The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Automated measuring of cyclist - motor vehicle post encroachment time at signalized intersections

Conflicts between motor vehicle and cyclists at a signalized intersection were characterized in this study using an objective conflict indicator; post encroachment time (PET). A total of 384 conflict events for PET (0, 3] seconds between cyclists and vehicles were analyzed in this study. An automated video analysis technique was developed to measure the PET between cyclists and motor vehicles. The results of the conflict analysis showed that the average absolute error of PET between the frame count measurement (MFCM) and automated measurement (AM) methods was 0.12 s and the standard deviation was 0.10 s. The evaluation result showed that the coefficient of determination between the AM and MFCM methods was found to be 0.938 and there was a very good agreement in the PET classification of individual conflicts between the MFCM and AM methods. This study includes procedures to better interpret the conflict point of the motor vehicle and the cyclist in an automated manner (based on the geometry of the bounding box and direction of the travel), which appears to be a contribution for the analysis of cyclist - motor vehicle collisions

Feasibility of electromagnetic communication in underwater wireless sensor networks

Underwater Wireless Sensor networks (UWSNs) comprised of a number of sensor nodes that are deployed to perform collaborative monitoring tasks. Sensor nodes are connected to each other through wireless signals. Acoustic signal is the dominant wave used for UWSNs communications. Acoustic signals face a lot of challenges such as ambient noise, manmade noise, limited bandwidth, multipath and low propagation speed. These challenges become more severe in shallow water environment where a high level of ambient and manmade noise, turbidity and multipath is available. Therefore, Electromagnetic signals can be applied for using as a communication signal for UWSNs. In this work, the performance of electromagnetic communication in the water environment is investigated. The investigation is conducted for fresh and seawater environment. Results show that freshwater environment can permit short range communication while the communication is more difficult for seawater due to the high value of attenuation

Loxoprofen Sodium Versus Diclofenac Potassium for Post-Dental Extraction Pain Relief: A Randomized, Triple-Blind, Clinical Trial

One of the most common post-operative complications of tooth extraction is pain. Oral analgesics, namely loxoprofen sodium and diclofenac potassium, are often prescribed; however, the efficacy of these drugs irrespective of gender and type of extraction has not been tested. Therefore, this study aimed to compare the efficacy of these two drugs in post-dental extraction pain relief among male and female patients in cases of simple and surgical tooth extraction. A single-center, triple-blind, randomized clinical trial was conducted among 100 male and female patients who underwent tooth extraction at Taibah University Dental College and Hospital in Al-Madinah, Saudi Arabia. The patients reported their pain post-operatively after 6 hours and every 12 h for 3 days using the Verbal Descriptor Scale (e.g., “no pain”, “mild pain”). Descriptive statistics and chi-square tests were run to analyze the data. An equal number of patients received either the drug loxoprofen sodium or diclofenac potassium and completed the study follow-up. Patients allocated to the diclofenac potassium drug group after 36 h were statistically significantly in their reporting of “no pain” and “mild pain” compared to patients allocated to the loxoprofen sodium group (86% vs. 66%, respectively; p = 0.019), irrespective of gender or type of tooth extraction. However, both groups demonstrated comparable (p > 0.05) post-operative pain relief over the other aforementioned allocated time intervals. In conclusion, the diclofenac potassium group had slightly better control over post-operative pain than the group receiving loxoprofen sodium

Feasibility of electromagnetic communication in underwater wireless sensor networks

Underwater Wireless Sensor networks (UWSNs) comprised of a number of sensor nodes that are deployed to perform collaborative monitoring tasks. Sensor nodes are connected to each other through wireless signals. Acoustic signal is the dominant wave used for UWSNs communications. Acoustic signals face a lot of challenges such as ambient noise, manmade noise, limited bandwidth, multipath and low propagation speed. These challenges become more severe in shallow water environment where a high level of ambient and manmade noise, turbidity and multipath is available. Therefore, Electromagnetic signals can be applied for using as a communication signal for UWSNs. In this work, the performance of electromagnetic communication in the water environment is investigated. The investigation is conducted for fresh and seawater environment. Results show that freshwater environment can permit short range communication while the communication is more difficult for seawater due to the high value of attenuation

The effect of phosphorus and copper oxide on the photoluminescence characteristics of li2co3-k2co3-h3bo3 glass

In this paper, glass sample was prepared by the conventional wet chemical method. A series of borate glass consists of lithium and potassium carbonate doped with 0.1 mol% of NH4H2PO4 and copper oxides have been well prepared. The structural and the optical properties of the glass have been measured by means of their XRD, FTIR, PL and UV-VIS spectra. From the results, the current sample shows a nonlinear optical property by emitting two prominent peaks at 504 and 540 nm (green light emission) under the excitation of 630 nm. A significant enhancement on the PL spectra due to increment of phosphorus impurities dopant has also been observed. Some other physical parameters were also been measured and identified. The results of structural as well as the optical were then being estimated and discussed

Global variations in heart failure etiology, management, and outcomes

Importance: Most epidemiological studies of heart failure (HF) have been conducted in high-income countries with limited comparable data from middle- or low-income countries. Objective: To examine differences in HF etiology, treatment, and outcomes between groups of countries at different levels of economic development. Design, Setting, and Participants: Multinational HF registry of 23 341 participants in 40 high-income, upper–middle-income, lower–middle-income, and low-income countries, followed up for a median period of 2.0 years. Main Outcomes and Measures: HF cause, HF medication use, hospitalization, and death. Results: Mean (SD) age of participants was 63.1 (14.9) years, and 9119 (39.1%) were female. The most common cause of HF was ischemic heart disease (38.1%) followed by hypertension (20.2%). The proportion of participants with HF with reduced ejection fraction taking the combination of a β-blocker, renin-angiotensin system inhibitor, and mineralocorticoid receptor antagonist was highest in upper–middle-income (61.9%) and high-income countries (51.1%), and it was lowest in low-income (45.7%) and lower–middle-income countries (39.5%) (P < .001). The age- and sex- standardized mortality rate per 100 person-years was lowest in high-income countries (7.8 [95% CI, 7.5-8.2]), 9.3 (95% CI, 8.8-9.9) in upper–middle-income countries, 15.7 (95% CI, 15.0-16.4) in lower–middle-income countries, and it was highest in low-income countries (19.1 [95% CI, 17.6-20.7]). Hospitalization rates were more frequent than death rates in high-income countries (ratio = 3.8) and in upper–middle-income countries (ratio = 2.4), similar in lower–middle-income countries (ratio = 1.1), and less frequent in low-income countries (ratio = 0.6). The 30-day case-fatality rate after first hospital admission was lowest in high-income countries (6.7%), followed by upper–middle-income countries (9.7%), then lower–middle-income countries (21.1%), and highest in low-income countries (31.6%). The proportional risk of death within 30 days of a first hospital admission was 3- to 5-fold higher in lower–middle-income countries and low-income countries compared with high-income countries after adjusting for patient characteristics and use of long-term HF therapies. Conclusions and Relevance: This study of HF patients from 40 different countries and derived from 4 different economic levels demonstrated differences in HF etiologies, management, and outcomes. These data may be useful in planning approaches to improve HF prevention and treatment globally