The Analysis of Oral and Fecal Virome Detects Multiple Novel Emerging Viruses in Snakes

Wild animals are considered reservoirs for emerging and reemerging viruses, such as the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Previous studies have reported that bats and ticks harbored variable important pathogenic viruses, some of which could cause potential diseases in humans and livestock, while viruses carried by reptiles were rarely reported. Our study first conducted snakes' virome analysis to establish effective surveillance of potential transboundary emerging diseases. Consequently, Adenoviridae, Circoviridae, Retroviridae, and Parvoviridae were identified in oral samples from Protobothrops mucrosquamatus, Elaphe dione, and Gloydius angusticeps based on sequence similarity to existing viruses. Picornaviridae and Adenoviridae were also identified in fecal samples of Protobothrops mucrosquamatus. Notably, the iflavirus and foamy virus were first reported in Protobothrops mucrosquamatus, enriching the transboundary viral diversity in snakes. Furthermore, phylogenetic analysis revealed that both the novel-identified viruses showed low genetic similarity with previously reported viruses. This study provided a basis for our understanding of microbiome diversity and the surveillance and prevention of emerging and unknown viruses in snakes.

Continuous evolution and emerging lineage of seasonal human coronaviruses: A multicenter surveillance study.

The seasonal human coronaviruses (HCoVs) have zoonotic origins, repeated infections, and global transmission. The objectives of this study are to elaborate the epidemiological and evolutionary characteristics of HCoVs from patients with acute respiratory illness. We conducted a multicenter surveillance at 36 sentinel hospitals of Beijing Metropolis, China, during 2016-2019. Patients with influenza-like illness (ILI) and severe acute respiratory infection (SARI) were included, and submitted respiratory samples for screening HCoVs by multiplex real-time reverse transcription-polymerase chain reaction assays. All the positive samples were used for metatranscriptomic sequencing to get whole genomes of HCoVs for genetical and evolutionary analyses. Totally, 321 of 15 677 patients with ILI or SARI were found to be positive for HCoVs, with an infection rate of 2.0% (95% confidence interval, 1.8%-2.3%). HCoV-229E, HCoV-NL63, HCoV-OC43, and HCoV-HKU1 infections accounted for 18.7%, 38.3%, 40.5%, and 2.5%, respectively. In comparison to ILI cases, SARI cases were significantly older, more likely caused by HCoV-229E and HCoV-OC43, and more often co-infected with other respiratory pathogens. A total of 179 full genome sequences of HCoVs were obtained from 321 positive patients. The phylogenetical analyses revealed that HCoV-229E, HCoV-NL63 and HCoV-OC43 continuously yielded novel lineages, respectively. The nonsynonymous to synonymous ratio of all key genes in each HCoV was less than one, indicating that all four HCoVs were under negative selection pressure. Multiple substitution modes were observed in spike glycoprotein among the four HCoVs. Our findings highlight the importance of enhancing surveillance on HCoVs, and imply that more variants might occur in the future.

Whole genome sequence analyses of Indonesian isolates SARS-CoV-2 variants and their clinical manifestations

The SARS-CoV-2 virus has been the cause of the global pandemic since the end of 2019. Since then, the virus has mutated to create different types of variants with numerous effects on those infected. This has complicated human intervention for prevention. Indonesia was heavily affected by the pandemic, specifically from May to August 2021, and as a country has recorded many distinct isolates. Thus, characterization of the virus strains from Indonesia is important. GISAID, NCBI BLAST, and MAFFT version 7 were used. There were 9,488 isolates in Indonesia as of November 2021, with the majority including the Delta variant. While most of the isolates have mutations common to those from other countries, there are some atypical ones, such as mutation V1264L in the Delta variant that was suspected to play a role in worsening the pandemic. The Delta variant had the most mutations in the spike protein when compared to the Alpha and Beta variants, giving it important roles in infectivity and vigorous entry into cells, with some general clinical manifestations like fever and sore throat;however, the severity of the Delta variant is attributable to its rapid growth. This is why, from May to November 2021 in Indonesia, cases of the Delta variant rocketed, unlike the other variants. Copyright © 2023 THE AUTHOR(S).

