Genome-wide association study identifies human genetic variants associated with fatal outcome from Lassa fever

Infection with Lassa virus (LASV) can cause Lassa fever, a haemorrhagic illness with an estimated fatality rate of 29.7%, but causes no or mild symptoms in many individuals. Here, to investigate whether human genetic variation underlies the heterogeneity of LASV infection, we carried out genome-wide association studies (GWAS) as well as seroprevalence surveys, human leukocyte antigen typing and high-throughput variant functional characterization assays. We analysed Lassa fever susceptibility and fatal outcomes in 533 cases of Lassa fever and 1,986 population controls recruited over a 7 year period in Nigeria and Sierra Leone. We detected genome-wide significant variant associations with Lassa fever fatal outcomes near GRM7 and LIF in the Nigerian cohort. We also show that a haplotype bearing signatures of positive selection and overlapping LARGE1, a required LASV entry factor, is associated with decreased risk of Lassa fever in the Nigerian cohort but not in the Sierra Leone cohort. Overall, we identified variants and genes that may impact the risk of severe Lassa fever, demonstrating how GWAS can provide insight into viral pathogenesis.

Ebola Virus Disease Sensitization: Community-Driven Efforts in Sierra Leone

The 2014-2016 West Africa Ebola outbreak was the largest in history, resulting in approximately 11,000 deaths. Despite the outbreak's eventual end, national and international health sensitization and containment efforts were subject to criticism. This study investigates disease-related knowledge and beliefs, as well as trusted sources of health information among EVD-survivors and their family members, highlighting the importance of community-informed public health responses. Participants (n = 134) were adults who were either EVD-infected, affected families/caregivers, or community leaders. In-depth interviews and focus groups explored EVD-related experiences, including health effects, stigma, and community relationships. Using a grounded theory and thematic content analysis approach, transcripts were coded for evidence of health sensitization, as well as compliance with mitigation measures and trusted sources of information. Participants displayed a high level of knowledge around EVD and reported compliance with mandated and personal prevention measures. Levels of health sensitization and subsequent reintegration of survivors were reported to be largely the products of community-based efforts, rather than the top-down, national public health response. Primary sources of trusted information included EVD survivors acting as peer educators; local leaders; and EVD sensitization by community health workers. This study highlights the importance of a community-based response for increasing the effectiveness of public health campaigns. Participants expressed that relying on the experiences of trusted cultural insiders led to a deeper understanding of Ebola compared to top-down public health campaigns, and helped infected and affected community members reintegrate. Future public health efforts should incorporate community-based participatory approaches to address infectious disease outbreaks.

Respiratory virus surveillance in hospitalized children less than two-years of age in Kenema, Sierra Leone during the COVID-19 pandemic (October 2020- October 2021)

Globally, viral pathogens are the leading cause of acute respiratory infection in children under-five years. We aim to describe the epidemiology of viral respiratory pathogens in hospitalized children under-two years of age in Eastern Province of Sierra Leone, during the second year of the SARS-CoV-2 pandemic. We conducted a prospective study of children hospitalized with respiratory symptoms between October 2020 and October 2021. We collected demographic and clinical characteristics and calculated each participant´s respiratory symptom severity. Nose and throat swabs were collected at enrollment. Total nucleic acid was purified and tested for multiple respiratory viruses. Statistical analysis was performed using R version 4.2.0 software. 502 children less than two-years of age were enrolled. 376 (74.9%) had at least one respiratory virus detected. The most common viruses isolated were HRV/EV (28.2%), RSV (19.5%) and PIV (13.1%). Influenza and SARS-CoV-2 were identified in only 9.2% and 3.9% of children, respectively. Viral co-detection was common. Human metapneumovirus and RSV had more than two-fold higher odds of requiring O2 therapy while hospitalized. Viral pathogen prevalence was high (74.9%) in our study population. Despite this, 100% of children received antibiotics, underscoring a need to expand laboratory diagnostic capacity and to revisit clinical guidelines implementation in these children. Continuous surveillance and serologic studies among more diverse age groups, with greater geographic breadth, are needed in Sierra Leone to better characterize the long-term impact of COVID-19 on respiratory virus prevalence and to better characterize the seasonality of respiratory viruses in Sierra Leone.

Antibiotic prescribing practices for acute respiratory illness in children less than 24 months of age in Kenema, Sierra Leone: is it time to move beyond algorithm driven decision making?

BACKGROUND

Lower respiratory tract infections are the leading cause of mortality in young children globally. In many resource-limited settings clinicians rely on guidelines such as IMCI or ETAT + that promote empiric antibiotic utilization for management of acute respiratory illness (ARI). Numerous evaluations of both guidelines have shown an overall positive response however, several challenges have also been reported, including the potential for over-prescribing of unnecessary antibiotics. The aims of this study were to describe the antibiotic prescribing practices for children less than 24 months of age with symptoms of ARI, that were admitted to Kenema Government Hospital (KGH) in the Eastern Province of Sierra Leone, and to identify the number of children empirically prescribed antibiotics who were admitted to hospital with ARI, as well as their clinical signs, symptoms, and outcomes.

METHODS

We conducted a prospective study of children < 24 months of age admitted to the KGH pediatric ward with respiratory symptoms between October 1, 2020 and May 31, 2022. Study nurses collected data on demographic information, medical and medication history, and information on clinical course while hospitalized.

RESULTS

A total of 777 children were enrolled. Prior to arrival at the hospital, 224 children (28.8%) reported taking an antibiotic for this illness without improvement. Only 15 (1.9%) children received a chest radiograph to aid in diagnosis and 100% of patients were placed on antibiotics during their hospital stay.

CONCLUSIONS

Despite the lives saved, reliance on clinical decision-support tools such as IMCI and ETAT + for pediatric ARI, is resulting in the likely over-prescribing of antibiotics. Greater uptake of implementation research is needed to develop strategies and tools designed to optimize antibiotic use for ARI in LMIC settings. Additionally, much greater priority needs to be given to ensuring clinicians have the basic tools for clinical diagnosis, as well as greater investments in essential laboratory and radiographic diagnostics that help LMIC clinicians move beyond the sole reliance on algorithm based clinical decision making.

Structural conservation of Lassa virus glycoproteins and recognition by neutralizing antibodies

Lassa fever is an acute hemorrhagic fever caused by the zoonotic Lassa virus (LASV). The LASV glycoprotein complex (GPC) mediates viral entry and is the sole target for neutralizing antibodies. Immunogen design is complicated by the metastable nature of recombinant GPCs and the antigenic differences among phylogenetically distinct LASV lineages. Despite the sequence diversity of the GPC, structures of most lineages are lacking. We present the development and characterization of prefusion-stabilized, trimeric GPCs of LASV lineages II, V, and VII, revealing structural conservation despite sequence diversity. High-resolution structures and biophysical characterization of the GPC in complex with GP1-A-specific antibodies suggest their neutralization mechanisms. Finally, we present the isolation and characterization of a trimer-preferring neutralizing antibody belonging to the GPC-B competition group with an epitope that spans adjacent protomers and includes the fusion peptide. Our work provides molecular detail information on LASV antigenic diversity and will guide efforts to design pan-LASV vaccines.

Lassa Fever Natural History and Clinical Management

Lassa fever is caused by Lassa virus (LASV), an Old World Mammarenavirus that is carried by Mastomys natalensis and other rodents. It is endemic in Sierra Leone, Nigeria, and other countries in West Africa. The clinical presentation of LASV infection is heterogenous varying from an inapparent or mild illness to a fatal hemorrhagic fever. Exposure to LASV is usually through contact with rodent excreta. After an incubation period of 1-3 weeks, initial symptoms such as fever, headache, and fatigue develop that may progress to sore throat, retrosternal chest pain, conjunctival injection, vomiting, diarrhea, and abdominal pain. Severe illness, including hypotension, shock, and multiorgan failure, develops in a minority of patients. Patient demographics and case fatality rates are distinctly different in Sierra Leone and Nigeria. Laboratory diagnosis relies on the detection of LASV antigens or genomic RNA. LASV-specific immunoglobulin G and M assays can also contribute to clinical management. The mainstay of treatment for Lassa fever is supportive care. The nucleoside analog ribavirin is commonly used to treat acute Lassa fever but is considered useful only if treatment is begun early in the disease course. Drugs in development, including a monoclonal antibody cocktail, have the potential to impact the management of Lassa fever.

