Global health security: the wider lessons from the west African Ebola virus disease epidemic.
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ABSTRACT:
SUBMITTER: Heymann DL
PROVIDER: S-EPMC5856330 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND:Pandemics pose significant security/stability risks to nations with fragile infrastructures. We evaluated characteristics of the 2014 West African Ebola outbreak to elucidate lessons learned for managing transnational public health security threats. METHODS:We used publically available data to compare demographic and outbreak-specific data for Guinea, Sierra Leone, and Liberia, including key indicator data by the World Health Organization. Pearson correlation statistics were calculated to compare country-level infrastructure characteristics with outbreak size and duration. RESULTS:Hospital bed density was inversely correlated with longer EVD outbreak duration (r?=?-?0.99). Country-specific funding amount allocations were more likely associated with number of incident cases than the population at-risk or infrastructure needs. Key indicators demonstrating challenges for Guinea included: number of unsafe burials, percent of EVD-positive samples, and days between symptom onset and case hospitalization. Sierra Leone's primary key indicator was the number of districts with ?1 security incident. Liberia controlled their outbreak before much of the key-indicator data were collected. CONCLUSION:Many of the country-level factors, particularly the WHO key indicators were associated with controlling the epidemic. The infrastructure of countries affected by communicable diseases should be assessed by international political and public health leaders.
| S-EPMC6064117 | biostudies-literature
Project description:BackgroundThe 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 textUsing 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.ConclusionsThe 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.
| S-EPMC5710062 | biostudies-literature
Project description:The severe Ebola virus disease epidemic occurring in West Africa stems from a single zoonotic transmission event to a 2-year-old boy in Meliandou, Guinea. We investigated the zoonotic origins of the epidemic using wildlife surveys, interviews, and molecular analyses of bat and environmental samples. We found no evidence for a concurrent outbreak in larger wildlife. Exposure to fruit bats is common in the region, but the index case may have been infected by playing in a hollow tree housing a colony of insectivorous free-tailed bats (Mops condylurus). Bats in this family have previously been discussed as potential sources for Ebola virus outbreaks, and experimental data have shown that this species can survive experimental infection. These analyses expand the range of possible Ebola virus sources to include insectivorous bats and reiterate the importance of broader sampling efforts for understanding Ebola virus ecology.
| S-EPMC4309665 | biostudies-literature
Project description:In 49 patients with known Ebola virus disease outcomes during the ongoing outbreak in Sierra Leone, 13 were coinfected with the immunomodulatory pegivirus GB virus C (GBV-C). Fifty-three percent of these GBV-C(+) patients survived; in contrast, only 22% of GBV-C(-) patients survived. Both survival and GBV-C status were associated with age, with older patients having lower survival rates and intermediate-age patients (21 to 45 years) having the highest rate of GBV-C infection. Understanding the separate and combined effects of GBV-C and age on Ebola virus survival may lead to new treatment and prevention strategies, perhaps through age-related pathways of immune activation.
| S-EPMC4338908 | biostudies-literature
Project description:Following the end of the Ebola virus outbreak in West Africa in March 2016, the lingering effects of stigma on Ebola survivors, as well as children orphaned by the disease, have become evident. However, there was little scholarly attention paid to stigma while the outbreak was still active. This chapter explores the effects of stigmatization on the health care services that pregnant women, both with and without Ebola, were able to access and receive during the outbreak. We propose three primary ways in which stigma operated to reduce pregnant women’s access to health care services during the outbreak: (1) Women and their relatives were afraid to go to health facilities for fear of being infected with Ebola while there, i.e., stigmatization of health care facilities; (2) Health care workers frequently died due to their occupational exposure to EVD while caring for others, i.e., they were stigmatized as carriers or transmitters of Ebola; and (3) Pregnant women themselves were refused services at health facilities due to fears that they were infected with Ebola, i.e., the physiological processes of birth, which involve high levels of potential for exposure to bodily fluids, led to health care workers’ stigmatization of these women when they sought services during pregnancy or, particularly, at the time of giving birth. In several of the countries that experienced the worst of the outbreak, women already faced some of the world’s highest rates of pregnancy-related death even prior to the advent of the epidemic. We argue that the high fatality rate for pregnant women with Ebola, the drastic effects of the epidemic on countries’ health care workforce, and the inherent messiness of birth, all coalesced to create heightened discrimination and stigma around seeking care during pregnancy and birth.
