1
|
Reichler MR, Bruden D, Thomas H, Erickson BR, Knust B, Duffy N, Klena J, Hennessy T. Ebola Patient Virus Cycle Threshold and Risk of Household Transmission of Ebola Virus. J Infect Dis 2020; 221:707-714. [PMID: 31858125 DOI: 10.1093/infdis/jiz511] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 10/23/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Identifying risk factors for household transmission of Ebola virus (EBOV) is important to guide preventive measures during Ebola outbreaks. METHODS We enrolled all confirmed persons with EBOV disease who were the first case patient in a household from December 2014 to April 2015 in Freetown, Sierra Leone, and their household contacts. Index patients and contacts were interviewed, and contacts were followed up for 21 days to identify secondary cases. Epidemiologic data were linked to EBOV real-time reverse-transcription polymerase chain reaction cycle threshold (Ct) data from initial diagnostic specimens obtained from enrolled index case patients. RESULTS Ct data were available for 106 (71%) of 150 enrolled index patients. Of the Ct results, 85 (80%) were from blood specimens from live patients and 21 (20%) from oral swab specimens from deceased patients. The median Ct values for blood and swab specimens were 21.0 and 24.0, respectively (P = .007). In multivariable analysis, a Ct value from blood specimens in the lowest quintile was an independent predictor of both increased risk of household transmission (P = .009) and higher secondary attack rate among household contacts (P = .03), after adjustment for epidemiologic factors. CONCLUSIONS Our findings suggest the potential to use Ct values from acute EBOV diagnostic specimens for index patients as an early predictor of high-risk households and high-risk groups of contacts to help prioritize EBOV disease investigation and control efforts.
Collapse
Affiliation(s)
- Mary R Reichler
- Division of Tuberculosis Elimination, National Center for HIV/AIDS, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Dana Bruden
- Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic diseases, Centers for Disease Control and Prevention, Anchorage, Alaska, USA
| | - Harold Thomas
- Directorate of Disease Prevention and Control, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Bobbie Rae Erickson
- Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Diseases , Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Barbara Knust
- Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Diseases , Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Nadia Duffy
- Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - John Klena
- Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Diseases , Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Thomas Hennessy
- Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic diseases, Centers for Disease Control and Prevention, Anchorage, Alaska, USA
| |
Collapse
|
2
|
Reichler MR, Bangura J, Bruden D, Keimbe C, Duffy N, Thomas H, Knust B, Farmar I, Nichols E, Jambai A, Morgan O, Hennessy T. Household Transmission of Ebola Virus: Risks and Preventive Factors, Freetown, Sierra Leone, 2015. J Infect Dis 2019; 218:757-767. [PMID: 29659910 DOI: 10.1093/infdis/jiy204] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/05/2018] [Indexed: 11/15/2022] Open
Abstract
Background Knowing risk factors for household transmission of Ebola virus is important to guide preventive measures during Ebola outbreaks. Methods We enrolled all confirmed persons with Ebola who were the first case in a household, December 2014-April 2015, in Freetown, Sierra Leone, and their household contacts. Cases and contacts were interviewed, contacts followed prospectively through the 21-day incubation period, and secondary cases confirmed by laboratory testing. Results We enrolled 150 index Ebola cases and 838 contacts; 83 (9.9%) contacts developed Ebola during 21-day follow-up. In multivariable analysis, risk factors for transmission included index case death in the household, Ebola symptoms but no reported fever, age <20 years, more days with wet symptoms; and providing care to the index case (P < .01 for each). Protective factors included avoiding the index case after illness onset and a piped household drinking water source (P < .01 for each). Conclusions To reduce Ebola transmission, communities should rapidly identify and follow-up all household contacts; isolate those with Ebola symptoms, including those without reported fever; and consider closer monitoring of contacts who provided care to cases. Households could consider efforts to minimize risk by designating one care provider for ill persons with all others avoiding the suspected case.