Novel Tools for Lassa Virus Surveillance in Peri-domestic Rodents

Background

Lassa fever (LF) is a rodent-borne disease endemic to West Africa. In the absence of licensed therapeutics or vaccines, rodent exclusion from living spaces remains the primary method of preventing LF. Zoonotic surveillance of Lassa virus (LASV), the etiologic agent of LF, can assess the burden of LASV in a region and guide public health measures against LF.

Methods

In this study, we adapted commercially available LASV human diagnostics to assess the prevalence of LASV in peri-domestic rodents in Eastern Sierra Leone. Small mammal trapping was conducted in Kenema district, Sierra Leone between November 2018-July 2019. LASV antigen was detected using a commercially available LASV NP antigen rapid diagnostic test. LASV IgG antibodies against LASV nucleoprotein (NP) and glycoprotein (GP) were tested by adapting a commercially available semi-quantitative enzyme linked immunosorbent assay (ELISA) for detection of mouse-related and rat-related species IgG.

Findings

Of the 373 tested specimens, 74 (20%) tested positive for LASV antigen. 40 (11%) specimens tested positive for LASV NP IgG, while an additional 12 (3%) specimens only tested positive for LASV GP IgG. Simultaneous antigen presence and IgG antibody presence was linked in Mastomys sp. specimens (p < 0.01), but not Rattus sp. specimens (p = 1). Despite the link between antigen presence and IgG antibody presence in Mastomys sp., the strength of antigen response did not correlate with the strength of IgG response to either GP IgG or NP IgG.

Interpretation

The tools developed in this study can aid in the generation of valuable public health data for rapid field assessment of LASV burden during outbreak investigations and general LASV surveillance.

Funding

Funding for this work was supported by the National Institute of Allergy and Infectious Diseases National Institute of Health, Department of Health and Human Services under the following grants: International Collaboration in Infectious Disease Research on Lassa fever and Ebola - ICIDR - U19 AI115589, Consortium for Viral Systems Biology - CViSB - 5U19AI135995, West African Emerging Infectious Disease Research Center - WARN-ID - U01AI151812, West African Center for Emerging Infectious Diseases: U01AI151801.

Seroprevalence of anti-Lassa Virus IgG antibodies in three districts of Sierra Leone: A cross-sectional, population-based study

BACKGROUND

Lassa virus (LASV), the cause of the acute viral hemorrhagic illness Lassa fever (LF), is endemic in West Africa. Infections in humans occur mainly after exposure to infected excrement or urine of the rodent-host, Mastomys natalensis. The prevalence of exposure to LASV in Sierra Leone is crudely estimated and largely unknown. This cross-sectional study aimed to establish a baseline point seroprevalence of IgG antibodies to LASV in three administrative districts of Sierra Leone and identify potential risk factors for seropositivity and LASV exposure.

METHODOLOGY AND PRINCIPAL FINDINGS

Between 2015 and 2018, over 10,642 participants from Kenema, Tonkolili, and Port Loko Districts were enrolled in this cross-sectional study. Previous LASV and LF epidemiological studies support classification of these districts as "endemic," "emerging," and "non-endemic", respectively. Dried blood spot samples were tested for LASV antibodies by ELISA to determine the seropositivity of participants, indicating previous exposure to LASV. Surveys were administered to each participant to assess demographic and environmental factors associated with a higher risk of exposure to LASV. Overall seroprevalence for antibodies to LASV was 16.0%. In Kenema, Port Loko, and Tonkolili Districts, seroprevalences were 20.1%, 14.1%, and 10.6%, respectively. In a multivariate analysis, individuals were more likely to be LASV seropositive if they were living in Kenema District, regardless of sex, age, or occupation. Environmental factors contributed to an increased risk of LASV exposure, including poor housing construction and proximity to bushland, forested areas, and refuse.

CONCLUSIONS AND SIGNIFICANCE

In this study we determine a baseline LASV seroprevalence in three districts which will inform future epidemiological, ecological, and clinical studies on LF and the LASV in Sierra Leone. The heterogeneity of the distribution of LASV and LF over both space, and time, can make the design of efficacy trials and intervention programs difficult. Having more studies on the prevalence of LASV and identifying potential hyper-endemic areas will greatly increase the awareness of LF and improve targeted control programs related to LASV.

A prospective, multi-site, cohort study to estimate incidence of infection and disease due to Lassa fever virus in West African countries (the Enable Lassa research programme)-Study protocol

BACKGROUND

Lassa fever (LF), a haemorrhagic illness caused by the Lassa fever virus (LASV), is endemic in West Africa and causes 5000 fatalities every year. The true prevalence and incidence rates of LF are unknown as infections are often asymptomatic, clinical presentations are varied, and surveillance systems are not robust. The aim of the Enable Lassa research programme is to estimate the incidences of LASV infection and LF disease in five West African countries. The core protocol described here harmonises key study components, such as eligibility criteria, case definitions, outcome measures, and laboratory tests, which will maximise the comparability of data for between-country analyses.

METHOD

We are conducting a prospective cohort study in Benin, Guinea, Liberia, Nigeria (three sites), and Sierra Leone from 2020 to 2023, with 24 months of follow-up. Each site will assess the incidence of LASV infection, LF disease, or both. When both incidences are assessed the LASV cohort (nmin = 1000 per site) will be drawn from the LF cohort (nmin = 5000 per site). During recruitment participants will complete questionnaires on household composition, socioeconomic status, demographic characteristics, and LF history, and blood samples will be collected to determine IgG LASV serostatus. LF disease cohort participants will be contacted biweekly to identify acute febrile cases, from whom blood samples will be drawn to test for active LASV infection using RT-PCR. Symptom and treatment data will be abstracted from medical records of LF cases. LF survivors will be followed up after four months to assess sequelae, specifically sensorineural hearing loss. LASV infection cohort participants will be asked for a blood sample every six months to assess LASV serostatus (IgG and IgM).

DISCUSSION

Data on LASV infection and LF disease incidence in West Africa from this research programme will determine the feasibility of future Phase IIb or III clinical trials for LF vaccine candidates.

Social distancing, community stigma, and implications for psychological distress in the aftermath of Ebola virus disease

Background

The 2013–2016 Ebola virus disease (EVD) epidemic resulted in more infections and deaths than all prior outbreaks in the 40-year history of this virus combined. This study examines how experiences of EVD infection, and preventive measures such as social distancing, were linked to experiences of stigma and social exclusion among those reintegrating into their communities.

Methods

Key informant interviews (n = 42) and focus group discussions (n = 27) were conducted in districts with a high prevalence of EVD and representing geographical and ethnic diversity (n = 228 participants). The final sample was composed of adults (52%) and children (48%) who were EVD-infected (46%) and -affected (42%) individuals, and community leaders (12%). Data were coded using a Grounded Theory approach informed by Thematic Content Analysis, and analyzed using NVivo. Interrater reliability was high, with Cohen’s κ = 0.80 or higher.

Findings

Participants described two main sources of EVD-related stress: isolation from the community because of social distancing and other prevention measures such as quarantine, and stigma related to infected or affected status. Participants linked experiences of social isolation and stigma to significant distress and feelings of ostracization. These experiences were particularly pronounced among children. Sources of support included community reintegration over time, and formal community efforts to provide education and establish protection bylaws.

Interpretation

This study found that social distancing and EVD-related stigma were each prominent sources of distress among participants. These results suggest that isolation because of infection, and the enduring stigmatization of infected individuals and their families, demand coordinated responses to prevent and mitigate additional psychosocial harm. Such responses should include close engagement with community leaders to combat misinformation and promote community reintegration.

Expansion of CD8+ T cell population in Lassa virus survivors with low T cell precursor frequency reveals durable immune response in most survivors

INTRODUCTION

Lassa virus is a priority pathogen for vaccine research and development, however the duration of cellular immunity and protection in Lassa fever (LF) survivors remains unclear.

METHODS

We investigated Lassa virus specific CD8+ T cell responses in 93 LF survivors. Peripheral blood mononuclear cells from these individuals were infected with recombinant vesicular stomatitis virus encoding Lassa virus antigens and virus specific T cell responses were measured after 18-hour incubation. Participants who had undetectable CD8+ T cell response underwent further analysis using a 10-day T cell proliferation assays to evaluate for low T cell precursor frequency.

RESULTS

Forty-five of the 93 LF survivors did not have a Lassa virus specific CD8+ T cell response. Of those with responses and a known date of onset of LF (N = 11), 9 had LF within the last ten years. Most participants without a measurable CD8+ T cell response were more than 10 years removed from a clinical history of LF (N = 14/16). Fourteen of 21 patients (67%) with undetectable CD8+ T cell response had a measurable Lassa virus specific CD8+ T cell response with the 10-day assay.

