Predicting the fine-scale spatial distribution of zoonotic reservoirs using computer vision.

Zoonotic diseases threaten human health worldwide and are often associated with anthropogenic disturbance. Predicting how disturbance influences spillover risk is critical for effective disease intervention but difficult to achieve at fine spatial scales. Here, we develop a method that learns the spatial distribution of a reservoir species from aerial imagery. Our approach uses neural networks to extract features of known or hypothesized importance from images. The spatial distribution of these features is then summarized and linked to spatially explicit reservoir presence/absence data using boosted regression trees. We demonstrate the utility of our method by applying it to the reservoir of Lassa virus, Mastomys natalensis, within the West African nations of Sierra Leone and Guinea. We show that, when trained using reservoir trapping data and publicly available aerial imagery, our framework learns relationships between environmental features and reservoir occurrence and accurately ranks areas according to the likelihood of reservoir presence.

Improving global health security through implementation of the National Action Plan for Health Security in Sierra Leone, 2018-2021: lessons from the field.

BACKGROUND: All countries are required to implement International Health Regulations (IHR) through development and implementation of multi-year National Action Plans for Health Security (NAPHS). IHR implementation requires annual operational planning which involves several tools such as NAPHS, State Party Annual Report (SPAR), Joint External Evaluation (JEE) and WHO IHR Benchmarks tool. Sierra Leone has successfully improved IHR capacities across the years through successful annual operational planning using the above tools. We conducted a study to document and share the country's unique approach to implementation of NAPHS. METHODS: This was an observational study where the process of implementing and monitoring NAPHS in Sierra Leone was observed at the national level from 2018 to 2021. Data was obtained through review and analysis of NAPHS annual operational plans, quarterly review reports and annual IHR assessment reports. Available data was supplemented by information from key informants. Qualitative data was captured as notes and analysed for various themes while quantitative data was analyzed mainly for means and proportions. RESULTS: The overall national IHR Joint External Evaluation self-assessment score for human health improved from 44% in 2018 to 51% in 2019 and 57% in 2020. The score for the animal sector improved from 32% in 2018 to 43% in 2019 and 52% in 2020. A new JEE tool with new indicators was used in 2021 and the score for both human and animal sectors declined slightly to 51%. Key enablers of success included strong political commitment, whole-of-government approach, annual assessments using JEE tool, annual operational planning using WHO IHR Benchmarks tool and real time online monitoring of progress. Key challenges included disruption created by COVID-19 response, poor health infrastructure, low funding and inadequate health workforce. CONCLUSION: IHR annual operational planning and implementation using evidence-based data and tools can facilitate strengthening of IHR capacity and should be encouraged.

Fabrication and application of complex microcapsules: a review.

The development of new functional materials requires cutting-edge technologies for incorporating different functional materials without reducing their functionality. Microencapsulation is a method to encapsulate different functional materials at nano- and micro-scales, which can provide the necessary protection for the encapsulated materials. In this review, microencapsulation is categorized into chemical, physical, physico-chemical and microfluidic methods. The focus of this review is to describe these four categories in detail by elaborating their various microencapsulation methods and mechanisms. This review further discusses the key features and potential applications of each method. Through this review, the readers could be aware of many aspects of this field from the fabrication processes, to the main properties, and to the applications of microcapsules.

Health Conditions in an Adult Population in Sierra Leone: Data Reported From the Sierra Leone Trial to Introduce a Vaccine Against Ebola (STRIVE).

Clinical Trials Registration: ClinicalTrials.gov [NCT02378753] and Pan African Clinical Trials Registry [PACTR201502001037220].

Monitoring Serious Adverse Events in the Sierra Leone Trial to Introduce a Vaccine Against Ebola.

Clinical Trials Registration: ClinicalTrials.gov [NCT02378753] and Pan African Clinical Trials Registry [PACTR201502001037220].

Nature-based solution enhances resilience to flooding and catalyzes multi-benefits in coastal cities in the Global South.