A Novel SARS-COV-2 Variant Omicron Disseminating Evaluation

Omicron is a relatively new form of COVID-19 that has created an unavoidable and life-threatening situation to the entire world since late 2021. Absence of appropriate vaccination, medication, the epidemiological cycle has become more complex. This study primarily concentrates on the analysis of genome sequence for COVID-19 variants. To conduct such analysis, two datasets are collected from Kaggle and GISAID. Using these datasets, the globally existing genome sequences are identified and insights regarding the countries that are carrying significantly higher genome sequence count are provided. This investigation analyzes the worldwide virus variants and further identifies that the United States and United Kingdom are the countries where proper inspection should be provided because of the genome sequence count. An adequate idea regarding the mutations of the Omicron virus is also considered in this study. To address this issue, recent genome sequence data ranging from February, 2022 to 10th March, 2022 is analyzed to understand how the latest arrival, Omicron, is perturbing the world. This study emphasizes on the constant surveillance of genome sequences among all the countries which in turn will benefit the health care professionals and frontline healthcare workers as well as the Governments can take necessary policies and precautions to combat such pandemic. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

Analysis of Mutations in Conserved and Susceptible Regions Across the Whole Genome Sequencing Analysis for SARS-CoV-2 in Iraqi Patients

This study aimed to get a better understanding of molecular epidemiology and genetic variation in the spike glycoprotein as a key viral component involved in viral entrance into host cells and as a potential vaccination target. Three Iraqi SARSCoV- 2 strains were investigated using whole-genome sequencing, with two of them clustering into the 20A (GH) clade, and the remaining strain is clustered in 20E (GV) clade, belonging to the B.1.36.1 and B.1.177.80 lineage, respectively. Wholegenome sequencing of the viral RNA samples revealed nine sporadic nonsynonymous uncommon mutations with frequency ranged from 0.00 to 0.19%. The ORF1ab, ORF1a, ORF3a, S, N, intergenic, ORF7 and ORF8 areas have seen the most changes. Furthermore, in all of our sequences, we discovered a D614G (aspartic acid to glycine) mutation in spike protein that co-occurred with an NSP12 P323L (viral RNA-dependent RNA polymerase) mutation. The findings point to several viral introductions in Iraq and provide new genetic information on SARSCoV- 2 at the worldwide level. Pathogenesis, diagnostics and vaccine development require information such as SNPs and mutations. © 2023 Publishing house Mining book. All rights reserved.

Molecular Epidemiology and Diversity of SARS-CoV-2 in Ethiopia, 2020-2022.

Ethiopia is the second most populous country in Africa and the sixth most affected by COVID-19 on the continent. Despite having experienced five infection waves, >499,000 cases, and ~7500 COVID-19-related deaths as of January 2023, there is still no detailed genomic epidemiological report on the introduction and spread of SARS-CoV-2 in Ethiopia. In this study, we reconstructed and elucidated the COVID-19 epidemic dynamics. Specifically, we investigated the introduction, local transmission, ongoing evolution, and spread of SARS-CoV-2 during the first four infection waves using 353 high-quality near-whole genomes sampled in Ethiopia. Our results show that whereas viral introductions seeded the first wave, subsequent waves were seeded by local transmission. The B.1.480 lineage emerged in the first wave and notably remained in circulation even after the emergence of the Alpha variant. The B.1.480 was outcompeted by the Delta variant. Notably, Ethiopia's lack of local sequencing capacity was further limited by sporadic, uneven, and insufficient sampling that limited the incorporation of genomic epidemiology in the epidemic public health response in Ethiopia. These results highlight Ethiopia's role in SARS-CoV-2 dissemination and the urgent need for balanced, near-real-time genomic sequencing.

Genome sequence analysis of SARS-COV-2 isolated from a COVID-19 patient in Erbil, Iraq.

In the city of Wuhan, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first recognized among humans at the end of December 2019, and has since spread to every country around the world. The emergence of this new coronavirus has attracted global attention to work towards finding a treatment and developing an effective vaccine against the virus. In this study, we sequence a full genome of SARS-COV-2 isolated from a male patient in the city of Erbil, Iraq. The virus was sequenced using Sanger sequencer and 21 distinct mutations were found in our isolate compared to the full genome sequence of the SARS-COV-2 isolated from the city of Wuhan/China (Accession number: NC_045512.2). Sequence analysis showed that four of the mutations were located at the spike glycoprotein (S), and ten of them were in nonstructural proteins (nsp1, nsp3, nsp12, and orf3a), which had been shown to be related to structural changes at various sites. Moreover, phylogenetic analysis and transmission supported the conclusion that the cases in Iraq were of independent origins of infections and had a close relation to the isolates from Iran. This is the first report on the DNA sequence of the SARS-CoV-2 genome isolated from the Kurdistan region of Iraq.