Collapse
Affiliation(s)
- Mary R Reichler
- Division of Tuberculosis Elimination, National Center for HIV/AIDS, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - James Bangura
- Directorate of Disease Prevention and Control, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Dana Bruden
- Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic Diseases, Centers for Disease Control and Prevention, Anchorage, Alaska
| | - Charles Keimbe
- Directorate of Disease Prevention and Control, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | | | - Harold Thomas
- Directorate of Disease Prevention and Control, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Barbara Knust
- Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Ishmail Farmar
- Directorate of Disease Prevention and Control, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Erin Nichols
- National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, Maryland
| | - Amara Jambai
- Directorate of Disease Prevention and Control, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Oliver Morgan
- Health Emergencies Program, World Health Organization, Geneva, Switzerland
| | - Thomas Hennessy
- Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic Diseases, Centers for Disease Control and Prevention, Anchorage, Alaska
| | | |
Collapse
|
3
|
Robert A, Edmunds WJ, Watson CH, Henao-Restrepo AM, Gsell PS, Williamson E, Longini IM, Sakoba K, Kucharski AJ, Touré A, Nadlaou SD, Diallo B, Barry MS, Fofana TO, Camara L, Kaba IL, Sylla L, Diaby ML, Soumah O, Diallo A, Niare A, Diallo A, Eggo RM. Determinants of Transmission Risk During the Late Stage of the West African Ebola Epidemic. Am J Epidemiol 2019; 188:1319-1327. [PMID: 30941398 PMCID: PMC6601535 DOI: 10.1093/aje/kwz090] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 11/14/2022] Open
Abstract
Understanding risk factors for Ebola transmission is key for effective prediction and design of interventions. We used data on 860 cases in 129 chains of transmission from the latter half of the 2013-2016 Ebola epidemic in Guinea. Using negative binomial regression, we determined characteristics associated with the number of secondary cases resulting from each infected individual. We found that attending an Ebola treatment unit was associated with a 38% decrease in secondary cases (incidence rate ratio (IRR) = 0.62, 95% confidence interval (CI): 0.38, 0.99) among individuals that did not survive. Unsafe burial was associated with a higher number of secondary cases (IRR = 1.82, 95% CI: 1.10, 3.02). The average number of secondary cases was higher for the first generation of a transmission chain (mean = 1.77) compared with subsequent generations (mean = 0.70). Children were least likely to transmit (IRR = 0.35, 95% CI: 0.21, 0.57) compared with adults, whereas older adults were associated with higher numbers of secondary cases. Men were less likely to transmit than women (IRR = 0.71, 95% CI: 0.55, 0.93). This detailed surveillance data set provided an invaluable insight into transmission routes and risks. Our analysis highlights the key role that age, receiving treatment, and safe burial played in the spread of EVD.
Collapse
Affiliation(s)
- Alexis Robert
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - W John Edmunds
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Conall H Watson
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | | | - Elizabeth Williamson
- Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ira M Longini
- Department of Biostatistics, University of Florida, Gainesville, Florida
| | - Keïta Sakoba
- World Health Organization Ebola Vaccination Team, Conakry, Guinea
| | - Adam J Kucharski
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Alhassane Touré
- World Health Organization Ebola Vaccination Team, Conakry, Guinea
| | | | | | | | | | - Louceny Camara
- World Health Organization Ebola Vaccination Team, Conakry, Guinea
| | | | - Lansana Sylla
- World Health Organization Ebola Vaccination Team, Conakry, Guinea
| | | | - Ousmane Soumah
- World Health Organization Ebola Vaccination Team, Conakry, Guinea
| | | | - Amadou Niare
- World Health Organization Ebola Vaccination Team, Conakry, Guinea
| | | | - Rosalind M Eggo
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| |
Collapse
|
4
|
Glynn JR, Bower H, Johnson S, Turay C, Sesay D, Mansaray SH, Kamara O, Kamara AJ, Bangura MS, Checchi F. Variability in Intrahousehold Transmission of Ebola Virus, and Estimation of the Household Secondary Attack Rate. J Infect Dis 2019; 217:232-237. [PMID: 29140442 PMCID: PMC5853870 DOI: 10.1093/infdis/jix579] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 11/06/2017] [Indexed: 11/14/2022] Open
Abstract
Transmission between family members accounts for most Ebola virus transmission, but little is known about determinants of intrahousehold spread. From detailed exposure histories, intrahousehold transmission chains were created for 94 households of Ebola survivors in Sierra Leone: 109 (co-)primary cases gave rise to 317 subsequent cases (0-100% of those exposed). Larger households were more likely to have subsequent cases, and the proportion of household members affected depended on individual and household-level factors. More transmissions occurred from older than from younger cases, and from those with more severe disease. The estimated household secondary attack rate was 18%.
