , Amankwa J , Koivogui L , Sow S , Elkory MB , Collard JM , Dalhatu I , Niang MN , Lafond K , Moniz F , Coulibaly D , Kronman KC , Oyofo BA , Ampofo W , Tamboura B , Bara AO , Jusot JF , Ekanem E , Sarr FD , Hwang I , Cornelius C , Coker B , Lindstrom S , Davis R , Dueger E , Moen A , Widdowson MA . J Infect Dis 2012 206 Suppl 1 S101-7 To understand 2009 pandemic influenza A virus subtype H1N1 (A[H1N1]pdm09) circulation in West Africa, we collected influenza surveillance data from ministries of health and influenza laboratories in 10 countries, including Cameroon, from 4 May 2009 through 3 April 2010. A total of 10,203 respiratory specimens were tested, of which 25% were positive for influenza virus. Until the end of December 2009, only 14% of all detected strains were A(H1N1)pdm09, but the frequency increased to 89% from January through 3 April 2010. Five West African countries did not report their first A(H1N1)pdm09 case until 6 months after the emergence of the pandemic in North America, in April 2009. The time from first detection of A(H1N1)pdm09 in a country to the time of A(H1N1)pdm09 predominance varied from 0 to 37 weeks. Seven countries did not report A(H1N1)pdm09 predominance until 2010. Introduction and transmission of A(H1N1)pdm09 were delayed in this region. |
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