Coastal cities are facing a rise in groundwater levels induced by sea level rise, further triggering saturation excess flooding where groundwater levels reach the topographic surface or reduce the storage capacity of the soil, thus stressing the existing infrastructure. Lowering groundwater levels is a priority for sustaining the long-term livelihood of coastal cities. In the absence of studies assessing the possibility of using tree-planting as a measure of alleviating saturation excess flooding in the context of rising groundwater levels, the multi-benefit nature of tree-planting programs as sustainable Nature-based solutions (NBSs) in coastal cities in the Global South is discussed. In environments where groundwater is shallow, trees uptake groundwater or reduce groundwater recharge, thereby contributing to lower groundwater levels and increasing the unsaturated zone thickness, further reducing the risk of saturation excess flooding. Tree-planting programs represent long-term solutions sustained by environmental factors that are complementary to conventional engineering solutions. The multi-benefit nature of such NBSs and the expected positive environmental, economic, and social outcomes make them particularly promising. Wide social acceptance was identified as crucial for the long-term success of any tree-planting program, as the social factor plays a major role in addressing most weaknesses and threats of the solution. In the case of Nouakchott City (Mauritania), where a rise in groundwater levels has led to permanent saturation excess flooding, a tree-planting program has the potential to lower the groundwater levels, thereby reducing flooding during the rainy season.

Impact assessment of onchocerciasis through lymphatic filariasis transmission assessment surveys using Ov-16 rapid diagnostic tests in Sierra Leone.

BACKGROUND: Onchocerciasis is endemic in 14 of Sierra Leone's 16 districts with high prevalence (47-88.5%) according to skin snips at baseline. After 11 rounds of mass treatment with ivermectin with good coverage, an impact assessment was conducted in 2017 to assess the progress towards eliminating onchocerciasis in the country. METHODS: A cluster survey was conducted, either integrated with lymphatic filariasis (LF) transmission assessment survey (TAS) or standalone with the LF TAS sampling strategy in 12 (now 14) endemic districts. Finger prick blood samples of randomly selected children in Grades 1-4 were tested in the field using SD Bioline Onchocerciasis IgG4 rapid tests. RESULTS: In total, 17,402 children aged 4-19 years in 177 schools were tested, and data from 17,364 children aged 4-14 years (14,230 children aged 5-9 years) were analyzed. Three hundred forty-six children were confirmed positive for Ov-16 IgG4 antibodies, a prevalence of 2.0% (95% CI 1.8-2.2%) in children aged 4-14 years with prevalence increasing with age. Prevalence in boys (2.4%; 95% CI 2.1-2.7%) was higher than in girls (1.6%; 95% CI 1.4-1.9%). There was a trend of continued reduction from baseline to 2010. Using data from children aged 5-9 years, overall prevalence was 1.7% (95% CI 1.5-1.9%). The site prevalence ranged from 0 to 33.3% (median prevalence = 0.0%): < 2% in 127 schools, 2 to < 5% in 34 schools and ≥ 5% in 16 schools. There was a significant difference in average prevalence between districts. Using spatial analysis, the Ov-16 IgG4 antibody prevalence was predicted to be < 2% in coastal areas and in large parts of Koinadugu, Bombali and Tonkolili Districts, while high prevalence (> 5%) was predicted in some focal areas, centered in Karene, Kailahun and Moyamba/Tonkolili. CONCLUSIONS: Low Ov-16 IgG4 antibody prevalence was shown in most areas across Sierra Leone. In particular, low seroprevalence in children aged 5-9 years suggests that the infection was reduced to a low level after 11 rounds of treatment intervention. Sierra Leone has made major progress towards elimination of onchocerciasis. However, attention must be paid to those high prevalence focal areas.

Re-assessment of schistosomiasis in nine endemic districts with cluster sampling in Sierra Leone.