Collapse
Affiliation(s)
- Judith R Glynn
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, United Kingdom
- Correspondence: J. R. Glynn, PhD, FRCP, London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT, UK ()
| | - Hilary Bower
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Kelly JD, Richardson ET, Drasher M, Barrie MB, Karku S, Kamara M, Hann K, Dierberg K, Hubbard A, Lindan CP, Farmer PE, Rutherford GW, Weiser SD. Food Insecurity as a Risk Factor for Outcomes Related to Ebola Virus Disease in Kono District, Sierra Leone: A Cross-Sectional Study. Am J Trop Med Hyg 2018; 98:1484-1488. [PMID: 29557329 DOI: 10.4269/ajtmh.17-0820] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Studies have shown that people suffering from food insecurity are at higher risk for infectious and noncommunicable diseases and have poorer health outcomes. No study, however, has examined the association between food insecurity and outcomes related to Ebola virus disease (EVD). We conducted a cross-sectional study in two Ebola-affected communities in Kono district, Sierra Leone, from November 2015 to September 2016. We enrolled persons who were determined to have been exposed to Ebola virus. We assessed the association of food insecurity, using an adapted version of the Household Food Insecurity Access Scale, a nine-item scale well validated across Africa, with having been diagnosed with EVD and having died of EVD, using logistic regression models with cluster-adjusted standard errors. We interviewed 326 persons who were exposed to Ebola virus; 61 (19%) were diagnosed with EVD and 45/61 (74%) died. We found high levels (87%) of food insecurity, but there was no association between food insecurity and having been diagnosed with EVD. Among EVD cases, those who were food insecure had 18.3 times the adjusted odds of death than those who were food secure (P = 0.03). This is the first study to demonstrate a potential relationship between food insecurity and having died of EVD, although larger prospective studies are needed to confirm these findings.
Collapse
Affiliation(s)
- J Daniel Kelly
- Partners In Health, Freetown, Sierra Leone.,Department of Medicine, University of California, San Francisco, San Francisco, California
| | - Eugene T Richardson
- Division of Global Health Equity, Brigham and Women's Hospital, Boston, Massachusetts.,Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts.,Partners In Health, Freetown, Sierra Leone
| | | | - M Bailor Barrie
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts.,Partners In Health, Freetown, Sierra Leone
| | - Sahr Karku
- Partners In Health, Freetown, Sierra Leone
| | | | | | | | - Allan Hubbard
- Division of Biostatistics, School of Public Health, University of California, Berkeley, Berkeley, California
| | - Christina P Lindan
- Institute for Global Health Sciences, University of California, San Francisco, California
| | - Paul E Farmer
- Division of Global Health Equity, Brigham and Women's Hospital, Boston, Massachusetts.,Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts.,Partners In Health, Freetown, Sierra Leone
| | - George W Rutherford
- Institute for Global Health Sciences, University of California, San Francisco, California
| | - Sheri D Weiser
- Department of Medicine, University of California, San Francisco, San Francisco, California
| |
Collapse
|
6
|
Caleo G, Duncombe J, Jephcott F, Lokuge K, Mills C, Looijen E, Theoharaki F, Kremer R, Kleijer K, Squire J, Lamin M, Stringer B, Weiss HA, Culli D, Di Tanna GL, Greig J. The factors affecting household transmission dynamics and community compliance with Ebola control measures: a mixed-methods study in a rural village in Sierra Leone. BMC Public Health 2018; 18:248. [PMID: 29439682 PMCID: PMC5812186 DOI: 10.1186/s12889-018-5158-6] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 02/06/2018] [Indexed: 11/30/2022] Open
Abstract
Background Little is understood of Ebola virus disease (EVD) transmission dynamics and community compliance with control measures over time. Understanding these interactions is essential if interventions are to be effective in future outbreaks. We conducted a mixed-methods study to explore these factors in a rural village that experienced sustained EVD transmission in Kailahun District, Sierra Leone. Methods We reconstructed transmission dynamics using a cross-sectional survey conducted in April 2015, and cross-referenced our results with surveillance, burial, and Ebola Management Centre (EMC) data. Factors associated with EVD transmission were assessed with Cox proportional hazards regression. Following the survey, qualitative semi-structured interviews explored views of community informants and households. Results All households (n = 240; 1161 individuals) participated in the survey. 