Last data update: Apr 29, 2024. (Total: 46658 publications since 2009)
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Rapid outbreak sequencing of Ebola virus in Sierra Leone identifies transmission chains linked to sporadic cases.
Arias A , Watson SJ , Asogun D , Tobin EA , Lu J , Phan MVT , Jah U , Wadoum REG , Meredith L , Thorne L , Caddy S , Tarawalie A , Langat P , Dudas G , Faria NR , Dellicour S , Kamara A , Kargbo B , Kamara BO , Gevao S , Cooper D , Newport M , Horby P , Dunning J , Sahr F , Brooks T , Simpson AJH , Groppelli E , Liu G , Mulakken N , Rhodes K , Akpablie J , Yoti Z , Lamunu M , Vitto E , Otim P , Owilli C , Boateng I , Okoror L , Omomoh E , Oyakhilome J , Omiunu R , Yemisis I , Adomeh D , Ehikhiametalor S , Akhilomen P , Aire C , Kurth A , Cook N , Baumann J , Gabriel M , Wölfel R , Di Caro A , Carroll MW , Günther S , Redd J , Naidoo D , Pybus OG , Rambaut A , Kellam P , Goodfellow I , Cotten M . Virus Evol 2016 2 (1) vew016 To end the largest known outbreak of Ebola virus disease (EVD) in West Africa and to prevent new transmissions, rapid epidemiological tracing of cases and contacts was required. The ability to quickly identify unknown sources and chains of transmission is key to ending the EVD epidemic and of even greater importance in the context of recent reports of Ebola virus (EBOV) persistence in survivors. Phylogenetic analysis of complete EBOV genomes can provide important information on the source of any new infection. A local deep sequencing facility was established at the Mateneh Ebola Treatment Centre in central Sierra Leone. The facility included all wetlab and computational resources to rapidly process EBOV diagnostic samples into full genome sequences. We produced 554 EBOV genomes from EVD cases across Sierra Leone. These genomes provided a detailed description of EBOV evolution and facilitated phylogenetic tracking of new EVD cases. Importantly, we show that linked genomic and epidemiological data can not only support contact tracing but also identify unconventional transmission chains involving body fluids, including semen. Rapid EBOV genome sequencing, when linked to epidemiological information and a comprehensive database of virus sequences across the outbreak, provided a powerful tool for public health epidemic control efforts. |
Findings the graves: SLED Family Reunification Program: SLED Family Reunification Program.
Bensyl D , Bangura B , Cundy S , Gegbai F , Gorina Y , Harding JD , Hersey S , Jambai A , Kamara AS , Kargbo A , Kamara MAM , Lansana P , Otieno D , Redd JT , Samba TT , Singh T , Vandi MA . Ann Epidemiol 2021 64 15-22 In 2015, the Sierra Leone Ministry of Health and Sanitation (MoHS) and the Centers for Disease Control and Prevention (CDC) agreed to consolidate data recorded by MoHS and international partners during the Ebola epidemic and create the Sierra Leone Ebola Database (SLED). The primary objectives were helping families to identify the location of graves of their loved ones who died from any cause at the time of the Ebola epidemic and creating a data source for epidemiological research. The Family Reunification Program fulfils the first SLED objective. The purpose of this paper is to describe the Family Reunification Program (Program) development, functioning and results. The MoHS, CDC, SLED Team, and Concern Worldwide developed, tested, and implemented methodology and tools to conduct the Program. Family liaisons were trained in protection of the personally identifiable information. The SLED Family Reunification Program allows families in Sierra Leone, who did not know the final resting place of their loved ones, to be reunited with their graves and to bring them relief and closure. Continuing family requests in search of the burial place of loved ones five years after the end of the epidemic shows that the emotional burden of losing a family member and not knowing the place of burial does not diminish with time. As of February 2021, the Program continues and is described to allow its replication for other emergency events including COVID-19 and new Ebola outbreaks. |
Implementing nationwide facility-based electronic disease surveillance in Sierra Leone: Lessons learned