Background: Baseline mapping showed that schistosomiasis was highly/moderately endemic in nine districts in Sierra Leone. Mass drug administration (MDA) with praziquantel started in 2009, and after multiple rounds of treatment, an impact assessment was conducted in 2016 followed by a second re-assessment in 2022 using cluster sampling to provide more granular data for refining chiefdom (sub-district) treatment strategies. Methods: On average, 20 rural villages were systematically selected per district by probability proportional to population size across the nine districts. Surveys were conducted in schools, and 24 school children aged between 5 and 14 years were randomly selected, with an equal number of boys and girls. One stool sample and one urine sample were collected per child. Two Kato-Katz slides were examined per stool for Schistosoma mansoni infection. Hemastix strips were used as a proxy for S. haematobium infection with urine filtration used for egg counts on hematuria-positive samples. Results: In total, 4,736 stool samples and 4,618 urine samples were examined across 200 schools in 125 chiefdoms. Overall, the prevalence of S. mansoni was 16.3% (95% CI: 15.3-17.4%), while the overall prevalence of S. haematobium was 2.0% (95% CI: 1.6-2.4%) by hematuria. The prevalence of heavy infections for S. mansoni and S. haematobium was 1.5% (95% CI: 1.1-1.9%) and 0.02% (95% CI: 0.0-0.14%), respectively. Among 125 chiefdoms surveyed, the overall schistosomiasis prevalence was <10% in 65 chiefdoms, 10-49.9% in 47 chiefdoms, and ≥ 50% in 13 chiefdoms. There was a mixed relationship between schistosomiasis in school children and WASH access in schools. Conclusion: Sierra Leone has made significant progress in reducing schistosomiasis prevalence across the country after a decade of MDA intervention. However, high prevalence remains in some hotspot chiefdoms. The next steps are for the national program to investigate and address any potential issues such as low coverage or poor knowledge of schistosomiasis risk behaviors and, where appropriate, consider broadening to community-wide treatment in hotspot chiefdoms or communities.

Reservoir displacement by an invasive rodent reduces Lassa virus zoonotic spillover risk.

The black rat (Rattus rattus) is a globally invasive species that has been widely introduced across Africa. Within its invasive range in West Africa, R. rattus may compete with the native rodent Mastomys natalensis, the primary reservoir host of Lassa virus, a zoonotic pathogen that kills thousands annually. Here, we use rodent trapping data from Sierra Leone and Guinea to show that R. rattus presence reduces M. natalensis density within the human dwellings where Lassa virus exposure is most likely to occur. Further, we integrate infection data from M. natalensis to demonstrate that Lassa virus zoonotic spillover risk is lower at sites with R. rattus. While non-native species can have numerous negative effects on ecosystems, our results suggest that R. rattus invasion has the indirect benefit of decreasing zoonotic spillover of an endemic pathogen, with important implications for invasive species control across West Africa.

Effectiveness of a water-vending kiosk intervention toward household water quality and surveyed water security in Freetown, Sierra Leone.

Low-income urban residents of Freetown, Sierra Leone, have limited access to safely managed piped drinking water services. The Government of Sierra Leone, in partnership with the United States Millennium Challenge Corporation, implemented a demonstration project of ten water kiosks providing distributed, stored, treated water among two neighborhoods in Freetown. This study quantifies the impact of the water kiosk intervention by utilizing a quasi-experimental propensity score matched difference-in-differences study design. Results indicate a 0.6 % improvement in household microbial water quality and an 8.2 % improvement in surveyed water security within the treatment group. Furthermore, low functionality and adoption of the water kiosks were observed.

Toward Learning Joint Inference Tasks for IASS-MTS Using Dual Attention Memory With Stochastic Generative Imputation.

Irregularly, asynchronously and sparsely sampled multivariate time series (IASS-MTS) are characterized by sparse and uneven time intervals and nonsynchronous sampling rates, posing significant challenges for machine learning models to learn complex relationships within and beyond IASS-MTS to support various inference tasks. The existing methods typically either focus solely on single-task forecasting or simply concatenate them through a separate preprocessing imputation procedure for the subsequent classification application. However, these methods often ignore valuable annotated labels or fail to discover meaningful patterns from unlabeled data. Moreover, the approach of separate prefilling may introduce errors due to the noise in raw records, and thus degrade the downstream prediction performance. To overcome these challenges, we propose the time-aware dual attention and memory-augmented network (DAMA) with stochastic generative imputation (SGI). Our model constructs a joint task learning architecture that unifies imputation and classification tasks collaboratively. First, we design a new time-aware DAMA that accounts for irregular sampling rates, inherent data nonalignment, and sparse values in IASS-MTS data. The proposed network integrates both attention and memory to effectively analyze complex interactions within and across IASS-MTS for the classification task. Second, we develop the stochastic generative imputation (SGI) network that uses auxiliary information from sequence data for inferring the time series missing observations. By balancing joint tasks, our model facilitates interaction between them, leading to improved performance on both classification and imputation tasks. Third, we evaluate our model on real-world datasets and demonstrate its superior performance in terms of imputation accuracy and classification results, outperforming the baselines.