| S-EPMC7123537 | biostudies-literature
Project description:The 2013-2016 outbreak of Ebola virus (EBOV) in West Africa was the largest recorded. It began following the cross-species transmission of EBOV from an animal reservoir, most likely bats, into humans, with phylogenetic analysis revealing the co-circulation of several viral lineages. We hypothesized that this prolonged human circulation led to genomic changes that increased viral transmissibility in humans. We generated a synthetic glycoprotein (GP) construct based on the earliest reported isolate and introduced amino acid substitutions that defined viral lineages. Mutant GPs were used to generate a panel of pseudoviruses, which were used to infect different human and bat cell lines. These data revealed that specific amino acid substitutions in the EBOV GP have increased tropism for human cells, while reducing tropism for bat cells. Such increased infectivity may have enhanced the ability of EBOV to transmit among humans and contributed to the wide geographic distribution of some viral lineages.
| S-EPMC5101188 | biostudies-literature
Project description: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.
| S-EPMC6601535 | biostudies-literature
Project description:BackgroundHealthcare and other front-line workers are at particular risk of infection with Ebola virus (EBOV). Despite the large-scale deployment of international responders, few cases of Ebola virus disease have been diagnosed in this group. Since asymptomatic or pauci-symptomatic infection has been described, it is plausible that infections have occurred in healthcare workers but have escaped being diagnosed. We aimed to assess the prevalence of asymptomatic or pauci-symptomatic infection, and of exposure events, among returned responders to the West African Ebola epidemic 2014-2016.Methods and findingsWe used snowball sampling to identify responders who had returned to the UK or Ireland, and used an online consent and questionnaire to determine their exposure to EBOV and their experience of illness. Oral fluid collection devices were sent and returned by post, and samples were tested using an EBOV IgG capture assay that detects IgG to Ebola glycoprotein. Blood was collected from returnees with reactive samples for further testing. Unexposed UK controls were also recruited. In all, 300 individuals consented, of whom 268 (89.3%) returned an oral fluid sample (OFS). The majority had worked in Sierra Leone in clinical, laboratory, research, and other roles. Fifty-three UK controls consented and provided samples using the same method. Of the returnees, 47 (17.5%) reported that they had had a possible EBOV exposure. Based on their free-text descriptions, using a published risk assessment method, we classified 43 (16%) as having had incidents with risk of Ebola transmission, including five intermediate-risk and one high-risk exposure. Of the returnees, 57 (21%) reported a febrile or diarrhoeal illness in West Africa or within 1 mo of return, of whom 40 (70%) were not tested at the time for EBOV infection. Of the 268 OFSs, 266 were unreactive. Two returnees, who did not experience an illness in West Africa or on return, had OFSs that were reactive on the EBOV IgG capture assay, with similar results on plasma. One individual had no further positive test results; the other had a positive result on a double-antigen bridging assay but not on a competitive assay or on an indirect EBOV IgG ELISA. All 53 controls had non-reactive OFSs. While the participants were not a random sample of returnees, the number participating was high.ConclusionsThis is the first study, to our knowledge, of the prevalence of EBOV infection in international responders. More than 99% had clear negative results. Sera from two individuals had discordant results on the different assays; both were negative on the competitive assay, suggesting that prior infection was unlikely. The finding that a significant proportion experienced "near miss" exposure events, and that most of those who experienced symptoms did not get tested for EBOV at the time, suggests a need to review and standardise protocols for the management of possible exposure to EBOV, and for the management of illness, across organisations that deploy staff to outbreaks.
| S-EPMC5433702 | biostudies-literature
Project description:The west Africa Ebola virus disease (EVD) epidemic was extraordinary in scale. Now that the epidemic has ended, it is a relevant time to examine published studies with direct relevance to clinical care and, more broadly, to examine the implications of the clinical research response mounted. Clinically relevant research includes literature detailing risk factors for and clinical manifestations of EVD, laboratory and other investigation findings in patients, experimental vaccine and therapeutic clinical trials, and analyses of survivor syndrome. In this Review, we discuss new insights from patient-oriented research completed during the west Africa epidemic, identify ongoing knowledge gaps, and suggest priorities for future research.
| S-EPMC5856335 | biostudies-literature
Project description:Genetic analyses have provided important insights into Ebola virus spread during the recent West African outbreak, but their implications for specific intervention scenarios remain unclear. Here, we address this issue using a collection of phylodynamic approaches. We show that long-distance dispersal events were not crucial for epidemic expansion and that preventing viral lineage movement to any given administrative area would, in most cases, have had little impact. However, major urban areas were critical in attracting and disseminating the virus: preventing viral lineage movement to all three capitals simultaneously would have contained epidemic size to one-third. We also show that announcements of border closures were followed by a significant but transient effect on international virus dispersal. By quantifying the hypothetical impact of different intervention strategies, as well as the impact of barriers on dispersal frequency, our study illustrates how phylodynamic analyses can help to address specific epidemiological and outbreak control questions.
| S-EPMC5993714 | biostudies-literature