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Undurraga EA, Carias C, Meltzer MI, Kahn EB. Potential for broad-scale transmission of Ebola virus disease during the West Africa crisis: lessons for the Global Health security agenda. Infect Dis Poverty 2017; 6:159. [PMID: 29191243 PMCID: PMC5710062 DOI: 10.1186/s40249-017-0373-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 10/27/2017] [Indexed: 01/19/2023] Open
Abstract
Background The 2014–2016 Ebola crisis in West Africa had approximately eight times as many reported deaths as the sum of all previous Ebola outbreaks. The outbreak magnitude and occurrence of multiple Ebola cases in at least seven countries beyond Liberia, Sierra Leone, and Guinea, hinted at the possibility of broad-scale transmission of Ebola. Main text Using a modeling tool developed by the US Centers for Disease Control and Prevention during the Ebola outbreak, we estimated the number of Ebola cases that might have occurred had the disease spread beyond the three countries in West Africa to cities in other countries at high risk for disease transmission (based on late 2014 air travel patterns). We estimated Ebola cases in three scenarios: a delayed response, a Liberia-like response, and a fast response scenario. Based on our estimates of the number of Ebola cases that could have occurred had Ebola spread to other countries beyond the West African foci, we emphasize the need for improved levels of preparedness and response to public health threats, which is the goal of the Global Health Security Agenda. Our estimates suggest that Ebola could have potentially spread widely beyond the West Africa foci, had local and international health workers and organizations not committed to a major response effort. Our results underscore the importance of rapid detection and initiation of an effective, organized response, and the challenges faced by countries with limited public health systems. Actionable lessons for strengthening local public health systems in countries at high risk of disease transmission include increasing health personnel, bolstering primary and critical healthcare facilities, developing public health infrastructure (e.g. laboratory capacity), and improving disease surveillance. With stronger local public health systems infectious disease outbreaks would still occur, but their rapid escalation would be considerably less likely, minimizing the impact of public health threats such as Ebola. Conclusions The Ebola outbreak could have potentially spread to other countries, where limited public health surveillance and response capabilities may have resulted in additional foci. Health security requires robust local health systems that can rapidly detect and effectively respond to an infectious disease outbreak. Electronic supplementary material The online version of this article (10.1186/s40249-017-0373-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Eduardo A Undurraga
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. .,Present address: School of Government, Pontificia Universidad Católica de Chile, Santiago, Región Metropolitana, Chile.
| | - Cristina Carias
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Martin I Meltzer
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Emily B Kahn
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Li ZJ, Tu WX, Wang XC, Shi GQ, Yin ZD, Su HJ, Shen T, Zhang DP, Li JD, Lv S, Cao CL, Xie RQ, Lu HZ, Jiang RM, Cao Z, An ZJ, Li LL, Xu J, Xiong YW, Zang W, Zhang W, Zhang HW, Chen WS, Ling H, Xu W, Cai J, Luo HJ, Xing XS, Zheng CJ, Wei Q, Li XX, Li M, Jiang H, Deng LQ, Chen MQ, Huo X, Xu F, Lai XH, Bai XC, Ye LJ, Yao JY, Yin WW, Sun JJ, Xiao L, Liu FQ, Liu XQ, Fan HW, Kou ZQ, Zhou JK, Zhang H, Ni DX, Samba TT, Li Q, Yu HJ, Wang Y, Liang XF. A practical community-based response strategy to interrupt Ebola transmission in sierra Leone, 2014-2015. Infect Dis Poverty 2016; 5:74. [PMID: 27491387 PMCID: PMC4974705 DOI: 10.1186/s40249-016-0167-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/01/2016] [Indexed: 11/30/2022] Open
Abstract
Background The Ebola virus disease spread rapidly in West Africa in 2014, leading to the loss of thousands of lives. Community engagement was one of the key strategies to interrupt Ebola transmission, and practical community level measures needed to be explored in the field and tailored to the specific context of communities. Methods First, community-level education on Ebola virus disease (EVD) prevention was launched for the community’s social mobilizers in six districts in Sierra Leone beginning in November 2014. Then, from January to May of 2015, in three pilot communities, local trained community members were organized to engage in implementation of EVD prevention and transmission interruption measures, by involving them in alert case report, contact tracing, and social mobilization. The epidemiological indicators of transmission interruption in three study communities were evaluated. Results A total of 6 016 community social mobilizers from 185 wards were trained by holding 279 workshops in the six districts, and EVD message reached an estimated 631 680 residents. In three pilot communities, 72 EVD alert cases were reported, with 70.8 % of them detected by trained local community members, and 14 EVD cases were finally identified. Contact tracing detected 64.3 % of EVD cases. The median duration of community infectivity for the cases was 1 day. The secondary attack rate was 4.2 %, and no third generation of infection was triggered. No health worker was infected, and no unsafe burial and noncompliance to EVD control measures were recorded. The community-based measures were modeled to reduce 77 EVD cases, and the EVD-free goal was achieved four months earlier in study communities than whole country of Sierra Leone. Conclusions The community-based strategy of social mobilization and community engagement was effective in case detection and reducing the extent of Ebola transmission in a country with weak health system. The successfully practical experience to reduce the risk of Ebola transmission in the community with poor resources would potentially be helpful for the global community to fight against the EVD and the other diseases in the future. Electronic supplementary material The online version of this article (doi:10.1186/s40249-016-0167-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zhong-Jie Li