Enhanced payload volume in the least significant bits image steganography using hash function.

The art of message masking is called steganography. Steganography keeps communication from being seen by any other person. In the domain of information concealment within images, numerous steganographic techniques exist. Digital photos stand out as prime candidates due to their widespread availability. This study seeks to develop a secure, high-capacity communication system that ensures private interaction while safeguarding information from the broader context. This study used the four least significant bits for steganography to hide the message in a secure way using a hash function. Before steganography, the message is encrypted using one of the encryption techniques: Caesar cipher or Vigenère cipher. By altering only the least significant bits (LSBs), the changes between the original and stego images remain invisible to the human eye. The proposed method excels in secret data capacity, featuring a high peak signal-to-noise ratio (PSNR) and low mean square error (MSE). This approach offers significant payload capacity and dual-layer security (encryption and steganography).

Improvement in the Surveillance System for Livestock Diseases and Antimicrobial Use Following Operational Research Studies in Sierra Leone January-March 2023.

In Sierra Leone, two operational research (OR) studies in 2019 and 2021 showed deficiencies in the data being captured by the Integrated Animal Disease Surveillance and Reporting (IADSR) system. This third OR study was conducted in 2023 to assess whether the second OR study's results and recommendations were disseminated with the key stakeholders, the uptake of the recommendations, improvements in data capture in the IADSR system, and to describe the data on livestock disease and antimicrobial use. In 2022, on seven occasions, the authors of the second OR study disseminated the study's findings. Of the four recommendations, the one on improving laboratory infrastructure for confirmation of animal disease was not implemented. The district animal health weekly surveillance reports received through the IADSR system were sustained at 88% between the second (2021) and third (2023) studies. In both studies, the proportion of sick animals receiving antibiotics (25%) remained the same, but the use of "critically important antimicrobials for veterinary use" declined from 77% (in 2021) to 69% (in 2023). The IADSR system has improved considerably in providing information on animal health and antibiotic use, and sequential OR studies have played a key role in its improvement.

Challenges and solutions to providing surgery in Sierra Leone hospitals: a qualitative analysis of surgical provider perspectives.

OBJECTIVE: This study aimed to use qualitative interviews with surgical providers to explore challenges and solutions to providing surgical and anaesthesia care in Sierra Leone's hospitals. DESIGN: Data were collected through anonymous, semistructured interviews. We used a qualitative framework approach to analyse interview data and determine themes relating to challenges that were reported. SETTING: A purposive sample of 12 hospitals was selected throughout Sierra Leone to include district and referral hospitals of varying ownership (private, non-governmental organisation and government). PARTICIPANTS: The most senior surgical provider available during each hospital site visit participated in a semistructured interview. A total of 12 interviews were conducted. RESULTS: Providers described both challenges and solutions relating to the following categories: equipment and supplies, access to services, human resources, infrastructure, management and patient factors. These challenges were found to affect surgical care in hospitals by delaying surgical care, decreasing operative capacity and decreasing quality of care. Providers identified not only the root causes of these challenges, but also the varied workarounds and solutions they employ to overcome them. CONCLUSION: Surgical providers can offer important insights into challenges affecting surgical services in hospitals. Despite working in challenging environments with limited resources, providers have developed innovative solutions to improve surgical and anaesthesia care in hospitals in Sierra Leone. Qualitative research has an important role to play in improving understanding of the challenges facing surgeons in low-income countries.

An Update on the Surveillance of Livestock Diseases and Antimicrobial Use in Sierra Leone in 2021-An Operational Research Study.