Fractal correlations in the Covid-19 genome sequence via multivariate rescaled range analysis

An approach based on fractal scaling analysis to characterize the organization of the Covid-19 genome sequences is presented in this work. The method is based on a multivariate version of the fractal rescaled range analysis implemented on a sliding window scheme to detect variations of long-range correlations over the genome sequence domains. As a preliminary step, the nucleotide sequence is mapped in a numerical sequence by following a Voss rule, resulting in a multichannel sequence represented as a binary matrix. Fractal correlations, quantified in terms of the Hurst exponent, depending on the region of the sequence, where the Covid-19 genome sequences are predominantly random, with some patches of weak long-range correlations. The analysis shows that the regions of randomness are more abundant in the Covid-19 sequences than in the primitive SARS sequence, which suggests that the Covid-19 virus possesses a more diverse genomic structure for replication and infection. The analysis constrained to the surface glycoprotein region shows that the Covid-19 sequence is less random as compared to the SARS sequence, which indicates that the Covid-19 virus can undergo more ordered replications of the spike protein. The Omicron variation exhibits an interesting pattern with some randomness similarities with the other SARS and the Covid-19 genome sequences. Overall, the results show that the multivariate rescaled range analysis provides a suitable framework to assess long-term correlations hidden in the internal organization of the Covid-19 genome sequence. © 2023

The Gift of Ancient Times:a Breakthrough in The Tracing ofModern Human Genes br

The2022Nobel Prize in Physiology or Medicine was awarded to Swedish biologist Svante Paabo forhis decisive contribution to paleoanthropogenomics and human origins.There are various theories about theorigin of human beings,and the current mainstream view is:out of the African doctrine.In other words,ancienthumans had about three times of migrations.The first time wasHomo erectus,the second was Neanderthals andDenisovans,and the third was the ancestors of modern humans.All migrated from Africa to Eurasia.Whilepioneering a new discipline,paleoanthropogenomics,Svante Paabo has been refining the"Out of Africa Theory".With the help of various biological techniques,he delved into the origin of human beings from the perspective ofgenomics and found that some genetic imprints from ancient humans were retained in our bodies.For example,the STAT2gene and TLR gene associated with immunity,the EPAS1gene that contributes to hypoxic respirationand the six genes of chromosome3are highly positively correlated with the incidence of COVID-19.Thisresearch means that we can go back to the root of certain diseases,rather than limiting our eyes to the genesthemselves,and exploring where a gene comes from will be a new way of studying diseases.We summarized hisinnovations in related biotechnology in the process of research,his exploration of ancient humans based onmitochondrial and nuclear genes and related results,and introduced some genes derived from ancient humans andtheir related information

A SARS-CoV-2 full genome sequence of the B.1.1 lineage sheds light on viral evolution in Sicily in late 2020.

To investigate the influence of geographic constrains to mobility on SARS-CoV-2 circulation before the advent of vaccination, we recently characterized the occurrence in Sicily of viral lineages in the second pandemic wave (September to December 2020). Our data revealed wide prevalence of the then widespread through Europe B.1.177 variant, although some viral samples could not be classified with the limited Sanger sequencing tools used. A particularly interesting sample could not be fitted to a major variant then circulating in Europe and has been subjected here to full genome sequencing in an attempt to clarify its origin, lineage and relations with the seven full genome sequences deposited for that period in Sicily, hoping to provide clues on viral evolution. The obtained genome is unique (not present in databases). It hosts 20 single-base substitutions relative to the original Wuhan-Hu-1 sequence, 8 of them synonymous and the other 12 encoding 11 amino acid substitutions, all of them already reported one by one. They include four highly prevalent substitutions, NSP12:P323L, S:D614G, and N:R203K/G204R; the much less prevalent S:G181V, ORF3a:G49V and N:R209I changes; and the very rare mutations NSP3:L761I, NSP6:S106F, NSP8:S41F and NSP14:Y447H. GISAID labeled this genome as B.1.1 lineage, a lineage that appeared early on in the pandemic. Phylogenetic analysis also confirmed this lineage diagnosis. Comparison with the seven genome sequences deposited in late 2020 from Sicily revealed branching leading to B.1.177 in one branch and to Alpha in the other branch, and suggested a local origin for the S:G118V mutation.

Characterization and phylogenetic analysis of Iranian SARS-CoV-2 genomes: A phylogenomic study.