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Wen-Xiao Tu
- Public Health Emergency Center, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xiao-Chun Wang
- National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Guo-Qing Shi
- Chinese Field Epidemiology Training Program, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Zun-Dong Yin
- National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Hai-Jun Su
- Bureau of Disease Prevention and Control, National Health and Family Planning Commission of the People's Republic of China, Beijing, China
| | - Tao Shen
- Chinese Field Epidemiology Training Program, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Da-Peng Zhang
- National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jian-Dong Li
- National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Shan Lv
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Chun-Li Cao
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Rui-Qian Xie
- Chinese Center for Health Education, Beijing, China
| | - Hong-Zhou Lu
- Department of Infectious Diseases, Shanghai Public Health Clinical Center, Shanghai, China
| | - Rong-Meng Jiang
- Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | | | - Zhi-Jie An
- National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Lei-Lei Li
- Public Health Emergency Center, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jie Xu
- National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yan-Wen Xiong
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Wei Zang
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Wei Zhang
- Department of Training, Chinese Center for Health Education, Beijing, China
| | - Hong-Wei Zhang
- Center for Infectious Diseases, Beijing Youan Hospital, Capital Medical University, Beijing, China
| | - Wen-Sen Chen
- Infection Management, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Hua Ling
- Chongqing Municipal Center for Disease Control and Prevention, Chongqing, China
| | - Wen Xu
- Yunnan Provincial Center for Disease Control and Prevention, Kunming, China
| | - Jian Cai
- Division of Infectious Disease Control and Prevention, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Huan-Jin Luo
- Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China
| | - Xue-Sheng Xing
- Division of Acute Infectious Disease Control and Prevention, Hubei Provincial Center for Disease Control and Prevention, Wuhan, China
| | - Can-Jun Zheng
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Qiang Wei
- Office of laboratory Management, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xin-Xu Li
- National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Mei Li
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Hai Jiang
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Li-Quan Deng
- Jilin Provincial Center for Disease Control and Prevention, Changchun, China
| | - Ming-Quan Chen
- Department of Infectious Diseases, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Xiang Huo
- Department of Acute Infectious Disease, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China
| | - Feng Xu
- Department of Infectious Diseases, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Xue-Hui Lai
- Zhongshan Center for Disease Control and Prevention, Zhongshan, Guangdong Province, China
| | - Xi-Chen Bai
- China Population Communication Center, Beijing, China
| | | | - Jian-Yi Yao
- Public Health Emergency Center, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Wen-Wu Yin
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jiao-Jin Sun
- National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Lin Xiao
- Jingzhou Center for Disease Control and Prevention, Jingzhou, Hubei Province, China
| | - Fu-Qiang Liu
- Hunan Provincial Center for Disease Control and Prevention, Changsha, China
| | - Xiao-Qiang Liu
- Yunnan Provincial Center for Disease Control and Prevention, Kunming, China
| | - Hong-Wei Fan
- Peking Union Medical College Hospital, Beijing, China
| | - Zeng-Qiang Kou
- Shandong Provincial Center for Disease Control and Prevention, Jinan, China
| | - Ji-Kun Zhou
- Shijiazhuang Center for Disease Control and Prevention, Shijiazhuang, Hebei Province, China
| | | | - Da-Xin Ni
- Public Health Emergency Center, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Thomas T Samba
- District Health Management Team, Western Area, Sierra Leone
| | - Qun Li
- Public Health Emergency Center, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Hong-Jie Yu
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yu Wang
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China. .,Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
| | - Xiao-Feng Liang
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China. .,Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
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Toth DJA, Tanner WD, Khader K, Gundlapalli AV. Estimates of the risk of large or long-lasting outbreaks of Middle East respiratory syndrome after importations outside the Arabian Peninsula. Epidemics 2016; 16:27-32. [PMID: 27663788 PMCID: PMC5047297 DOI: 10.1016/j.epidem.2016.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/25/2016] [Accepted: 04/25/2016] [Indexed: 01/12/2023] Open
Abstract
MERS outbreak clusters outside the Arabian Peninsula ranged in size from 1 to 186. Cluster data show declining transmission rate in later transmission generations. Model projects tempered risk of large, long-lasting outbreaks after importations. Explosive outbreaks are possible, but control measures are likely to be effective.
