Searching for the source of Ebola: the elusive factors driving its spillover into humans during the West African outbreak of 2013–2016

The natural ecology of Ebola virus infection remains enigmatic. No clear reservoir species has been confirmed but there is evidence of infection in a wide spectrum of mammals, including humans, non-human primates, domestic and wild ungulates and a variety of bat species, both frugivorous and insectivorous. Humans and most other species examined appear to be spillover hosts and suffer disease. Bats are the exception and are tolerant to infection in some laboratory studies. Some surveys show a low prevalence of antibodies against Zaire Ebola virus (ZEBOV) strains in bats during human outbreaks and inter-epidemic periods, and this order of mammals is considered to be the likely reservoir for the virus. Other putative sources include insects but this hypothesis is unproven in the field or laboratory. Moreover, some potential sources, such as aquatic species, have yet to be investigated. There are a number of environmental, human behavioural and ecological risk factors proposed with respect to spillover and spread. In the West African outbreak, which was unprecedented in scale and geographic spread, the source of the spillover remains unproven, although an association exists between the proposed index case and a colony of insectivorous bats. In all but a few Ebola virus disease events, spillover has only been superficially investigated and this was also the case in the West African epidemic. The authors suggest that, to address risks at the human–animal–environmental interface, using a One Health approach, more effort is needed to investigate spillover factors at the time of a ZEBOV epidemic, in addition to conducting inter-epidemic surveys in peridomestic environments. The true prevalence of ZEBOV infection in any species of bats remains unknown. Large-scale, expensive, non-randomised surveys, with low sampling numbers per species, are unlikely to provide evidence for Ebola virus reservoirs or to improve our epidemiological understanding

Participation of women and children in hunting activities in Sierra Leone and implications for control of zoonotic infections

The emergence of infectious diseases of zoonotic origin highlights the need to understand social practices at the animal-human interface. This study provides a qualitative account of interactions between humans and wild animals in predominantly Mende villages of southern Sierra Leone. We conducted fieldwork over 4 months including participant and direct observations, semi-structured interviews (n = 47), spontaneously occurring focus group discussions (n = 12), school essays and informal interviews to describe behaviours that may serve as pathways for zoonotic infection. In this region, hunting is the primary form of contact with wild animals. We describe how these interactions are shaped by socio-cultural contexts, including opportunities to access economic resources and by social obligations and constraints. Our research suggests that the potential for exposure to zoonotic pathogens is more widely distributed across different age, gender and social groups than previously appreciated. We highlight the role of children in hunting, an age group that has previously not been discussed in the context of hunting. The breadth of the "at risk" population forces reconsideration of how we conceptualize, trace and monitor pathogen exposure

Improving Ebola infection prevention and control in primary healthcare facilities in Sierra Leone: a single-group pretest post-test, mixed-methods study

Background Accomplishing infection prevention and control (IPC) in health facilities in Sub-Saharan Africa is challenging. Owing to poor IPC, healthcare workers (HCWs) were frequently infected during Sierra Leone's Ebola epidemic. In late 2014, IPC was rapidly and nationally scaled up. We carried out workshops in sampled facilities to further improve adherence to IPC. We investigated HCW experiences and observed practice gaps, before and after the workshops. Methods We conducted an uncontrolled, before and after, mixed-methods study in eight health facilities in Bo and Kenema Districts during December 2014 and January 2015. Quantitative methods administered to HCWs at baseline and follow-up included a survey on attitudes and self-efficacy towards IPC, and structured observations of behaviours. The intervention involved a workshop for HCWs to develop improvement plans for their facility. We analysed the changes between rounds in survey responses and behaviours. We used interviews to explore attitudes and self-efficacy throughout the study period. Results HCWs described IPC as ‘life-saving’ and personal protective equipment (PPE) as uncomfortable for providers and frightening for patients. At baseline, self-efficacy was high (median=4/strongly agree). Responses reflecting unfavourable attitudes were low for glove use (median=1/strongly disagree, IQR, 1–2) and PPE use with ill family members (median=1, IQR, 1–2), and mixed for PPE use with ill HCWs (median=2/disagree, IQR, 1–4). Observations demonstrated consistent glove reuse and poor HCW handwashing. The maintenance of distance (RR 1.09, 95% CI 1.02 to 1.16) and patient handwashing (RR 1.19, 95% CI 1.3 to 1.25) improved to >90%. Conclusions We found favourable attitudes towards IPC and gaps in practice. Risk perceptions of HCWs and tendencies to ration PPE where chronic supply chain issues normally lead to PPE stock-outs may affect practice. As Sierra Leone's Ebola Recovery Strategy aims to make all facilities IPC compliant, socio-behavioural improvements and a secure supply chain are essential

