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Chains of transmission and control of Ebola virus disease in Conakry, Guinea, in 2014: an observational study.

ABSTRACT: An epidemic of Ebola virus disease of unprecedented size continues in parts of west Africa. For the first time, large urban centres such as Conakry, the capital of Guinea, are affected. We did an observational study of patients with Ebola virus disease in three regions of Guinea, including Conakry, aiming to map the routes of transmission and assess the effect of interventions.Between Feb 10, 2014, and Aug 25, 2014, we obtained data from the linelist of all confirmed and probable cases in Guinea (as of Sept 16, 2014), a laboratory database of information about patients, and interviews with patients and their families and neighbours. With this information, we mapped chains of transmission, identified which setting infections most probably originated from (community, hospitals, or funerals), and computed the context-specific and overall reproduction numbers.Of 193 confirmed and probable cases of Ebola virus disease reported in Conakry, Boffa, and Télimélé, 152 (79%) were positioned in chains of transmission. Health-care workers contributed little to transmission. In March, 2014, individuals with Ebola virus disease who were not health-care workers infected a mean of 2·3 people (95% CI 1·6-3·2): 1·4 (0·9-2·2) in the community, 0·4 (0·1-0·9) in hospitals, and 0·5 (0·2-1·0) at funerals. After the implementation of infection control in April, the reproduction number in hospitals and at funerals reduced to lower than 0·1. In the community, the reproduction number dropped by 50% for patients that were admitted to hospital, but remained unchanged for those that were not. In March, hospital transmissions constituted 35% (seven of 20) of all transmissions and funeral transmissions constituted 15% (three); but from April to the end of the study period, they constituted only 9% (11 of 128) and 4% (five), respectively. 82% (119 of 145) of transmission occurred in the community and 72% (105) between family members. Our simulations show that a 10% increase in hospital admissions could have reduced the length of chains by 26% (95% CI 4-45).In Conakry, interventions had the potential to stop the epidemic, but reintroductions of the disease and poor cooperation of a few families led to prolonged low-level spread, showing the challenges of Ebola virus disease control in large urban centres. Monitoring of chains of transmission is crucial to assess and optimise local control strategies for Ebola virus disease.Labex IBEID, Reacting, PREDEMICS, NIGMS MIDAS initiative, Institut Pasteur de Dakar.

SUBMITTER: Faye O

PROVIDER: S-EPMC4373532 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature

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Chains of transmission and control of Ebola virus disease in Conakry, Guinea, in 2014: an observational study.

Faye Ousmane O Boëlle Pierre-Yves PY Heleze Emmanuel E Faye Oumar O Loucoubar Cheikh C Magassouba N'Faly N Soropogui Barré B Keita Sakoba S Gakou Tata T Bah El Hadji Ibrahima el HI Koivogui Lamine L Sall Amadou Alpha AA Cauchemez Simon S

The Lancet. Infectious diseases 20150123 3

<h4>Background</h4>An epidemic of Ebola virus disease of unprecedented size continues in parts of west Africa. For the first time, large urban centres such as Conakry, the capital of Guinea, are affected. We did an observational study of patients with Ebola virus disease in three regions of Guinea, including Conakry, aiming to map the routes of transmission and assess the effect of interventions.<h4>Methods</h4>Between Feb 10, 2014, and Aug 25, 2014, we obtained data from the linelist of all con ...[more]

PMID: 25619149

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Project description:BackgroundThe 2013-2016 West African Ebola outbreak infected 28,616 people and caused 11,310 deaths by 11 May 2016, across six countries. The outbreak has also resulted in the largest number of EVD survivors in history-over 17,000. Guinea was declared Ebola-free on 1 June 2016. Reports from the outbreak documented 3814 cases resulting in 2544 deaths and 1270 survivors. EVD survivors face various neuropsychological and psycho-affective alterations that have not been fully identified yet. This study aims to document the depressive symptoms among adult survivors in Guinea.MethodsDepressive symptoms were investigated using the French version of the Center for Epidemiologic Studies-Depression Scale (CES-D) administered to all adult survivors (≥ 20 years) participating in the PostEboGui study and receiving care in Conakry. The study was combined with a clinical consultation by a psychiatrist at the Donka National Hospital in Conakry that ensured adapted care was provided when needed.ResultsOverall, 256 adult participants receiving care in Conakry participated in this study: 55% were women, median age 31 years [IQR: 26-40]. The median time since the Ebola Treatment Center (ETC) discharge was 8.1 months [IQR: 4.1-11.7]. 15% had a score above the threshold values indicating psychological suffering (15% for men and 14% for women). 33 people (16 women and 17 men) met with the psychiatrist, which resulted in the diagnosis of 3 cases of post-traumatic stress disorder (PTSD), 3 cases of mild depression, 13 cases of moderate depression, and 11 cases of severe depression, including 1 with kinesthetic hallucinations and another with visual hallucinations, and 1 with suicidal ideation and 3 with attempted suicide. Severe depression was diagnosed between 1 and 19 months after ETC discharge. The various identified forms of depression responded favorably to conventional drug therapies and cognitive behavioral therapy.ConclusionLong-term follow-up for EVD survivors will be necessary to understand the evolution of these pathologies. In the current post-epidemic context, these cases underscore the need to strengthen mental health diagnostic systems and treatment on a national scale.

Project description:Ebola virus (EBOV) transmission is currently poorly characterized and is thought to occur primarily by direct contact with infectious material; however transmission from swine to nonhuman primates via the respiratory tract has been documented. To establish an EBOV transmission model for performing studies with statistical significance, groups of six guinea pigs (gps) were challenged intranasally (i.n.) or intraperitoneally (i.p.) with 10,000 times the 50% lethal dose (LD50) of gp-adapted EBOV, and naive gps were then introduced as cage mates for contact exposure at 1 day postinfection (p.i.). The animals were monitored for survival and clinical signs of disease and quantitated for virus shedding postexposure. Changes in the duration of contact of naive gps with infected animals were evaluated for their impact on transmission efficiency. Transmission was more efficient from i.n.- than from i.p.-challenged gps, with 17% versus 83% of naive gps surviving exposure, respectively. Virus shedding was detected beginning at 3 days p.i. from both i.n.- and i.p.-challenged animals. Contact duration positively correlated with transmission efficiency, and the abrogation of direct contact between infected and naive animals through the erection of a steel mesh was effective at stopping virus spread, provided that infectious animal bedding was absent from the cages. Histopathological and immunohistochemical findings show that i.n.-infected gps display enhanced lung pathology and EBOV antigen in the trachea, which supports increased virus transmission from these animals. The results suggest that i.n.-challenged gps are more infectious to naive animals than their systemically infected counterparts and that transmission occurs through direct contact with infectious materials, including those transported through air movement over short distances.Ebola is generally thought to be spread between humans though infectious bodily fluids. However, a study has shown that Ebola can be spread from pigs to monkeys without direct contact. Further studies have been hampered, because an economical animal model for Ebola transmission is not available. To address this, we established a transmission model in guinea pigs and determined the mechanisms behind virus spread. The survival data, in addition to microscopic examination of lung and trachea sections, show that mucosal infection of guinea pigs is an efficient model for Ebola transmission. Virus spread is increased with longer contact times with an infected animal and is possible without direct contact between an infected and a naive host but can be stopped if infectious materials are absent. These results warrant consideration for the development of future strategies against Ebola transmission and for a better understanding of the parameters involved in virus spread.

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Chains of transmission and control of Ebola virus disease in Conakry, Guinea, in 2014: an observational study.

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Chains of transmission and control of Ebola virus disease in Conakry, Guinea, in 2014: an observational study.

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