DISCUSSION

Despite reports of strong CD8+ T cell responses during acute Lassa virus infection, circulating Lassa virus-specific CD8+ T cells declined to undetectable levels in most Lassa fever survivors after ten years when evaluated with an 18-hour T cell stimulation. However, when Lassa virus-specific T cells were expanded prior to restimulation, a Lassa virus-specific CD8+ T cell response could be detected in many if the samples that were negative in the 18-hour stimulation assay, suggesting that prolonged cellular immunity does exist in Lassa fever survivors at low frequencies.

Evaluation of Three Clinical Prediction Tools to Predict Mortality in Hospitalized Patients with Lassa Fever

Lassa fever is a viral hemorrhagic illness with a case fatality rate for hospitalized patients as high as 69%. Identifying cases before they progress to serious illness can lead to earlier treatment and improved clinical outcomes. Three existing clinical prediction tools were evaluated on their ability to predict the in-hospital mortality in Lassa fever: the quick Sequential Organ Failure Assessment (qSOFA), the Modified Early Warning System (MEWS), and the Universal Vital Assessment (UVA). This was a retrospective cohort study of patients admitted to the dedicated Lassa fever ward of the Kenema Government Hospital in Sierra Leone between May 2013 and December 2019. Data among three serology groups were analyzed: Lassa antigen-positive (Ag+) regardless of IgM status, Lassa Ag- and IgM+, and Lassa Ag- and IgM- cases. There were 123 cases of suspected Lassa fever included in this study. Abnormalities in respiratory rate, oxygenation status, mental status, and serum markers of kidney and liver dysfunction were more likely seen in the Ag+ group, which had an in-hospital mortality of 85.7%. For the Lassa Ag+ group, the sensitivity and positive predictive value of qSOFA ≥ 2 was 70.6% and 92.3%, MEWS ≥ 5 was 96.9% and 86.1%, and UVA ≥ 5 was 60.0% and 100.0%. The MEWS and UVA scores show potential for use in Lassa fever, but there is opportunity for future development of a tool that includes the clinical and laboratory markers specific to Lassa fever.

The prevalence of Post-Ebola Syndrome hearing loss, Sierra Leone

BACKGROUND

Globally, hearing loss is the second leading cause of disability, affecting approximately 18.7% of the world's population. However, the burden of hearing loss is unequally distributed, with the majority of affected individuals located in Asia or Sub-Saharan Africa. Following the 2014 West African Ebola Outbreak, disease survivors began to describe hearing loss as part of the constellation of symptoms known as Post-Ebola Syndrome. The goal of this study was to more fully characterize hearing loss among Ebola Virus Disease (EVD) survivors.

METHODOLOGY AND PRINCIPAL FINDINGS

EVD survivors and their household contacts were recruited (n = 1,12) from Eastern Sierra Leone. Each individual completed a symptom questionnaire, physical exam, and a two-step audiometry process measuring both air and bone conduction thresholds. In comparison to contacts, EVD survivors were more likely to have complaints or abnormal findings affecting every organ system. A significantly greater percentage of EVD survivors were found to have hearing loss in comparison to contacts (23% vs. 9%, p < 0.001). Additionally, survivors were more likely to have bilateral hearing loss of a mixed etiology. Logistic regression revealed that the presence of any symptoms of middle or inner ear (p < 0.001), eye (p = 0.005), psychiatric (p = 0.019), and nervous system (p = 0.037) increased the odds of developing hearing loss.

CONCLUSIONS AND SIGNIFICANCE

This study is the first to use an objective and standardized measurement to report hearing loss among EVD survivors in a clinically meaningful manner. In this study it was found that greater than 1/5th of EVD survivors develop hearing loss. The association between hearing impairment and symptoms affecting the eye and nervous system may indicate a similar mechanism of pathogenesis, which should be investigated further. Due to the quality of life and socioeconomic detriments associated with untreated hearing loss, a greater emphasis must be placed on understanding and mitigating hearing loss following survival to aid in economic recovery following infectious disease epidemics.

Distinct antibody profiles against Ebola virus track with the development of Post-Ebola Syndrome

Survivors of Ebola virus disease (EVD) have reported a wide range of symptoms following recovery from infection. These long-term sequelae, collectively termed post-Ebola syndrome (PES), can significantly impact the daily lives of EVD survivors, yet little is known about the underlying mechanism of PES pathogenesis. Antibodies against Ebola virus provide protection against infection through both neutralization and recruitment of innate immune effector functions via the antibody Fc region, yet persistent antibody-mediated inflammation may contribute to PES manifestations. To investigate the potential role that virus-specific antibodies have in PES, we analyzed the antibody immune profiles in a cohort of EVD survivors and household contacts that had been previously characterized for clinical sequelae. Antibodies isolated from survivors an average of 2.5 years after recovery were measured for induction of Fc-mediated innate effector function against the immunodominant antigen Ebola glycoprotein-coated targets. We found that antibodies in asymptomatic EVD survivors were qualitatively different from survivors experiencing musculoskeletal and gastrointestinal manifestations of PES. Specifically, antibodies from asymptomatic individuals induced higher levels of antibody-dependent complement deposition and monocyte-mediated phagocytosis, but not neutrophil-mediated phagocytosis, and differed in NK cell activation profiles compared with individuals with PES. Together, these data suggest that the development of qualitatively different antibodies may shape susceptibility to/protection from the development of PES and may help identify potential therapeutic targets for EVD survivors suffering from PES.

Supported by Washington State University, College of Veterinary Medicine

T Cell Responses In Children With Asthma Against SARS-CoV-2 Correlates To Asthmatic Outcomes

SARS CoV-2 in children or special populations post-infection has not been well studied. Asthma is a heterogenous disease marked by chronic airway inflammation; triggers include cockroaches (CRA), and other inhaled irritants. Asthma also has links to viral infections like respiratory syncytial virus (RSV). Additionally, some with moderate to severe asthma are more likely to be hospitalized with COVID. T cells play key roles in asthma and control of viruses such; however, there is limited information connecting T cell responses in people with asthma to viral infections. We aimed to evaluate T cells and antibodies in an asthma confirmed cohort. Thirty-five children aged 5–17 years were included. We measured SARS CoV-2 spike (S) and Nucleoprotein (N) plasma antibody responses or effector functions and CD4, CD8 T cells specific to CRA or peptide pools made from RSV, S and N antigen using an activation induced markers (AIM) assay. Surprisingly, in this population many CD4 and CD8 T-cell AIM responses to S, N, CRA, and RSV were significantly associated, particularly for CD8 T-cells (Spearmans r = 0.57–0.76) and the restimulation antigens CRA and RSV. N-specific CD4 AIM was the only immune measure to correlate to a recent asthma attack within a month of the blood collection visit, though anti-N antibodies, CD4 AIM to CRA, RSV or CD8 AIM to CRA, RSV, or N antigens also correlated with asthmatic outcomes (e.g., ER visits, night waking from symptoms, etc.) whereas allergen specific IgE or anti-S IgG did not. Taken together these results indicate an immunological association between viral infection and asthma, broadly allowing for the conjecture that viral infections, in particular RSV and SARS-CoV-2 could act together as possible triggers of asthma.

SARS-CoV-2 seroprevalence rates of children seeking medical care in Louisiana during the state stay at home order

Serologic testing of residual blood samples from 812 children from a hospital in New Orleans, LA, between March and May 2020, demonstrated a SARS-CoV-2 seroprevalence of 6.8% based on S and N protein IgG; Black and Hispanic children, and children living in zip codes with lower household incomes were over-represented.

Cross-Reactive Antibodies to SARS-CoV-2 and MERS-CoV in Pre-COVID-19 Blood Samples from Sierra Leoneans

Many countries in sub-Saharan Africa have experienced lower COVID-19 caseloads and fewer deaths than countries in other regions worldwide. Under-reporting of cases and a younger population could partly account for these differences, but pre-existing immunity to coronaviruses is another potential factor. Blood samples from Sierra Leonean Lassa fever and Ebola survivors and their contacts collected before the first reported COVID-19 cases were assessed using enzyme-linked immunosorbent assays for the presence of antibodies binding to proteins of coronaviruses that infect humans. Results were compared to COVID-19 subjects and healthy blood donors from the United States. Prior to the pandemic, Sierra Leoneans had more frequent exposures than Americans to coronaviruses with epitopes that cross-react with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), SARS-CoV, and Middle Eastern respiratory syndrome coronavirus (MERS-CoV). The percentage of Sierra Leoneans with antibodies reacting to seasonal coronaviruses was also higher than for American blood donors. Serological responses to coronaviruses by Sierra Leoneans did not differ by age or sex. Approximately a quarter of Sierra Leonian pre-pandemic blood samples had neutralizing antibodies against SARS-CoV-2 pseudovirus, while about a third neutralized MERS-CoV pseudovirus. Prior exposures to coronaviruses that induce cross-protective immunity may contribute to reduced COVID-19 cases and deaths in Sierra Leone.