Background and Aim: Characterization of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) based on analyzing the evolution and mutations of viruses is crucial for tracking viral infections, potential mutants, and other pathogens. The purpose was to study the complete sequences of SARS-CoV-2 to reveal genetic distance and mutation rate among different provinces of Iran. Methods: As of March 2020-April 2021, a total of 131 SARS-CoV-2 whole genome sequences submitted from Tehran and 133 SARS-CoV-2 full-length sequences from 24 cities with high coverage submitted to EpiCoV GISAID database were analyzed to infer clades and mutation annotation compared with the wild-type variant Wuhan-Hu-1. Results: The results of variant annotation were revealed 11,204 and 9468 distinct genomes were identified among the samples from different cities and Tehran, respectively. The phylogenetic analysis of genomic sequences showed the presence of eight GISAID clades, namely GH, GR, O, GRY, G, GK, L, and GV, and six Nextstrain clades; that is, 19A, 20A, 20B, 20I (alpha, V1), 20H (Beta, V2), and 21I (Delta) in Iran. The GH (GISAID clade), 20A (Nextstrain clade), and B.1 (Pango lineage) were predominant in Iran. Notably, analysis of the spike protein revealed D614G mutation (S_D614G) in 56% of the sequences. Also, the delta variant of the coronavirus, the super-infectious strain that was first identified among the sequences submitted from the southern cities of the country such as Zahedan, Yazd and Bushehr, and most likely from these places to other cities of Iran as well has expanded. Conclusions: Our results indicate that most of the circulated viruses in Iran in the early time of the pandemic had collected in eight GISAID clades. Therefore, a continuous and extensive genome sequence analysis would be necessary to understand the genomic epidemiology of SARS-CoV-2 in Iran.

Fractal correlations in the Covid-19 genome sequence via multivariate rescaled range analysis

An approach based on fractal scaling analysis to characterize the organization of the Covid-19 genome sequences is presented in this work. The method is based on a multivariate version of the fractal rescaled range analysis implemented on a sliding window scheme to detect variations of long-range correlations over the genome sequence domains. As a preliminary step, the nucleotide sequence is mapped in a numerical sequence by following a Voss rule, resulting in a multichannel sequence represented as a binary matrix. Fractal correlations, quantified in terms of the Hurst exponent, depending on the region of the sequence, where the Covid-19 genome sequences are predominantly random, with some patches of weak long-range correlations. The analysis shows that the regions of randomness are more abundant in the Covid-19 sequences than in the primitive SARS sequence, which suggests that the Covid-19 virus possesses a more diverse genomic structure for replication and infection. The analysis constrained to the surface glycoprotein region shows that the Covid-19 sequence is less random as compared to the SARS sequence, which indicates that the Covid-19 virus can undergo more ordered replications of the spike protein. The Omicron variation exhibits an interesting pattern with some randomness similarities with the other SARS and the Covid-19 genome sequences. Overall, the results show that the multivariate rescaled range analysis provides a suitable framework to assess long-term correlations hidden in the internal organization of the Covid-19 genome sequence.

Epidemiological and molecular description of nosocomial outbreak of COVID-19 Alpha (B.1.1.7) variant in Saudi Arabia.

BACKGROUND: Nosocomial outbreaks frequently occurred during the Coronavirus disease 2019 (COVID-19) pandemic; however, sharing experiences on outbreak containment is vital to reduce the related burden in different locations. OBJECTIVES: This article aims at sharing a practical experience on COVID-19 outbreak containment, including contact tracing, screening of target population, testing including molecular analysis, and preventive modalities. It also provides an epidemiological and molecular analysis of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS­CoV­2) infection outbreak in a tertiary care hospital in Saudi Arabia. METHODS: The outbreak occurred in a non-COVID medical ward at a tertiary care hospital in Jeddah, Saudi Arabia, from 22nd March and 15th April 2021. The multidisciplinary outbreak response team performed clinical and epidemiological investigations. Whole-Genome Sequencing (WGS) was implemented on selected isolates for further molecular characterization. RESULTS: A total of eight nurses (20 % of the assigned ward nurses) and six patients (16.2 % of the ward admitted patients at the time of the outbreak) tested positive for the SARS-CoV-2 virus based on PCR testing. The outbreak investigation identified strong evidence of an epidemiologic link between the affected cases. WGS revealed a set of spike mutations and deletions specific to the Alpha variant (B.1.1.7 lineage). All the nurses had mild symptoms, and the fatality among the patients was 50 % (three out of the six patients). CONCLUSIONS: The current nosocomial COVID-19 outbreak, caused by the Alpha variant, revealed multiple breaches in the adherence to the hospital infection control recommended measures. Containment strategies were successful in controlling the outbreak and limiting infection spread. Molecular analysis and genome sequencing are essential tools besides epidemiological investigation to inform appropriate actions, especially with emerging pathogens.