Martin DW , Sloan ML , Gleason BL , de Wit L , Vandi MA , Kargbo DK , Clemens N , Kamara A , Njuguna C , Sesay S , Singh T . Health Secur 2020 18 S72-s80 The Global Health Security Agenda aims to improve countries' ability to prevent, detect, and respond to infectious disease threats by building or strengthening core capacities required by the International Health Regulations (2005). One of those capacities is the development of surveillance systems to rapidly detect and respond to occurrences of diseases with epidemic potential. Since 2015, the US Centers for Disease Control and Prevention (CDC) has worked with partners in Sierra Leone to assist the Ministry of Health and Sanitation in developing an Integrated Disease Surveillance and Response (IDSR) system. Beginning in 2016, CDC, in collaboration with the World Health Organization and eHealth Africa, has supported the ministry in the development of Android device mobile data entry at the health facility for electronic IDSR (eIDSR), also known as health facility-based eIDSR. Health facility-based eIDSR was introduced via a pilot program in 1 district, and national rollout began in 2018. With more than 1,100 health facilities now reporting, the Sierra Leone eIDSR system is substantially larger than most mobile-device health (mHealth) projects found in the literature. Several technical innovations contributed to the success of health facility-based eIDSR in Sierra Leone. Among them were data compression and dual-mode (internet and text) message transmission to mitigate connectivity issues, user interface design tailored to local needs, and a continuous-feedback process to iteratively detect user or system issues and remediate challenges identified. The resultant system achieved high user acceptance and demonstrated the feasibility of an mHealth-based surveillance system implemented on a national scale. |
Isolation of Angola-like Marburg virus from Egyptian rousette bats from West Africa
Amman BR , Bird BH , Bakarr IA , Bangura J , Schuh AJ , Johnny J , Sealy TK , Conteh I , Koroma AH , Foday I , Amara E , Bangura AA , Gbakima AA , Tremeau-Bravard A , Belaganahalli M , Dhanota J , Chow A , Ontiveros V , Gibson A , Turay J , Patel K , Graziano J , Bangura C , Kamanda ES , Osborne A , Saidu E , Musa J , Bangura D , Williams SMT , Wadsworth R , Turay M , Edwin L , Mereweather-Thompson V , Kargbo D , Bairoh FV , Kanu M , Robert W , Lungai V , Guetiya Wadoum RE , Coomber M , Kanu O , Jambai A , Kamara SM , Taboy CH , Singh T , Mazet JAK , Nichol ST , Goldstein T , Towner JS , Lebbie A . Nat Commun 2020 11 (1) 510 Marburg virus (MARV) causes sporadic outbreaks of severe Marburg virus disease (MVD). Most MVD outbreaks originated in East Africa and field studies in East Africa, South Africa, Zambia, and Gabon identified the Egyptian rousette bat (ERB; Rousettus aegyptiacus) as a natural reservoir. However, the largest recorded MVD outbreak with the highest case-fatality ratio happened in 2005 in Angola, where direct spillover from bats was not shown. Here, collaborative studies by the Centers for Disease Control and Prevention, Njala University, University of California, Davis USAID-PREDICT, and the University of Makeni identify MARV circulating in ERBs in Sierra Leone. PCR, antibody and virus isolation data from 1755 bats of 42 species shows active MARV infection in approximately 2.5% of ERBs. Phylogenetic analysis identifies MARVs that are similar to the Angola strain. These results provide evidence of MARV circulation in West Africa and demonstrate the value of pathogen surveillance to identify previously undetected threats. |
Clinical presentation of pregnant women in isolation units for Ebola virus disease in Sierra Leone, 2014
Mpofu JJ , Soud F , Lyman M , Koroma AP , Morof D , Ellington S , Kargbo SS , Callaghan W . Int J Gynaecol Obstet 2019 145 (1) 76-82 OBJECTIVES: To examine Ebola virus disease (EVD) symptom prevalence and EVD status among pregnant women in Ebola isolation units in Sierra Leone. METHODS: In an observational study, data were obtained for pregnant women admitted to Ebola isolation units across four districts in Sierra Leone from June 29, 2014, to December 20, 2014. Women were admitted to isolation units if they had suspected EVD exposures or fever (temperature >38 degrees C) and three or more self-reported symptoms suggestive of EVD. Associations were examined between EVD status and each symptom using chi(2) tests and logistic regression adjusting for age/labor status. RESULTS: Of 176 pregnant women isolated, 