Post-Ebola Syndrome Presents With Multiple Overlapping Symptom Clusters: Evidence From an Ongoing Cohort Study in Eastern Sierra Leone

BACKGROUND

Following the 2013-2016 West African Ebola outbreak, distinct, persistent health complaints were recognized in Ebola virus disease (EVD) survivors. Here we provide an in-depth characterization of post-Ebola syndrome >2.5 years after resolution of disease. Additionally, we report subphenotypes of post-Ebola syndrome with overlapping symptom clusters in survivors from Eastern Sierra Leone.

METHODS

Participants in Eastern Sierra Leone were identified by the Sierra Leone Association of Ebola survivors. Survivors and their contacts were administered a questionnaire assessing self-reported symptoms and a physical examination. Comparisons between survivors and contacts were conducted using conditional logistic regression. Symptom groupings were identified using hierarchical clustering approaches. Simplified presentation of incredibly complex evaluations (SPICE), correlation analysis, logistic regression, and principal component analysis (PCA) were performed to explore the relationships between symptom clusters.

RESULTS

Three hundred seventy-five EVD survivors and 1040 contacts were enrolled into the study. At enrollment, EVD survivors reported significantly more symptoms than their contacts in all categories (P < .001). Symptom clusters representing distinct organ systems were identified. Correlation and logistic regression analysis identified relationships between symptom clusters, including stronger relationships between clusters including musculoskeletal symptoms (r = 0.63, P < .001; and P < .001 for correlation and logistic regression, respectively). SPICE and PCA further highlighted subphenotypes with or without musculoskeletal symptoms.

CONCLUSIONS

This study presents an in-depth characterization of post-Ebola syndrome in Sierra Leonean survivors >2.5 years after disease. The interrelationship between symptom clusters indicates that post-Ebola syndrome is a heterogeneous disease. The distinct musculoskeletal and non-musculoskeletal phenotypes identified likely require targeted therapies to optimize long-term treatment for EVD survivors.

Health seeking behavior after the 2013-16 Ebola epidemic: Lassa fever as a metric of persistent changes in Kenema District, Sierra Leone

BACKGROUND

The West African Ebola epidemic of 2013-2016 killed nearly 4,000 Sierra Leoneans and devastated health infrastructure across West Africa. Changes in health seeking behavior (HSB) during the outbreak resulted in dramatic underreporting and substantial declines in hospital presentations to public health facilities, resulting in an estimated tens of thousands of additional maternal, infant, and adult deaths per year. Sierra Leone's Kenema District, a major Ebola hotspot, is also endemic for Lassa fever (LF), another often-fatal hemorrhagic disease. Here we assess the impact of the West African Ebola epidemic on health seeking behaviors with respect to presentations to the Kenema Government Hospital (KGH) Lassa Ward, which serves as the primary health care referral center for suspected Lassa fever cases in the Eastern Province of Sierra Leone.

METHODOLOGY/PRINCIPAL FINDINGS

Presentation frequencies for suspected Lassa fever presenting to KGH or one of its referral centers from 2011-2019 were analyzed to consider the potential impact of the West African Ebola epidemic on presentation patterns. There was a significant decline in suspected LF cases presenting to KGH following the epidemic, and a lower percentage of subjects were admitted to the KGH Lassa Ward following the epidemic. To assess general HSB, a questionnaire was developed and administered to 200 residents from 8 villages in Kenema District. Among 194 completed interviews, 151 (78%) of respondents stated they felt hospitals were safer post-epidemic with no significant differences noted among subjects according to religious background, age, gender, or education. However, 37 (19%) subjects reported decreased attendance at hospitals since the epidemic, which suggests that trust in the healthcare system has not fully rebounded. Cost was identified as a major deterrent to seeking healthcare.

CONCLUSIONS/SIGNIFICANCE

Analysis of patient demographic data suggests that fewer individuals sought care for Lassa fever and other febrile illnesses in Kenema District after the West African Ebola epidemic. Re-establishing trust in health care services will require efforts beyond rebuilding infrastructure and require concerted efforts to rebuild the trust of local residents who may be wary of seeking healthcare post epidemic.

A Fc engineering approach to define functional humoral correlates of immunity against Ebola virus

Protective Ebola virus (EBOV) antibodies have neutralizing activity and induction of antibody constant domain (Fc)-mediated innate immune effector functions. Efforts to enhance Fc effector functionality often focus on maximizing antibody-dependent cellular cytotoxicity, yet distinct combinations of functions could be critical for antibody-mediated protection. As neutralizing antibodies have been cloned from EBOV disease survivors, we sought to identify survivor Fc effector profiles to help guide Fc optimization strategies. Survivors developed a range of functional antibody responses, and we therefore applied a rapid, high-throughput Fc engineering platform to define the most protective profiles. We generated a library of Fc variants with identical antigen-binding fragments (Fabs) from an EBOV neutralizing antibody. Fc variants with antibody-mediated complement deposition and moderate natural killer (NK) cell activity demonstrated complete protective activity in a stringent in vivo mouse model. Our findings highlight the importance of specific effector functions in antibody-mediated protection, and the experimental platform presents a generalizable resource for identifying correlates of immunity to guide therapeutic antibody design.

Clinical features and viral RNA shedding of imported and local cases with COVID-19 in Wenzhou, China

ABSTRACT

Wenzhou had the highest number of confirmed novel coronavirus 2019 (COVID-19) cases outside the Hubei province. The aim of this study was to identify the difference in clinical features and viral RNA shedding between the imported and local COVID-19 cases in Wenzhou.All patients with confirmed COVID-19 admitted to Wenzhou Sixth People's Hospital, Wenzhou Central Hospital Medical Group, from January 17 to February 11, 2020, were enrolled in this study. Data was analyzed and compared for the imported and local cases with regard to epidemiological, demographic, clinical, radiological features, and laboratory findings. Outcomes for the enrolled participants were followed up until May 7, 2020.Of the 136 cases, 50 were imported from Wuhan. The median age was 45 years and 73 (53.7%) were men. The most common symptoms at onset were fever (104 [76.5%]) and cough (85[62.5%]). Pleural effusion was more common among imported cases compared to local cases. The white blood cell count, neutrophil count, lymphocyte count and platelet count of the imported cases were significantly lower than those of the local cases, while the prothrombin time was significantly longer than that of the local cases. Severe and critically ill patients accounted for 15.4% and 2.9%, respectively. The median duration of SARS-CoV-2 RNA shedding from symptom onset was 26 days (IQR 17-32.3 days) and there were no significant differences in duration of viral RNA shedding between the two groups.The study findings suggest that imported cases from Wuhan were more likely to be severe compared to the local cases in Wenzhou. However, there was no difference between imported and local cases on the viral shedding among the COVID patients.

Space-Time Trends in Lassa Fever in Sierra Leone by ELISA Serostatus, 2012-2019

Lassa fever (LF) is a viral hemorrhagic disease found in Sub-Saharan Africa and is responsible for up to 300,000 cases and 5000 deaths annually. LF is highly endemic in Sierra Leone, particularly in its Eastern Province. Kenema Government Hospital (KGH) maintains one of only a few LF isolation facilities in the world with year-round diagnostic testing. Here we focus on space-time trends for LF occurring in Sierra Leone between 2012 and 2019 to provide a current account of LF in the wake of the 2014–2016 Ebola epidemic. Data were analyzed for 3277 suspected LF cases and classified as acute, recent, and non-LF or prior LF exposure using enzyme-linked immunosorbent assays (ELISAs). Presentation rates for acute, recent, and non-LF or prior LF exposure were 6.0% (195/3277), 25.6% (838/3277), and 68.4% (2244/3277), respectively. Among 2051 non-LF or prior LF exposures, 33.2% (682/2051) tested positive for convalescent LF exposure. The overall LF case-fatality rate (CFR) was 78.5% (106/135). Both clinical presentations and confirmed LF cases declined following the Ebola epidemic. These declines coincided with an increased duration between illness onset and clinical presentation, perhaps suggesting more severe disease or presentation at later stages of illness. Acute LF cases and their corresponding CFRs peaked during the dry season (November to April). Subjects with recent (but not acute) LF exposure were more likely to present during the rainy season (May to October) than the dry season (p < 0.001). The findings here suggest that LF remains endemic in Sierra Leone and that caseloads are likely to resume at levels observed prior to the Ebola epidemic. The results provide insight on the current epidemiological profile of LF in Sierra Leone to facilitate LF vaccine studies and accentuate the need for LF cohort studies and continued advancements in LF diagnostics.