Method to Find the Original Source of COVID-19 by Genome Sequence and Probability of Electron Capture

The purpose of this study was to find the original source of envelope protein (spiked surface) of the Covid-19. It was assumed that the envelope protein was related to ordinary proteins like the human liver enzymes as possible original sources. A comparison was made on the genome sequences of the envelope protein and the human liver enzymes. The results of computational experiments showed that the longest sequence, common in both groups, was as follows: glutamine acid (e) - glutamine acid (e) - threonine (t) - glycine (g). Upon this finding further investigation was performed on the molecular structure of this sequence;and the probabilities of electron captures by the protons of the atoms were computed to determine which atoms could connect the amino acids using the approximation method taken from the quantum mechanics. The study was continued to identify which amino acid grew the genome sequence of the envelope protein differently from the human liver enzymes. And it was found that the electron capture by the proton of the atom could explain the process that formed the genome sequence of the Covid-19’s envelope protein out from the human liver enzymes. To our opinion this method could be used for identification of other candidate proteins so that to find the original source of the virus. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Mutation Prediction for Coronaviruses Using Genome Sequence and Recurrent Neural Networks

The study of viruses and their genetics has been an opportunity as well as a challenge for the scientific community. The recent ongoing SARSCov2 (Severe Acute Respiratory Syndrome) pandemic proved the unpreparedness for these situations. Not only the countermeasures for the effect caused by virus need to be tackled but the mutation taking place in the very genome of the virus is needed to be kept in check frequently. One major way to find out more information about such pathogens is by extracting the genetic data of such viruses. Though genetic data of viruses have been cultured and stored as well as isolated in form of their genome sequences, there is still limited methods on what new viruses can be generated in future due to mutation. This research proposes a deep learning model to predict the genome sequences of the SARS-Cov2 virus using only the previous viruses of the coronaviridae family with the help of RNN-LSTM (Recurrent Neural Network-Long ShortTerm Memory) and RNN-GRU (Gated Recurrent Unit) so that in the future, several counter measures can be taken by predicting possible changes in the genome with the help of existing mutations in the virus. After the process of testing the model, the F1-recall came out to be more than 0.95. The mutation detection???s accuracy of both the models come out about 98.5% which shows the capability of the recurrent neural network to predict future changes in the genome of virus.

Complete genome sequencing of SARS-CoV-2 strains: A pilot survey in Palestine reveals spike mutation H245N.

OBJECTIVES: SARS-CoV-2, severe respiratory syndrome coronavirus-2, is an RNA virus that emerged from China sweeping the globe in the form of a pandemic that became an international public health concern. This pilot study aimed to describe the genetic variation and molecular epidemiology of SARS-CoV-2 in Palestine in fall 2020. RESULTS: To achieve these aims, whole genome sequencing of SARS-CoV-2, phylogenetic analysis, haplotype networking and genetic diversity analysis were performed. These analyses revealed a unique spike mutation H245N that has never been reported before. The phylogenetic analysis depicted that three clusters existed in Palestinian SARS-CoV-2 genome sequences, in which cluster-I comprised the majority of clusters by 90%. Congruently, the haplotype network analysis depicted the same three clusters with a total of 39 haplotypes. The genetic diversity analysis showed that Cluster-I is highly diverse as confirmed by statistically significant mutation rate indices, Tajima's D and Fu-Li's-F tests (- 2.11 and 2.74, respectively), highest number of mutations (Eta = 120), highest number of haplotypes (h = 17), and highest average number of nucleotide differences between any two sequences (S = 118). The study confirmed the high genetic diversity among the Palestinian of SARS-CoV-2 which possessed high number of mutations including one which was reported for the first time.

Tracking of SARS-CoV-2 Alpha variant (B.1.1.7) in Palestine.