55 (32.5%) tested positive for EVD. Using logistic regression models adjusted for age, EVD-positive women were significantly more likely to have fever, self-reported fatigue/weakness, nausea/vomiting, headache, muscle/joint pain, chest pain, vaginal bleeding, unexplained bleeding, or sore throat upon admission. In models adjusted for age/labor, only women with fever or vaginal bleeding upon admission were significantly more likely to be EVD-positive. CONCLUSIONS: Several EVD symptoms and complications increased the odds of testing EVD-positive; some of these were also signs and symptoms of labor/pregnancy complications. The study results highlight the need to refine screening for pregnant women with EVD. This article is protected by copyright. All rights reserved. |
Clinical surveillance and evaluation of suspected Ebola cases in a vaccine trial during an Ebola epidemic: The Sierra Leone Trial to Introduce a Vaccine Against Ebola
Conteh MA , Goldstein ST , Wurie HR , Gidudu J , Lisk DR , Carter RJ , Seward JF , Hampton LM , Wang D , Andersen LE , Arvay M , Schrag SJ , Dawson P , Fombah AE , Petrie CR , Feikin DR , Russell JBW , Lindblad R , Kargbo SAS , Samai M , Mahon BE . J Infect Dis 2018 217 S33-s39 Clinical Trials Registration: ClinicalTrials.gov [NCT02378753] and Pan African Clinical Trials Registry [PACTR201502001037220]. |
Participant retention in a randomized clinical trial in an outbreak setting: Lessons from the Sierra Leone Trial to Introduce a Vaccine Against Ebola (STRIVE)
Carter RJ , Senesi RGB , Dawson P , Gassama I , Kargbo SAS , Petrie CR , Rogers MH , Samai M , Luman ET . J Infect Dis 2018 217 S65-s74 Clinical Trials Registration: ClinicalTrials.gov [NCT02378753] and Pan African Clinical Trials Registry [PACTR201502001037220]. |
The Sierra Leone Trial to Introduce a Vaccine Against Ebola: An evaluation of rVSVG-ZEBOV-GP vaccine tolerability and safety during the West Africa Ebola outbreak
Samai M , Seward JF , Goldstein ST , Mahon BE , Lisk DR , Widdowson MA , Jalloh MI , Schrag SJ , Idriss A , Carter RJ , Dawson P , Kargbo SAS , Leigh B , Bawoh M , Legardy-Williams J , Deen G , Carr W , Callis A , Lindblad R , Russell JBW , Petrie CR , Fombah AE , Kargbo B , McDonald W , Jarrett OD , Walker RE , Gargiullo P , Bash-Taqi D , Gibson L , Fofanah AB , Schuchat A . J Infect Dis 2018 217 S6-s15 Clinical Trials Registration: ClinicalTrials.gov [NCT02378753] and Pan African Clinical Trials Registry [PACTR201502001037220]. |
The 117 call alert system in Sierra Leone: from rapid Ebola notification to routine death reporting
Alpren C , Jalloh MF , Kaiser R , Diop M , Kargbo S , Castle E , Dafae F , Hersey S , Redd JT , Jambai A . BMJ Glob Health 2017 2 (3) e000392 A toll-free, nationwide phone alert system was established for rapid notification and response during the 2014-2015 Ebola epidemic in Sierra Leone. The system remained in place after the end of the epidemic under a policy of mandatory reporting and Ebola testing for all deaths, and, from June 2016, testing only in case of suspected Ebola. We describe the design, implementation and changes in the system; analyse calling trends during and after the Ebola epidemic; and discuss strengths and limitations of the system and its potential role in efforts to improve death reporting in Sierra Leone. Numbers of calls to report deaths of any cause (death alerts) and persons suspected of having Ebola (live alerts) were analysed by province and district and compared with numbers of Ebola cases reported by the WHO. Nearly 350 000 complete, non-prank calls were made to 117 between September 2014 and December 2016. The maximum number of daily death and live alerts was 9344 (October 2014) and 3031 (December 2014), respectively. Call volumes decreased as Ebola incidence declined and continued to decrease in the post-Ebola period. A national social mobilisation strategy was especially targeted to influential religious leaders, traditional healers and women's groups. The existing infrastructure and experience with the system offer an opportunity to consider long-term use as a death reporting tool for civil registration and mortality surveillance, including rapid detection and control of public health threats. A routine social mobilisation component should be considered to increase usage. |
Virus genomes reveal factors that spread and sustained the Ebola epidemic.