In Sierra Leone, in 2020, a study by the Livestock and Veterinary Services Division (Ministry of Agriculture and Forestry) on the surveillance system of animal diseases and antimicrobial use found poor reporting. Of the expected weekly districts reports, <1% were received and only three of the 15 districts had submitted reports occasionally between 2016 and 2019. Following this, staff-capacity-building on reporting was undertaken. In 2021, we reassessed the improvement in reporting and used the reports to describe livestock diseases and antimicrobials utilized in their treatment. Between March and October 2021, 88% of expected weekly reports from all 15 districts were received. There were minor deficiencies in completeness and consistency in the terminology used for reporting animal disease and antimicrobials. Available reports showed that 25% of the livestock had an infectious disease, and a quarter of the sick animals had received an antimicrobial drug. Most animals received antimicrobials belonging to World Organization for Animal Health's "veterinary critically important" category (77%) and World Health Organization's "critically" (17%) and "highly important" (60%) categories for human health. These indicate a significant improvement in the animal health surveillance system and highlight the need for enhanced antimicrobial stewardship to prevent misuse of antimicrobials that are significant in animal and human health.

Mosquito survey in Mauritania: Detection of Rift Valley fever virus and dengue virus and the determination of feeding patterns.

In Mauritania, several mosquito-borne viruses have been reported that can cause devastating diseases in animals and humans. However, monitoring data on their occurrence and local distribution are limited. Rift Valley fever virus (RVFV) is an arthropod-borne virus that causes major outbreaks throughout the African continent and the Arabian Peninsula. The first Rift Valley fever (RVF) epidemic in Mauritania occurred in 1987 and since then the country has been affected by recurrent outbreaks of the disease. To gain information on the occurrence of RVFV as well as other mosquito-borne viruses and their vectors in Mauritania, we collected and examined 4,950 mosquitoes, belonging to four genera and 14 species. The mosquitoes were captured during 2018 in the capital Nouakchott and in southern parts of Mauritania. Evidence of RVFV was found in a mosquito pool of female Anopheles pharoensis mosquitoes collected in December on a farm near the Senegal River. At that time, 37.5% of 16 tested Montbéliarde cattle on the farm showed RVFV-specific IgM antibodies. Additionally, we detected IgM antibodies in 10.7% of 28 indigenous cattle that had been sampled on the same farm one month earlier. To obtain information on potential RVFV reservoir hosts, blood meals of captured engorged mosquitoes were analyzed. The mosquitoes mainly fed on humans (urban areas) and cattle (rural areas), but also on small ruminants, donkeys, cats, dogs and straw-colored fruit bats. Results of this study demonstrate the circulation of RVFV in Mauritania and thus the need for further research to investigate the distribution of the virus and its vectors. Furthermore, factors that may contribute to its maintenance should be analyzed more closely. In addition, two mosquito pools containing Aedes aegypti and Culex quinquefasciatus mosquitoes showed evidence of dengue virus (DENV) 2 circulation in the city of Rosso. Further studies are therefore needed to also examine DENV circulation in Mauritania.

Genome Sequences of Five Arenaviruses from Pygmy Mice (Mus minutoides) in Sierra Leone.

The genome sequences of five strains of a mammarenavirus were assembled from metagenomic data from pygmy mice (Mus minutoides) captured in Sierra Leone. The nearest fully sequenced relatives of this virus, which was named Seli virus, are lymphocytic choriomeningitis virus, Lunk virus, and Ryukyu virus.

Crimean-Congo hemorrhagic fever virus antibody prevalence in Mauritanian livestock (cattle, goats, sheep and camels) is stratified by the animal's age.