Ebola-Specific CD8+ and CD4+ T-Cell Responses in Sierra Leonean Ebola Virus Survivors With or Without Post-Ebola Sequelae

BACKGROUND

Ebola virus (EBOV) disease has killed thousands of West and Central Africans over the past several decades. Many who survive the acute disease later experience post-Ebola syndrome, a constellation of symptoms whose causative pathogenesis is unclear.

METHODS

We investigated EBOV-specific CD8+ and CD4+ T-cell responses in 37 Sierra Leonean EBOV disease survivors with (n = 19) or without (n = 18) sequelae of arthralgia and ocular symptoms. Peripheral blood mononuclear cells were infected with recombinant vesicular stomatitis virus encoding EBOV antigens. We also studied the presence of EBOV-specific immunoglobulin G, antinuclear antibodies, anti-cyclic citrullinated peptide antibodies, rheumatoid factor, complement levels, and cytokine levels in these 2 groups.

RESULTS

Survivors with sequelae had a significantly higher EBOV-specific CD8+ and CD4+ T-cell response. No differences in EBOV-specific immunoglobulin G, antinuclear antibody, or anti-cyclic citrullinated peptide antibody levels were found. Survivors with sequelae showed significantly higher rheumatoid factor levels.

CONCLUSION

EBOV-specific CD8+ and CD4+ T-cell responses were significantly higher in Ebola survivors with post-Ebola syndrome. These findings suggest that pathogenesis may occur as an immune-mediated disease via virus-specific T-cell immune response or that persistent antigen exposure leads to increased and sustained T-cell responses.

Elevated L-threonine is a biomarker for Lassa fever and Ebola

Background

Lassa fever and Ebola are characterized by non-specific initial presentations that can progress to severe multisystem illnesses with high fatality rates. Samples from additional subjects are examined to extend and corroborate biomarkers with prognostic value for these diseases.

Methods

Liquid Chromatography Mass Spectrometry metabolomics was used to identify and confirm metabolites disrupted in the blood of Lassa fever and Ebola patients. Authenticated standards are used to confirm the identify of key metabolites.

Results

We confirm prior results by other investigators that the amino acid l-threonine is elevated during Ebola virus infection. l-Threonine is also elevated during Lassa virus infection. We also confirmed that platelet-activating factor (PAF) and molecules with PAF moiety are reduced in the blood of patients with fatal Lassa fever. Similar changes in PAF and PAF-like molecules were not observed in the blood of Ebola patients.

Conclusions

Metabolomics may provide tools to identify pathways that are differentially affected during viral hemorrhagic fevers and guide development of diagnostics to monitor and predict outcome.

Lassa Fever among Children in Eastern Province, Sierra Leone: A 7-year Retrospective Analysis (2012-2018)

Pediatric Lassa fever (LF) usually presents as a nonspecific febrile illness, similar to other endemic diseases in countries like Sierra Leone, where LF is considered to be hyperendemic. The nonspecificity of presentation and lack of research have made it difficult to fully understand best practices for pediatric management. We aim to describe clinical characteristics of hospitalized pediatric patients suspected or diagnosed with LF and assess factors associated with hospital outcomes among those with LF antigen-positive results. We conducted a 7-year retrospective cohort study using routine data for all children younger than 18 years admitted at the Kenema Government Hospital's LF ward. A total of 292 children with suspected or confirmed LF were analyzed. Overall, mortality was high (21%). Children with antigen-positive results had a high case fatality rate of 63% (P < 0.01). In univariate analyses, children who presented with unexplained bleeding (odds ratio [OR]: 3.58; 95% CI: 1.08-11.86; P = 0.040) and confusion (altered sensorium) (OR: 5.37; 95% CI: 1.34-21.48; P = 0.020) had increased odds of death. Abnormal serum levels of alanine aminotransferase (P = 0.001), creatinine (P = 0.004), and potassium (P = 0.003) were associated with increased likelihood of death in these children. Treatment with ribavirin was not significantly associated with survival (P = 0.916). Our findings provide insights into current pediatric LF clinical presentation and management. More evidence-based, high-quality research in creating predictive algorithms of antigen-positivity and hospital outcomes is needed in the management of pediatric LF.

Endotheliopathy and Platelet Dysfunction as Hallmarks of Fatal Lassa Fever

Lassa fever (LF) causes multisystem disease and has a fatality rate <70%. Severe cases exhibit abnormal coagulation, endothelial barrier disruption, and dysfunctional platelet aggregation but the underlying mechanisms remain poorly understood. In Sierra Leone during 2015-2018, we assessed LF patients' day-of-admission plasma samples for levels of proteins necessary for coagulation, fibrinolysis, and platelet function. P-selectin, soluble endothelial protein C receptor, soluble thrombomodulin, plasminogen activator inhibitor 1, ADAMTS-13, von Willebrand factor, tissue factor, soluble intercellular adhesion molecule 1, and vascular cell adhesion molecule 1 were more elevated in LF patients than in controls. Endothelial protein C receptor, thrombomodulin, intercellular adhesion molecule 1, plasminogen activator inhibitor 1, D-dimer, and hepatocyte growth factor were higher in fatal than nonfatal LF cases. Platelet disaggregation occurred only in samples from fatal LF cases. The impaired homeostasis and platelet dysfunction implicate alterations in the protein C pathway, which might contribute to the loss of endothelial barrier function in fatal infections.

Lassa Fever Induced Hearing Loss: The Neglected Disability of Hemorrhagic Fever

OBJECTIVE

Lassa fever (LF) a hemorrhagic fever endemic to Western has an incidence of approximately 500,000 cases per year. Here, we evaluate hearing loss and other sequelae following LF.

METHODS

This case-control study enrolled laboratory confirmed LF survivors, non-LF Febrile controls and Matched Community controls with no history of LF or recent hospitalization for a febrile illness. Study participants completed a symptom questionnaire. Pure-tone audiometry was completed by a subset of participants.

RESULTS

One hundred forty-seven subjects were enrolled aged from 3-66 years (mean = 23.3). LF survivors were significantly more likely to report balance difficulties (55% vs 20%, p < 0.001), hair loss (32% vs 7%, p < 0.001), difficulty speaking (19% vs 1%, p < 0.001), social isolation (50% vs 0%, p < 0.001), and hearing loss (17% vs 1%, p = 0.002) in comparison to Matched-Community Controls. Similar trends were noted in comparison to Febrile Controls, although these findings were non-significant. Fifty subjects completed audiometry. Audiometry found that LF survivors had significantly more bilateral hearing loss in comparison to Matched-Community Controls (30% vs 4%, p = 0.029).

CONCLUSION

This study characterizes the sequelae of LF and highlights the need for increased access to hearing care in West Africa.

Responses of three urban U.S. Children's Hospitals to COVID-19: Seattle, New York and New Orleans

Since January 2020, there has been a worldwide pandemic of COVID-19, caused by a novel coronavirus-severe acute respiratory syndrome coronavirus 2. The United States has been particularly affected, with the largest number of confirmed cases in a single country in the world. Healthcare systems for adults as well as children have dealt with challenges. This article will reflect on the experiences of selected children's hospitals in Seattle, New York City, and New Orleans, three of the "hotspots" in the US and share common aspects and lessons learned from these experiences. This article discusses testing and cohorting of patients, personal protective equipment utilization, limiting workplace exposure, and information sharing.

Survivors of Ebola Virus Disease Develop Polyfunctional Antibody Responses

Monoclonal antibodies can mediate protection against Ebola virus (EBOV) infection through direct neutralization as well as through the recruitment of innate immune effector functions. However, the antibody functional response following survival of acute EBOV disease has not been well characterized. In this study, serum antibodies from Ebola virus disease (EVD) survivors from Sierra Leone were profiled to capture variation in overall subclass/isotype abundance, neutralizing activity, and innate immune effector functions. Antibodies from EVD survivors exhibited robust innate immune effector functions, mediated primarily by IgG1 and IgA1. In conclusion, development of functional antibodies follows survival of acute EVD.