Dudas G , Carvalho LM , Bedford T , Tatem AJ , Baele G , Faria NR , Park DJ , Ladner JT , Arias A , Asogun D , Bielejec F , Caddy SL , Cotten M , D'Ambrozio J , Dellicour S , Caro AD , Diclaro JW , Duraffour S , Elmore MJ , Fakoli LS , Faye O , Gilbert ML , Gevao SM , Gire S , Gladden-Young A , Gnirke A , Goba A , Grant DS , Haagmans BL , Hiscox JA , Jah U , Kugelman JR , Liu D , Lu J , Malboeuf CM , Mate S , Matthews DA , Matranga CB , Meredith LW , Qu J , Quick J , Pas SD , Phan MV , Pollakis G , Reusken CB , Sanchez-Lockhart M , Schaffner SF , Schieffelin JS , Sealfon RS , Simon-Loriere E , Smits SL , Stoecker K , Thorne L , Tobin EA , Vandi MA , Watson SJ , West K , Whitmer S , Wiley MR , Winnicki SM , Wohl S , Wolfel R , Yozwiak NL , Andersen KG , Blyden SO , Bolay F , Carroll MW , Dahn B , Diallo B , Formenty P , Fraser C , Gao GF , Garry RF , Goodfellow I , Gunther S , Happi CT , Holmes EC , Kargbo B , Keita S , Kellam P , Koopmans MP , Kuhn JH , Loman NJ , Magassouba N , Naidoo D , Nichol ST , Nyenswah T , Palacios G , Pybus OG , Sabeti PC , Sall A , Stroher U , Wurie I , Suchard MA , Lemey P , Rambaut A . Nature 2017 544 (7650) 309-315 The 2013-2016 West African epidemic caused by the Ebola virus was of unprecedented magnitude, duration and impact. Here we reconstruct the dispersal, proliferation and decline of Ebola virus throughout the region by analysing 1,610 Ebola virus genomes, which represent over 5% of the known cases. We test the association of geography, climate and demography with viral movement among administrative regions, inferring a classic 'gravity' model, with intense dispersal between larger and closer populations. Despite attenuation of international dispersal after border closures, cross-border transmission had already sown the seeds for an international epidemic, rendering these measures ineffective at curbing the epidemic. We address why the epidemic did not spread into neighbouring countries, showing that these countries were susceptible to substantial outbreaks but at lower risk of introductions. Finally, we reveal that this large epidemic was a heterogeneous and spatially dissociated collection of transmission clusters of varying size, duration and connectivity. These insights will help to inform interventions in future epidemics. |
Exposure patterns driving Ebola transmission in West Africa: a retrospective observational study
Agua-Agum J , Ariyarajah A , Aylward B , Bawo L , Bilivogui P , Blake IM , Brennan RJ , Cawthorne A , Cleary E , Clement P , Conteh R , Cori A , Dafae F , Dahl B , Dangou JM , Diallo B , Donnelly CA , Dorigatti I , Dye C , Eckmanns T , Fallah M , Ferguson NM , Fiebig L , Fraser C , Garske T , Gonzalez L , Hamblion E , Hamid N , Hersey S , Hinsley W , Jambei A , Jombart T , Kargbo D , Keita S , Kinzer M , George FK , Godefroy B , Gutierrez G , Kannangarage N , Mills HL , Moller T , Meijers S , Mohamed Y , Morgan O , Nedjati-Gilani G , Newton E , Nouvellet P , Nyenswah T , Perea W , Perkins D , Riley S , Rodier G , Rondy M , Sagrado M , Savulescu C , Schafer IJ , Schumacher D , Seyler T , Shah A , Van Kerkhove MD , Wesseh CS , Yoti Z . PLoS Med 2016 13 (11) e1002170 BACKGROUND: The ongoing West African Ebola epidemic began in December 2013 in Guinea, probably from a single zoonotic introduction. As a result of ineffective initial control efforts, an Ebola outbreak of unprecedented scale emerged. As of 4 May 