We quantify outbreak risk after importations of Middle East respiratory syndrome outside the Arabian Peninsula. Data from 31 importation events show strong statistical support for lower transmissibility after early transmission generations. Our model projects the risk of ≥10, 100, and 500 transmissions as 11%, 2%, and 0.02%, and ≥1, 2, 3, and 4 generations as 23%, 14%, 0.9%, and 0.05%, respectively. Our results suggest tempered risk of large, long-lasting outbreaks with appropriate control measures.
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Affiliation(s)
- Damon J A Toth
- Division of Epidemiology, Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA; U.S. Department of Veterans Affairs Salt Lake City Health Care System, Salt Lake City, UT, USA.
| | - Windy D Tanner
- Division of Epidemiology, Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Karim Khader
- Division of Epidemiology, Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA; U.S. Department of Veterans Affairs Salt Lake City Health Care System, Salt Lake City, UT, USA
| | - Adi V Gundlapalli
- Division of Epidemiology, Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA; U.S. Department of Veterans Affairs Salt Lake City Health Care System, Salt Lake City, UT, USA; Department of Pathology, University of Utah, Salt Lake City, UT, USA; Department of Biomedical Informatics, University of Utah, Salt Lake City, UT, USA
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Abbate JL, Murall CL, Richner H, Althaus CL. Potential Impact of Sexual Transmission on Ebola Virus Epidemiology: Sierra Leone as a Case Study. PLoS Negl Trop Dis 2016; 10:e0004676. [PMID: 27135922 PMCID: PMC4852896 DOI: 10.1371/journal.pntd.0004676] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 04/08/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Sexual transmission of Ebola virus disease (EVD) 6 months after onset of symptoms has been recently documented, and Ebola virus RNA has been detected in semen of survivors up to 9 months after onset of symptoms. As countries affected by the 2013-2015 epidemic in West Africa, by far the largest to date, are declared free of Ebola virus disease (EVD), it remains unclear what threat is posed by rare sexual transmission events that could arise from survivors. METHODOLOGY/PRINCIPAL FINDINGS We devised a compartmental mathematical model that includes sexual transmission from convalescent survivors: a SEICR (susceptible-exposed-infectious-convalescent-recovered) transmission model. We fitted the model to weekly incidence of EVD cases from the 2014-2015 epidemic in Sierra Leone. Sensitivity analyses and Monte Carlo simulations showed that a 0.1% per sex act transmission probability and a 3-month convalescent period (the two key unknown parameters of sexual transmission) create very few additional cases, but would extend the epidemic by 83 days [95% CI: 68-98 days] (p < 0.0001) on average. Strikingly, a 6-month convalescent period extended the average epidemic by 540 days (95% CI: 508-572 days), doubling the current length, despite an insignificant rise in the number of new cases generated. CONCLUSIONS/SIGNIFICANCE Our results show that reductions in the per sex act transmission probability via abstinence and condom use should reduce the number of sporadic sexual transmission events, but will not significantly reduce the epidemic size and may only minimally shorten the length of time the public health community must maintain response preparedness. While the number of infectious survivors is expected to greatly decline over the coming months, our results show that transmission events may still be expected for quite some time as each event results in a new potential cluster of non-sexual transmission. Precise measurement of the convalescent period is thus important for planning ongoing surveillance efforts.
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Affiliation(s)
- Jessica L. Abbate
- Institute for Ecology and Evolution, University of Bern, Bern, Switzerland
- UMR MIVEGEC (UMR CNRS 5290, IRD 224, UM), Institute for Research of Development (IRD), Montpellier, France
- UMR UMMISCO (UMI 209 IRD-UPMC), Bondy, France
- * E-mail:
| | - Carmen Lia Murall
- Max-Planck Institute for Dynamics and Self-Organization, Gottingen, Germany
| | - Heinz Richner
- Institute for Ecology and Evolution, University of Bern, Bern, Switzerland
| | - Christian L. Althaus
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
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