Field evaluation of a Pan-Lassa rapid diagnostic test during the 2018 Nigerian Lassa fever outbreak

Lassa virus (LASV) is the causative agent of Lassa fever (LF), an often-fatal hemorrhagic disease. LF is endemic in Nigeria, Sierra Leone and other West African countries. Diagnosis of LASV infection is challenged by the genetic diversity of the virus, which is greatest in Nigeria. The ReLASV Pan-Lassa Antigen Rapid Test (Pan-Lassa RDT) is a point-of-care, in vitro diagnostic test that utilizes a mixture of polyclonal antibodies raised against recombinant nucleoproteins of representative strains from the three most prevalent LASV lineages (II, III and IV). We compared the performance of the Pan-LASV RDT to available quantitative PCR (qPCR) assays during the 2018 LF outbreak in Nigeria. For patients with acute LF (RDT positive, IgG/IgM negative) during initial screening, RDT performance was 83.3% sensitivity and 92.8% specificity when compared to composite results of two qPCR assays. 100% of samples that gave Ct values below 22 on both qPCR assays were positive on the Pan-Lassa RDT. There were significantly elevated case fatality rates and elevated liver transaminase levels in subjects whose samples were RDT positive compared to RDT negative.

Zika virus infection of mast cells is not associated with a degranulation response

Dengue virus (DENV) infection is augmented by a process called antibody-dependent enhancement (ADE), in which pre-existing DENV immunity can render an individual more susceptible to a subsequent DENV exposure. Based on Zika virus (ZIKV) and DENV structural similarities, emerging evidence suggests anti-DENV antibodies can cross-react with ZIKV at non-neutralizing levels characteristic of ADE. Mast cells (MC), sentinel white blood cells integral in coordinating early immune defences, have been identified as a principle contributor to DENV vascular leakage. This clinical manifestation is attributed to significant histamine release caused by MC degranulation, a characteristic MC activation response. However, to our knowledge ZIKV-MC interactions remain unexplored. MC responses to virus can be modelled in vitro, including via use of the well-characterized KU812 cell line which express Fcγ receptors. Here, we sought to determine if the KU812 MC is susceptible to (1) direct ZIKV infection; and (2) ADE in the presence of anti-DENV antibodies that cross-react with ZIKV. A significant increase in viral titre (104 PFU/mL) was detected, by plaque assay, in MC directly infected with ZIKV compared to MC infected with UV-inactivated ZIKV (0 PFU/mL). Furthermore, a significant viral titre (106 PFU/mL) was detected in MC infected with ZIKV pre-incubated with anti-DENV antibodies when compared to MC infected with ZIKV pre-incubated with isotype control antibodies (104 PFU/mL). Furthermore, unlike DENV induced degranulation of MC, ZIKV did not activate a degranulation response in this model or in a primary murine model. Therefore, MC may be a contributor in ZIKV pathogenesis without the classical degranulation response seen in DENV infected MC.

Reevaluating HLA-A2-restricted Lassa epitopes in human Lassa fever survivors

Many factors contribute to the selection of epitope-specific T cells. Often, candidate epitopes are generated through in silico prediction of various biological processes, mainly peptide generation and MHC binding, that are then tested in relevant biological assays. This is especially true of epitopes derived from BSL-4 pathogens or where relevant patient samples are difficult to obtain. Two previous studies identified CD8+ T cell epitopes from the Lassa virus glycoprotein through in silico prediction, experimental MHC binding assays, and epitope generation in HLA-A2 transgenic mice. Using samples from ten HLA-A*02:01 Lassa fever survivors, we tested whether these previously described epitope-specific CD8+ T cells were present and their relation to the broader Lassa virus-specific T cell response. Using overnight stimulation assays, we detected robust LASV-specific responses to the glycoprotein and nucleoprotein, but only one of the three epitopes (GP60–68)shown to be present and protective in mice made a substantial contribution to the overall LASV-specific response. Using a more sensitive proliferation assay, we detected the remaining two epitopes in some individuals at a very low frequency. Overall, this study shows the limitations of epitope discovery through in silico prediction, MHC binding and transgenic mouse models and highlights the complex nature of T cell selection during natural infection of humans.

A Review of Hearing Loss Associated with Zika, Ebola, and Lassa Fever

The neglected tropical diseases Zika, Ebola, and Lassa fever (LF) have all been noted to cause some degree of hearing loss (HL). Hearing loss is a chronic disability that can lead to a variety of detrimental effects, including speech and language delays in children, decreased economic productivity in adults, and accelerated cognitive decline in older adults. The objective of this review is to summarize what is known regarding HL secondary to these viruses. Literature for this review was gathered using the PubMed database. Articles were excluded if there were no data of the respective viruses, postinfectious complications, or conditions related to survivorship. A total of 50 articles were included in this review. Fourteen articles discussing Zika virus and subsequent complications were included. Across these studies, 56 (21.2%) of 264 Zika-infected individuals were found to have HL. Twenty-one articles discussing Ebola virus and subsequent complications were included, with 190 (5.7%) of 3,350 Ebola survivors found to have HL. Fifteen additional articles discussing LF and subsequent complications were included. Of 926 individuals with LF, 79 (8.5%) were found to have HL. These results demonstrate a relationship between HL and infection. The true prevalence is likely underestimated, however, because of lack of standardization of reporting and measurement. Future studies of viral sequelae would benefit from including audiometric evaluation. This information is critical to understanding pathophysiology, preventing future cases of this disability, and improving quality of life after survival of infection.

Emerging Trends in Clinical Tropical Medicine Research

The American Society for Tropical Medicine and Hygiene recently inaugurated an award for the best clinical research article published in the society’s journal in the previous year. This article summarizes both the process of selecting the winner and several themes that stood out in those articles which rose to the top for consideration. Themes of note included the importance of doing clinical research outside of referral centers, the complexity that must be considered when implementing interventions, incorporation of both ends of the age spectrum into studies, and considering cost-effectiveness and opportunity cost of interventions.

Expanding Research Capacity in Sub-Saharan Africa Through Informatics, Bioinformatics, and Data Science Training Programs in Mali

Bioinformatics and data science research have boundless potential across Africa due to its high levels of genetic diversity and disproportionate burden of infectious diseases, including malaria, tuberculosis, HIV and AIDS, Ebola virus disease, and Lassa fever. This work lays out an incremental approach for reaching underserved countries in bioinformatics and data science research through a progression of capacity building, training, and research efforts. Two global health informatics training programs sponsored by the Fogarty International Center (FIC) were carried out at the University of Sciences, Techniques and Technologies of Bamako, Mali (USTTB) between 1999 and 2011. Together with capacity building efforts through the West Africa International Centers of Excellence in Malaria Research (ICEMR), this progress laid the groundwork for a bioinformatics and data science training program launched at USTTB as part of the Human Heredity and Health in Africa (H3Africa) initiative. Prior to the global health informatics training, its trainees published first or second authorship and third or higher authorship manuscripts at rates of 0.40 and 0.10 per year, respectively. Following the training, these rates increased to 0.70 and 1.23 per year, respectively, which was a statistically significant increase (p < 0.001). The bioinformatics and data science training program at USTTB commenced in 2017 focusing on student, faculty, and curriculum tiers of enhancement. The program's sustainable measures included institutional support for core elements, university tuition and fees, resource sharing and coordination with local research projects and companion training programs, increased student and faculty publication rates, and increased research proposal submissions. Challenges reliance of high-speed bandwidth availability on short-term funding, lack of a discounted software portal for basic software applications, protracted application processes for United States visas, lack of industry job positions, and low publication rates in the areas of bioinformatics and data science. Long-term, incremental processes are necessary for engaging historically underserved countries in bioinformatics and data science research. The multi-tiered enhancement approach laid out here provides a platform for generating bioinformatics and data science technicians, teachers, researchers, and program managers. Increased literature on bioinformatics and data science training approaches and progress is needed to provide a framework for establishing benchmarks on the topics.