2015, it had resulted in more than 19,000 probable and confirmed Ebola cases, mainly in Guinea (3,529), Liberia (5,343), and Sierra Leone (10,746). Here, we present analyses of data collected during the outbreak identifying drivers of transmission and highlighting areas where control could be improved. METHODS AND FINDINGS: Over 19,000 confirmed and probable Ebola cases were reported in West Africa by 4 May 2015. Individuals with confirmed or probable Ebola ("cases") were asked if they had exposure to other potential Ebola cases ("potential source contacts") in a funeral or non-funeral context prior to becoming ill. We performed retrospective analyses of a case line-list, collated from national databases of case investigation forms that have been reported to WHO. These analyses were initially performed to assist WHO's response during the epidemic, and have been updated for publication. We analysed data from 3,529 cases in Guinea, 5,343 in Liberia, and 10,746 in Sierra Leone; exposures were reported by 33% of cases. The proportion of cases reporting a funeral exposure decreased over time. We found a positive correlation (r = 0.35, p < 0.001) between this proportion in a given district for a given month and the within-district transmission intensity, quantified by the estimated reproduction number (R). We also found a negative correlation (r = -0.37, p < 0.001) between R and the district proportion of hospitalised cases admitted within ≤4 days of symptom onset. These two proportions were not correlated, suggesting that reduced funeral attendance and faster hospitalisation independently influenced local transmission intensity. We were able to identify 14% of potential source contacts as cases in the case line-list. Linking cases to the contacts who potentially infected them provided information on the transmission network. This revealed a high degree of heterogeneity in inferred transmissions, with only 20% of cases accounting for at least 73% of new infections, a phenomenon often called super-spreading. Multivariable regression models allowed us to identify predictors of being named as a potential source contact. These were similar for funeral and non-funeral contacts: severe symptoms, death, non-hospitalisation, older age, and travelling prior to symptom onset. Non-funeral exposures were strongly peaked around the death of the contact. There was evidence that hospitalisation reduced but did not eliminate onward exposures. We found that Ebola treatment units were better than other health care facilities at preventing exposure from hospitalised and deceased individuals. The principal limitation of our analysis is limited data quality, with cases not being entered into the database, cases not reporting exposures, or data being entered incorrectly (especially dates, and possible misclassifications). CONCLUSIONS: Achieving elimination of Ebola is challenging, partly because of super-spreading. Safe funeral practices and fast hospitalisation contributed to the containment of this Ebola epidemic. Continued real-time data capture, reporting, and analysis are vital to track transmission patterns, inform resource deployment, and thus hasten and maintain elimination of the virus from the human population. |
Ebola Virus Disease Diagnostics, Sierra Leone: Analysis of Real-time Reverse Transcription-Polymerase Chain Reaction Values for Clinical Blood and Oral Swab Specimens.