29 of 31 EVD probable/confirmed cases died (93·5% case fatality rate); six deaths (20·6%) had been missed by other surveillance systems. Transmission over five generations lasted 16 weeks. Although most households had ≤5 members there was a significant increase in risk of Ebola in households with > 5 members. Risk of EVD was also associated with older age. Cases were spatially clustered; all occurred in 15 households. EVD transmission was better understood when the community experience started to concord with public health messages being given. Perceptions of contact tracing changed from invading privacy and selling people to ensuring community safety. Burials in plastic bags, without female attendants or prayer, were perceived as dishonourable. Further reasons for low compliance were low EMC survival rates, family perceptions of a moral duty to provide care to relatives, poor communication with the EMC, and loss of livelihoods due to quarantine. Compliance with response measures increased only after the second generation, coinciding with the implementation of restrictive by-laws, return of the first survivor, reduced contact with dead bodies, and admission of patients to the EMC. Conclusions Transmission occurred primarily in a few large households, with prolonged transmission and a high death toll. Return of a survivor to the village and more effective implementation of control strategies coincided with increased compliance to control measures, with few subsequent cases. We propose key recommendations for management of EVD outbreaks based on this experience.
Collapse
Affiliation(s)
- Grazia Caleo
- Manson Unit, Médecins Sans Frontières (MSF), London, UK. .,MRC Tropical Epidemiology Group, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK.
| | | | - Freya Jephcott
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Kamalini Lokuge
- Manson Unit, Médecins Sans Frontières (MSF), London, UK.,National Centre for Epidemiology and Population Health, Research School of Population Health, Australian National University, Canberra, Australia
| | | | | | | | | | | | - James Squire
- District Health Management Team, Ministry of Health and Sanitation, Kailahun, Sierra Leone
| | - Manjo Lamin
- District Health Management Team, Ministry of Health and Sanitation, Kailahun, Sierra Leone
| | | | - Helen A Weiss
- MRC Tropical Epidemiology Group, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - Daniel Culli
- Manson Unit, Médecins Sans Frontières (MSF), London, UK
| | - Gian Luca Di Tanna
- Centre for Primary Care and Public Health, Queen Mary University of London, London, UK
| | - Jane Greig
- Manson Unit, Médecins Sans Frontières (MSF), London, UK
| |
Collapse
|
7
|
VanSteelandt A, Aho J, Franklin K, Likofata J, Kamgang JB, Keita S, Koivogui L, Magassouba N, Martel LD, Dahourou AG. Operational evaluation of rapid diagnostic testing for Ebola Virus Disease in Guinean laboratories. PLoS One 2017; 12:e0188047. [PMID: 29190713 DOI: 10.1371/journal.pone.0188047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 10/18/2017] [Indexed: 11/19/2022] Open
Abstract
Background Rapid Diagnostic Tests (RDTs) for Ebola Virus Disease (EVD) at the point of care have the potential to increase access and acceptability of EVD testing and the speed of patient isolation and secure burials for suspect cases. A pilot program for EVD RDTs in high risk areas of Guinea was introduced in October 2015. This paper presents concordance data between EVD RDTs and PCR testing in the field as well as an assessment of the acceptability, feasibility, and quality assurance of the RDT program. Methods and findings Concordance data were compiled from laboratory surveillance databases. The operational measures of the laboratory-based EVD RDT program were evaluated at all 34 sentinel sites in Guinea through: (1) a technical questionnaire filled by the lab technicians who performed the RDTs, (2) a checklist filled by the evaluator during the site visits, and (3) direct observation of the lab technicians performing the quality control test. Acceptability of the EVD RDT was good for technicians, patients, and families although many technicians (69.8%) expressed concern for their safety while performing the test. The feasibility of the program was good based on average technician knowledge scores (6.6 out of 8) but basic infrastructure, equipment, and supplies were lacking. There was much room for improvement in quality assurance of the program. Conclusions The implementation of new diagnostics in weak laboratory systems requires general training in quality assurance, biosafety and communication with patients in addition to specific training for the new test. Corresponding capacity building in terms of basic equipment and a long-term commitment to transfer supervision and quality improvement to national public health staff are necessary for successful implementation.