A medical records and data capture and management system for Lassa fever in Sierra Leone: Approach, implementation, and challenges

Situated in southeastern Sierra Leone, Kenema Government Hospital (KGH) maintains one of the world’s only Lassa fever isolation wards and was a strategic Ebola virus disease (EVD) treatment facility during the 2014 EVD outbreak. Since 2006, the Viral Hemorrhagic Fever Consortium (VHFC) has carried out research activities at KGH, capturing clinical and laboratory data for suspected cases of Lassa fever. Here we describe the approach, progress, and challenges in designing and maintaining a data capture and management system (DCMS) at KGH to assist infectious disease researchers in building and sustaining DCMS in low-resource environments. Results on screening patterns and case-fatality rates are provided to illustrate the context and scope of the DCMS covered in this study. A medical records system and DCMS was designed and implemented between 2010 and 2016 linking historical and prospective Lassa fever data sources across KGH Lassa fever units and its peripheral health units. Data were captured using a case report form (CRF) system, enzyme-linked immunosorbent assay (ELISA) plate readers, polymerase chain reaction (PCR) machines, blood chemistry analyzers, and data auditing procedures. Between 2008 and 2016, blood samples for 4,229 suspected Lassa fever cases were screened at KGH, ranging from 219 samples in 2008 to a peak of 760 samples in 2011. Lassa fever case-fatality rates before and following the Ebola outbreak were 65.5% (148/226) and 89.5% (17/19), respectively, suggesting that fewer, but more seriously ill subjects with Lassa fever presented to KGH following the 2014 EVD outbreak (p = .040). DCMS challenges included weak specificity of the Lassa fever suspected case definition, limited capture of patient survival outcome data, internet costs, lapses in internet connectivity, low bandwidth, equipment and software maintenance, lack of computer teaching laboratories, and workload fluctuations due to variable screening activity. DCMS are the backbone of international research efforts and additional literature is needed on the topic for establishing benchmarks and driving goal-based approaches for its advancement in developing countries.

Data set on Lassa fever in post-conflict Sierra Leone

Lassa fever is a rodent-borne illness that is endemic to parts of sub-Saharan Africa, including Sierra Leone, Nigeria, and Guinea. The disease is named after the town of Lassa, Nigeria where it was discovered in 1969. This data article focuses on the epidemiology of Lassa fever in Sierra Leone following a decade-long civil war that ended in 2002. The data were collected at Kenema Government Hospital (KGH) in Kenema, Sierra Leone, which maintains the country׳s only Lassa fever treatment facility and a biosafety level 3 (BSL-3) laboratory. The key data set variables include Lassa fever serostatus determined using antigen (Ag), immunoglobulin M (IgM), and immunoglobulin G (IgG) ELISA diagnostic techniques; and patient demographics, survival outcome, and treatment (ribavirin) status. The individual data used to generate the graphs and tables in the corresponding research manuscript published in PLOS Neglected Tropical Diseases in 2014 and its coding guide are provided as Supplementary material (Shaffer et al., 2014) [1].

Association of the Quick Sequential (Sepsis-Related) Organ Failure Assessment (qSOFA) Score With Excess Hospital Mortality in Adults With Suspected Infection in Low- and Middle-Income Countries

Importance

The quick Sequential (Sepsis-Related) Organ Failure Assessment (qSOFA) score has not been well-evaluated in low- and middle-income countries (LMICs).

Objective

To assess the association of qSOFA with excess hospital death among patients with suspected infection in LMICs and to compare qSOFA with the systemic inflammatory response syndrome (SIRS) criteria.

Design, Settings, and Participants

Retrospective secondary analysis of 8 cohort studies and 1 randomized clinical trial from 2003 to 2017. This study included 6569 hospitalized adults with suspected infection in emergency departments, inpatient wards, and intensive care units of 17 hospitals in 10 LMICs across sub-Saharan Africa, Asia, and the Americas.

Exposures

Low (0), moderate (1), or high (≥2) qSOFA score (range, 0 [best] to 3 [worst]) or SIRS criteria (range, 0 [best] to 4 [worst]) within 24 hours of presentation to study hospital.

Main Outcomes and Measures

Predictive validity (measured as incremental hospital mortality beyond that predicted by baseline risk factors, as a marker of sepsis or analogous severe infectious course) of the qSOFA score (primary) and SIRS criteria (secondary).

Results

The cohorts were diverse in enrollment criteria, demographics (median ages, 29-54 years; males range, 36%-76%), HIV prevalence (range, 2%-43%), cause of infection, and hospital mortality (range, 1%-39%). Among 6218 patients with nonmissing outcome status in the combined cohort, 643 (10%) died. Compared with a low or moderate score, a high qSOFA score was associated with increased risk of death overall (19% vs 6%; difference, 13% [95% CI, 11%-14%]; odds ratio, 3.6 [95% CI, 3.0-4.2]) and across cohorts (P < .05 for 8 of 9 cohorts). Compared with a low qSOFA score, a moderate qSOFA score was also associated with increased risk of death overall (8% vs 3%; difference, 5% [95% CI, 4%-6%]; odds ratio, 2.8 [95% CI, 2.0-3.9]), but not in every cohort (P < .05 in 2 of 7 cohorts). High, vs low or moderate, SIRS criteria were associated with a smaller increase in risk of death overall (13% vs 8%; difference, 5% [95% CI, 3%-6%]; odds ratio, 1.7 [95% CI, 1.4-2.0]) and across cohorts (P < .05 for 4 of 9 cohorts). qSOFA discrimination (area under the receiver operating characteristic curve [AUROC], 0.70 [95% CI, 0.68-0.72]) was superior to that of both the baseline model (AUROC, 0.56 [95% CI, 0.53-0.58; P < .001) and SIRS (AUROC, 0.59 [95% CI, 0.57-0.62]; P < .001).

Conclusions and Relevance

When assessed among hospitalized adults with suspected infection in 9 LMIC cohorts, the qSOFA score identified infected patients at risk of death beyond that explained by baseline factors. However, the predictive validity varied among cohorts and settings, and further research is needed to better understand potential generalizability.

Memory T cell responses in survivors of the 2013–2016 West African Ebola outbreak

Primary infection with Ebola virus protects against subsequent challenge, thus an optimal vaccine should generate immune responses similar to those found in disease survivors. To this end, we characterized CD8 and CD4 T cell responses in Ebola survivors to uncover the immunogenicity of seven of eight Ebola virus proteins. T cell responses of 33 Sierra Leonean Ebola survivors were examined. Nearly all individuals studied harbored nucleoprotein (NP)-specific CD8 T cell responses. Moreover, NP-specific T cells responded more strongly and were more numerous in 65% of NP responders compared to responses to other EBOV proteins in the same individual. Conversely, we found glycoprotein (GP) CD8+ T cell responses in only 37% of EBOV responders. GP responses were also weaker and less numerous than other responses in the same individual. Specificity of the CD4+ T cell responses were more evenly distributed. Altogether, our data indicate that NP is among the most immunogenic EBOV proteins while only VP30 was less immunogenic than GP in our cohort of Sierra Leonean survivors. An optimal vaccine designed to elicit both humoral and cell mediated immune responses in a broad human population should contain both NP and the GP.

Ebola Virus Persistence in Ocular Tissues and Fluids (EVICT) Study: Reverse Transcription-Polymerase Chain Reaction and Cataract Surgery Outcomes of Ebola Survivors in Sierra Leone

Background

Ebola virus disease (EVD) survivors are at risk for uveitis during convalescence. Vision loss has been observed following uveitis due to cataracts. Since Ebola virus (EBOV) may persist in the ocular fluid of EVD survivors for an unknown duration, there are questions about the safety and feasibility of vision restorative cataract surgery in EVD survivors.

Methods

We conducted a cross-sectional study of EVD survivors anticipating cataract surgery and patients with active uveitis to evaluate EBOV RNA persistence in ocular fluid, as well as vision outcomes post cataract surgery. Patients with aqueous humor that tested negative for EBOV RNA were eligible to proceed with manual small incision cataract surgery (MSICS).

Findings

We screened 137 EVD survivors from June 2016 – August 2017 for enrolment. We enrolled 50 EVD survivors; 46 with visually significant cataract, 1 with a subluxated lens, 2 with active uveitis and 1 with a blind painful eye due to uveitis. The median age was 24.0 years (IQR 17–35) and 35 patients (70%) were female. The median logMAR visual acuity (VA) was 3.0 (Snellen VA Hand motions; Interquartile Range, IQR: 1.2-3.0, Snellen VA 20/320 – Hand motions). All patients tested negative for EBOV RNA by RT-PCR in aqueous humor/vitreous fluid and conjunctiva at a median of 19 months (IQR 18-20) from EVD diagnosis in Phase 1 of ocular fluid sampling and 34 months (IQR 32-36) from EVD diagnosis in Phase 2 of ocular fluid sampling. Thirty-four patients underwent MSICS, with a preoperative median VA improvement from hand motions to 20/30 at three-month postoperative follow-up (P < 0.001).