Erickson BR , Sealy TK , Flietstra T , Morgan L , Kargbo B , Matt-Lebby VE , Gibbons A , Chakrabarti AK , Graziano J , Presser L , Flint M , Bird BH , Brown S , Klena JD , Blau DM , Brault AC , Belser JA , Salzer JS , Schuh AJ , Lo M , Zivcec M , Priestley RA , Pyle M , Goodman C , Bearden S , Amman BR , Basile A , Bergeron E , Bowen MD , Dodd KA , Freeman MM , McMullan LK , Paddock CD , Russell BJ , Sanchez AJ , Towner JS , Wang D , Zemtsova GE , Stoddard RA , Turnsek M , Guerrero LW , Emery SL , Stovall J , Kainulainen MH , Perniciaro JL , Mijatovic-Rustempasic S , Shakirova G , Winter J , Sexton C , Liu F , Slater K , Anderson R , Andersen L , Chiang CF , Tzeng WP , Crowe SJ , Maenner MJ , Spiropoulou CF , Nichol ST , Stroher U . J Infect Dis 2016 214 S258-S262 During the Ebola virus outbreak of 2013-2016, the Viral Special Pathogens Branch field laboratory in Sierra Leone tested approximately 26 000 specimens between August 2014 and October 2015. Analysis of the B2M endogenous control Ct values showed its utility in monitoring specimen quality, comparing results with different specimen types, and interpretation of results. For live patients, blood is the most sensitive specimen type and oral swabs have little diagnostic utility. However, swabs are highly sensitive for diagnostic testing of corpses. |
Implementing an Ebola vaccine study - Sierra Leone
Widdowson MA , Schrag SJ , Carter RJ , Carr W , Legardy-Williams J , Gibson L , Lisk DR , Jalloh MI , Bash-Taqi DA , Kargbo SA , Idriss A , Deen GF , Russell JB , McDonald W , Albert AP , Basket M , Callis A , Carter VM , Ogunsanya KR , Gee J , Pinner R , Mahon BE , Goldstein ST , Seward JF , Samai M , Schuchat A . MMWR Suppl 2016 65 (3) 98-106 In October 2014, the College of Medicine and Allied Health Sciences of the University of Sierra Leone, the Sierra Leone Ministry of Health and Sanitation, and CDC joined the global effort to accelerate assessment and availability of candidate Ebola vaccines and began planning for the Sierra Leone Trial to Introduce a Vaccine against Ebola (STRIVE). STRIVE was an individually randomized controlled phase II/III trial to evaluate efficacy, immunogenicity, and safety of the recombinant vesicular stomatitis virus Ebola vaccine (rVSV-ZEBOV). The study population was health care and frontline workers in select chiefdoms of the five most affected districts in Sierra Leone. Participants were randomized to receive a single intramuscular dose of rVSV-ZEBOV at enrollment or to receive a single intramuscular dose 18-24 weeks after enrollment. All participants were followed up monthly until 6 months after vaccination. Two substudies separately assessed detailed reactogenicity over 1 month and immunogenicity over 12 months. During the 5 months before the trial, STRIVE and partners built a research platform in Sierra Leone comprising participant follow-up sites, cold chain, reliable power supply, and vaccination clinics and hired and trained at least 350 national staff. Wide-ranging community outreach, informational sessions, and messaging were conducted before and during the trial to ensure full communication to the population of the study area regarding procedures and current knowledge about the trial vaccine. During April 9-August 15, 2015, STRIVE enrolled 8,673 participants, of whom 453 and 539 were also enrolled in the safety and immunogenicity substudies, respectively. As of April 28, 2016, no Ebola cases and no vaccine-related serious adverse events, which by regulatory definition include death, life-threatening illness, hospitalization or prolongation of hospitalization, or permanent disability, were reported in the study population. Although STRIVE will not produce an estimate of vaccine efficacy because of low case frequency as the epidemic was controlled, data on safety and immunogenicity will support decisions on licensure of rVSV-ZEBOV.The activities summarized in this report would not have been possible without collaboration with many U.S. and international partners (http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/partners.html). |
Ebola Virus Epidemiology, Transmission, and Evolution during Seven Months in Sierra Leone.