Crimean-Congo hemorrhagic fever virus (CCHFV) is one of the most widespread zoonotic arthropod-borne viruses in many parts of Africa, Europe and Asia. It belongs to the family of Nairoviridae in the genus of Orthonairovirus. The main reservoir and vector are ticks of the genus Hyalomma. Livestock animals (such as cattle, small ruminants and camels) develop a viremias lasting up to two weeks with absence of clinical symptoms, followed by seroconversion. This study was carried out to assess risk factors that affect seroprevalence rates in different species. In total, 928 livestock animal samples (cattle = 201; sheep = 247; goats = 233; camels = 247) from 11 out of 13 regions in Mauritania were assayed for CCHFV-specific immunoglobulin G (IgG) antibodies using enzyme-linked immunosorbent assays (ELISA) (including a novel indirect camel-IgG-specific CCHFV ELISA). Inconclusive results were resolved by an immunofluorescence assay (IFA). A generalized linear mixed-effects model (GLMM) was used to draw conclusions about the impact of certain factors (age, species, sex and region) which might have influenced the CCHFV antibody status of surveyed animals. In goats and sheep, about 15% of the animals were seropositive, whereas in cattle (69%) and camels (81%), the prevalence rate was significantly higher. On average, cattle and camels were up to twice to four times older than small ruminants. Interestingly, the seroprevalence in all species was directly linked to the age of the animals, i.e. older animals had significantly higher seroprevalence rates than younger animals. The highest CCHFV seroprevalence in Mauritania was found in camels and cattle, followed by small ruminants. The large proportion of positive animals in cattle and camels might be explained by the high ages of the animals. Future CCHFV prevalence studies should at least consider the age of surveyed animals in order to avoid misinterpretations.

Veterinary Healthcare Provision and Quality of Reported Data on Antimicrobial Use in the Treatment of Livestock in Sierra Leone, 2016-2019.

Antimicrobials help in the prevention and treatment of infections and are crucial for animal production, but overuse can result in antimicrobial resistance. Hence, understanding data quality on livestock antimicrobial use is essential. We assessed frequency of reporting, completeness, and concordance of reported data and availability of human resources and infrastructure in 14 districts in Sierra Leone. This was a cross-sectional study involving a review of district and sub-district animal treatment forms submitted from January 2016 to August 2019. Out of the 14 districts, only 3 had filled forms available for review: A total of 6 (0.97% of 616 expected) district forms and 79 (1.15% of 6840 expected) sub-district forms. Data between district and sub-district treatment forms were fully discordant. Hence, completeness of data could not be assessed. All districts had livestock officers (barring one) and livestock assistants but no veterinarians. The gap in community animal health workers ranged from 14 to 100% per district. No districts had a functional computer or internet access. Reporting was non-existent in 11 districts and poor in the other 3. Resources are urgently needed to address critical gaps in human resources and capacity and computer and Internet connectivity to develop critical One Health surveillance functions at the national and sub-national levels.

Co-circulation of Orthobunyaviruses and Rift Valley Fever Virus in Mauritania, 2015.

Ngari virus (NRIV) has been mostly detected during concurrent outbreaks of Rift Valley fever virus (RVFV). NRIV is grouped in the genus Orthobunyavirus within the Bunyaviridae family and RVFV in the genus Phlebovirus in the family Phenuiviridae. Both are zoonotic arboviruses and can induce hemorrhagic fever displaying the same clinical picture in humans and small ruminants. To investigate if NRIV and its parental viruses, Bunyamwera virus (BUNV) and Batai virus (BATV), played a role during the Mauritanian RVF outbreak in 2015/16, we analyzed serum samples of sheep and goats from central and southern regions in Mauritania by quantitative real-time RT-PCR, serum neutralization test (SNT) and ELISA. 41 of 458 samples exhibited neutralizing reactivity against NRIV, nine against BATV and three against BUNV. Moreover, complete virus genomes from BUNV could be recovered from two sheep as well as two NRIV isolates from a goat and a sheep. No RVFV-derived viral RNA was detected, but 81 seropositive animals including 22 IgM-positive individuals were found. Of these specimens, 61 samples revealed antibodies against RVFV and at least against one of the three orthobunyaviruses. An indirect ELISA based on NRIV/BATV and BUNV derived Gc protein was established as complement to SNT, which showed high performance regarding NRIV, but decreased sensitivity and specificity regarding BATV and BUNV. Moreover, we observed high cross-reactivity among NRIV and BATV serological assays. Taken together, the data indicate the co-circulation of at least BUNV and NRIV in the Mauritanian sheep and goat populations.