Collapse
|
8
|
Irwin KL, Jalloh MF, Corker J, Alpha Mahmoud B, Robinson SJ, Li W, James NE, Sellu M, Jalloh MB, Diallo AA, Tracy L, Hajjeh R, VanSteelandt A, Bunnell R, Martel L, Raghunathan PL, Marston B. Attitudes about vaccines to prevent Ebola virus disease in Guinea at the end of a large Ebola epidemic: Results of a national household survey. Vaccine 2017; 35:6915-6923. [PMID: 28716555 DOI: 10.1016/j.vaccine.2017.06.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/22/2017] [Accepted: 06/09/2017] [Indexed: 11/29/2022]
Abstract
INTRODUCTION In 2014-2016, an Ebola epidemic devastated Guinea; more than 3800 cases and 2500 deaths were reported to the World Health Organization. In August 2015, as the epidemic waned and clinical trials of an experimental, Ebola vaccine continued in Guinea and neighboring Sierra Leone, we conducted a national household survey about Ebola-related knowledge, attitudes, and practices (KAP) and opinions about "hypothetical" Ebola vaccines. METHODS Using cluster-randomized sampling, we selected participants aged 15+ years old in Guinea's 8 administrative regions, which had varied cumulative case counts. The questionnaire assessed socio-demographic characteristics, experiences during the epidemic, Ebola-related KAP, and Ebola vaccine attitudes. To assess the potential for Ebola vaccine introduction in Guinea, we examined the association between vaccine attitudes and participants' characteristics using categorical and multivariable analyses. RESULTS Of 6699 persons invited to participate, 94% responded to at least 1 Ebola vaccine question. Most agreed that vaccines were needed to fight the epidemic (85.8%) and that their family would accept safe, effective Ebola vaccines if they became available in Guinea (84.2%). These measures of interest and acceptability were significantly more common among participants who were male, wealthier, more educated, and lived with young children who had received routine vaccines. Interest and acceptability were also significantly higher among participants who understood Ebola transmission modes, had witnessed Ebola response teams, knew Ebola-affected persons, believed Ebola was not always fatal, and would access Ebola treatment centers. In multivariable analyses of the majority of participants living with young children, interest and acceptability were significantly higher among those living with vaccinated children than among those living with unvaccinated children. DISCUSSION The high acceptability of hypothetical vaccines indicates strong potential for introducing Ebola vaccines across Guinea. Strategies to build public confidence in use of Ebola vaccines should highlight any similarities with safe, effective vaccines routinely used in Guinea.
Collapse
Affiliation(s)
- Kathleen L Irwin
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA.
| | - Mohamed F Jalloh
- Focus 1000, 15 Main Motor Road, Brookfields, Freetown, Sierra Leone.
| | - Jamaica Corker
- Consultant to the Centers for Disease Control and Prevention, Atlanta, 1600 Clifton Road NE, Atlanta, GA 30329, USA.
| | | | - Susan J Robinson
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA.
| | - Wenshu Li
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA.
| | - Nyuma E James
- Focus 1000, 15 Main Motor Road, Brookfields, Freetown, Sierra Leone.
| | - Musa Sellu
- Focus 1000, 15 Main Motor Road, Brookfields, Freetown, Sierra Leone.