Park DJ , Dudas G , Wohl S , Goba A , Whitmer SL , Andersen KG , Sealfon RS , Ladner JT , Kugelman JR , Matranga CB , Winnicki SM , Qu J , Gire SK , Gladden-Young A , Jalloh S , Nosamiefan D , Yozwiak NL , Moses LM , Jiang PP , Lin AE , Schaffner SF , Bird B , Towner J , Mamoh M , Gbakie M , Kanneh L , Kargbo D , Massally JL , Kamara FK , Konuwa E , Sellu J , Jalloh AA , Mustapha I , Foday M , Yillah M , Erickson BR , Sealy T , Blau D , Paddock C , Brault A , Amman B , Basile J , Bearden S , Belser J , Bergeron E , Campbell S , Chakrabarti A , Dodd K , Flint M , Gibbons A , Goodman C , Klena J , McMullan L , Morgan L , Russell B , Salzer J , Sanchez A , Wang D , Jungreis I , Tomkins-Tinch C , Kislyuk A , Lin MF , Chapman S , MacInnis B , Matthews A , Bochicchio J , Hensley LE , Kuhn JH , Nusbaum C , Schieffelin JS , Birren BW , Forget M , Nichol ST , Palacios GF , Ndiaye D , Happi C , Gevao SM , Vandi MA , Kargbo B , Holmes EC , Bedford T , Gnirke A , Stroher U , Rambaut A , Garry RF , Sabeti PC . Cell 2015 161 (7) 1516-26 The 2013-2015 Ebola virus disease (EVD) epidemic is caused by the Makona variant of Ebola virus (EBOV). Early in the epidemic, genome sequencing provided insights into virus evolution and transmission and offered important information for outbreak response. Here, we analyze sequences from 232 patients sampled over 7 months in Sierra Leone, along with 86 previously released genomes from earlier in the epidemic. We confirm sustained human-to-human transmission within Sierra Leone and find no evidence for import or export of EBOV across national borders after its initial introduction. Using high-depth replicate sequencing, we observe both host-to-host transmission and recurrent emergence of intrahost genetic variants. We trace the increasing impact of purifying selection in suppressing the accumulation of nonsynonymous mutations over time. Finally, we note changes in the mucin-like domain of EBOV glycoprotein that merit further investigation. These findings clarify the movement of EBOV within the region and describe viral evolution during prolonged human-to-human transmission. |
Rapid assessment of Ebola infection prevention and control needs - six districts, Sierra Leone, October 2014
Pathmanathan I , O'Connor KA , Adams ML , Rao CY , Kilmarx PH , Park BJ , Mermin J , Kargbo B , Wurie AH , Clarke KR . MMWR Morb Mortal Wkly Rep 2014 63 (49) 1172-4 As of October 31, 2014, the Sierra Leone Ministry of Health and Sanitation had reported 3,854 laboratory-confirmed cases of Ebola virus disease (Ebola) since the outbreak began in May 2014; 199 (5.2%) of these cases were among health care workers. Ebola infection prevention and control (IPC) measures are essential to interrupt Ebola virus transmission and protect the health workforce, a population that is disproportionately affected by Ebola because of its increased risk of exposure yet is essential to patient care required for outbreak control and maintenance of the country's health system at large. To rapidly identify existing IPC resources and high priority outbreak response needs, an assessment by CDC Ebola Response Team members was conducted in six of the 14 districts in Sierra Leone, consisting of health facility observations and structured interviews with key informants in facilities and government district health management offices. Health system gaps were identified in all six districts, including shortages or absence of trained health care staff, personal protective equipment (PPE), safe patient transport, and standardized IPC protocols. Based on rapid assessment findings and key stakeholder input, priority IPC actions were recommended. Progress has since been made in developing standard operating procedures, increasing laboratory and Ebola treatment capacity and training the health workforce. However, further system strengthening is needed. In particular, a successful Ebola outbreak response in Sierra Leone will require an increase in coordinated and comprehensive district-level IPC support to prevent ongoing Ebola virus transmission. |
Cholera epidemic associated with consumption of unsafe drinking water and street-vended water - eastern Freetown, Sierra Leone, 2012
Nguyen VD , Sreenivasan N , Lam E , Ayers T , Kargbo D , Dafae F , Jambai A , Alemu W , Kamara A , Islam MS , Stroika S , Bopp C , Quick R , Mintz ED , Brunkard JM . Am J Trop Med Hyg 2014 90 (3) 518-23 During 2012, Sierra Leone experienced a cholera epidemic with 22,815 reported cases and 296 deaths. We conducted a matched case-control study to assess risk factors, enrolling 49 cases and 98 controls. Stool specimens were analyzed by culture, polymerase chain reaction (PCR), and pulsed-field gel electrophoresis (PFGE). Conditional logistic regression found that consuming unsafe water (matched odds ratio [mOR]: 3.4; 95% confidence interval [CI]: 1.1, 11.0), street-vended water (mOR: 9.4; 95% CI: 2.0, 43.7), and crab (mOR: 3.3; 95% CI: 1.03, 10.6) were significant risk factors for cholera infection. Of 30 stool specimens, 13 (43%) showed PCR evidence of toxigenic Vibrio cholerae O1. Six specimens yielded isolates of V. cholerae O1, El Tor; PFGE identified a pattern previously observed in seven countries. We recommended ensuring the quality of improved water sources, promoting household chlorination, and educating street vendors on water handling practices. |
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