Interpretation

EBOV persistence by RT-PCR was not identified in ocular fluid or conjunctivae of fifty EVD survivors with ocular disease. Cataract surgery can be performed safely with vision restorative outcomes in patients who test negative for EBOV RNA in ocular fluid specimens. These findings impact the thousands of West African EVD survivors at-risk for ocular complications who may also require eye surgery during EVD convalescence.

•

Ebola virus disease (EVD) survivors are at-risk for severe vision impairment due to uveitis and subsequent cataract development.

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Fifty EVD survivors underwent ocular fluid sampling and tested negative for Ebola virus by RT-PCR.

•

Thirty-four survivors underwent cataract surgery with excellent safety measures and vision restorative outcomes.

Ebola virus disease (EVD) survivors are at high risk for uveitis, an inflammatory condition affecting the eye that may lead to severe vision impairment, often from cataract. Because persistent Ebola virus (EBOV) has been identified within the immune privileged eye, understanding the prevalence of intraocular EBOV persistence is significant for patients, providers, and public health policy. In this study, 50 EVD survivors tested negative for EBOV by RT-PCR of their intraocular fluid. Thirty-four underwent cataract surgery with vision restorative outcomes. These findings improve our ability to impact vision care and quality-of-life for thousands of EVD survivors at-risk for eye disease.

Hansen's Disease and Rheumatoid Arthritis Crossover of Clinical Symptoms: A Case Series of 18 Patients in the United States

Hansen's Disease (HD) is a rare, chronic granulomatous infection of the skin and peripheral nerves caused by the noncultivable organism Mycobacterium leprae. Arthritis is the third most common symptom of HD. Subjects with both confirmed HD on skin biopsy and chronic arthritis were identified at the National Hansen's Disease Program (NHDP). We conducted a series of medical chart reviews and extracted and logged personally deidentified data into a database and carried out descriptive analyses. Eighteen of 261 subjects presented to the NDHP with both HD and chronic arthritis between 2001 and 2015. Among these, 16 were male, 16 were white, and 15 were residents of Louisiana. The median age at diagnosis of HD was 67 years. Ten of these subjects were diagnosed with borderline lepromatous leprosy, seven were diagnosed with lepromatous, and one was diagnosed with borderline tuberculoid leprosy. Patients were symptomatic with arthritis for a median of 5.3 years before HD diagnosis. Sixty-two percent of patients (11) were diagnosed with rheumatoid arthritis (RA) before HD diagnosis, and 10 of which were seronegative RA. Hands, feet, wrists, and elbows were most commonly reported as affected joints. Over half of the patients (61%) had completed HD multidrug therapy at the time of review, and 73% of these subjects had persistent joint pain requiring steroids or methotrexate for symptomatic control. Chronic arthritis in HD patients is present in a series of US-acquired cases of HD. Arthritis did not resolve with successful treatment of HD in most cases.

Virus genomes reveal factors that spread and sustained the Ebola epidemic

The 2013-2016 West African epidemic caused by the Ebola virus was of unprecedented magnitude, duration and impact. Here we reconstruct the dispersal, proliferation and decline of Ebola virus throughout the region by analysing 1,610 Ebola virus genomes, which represent over 5% of the known cases. We test the association of geography, climate and demography with viral movement among administrative regions, inferring a classic 'gravity' model, with intense dispersal between larger and closer populations. Despite attenuation of international dispersal after border closures, cross-border transmission had already sown the seeds for an international epidemic, rendering these measures ineffective at curbing the epidemic. We address why the epidemic did not spread into neighbouring countries, showing that these countries were susceptible to substantial outbreaks but at lower risk of introductions. Finally, we reveal that this large epidemic was a heterogeneous and spatially dissociated collection of transmission clusters of varying size, duration and connectivity. These insights will help to inform interventions in future epidemics.

Roots, Not Parachutes: Research Collaborations Combat Outbreaks

Recent infectious disease epidemics illustrate how health systems failures anywhere can create disease vulnerabilities everywhere. We must therefore prioritize investments in health care infrastructure in outbreak-prone regions of the world. We describe how "rooted" research collaborations can establish capacity for pathogen surveillance and facilitate rapid outbreak responses.

A Unified Framework for the Infection Dynamics of Zoonotic Spillover and Spread

A considerable amount of disease is transmitted from animals to humans and many of these zoonoses are neglected tropical diseases. As outbreaks of SARS, avian influenza and Ebola have demonstrated, however, zoonotic diseases are serious threats to global public health and are not just problems confined to remote regions. There are two fundamental, and poorly studied, stages of zoonotic disease emergence: ‘spillover’, i.e. transmission of pathogens from animals to humans, and ‘stuttering transmission’, i.e. when limited human-to-human infections occur, leading to self-limiting chains of transmission. We developed a transparent, theoretical framework, based on a generalization of Poisson processes with memory of past human infections, that unifies these stages. Once we have quantified pathogen dynamics in the reservoir, with some knowledge of the mechanism of contact, the approach provides a tool to estimate the likelihood of spillover events. Comparisons with independent agent-based models demonstrates the ability of the framework to correctly estimate the relative contributions of human-to-human vs animal transmission. As an illustrative example, we applied our model to Lassa fever, a rodent-borne, viral haemorrhagic disease common in West Africa, for which data on human outbreaks were available. The approach developed here is general and applicable to a range of zoonoses. This kind of methodology is of crucial importance for the scientific, medical and public health communities working at the interface between animal and human diseases to assess the risk associated with the disease and to plan intervention and appropriate control measures. The Lassa case study revealed important knowledge gaps, and opportunities, arising from limited knowledge of the temporal patterns in reporting, abundance of and infection prevalence in, the host reservoir.

Many dangerous diseases emerge via spillover from animals, with limited human-to-human infection (stuttering-transmission) often being the first stage of human disease spread. Understanding the conditions (biological, environmental and socio-economic factors) that regulate spillover and disease spread is key to its mitigation. Here we are interested in questions such as: If we have quantified pathogen dynamics in the reservoir, with some knowledge of the mechanism of contact, can we estimate the likelihood of spillover events? Can we tease apart how much the disease is transmitted by animals and how much by humans? We developed a unified mathematical framework, based on Poisson processes with memory of past events, to understand the dynamics of spillover and stuttering-transmission. This framework, which can be applied across the disease transmission spectrum, allows the teasing apart of the disease burden attributed to animal-human and human-human transmission. Using this model, we can infer human disease risk based on knowledge of infection patterns in the animal reservoir host and the contact mechanisms required for transmission to humans.

Analytical Validation of the ReEBOV Antigen Rapid Test for Point-of-Care Diagnosis of Ebola Virus Infection

BACKGROUND

Ebola virus disease (EVD) is a severe viral illness caused by Ebola virus (EBOV). The 2013-2016 EVD outbreak in West Africa is the largest recorded, with >11 000 deaths. Development of the ReEBOV Antigen Rapid Test (ReEBOV RDT) was expedited to provide a point-of-care test for suspected EVD cases.

METHODS

Recombinant EBOV viral protein 40 antigen was used to derive polyclonal antibodies for RDT and enzyme-linked immunosorbent assay development. ReEBOV RDT limits of detection (LOD), specificity, and interference were analytically validated on the basis of Food and Drug Administration (FDA) guidance.

RESULTS

The ReEBOV RDT specificity estimate was 95% for donor serum panels and 97% for donor whole-blood specimens. The RDT demonstrated sensitivity to 3 species of Ebolavirus (Zaire ebolavirus, Sudan ebolavirus, and Bundibugyo ebolavirus) associated with human disease, with no cross-reactivity by pathogens associated with non-EBOV febrile illness, including malaria parasites. Interference testing exhibited no reactivity by medications in common use. The LOD for antigen was 4.7 ng/test in serum and 9.4 ng/test in whole blood. Quantitative reverse transcription-polymerase chain reaction testing of nonhuman primate samples determined the range to be equivalent to 3.0 × 10⁵-9.0 × 10⁸ genomes/mL.

CONCLUSIONS

The analytical validation presented here contributed to the ReEBOV RDT being the first antigen-based assay to receive FDA and World Health Organization emergency use authorization for this EVD outbreak, in February 2015.