Presumptive self-diagnosis of malaria and other febrile illnesses in Sierra Leone

Introduction: The objective of this study was to evaluate the prevalence of self-diagnosis of malaria and other febrile illnesses in Bo, Sierra Leone. Methods: All households in two neighboring sections of Bo were invited to participate in a cross-sectional survey. Results: A total of 882 households (an 85% participation rate) that were home to 5410 individuals participated in the study. Of the 910 individuals reported to have had what the household considered to be malaria in the past month, only 41% were diagnosed by a healthcare professional or a laboratory test. Of the 1402 individuals reported to have had any type of febrile illness within the past six months, only 34% had sought a clinical or laboratory diagnosis. Self-diagnosis of influenza, yellow fever, typhoid, and pneumonia was also common. Conclusion: Self-diagnosis and presumptive treatment with antimalarial drugs and other antibiotic medications that are readily available without a prescription may compromise health outcomes for febrile adults and children.Key words: Malaria, fevers, self-care, health services accessibility, community pharmacy services, West Afric

The disproportionate case–fatality ratio of COVID-19 between countries with the highest vaccination rates and the rest of the world

Objectives: The global reported cumulative case–fatality ratios (rCFRs) and excess mortality rates of the 20 countries with the highest coronavirus disease 2019 (COVID-19) vaccination rates, the rest of the world and Sub-Saharan Africa (SSA) were compared before and after the commencement of vaccination programmes. Methods: A time series model was used to understand the trend of rCFR over time, and a generalized linear mixed model was used to understand the effect of vaccination on rCFR. Results: By 31 December 2022, an average of 260.3 doses of COVID-19 vaccine per 100 population had been administered in the top 20 vaccinated countries, compared with 152.1 doses in the rest of the world and 51.2 doses in SSA. The mean rCFR of COVID-19 had decreased by 69.0% in the top 20 vaccinated countries, 26.5% in the rest of the world and 7.6% in SSA. Excess mortality had decreased by 48.7% in the top 20 vaccinated countries, compared with 62.5% in the rest of the world and 60.7% in SSA. In a generalized linear mixed model, the reported number of vaccine doses administered (/100 population) (odds ratio 0.64) was associated with a steeper reduction in COVID-19 rCFR. Conclusions: Vaccine equity and faster roll-out across the world is critically important in reducing COVID-19 transmission and CFR

Increased outbreaks of monkeypox highlight gaps in actual disease burden in Sub-Saharan Africa and in animal reservoirs

We explain research gaps on Monkeypox (MPX) virus epidemiology in endemic countries and present hypotheses for the recent increase of MPX cases in West Africa as a possible explanation for the current epidemic in Europe, America, and Australia. The detection of >400 MPX cases in less than a month in May 2022, across many countries underscores the epidemic potential of MPX in humans and demonstrates several important research gaps. First, the true burden of MPX in West and Central Africa is poorly understood, although it is critical for prevention and control of future outbreaks. Second, the diversity and extent of the animal reservoir remain unknown. We hypothesize that the synanthropic rodent population has increased in recent years in Africa leading to more human-rodent interactions and thus increased transmission of MPXV. We further hypothesise that nearly 45 years after the end of routine smallpox vaccination, the larger and more interconnected immune-naïve population has crossed a threshold resulting in more sustainable human-to-human transmission of MPXV. The current epidemic in the Western World is possibly a consequence of increased local transmission of MPXV in Africa. A new estimation of the basic and effective reproduction rate (R0 and Re) in different populations is required. National, regional, and international collaborations are needed to address research gaps related to MPX outbreaks

The Use of Mobile Electronic Devices for Public Health Data Collection and Syndromic Surveillance at the Republic Of Sierra Leone Armed Forces