| | - Mohammad B Jalloh
- Focus 1000, 15 Main Motor Road, Brookfields, Freetown, Sierra Leone.
| | | | - LaRee Tracy
- Food and Drug Administration, Center for Drug Evaluation and Research, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA.
| | - Rana Hajjeh
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA.
| | - Amanda VanSteelandt
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA.
| | - Rebecca Bunnell
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA.
| | - Lise Martel
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA.
| | - Pratima L Raghunathan
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA.
| | - Barbara Marston
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA.
| | | |
Collapse
|
9
|
Glynn JR, Bower H, Johnson S, Houlihan CF, Montesano C, Scott JT, Semple MG, Bangura MS, Kamara AJ, Kamara O, Mansaray SH, Sesay D, Turay C, Dicks S, Wadoum REG, Colizzi V, Checchi F, Samuel D, Tedder RS. Asymptomatic infection and unrecognised Ebola virus disease in Ebola-affected households in Sierra Leone: a cross-sectional study using a new non-invasive assay for antibodies to Ebola virus. Lancet Infect Dis 2017; 17:645-53. [PMID: 28256310 DOI: 10.1016/S1473-3099(17)30111-1] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 12/08/2016] [Accepted: 01/16/2017] [Indexed: 01/19/2023]
Abstract
BACKGROUND The frequency of asymptomatic infection with Ebola virus is unclear: previous estimates vary and there is no standard test. Asymptomatic infection with Ebola virus could contribute to population immunity, reducing spread. If people with asymptomatic infection are infectious it could explain re-emergences of Ebola virus disease (EVD) without known contact. METHODS We validated a new oral fluid anti-glycoprotein IgG capture assay among survivors from Kerry Town Ebola Treatment Centre and controls from communities unaffected by EVD in Sierra Leone. We then assessed the seroprevalence of antibodies to Ebola virus in a cross-sectional study of household contacts of the survivors. All household members were interviewed. Two reactive tests were required for a positive result, with a third test to resolve any discrepancies. FINDINGS The assay had a specificity of 100% (95% CI 98·9-100; 339 of 339 controls tested negative) and sensitivity of 95·9% (89·8-98·9; 93 of 97 PCR-confirmed survivors tested positive). Of household contacts not diagnosed with EVD, 47·6% (229 of 481) had high level exposure (direct contact with a corpse, body fluids, or a case with diarrhoea, vomiting, or bleeding). Among the contacts, 12·0% (95% CI 6·1-20·4; 11 of 92) with symptoms at the time other household members had EVD, and 2·6% (1·2-4·7; 10 of 388) with no symptoms tested positive. Among asymptomatic contacts, seropositivity was weakly correlated with exposure level. INTERPRETATION This new highly specific and sensitive assay showed asymptomatic infection with Ebola virus was uncommon despite high exposure. The low prevalence suggests asymptomatic infection contributes little to herd immunity in Ebola, and even if infectious, would account for few transmissions. FUNDING Wellcome Trust ERAES Programme, Save the Children.
Collapse
|
10
|
Abstract
As of the end of March 2016, the West Africa epidemic of Ebola virus disease (Ebola) had resulted in a total of 28,646 cases, 11,323 of them fatal, reported to the World Health Organization. Guinea, Liberia, and Sierra Leone were most heavily affected, but Ebola cases were exported to several other African and European countries as well as the United States, with limited further transmission, including to healthcare workers. We review the descriptive epidemiology of the outbreak, novel aspects and insights concerning the unprecedented response, scientific observations, and public health implications. The large number of Ebola survivors has highlighted the frequency of persistent symptoms and the possibility of virus persistence in sanctuary sites, sometimes leading to delayed transmission. Although transmission appears to have ceased in 2016, the West Africa Ebola epidemic has profoundly influenced discussions and practice concerning global health security.
Collapse
Affiliation(s)
- Terrence Q Lo
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30333; , , ,
| | - Barbara J Marston
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30333; , , ,
| | - Benjamin A Dahl
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30333; , , ,
| | - Kevin M De Cock
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30333; , , ,
| |
Collapse
|