Minimally Symptomatic Infection in an Ebola ‘Hotspot’: A Cross-Sectional Serosurvey

Introduction: Evidence for minimally symptomatic Ebola virus (EBOV) infection is limited. During the 2013–16 outbreak in West Africa, it was not considered epidemiologically relevant to published models or projections of intervention effects. In order to improve our understanding of the transmission dynamics of EBOV in humans, we investigated the occurrence of minimally symptomatic EBOV infection in quarantined contacts of reported Ebola virus disease cases in a recognized ‘hotspot.’ Methodology/Principal Findings We conducted a cross-sectional serosurvey in Sukudu, Kono District, Sierra Leone, from October 2015 to January 2016. A blood sample was collected from 187 study participants, 132 negative controls (individuals with a low likelihood of previous exposure to Ebola virus), and 30 positive controls (Ebola virus disease survivors). IgG responses to Ebola glycoprotein and nucleoprotein were measured using Alpha Diagnostic International ELISA kits with plasma diluted at 1:200. Optical density was read at 450 nm (subtracting OD at 630nm to normalize well background) on a ChroMate 4300 microplate reader. A cutoff of 4.7 U/mL for the anti-GP ELISA yielded 96.7% sensitivity and 97.7% specificity in distinguishing positive and negative controls. We identified 14 seropositive individuals not known to have had Ebola virus disease. Two of the 14 seropositive individuals reported only fever during quarantine while the remaining 12 denied any signs or symptoms during quarantine. Conclusions/Significance: By using ELISA to measure Zaire Ebola virus antibody concentrations, we identified a significant number of individuals with previously undetected EBOV infection in a ‘hotspot’ village in Sierra Leone, approximately one year after the village outbreak. The findings provide further evidence that Ebola, like many other viral infections, presents with a spectrum of clinical manifestations, including minimally symptomatic infection. These data also suggest that a significant portion of Ebola transmission events may have gone undetected during the outbreak. Further studies are needed to understand the potential risk of transmission and clinical sequelae in individuals with previously undetected EBOV infection

Biosocial Approaches to the 2013-2016 Ebola Pandemic

Abstract Despite more than 25 documented outbreaks of Ebola since 1976, our understanding of the disease is limited, in particular the social, political, ecological, and economic forces that promote (or limit) its spread. In the following study, we seek to provide new ways of understanding the 2013-2016 Ebola pandemic. We use the term, ‘pandemic,’ instead of ‘epidemic,’ so as not to elide the global forces that shape every localized outbreak of infectious disease. By situating life histories via a biosocial approach, the forces promoting or retarding Ebola transmission come into sharper focus. We conclude that biomedical and culturalist claims of causality have helped obscure the role of human rights failings (colonial legacies, structural adjustment, exploitative mining companies, enabled civil war, rural poverty, and the near absence of quality health care, to name but a few) in the genesis of the 2013-16 pandemic. From early 20th century smallpox and influenza outbreaks to 21st century Ebola, transnational relations of inequality continue to be embodied as viral disease in West Africa, resulting in the preventable deaths of hundreds of thousands of people

What factors are associated with paediatric admissions and their outcomes in a rural hospital in northern Sierra Leone? Insights from a pilot observational study

Introduction: Data on the pattern of admissions and causes of child death are crucial in informing priorities for improving child survival. In many health facilities in sub-Saharan Africa, understanding the pattern of paediatric admissions and their outcomes is constrained by poor documentation of these important features. Methods: We developed and piloted a simple paper-based tool for documentation of basic, standardised patient-level information on causes of admissions, diagnoses, treatments and outcomes in children admitted to a rural hospital in Sierra Leone. The tool contained sections covering basic sociodemographic information about a patient, chief medical complaints, findings from clinical examinations and tests conducted at admission, results from subsequent clinical and laboratory investigations, working/definitive diagnoses, management and treatment outcomes. Results: From 1 August 2019 to 31 July 2021, we used this tool to document the admissions, treatments and clinical outcomes of 1663 children admitted to Kambia district hospital in northern Sierra Leone. The majority of the children (1015, 62%) were aged 12–59 months, were boys (942, 57%), were wasted (516, 31%), stunted (238, 14%) or underweight (537, 32%). Above a half of the children lived more than 1 km distance from the hospital (876/1410, 62%). The highest number of admissions occurred in November 2019 and the lowest in April 2020. Severe malaria was the leading cause of admission. More than 80% of the children were successfully treated and discharged home (1356/1663, 81.5%) while 122/1663 (7.3%) died. Children aged under 5 years who were underweight, and those who presented with danger signs (eg, signs of breathing difficulty, dehydration, head injury or severe infections) had a higher risk of death than children without these features (p<0.01; p=0.03; p=0.011 and p=0.009, respectively). Conclusion: Lack of systematic documentation of medical histories and poor record keeping of hospital admissions and outcomes can be overcome by using a simple tool. Continuous use of the tool with regular audits could improve delivery of paediatric care in resource-limited settings

Anatomy of a Hotspot: Chain and Seroepidemiology of Ebola Virus Transmission, Sukudu, Sierra Leone, 2015-16.

Studies have yet to include minimally symptomatic Ebola virus (EBOV) infections and unrecognized Ebola virus disease (EVD) in Ebola-related transmission chains and epidemiologic risk estimates. We conducted a cross-sectional, sero-epidemiological survey from October 2015 to January 2016 among 221 individuals living in quarantined households from November 2014 to February 2015 during the Ebola outbreak in the village of Sukudu, Sierra Leone. Of 48 EBOV-infected persons, 25% (95% confidence interval [CI], 14%-40%) had minimally symptomatic EBOV infections and 4% (95% CI, 1%-14%) were unrecognized EVD cases. The pattern of minimally symptomatic EBOV infections in the transmission chain was nonrandom (P < .001, permutation test). Not having lived in the same house as an EVD case was significantly associated with minimally symptomatic infection. This is the first study to investigate a chain of EBOV transmission inclusive of minimally symptomatic EBOV infections and unrecognized EVD. Our findings provide new insights into Ebola transmission dynamics and quarantine practices

Anatomy of a Hotspot: Chain and Seroepidemiology of Ebola Virus Transmission, Sukudu, Sierra Leone, 2015–16

Studies have yet to include minimally symptomatic Ebola virus (EBOV) infections and unrecognized Ebola virus disease (EVD) in Ebola-related transmission chains and epidemiologic risk estimates. We conducted a cross-sectional, sero-epidemiological survey from October 2015 to January 2016 among 221 individuals living in quarantined households from November 2014 to February 2015 during the Ebola outbreak in the village of Sukudu, Sierra Leone. Of 48 EBOV-infected persons, 25% (95% confidence interval [CI], 14%-40%) had minimally symptomatic EBOV infections and 4% (95% CI, 1%-14%) were unrecognized EVD cases. The pattern of minimally symptomatic EBOV infections in the transmission chain was nonrandom (P < .001, permutation test). Not having lived in the same house as an EVD case was significantly associated with minimally symptomatic infection. This is the first study to investigate a chain of EBOV transmission inclusive of minimally symptomatic EBOV infections and unrecognized EVD. Our findings provide new insights into Ebola transmission dynamics and quarantine practices