Public health data collection methods in Sierra Leone were compared. First, a household health census was conducted with some interviewers using paper-based forms requiring later data entry and others using tablet computers for immediate electronic data inputting. Electronic data-entry surveys were more time-efficient and accurate than paper-based surveys. In a second evaluation, military Medical Inspection rooms (MIRs) sent syndromic surveillance reports to a central communications hub via cell phone or paper-based forms. The report compliance rate was 89% for daily SMS and 100% for weekly SMS versus 76% for weekly paper reports. Electronic data collection and reporting is feasible and cost-efficient in low-resource settings.Keywords: mobile phones, text messaging, database management systems, census methods, sentinelsurveillanc

The niche of One Health approaches in Lassa fever surveillance and control

Lassa fever (LF), a zoonotic illness, represents a public health burden in West African countries where the Lassa virus (LASV) circulates among rodents. Human exposure hinges significantly on LASV ecology, which is in turn shaped by various parameters such as weather seasonality and even virus and rodent-host genetics. Furthermore, human behaviour, despite playing a key role in the zoonotic nature of the disease, critically affects either the spread or control of human-to-human transmission. Previous estimations on LF burden date from the 80s and it is unclear how the population expansion and the improvement on diagnostics and surveillance methods have affected such predictions. Although recent data have contributed to the awareness of epidemics, the real impact of LF in West African communities will only be possible with the intensification of interdisciplinary efforts in research and public health approaches. This review discusses the causes and consequences of LF from a One Health perspective, and how the application of this concept can improve the surveillance and control of this disease in West Africa

Taking forward a 'One Health' approach for turning the tide against the Middle East respiratory syndrome coronavirus and other zoonotic pathogens with epidemic potential.

The appearance of novel pathogens of humans with epidemic potential and high mortality rates have threatened global health security for centuries. Over the past few decades new zoonotic infectious diseases of humans caused by pathogens arising from animal reservoirs have included West Nile virus, Yellow fever virus, Ebola virus, Nipah virus, Lassa Fever virus, Hanta virus, Dengue fever virus, Rift Valley fever virus, Crimean-Congo haemorrhagic fever virus, severe acute respiratory syndrome coronavirus, highly pathogenic avian influenza viruses, Middle East Respiratory Syndrome Coronavirus, and Zika virus. The recent Ebola Virus Disease epidemic in West Africa and the ongoing Zika Virus outbreak in South America highlight the urgent need for local, regional and international public health systems to be be more coordinated and better prepared. The One Health concept focuses on the relationship and interconnectedness between Humans, Animals and the Environment, and recognizes that the health and wellbeing of humans is intimately connected to the health of animals and their environment (and vice versa). Critical to the establishment of a One Health platform is the creation of a multidisciplinary team with a range of expertise including public health officers, physicians, veterinarians, animal husbandry specialists, agriculturalists, ecologists, vector biologists, viral phylogeneticists, and researchers to co-operate, collaborate to learn more about zoonotic spread between animals, humans and the environment and to monitor, respond to and prevent major outbreaks. We discuss the unique opportunities for Middle Eastern and African stakeholders to take leadership in building equitable and effective partnerships with all stakeholders involved in human and health systems to take forward a 'One Health' approach to control such zoonotic pathogens with epidemic potential

Tuberculosis, HIV/AIDS and Malaria Health Services in sub-Saharan Africa – A Situation Analysis of the Disruptions and Impact of the COVID-19 Pandemic

Background: The unprecedented and ongoing COVID-19 pandemic has exposed weaknesses in African countries’ health systems. The impact of shifted focus on COVID-19 for the past 2 years on routine health services, especially those for the epidemics of Tuberculosis, HIV/AIDS and Malaria, have been dramatic in both quantity and quality. Methods: In this article, we reflect on the COVID-19 related disruptions on the Tuberculosis, HIV/AIDS and Malaria routine health services across Africa. Results: The COVID-19 pandemic resulted in disruptions of routine health services and diversion of already limited available resources in sub-Saharan Africa. As a result, disease programs like TB, malaria and HIV have recorded gaps in prevention and treatment with the prospects of reversing gains made towards meeting global targets. The extent of the disruption is yet to be fully quantified at country level as most data available is from modelling estimates before and during the pandemic. Conclusions: Accurate country-level data is required to convince donors and governments to invest more into revamping these health services and help prepare for managing future pandemics without disruption of routine services. Increasing government expenditure on health is a critical part of Africa's economic policy. Strengthening health systems at various levels to overcome the negative impacts of COVID-19, and preparing for future epidemics will require strong visionary political leadership. Innovations in service delivery and technological adaptations are required as countries aim to limit disruptions to routine services