As surges of the COVID-19 pandemic continue globally, including in Palestine, several new SARS-CoV-2 variants have been introduced. This expansion has impacted transmission, disease severity, virulence, diagnosis, therapy, and natural and vaccine-induced immunity. Here, 183 whole genome sequences (WGS) were analyzed, of which 129 were from Palestinian cases, 62 of which were collected in 11 Palestinian districts between October 2020 and April 2021 and sequenced completely. A dramatic shift from the wild type to the Alpha variant (B 1.1.7) was observed within a short period of time. Cluster mapping revealed statistically significant clades in two main Palestinian cities, Al-Khalil (Monte Carlo hypothesis test-Poisson model, P = 0.00000000012) and Nablus (Monte Carlo hypothesis test-Poisson model, P = 0.014 and 0.015). The phylogenetic tree showed three main clusters of SARS-CoV-2 with high bootstrap values (>90). However, population genetics analysis showed a genetically homogenous population supported by low Wright's F-statistic values (Fst <0.25), high gene flow (Nm > 3), and statistically insignificant Tajima's D values (Tajima's test, neutrality model prediction, P = 0.02). The Alpha variant, rapidly replaced the wild type, causing a major surge that peaked in April 2021, with an increased COVID-19 mortality rate, especially, in the Al-Khalil and Nablus districts. The source of introduction remains uncertain, despite the minimal genetic variation. The study substantiates the use of WGS for SARS-CoV-2 surveillance as an early warning system to track down new variants requiring effective control.

Wastewater surveillance for SARS-CoV-2 in a small coastal community: Effects of tourism on viral presence and variant identification among low prevalence populations.

Wastewater-based epidemiology has been used to measure SARS-CoV-2 prevalence in cities worldwide as an indicator of community health, however, few longitudinal studies have followed SARS-CoV-2 in wastewater in small communities from the start of the pandemic or evaluated the influence of tourism on viral loads. Therefore the objective of this study was to use measurements of SARS-CoV-2 in wastewater to monitor viral trends and variants in a small island community over a twelve-month period beginning May 1, 2020, before the community re-opened to tourists. Wastewater samples were collected weekly and analyzed to detect and quantify SARS-CoV-2 genome copies. Sanger sequencing was used to determine genome sequences from total RNA extracted from wastewater samples positive for SARS-CoV-2. Visitor data was collected from the local Chamber of Commerce. We performed Poisson and linear regression to determine if visitors to the Cedar Key Chamber of Commerce were positively associated with SARS-CoV-2-positive wastewater samples and the concentration of SARS-CoV-2 RNA. Results indicated that weekly wastewater samples were negative for SARS-CoV-2 until mid-July when positive samples were recorded in four of five consecutive weeks. Additional positive results were recorded in November and December 2020, as well as January, March, and April 2021. Tourism data revealed that the SARS-CoV-2 RNA concentration in wastewater increased by 1.06 Log10 genomic copies/L per 100 tourists weekly. Sequencing from six positive wastewater samples yielded two complete sequences of SARS-CoV-2, two overlapping sequences, and two low yield sequences. They show arrival of a new variant SARS-CoV-2 in January 2021. Our results demonstrate the utility of wastewater surveillance for SARS-CoV-2 in a small community. Wastewater surveillance and viral genome sequencing suggest that population mobility likely plays an important role in the introduction and circulation of SARS-CoV-2 variants among communities experiencing high tourism and who have a small population size.

A fractal scaling analysis of the SARS-CoV-2 genome sequence.

An approach based on fractal scaling analysis to characterize the organization of the SARS-CoV-2 genome sequence was used. The method is based on the detrended fluctuation analysis (DFA) implemented on a sliding window scheme to detect variations of long-range correlations over the genome sequence regions. The nucleotides sequence is mapped in a numerical sequence by using four different assignation rules: amino-keto, purine-pyrimidine, hydrogen-bond and hydrophobicity patterns. The originally reported sequence from Wuhan isolates (Wuhan Hu-1) was considered as a reference to contrast the structure of the 2002-2004 SARS-CoV-1 strain. Long-range correlations, quantified in terms of a scaling exponent, depended on both the mapping rule and the sequence region. Deviations from randomness were attributed to serial correlations or anti-correlations, which can be ascribed to ordered regions of the genome sequence. It was found that the Wuhan Hu-1 sequence was more random than the SARS-CoV-1 sequence, which suggests that the SARS-CoV-2 possesses a more efficient genomic structure for replication and infection. In general, the virus isolated in the early 2020 months showed slight correlation differences with the Wuhan Hu-1 sequence. However, early isolates from India and Italy presented visible differences that led to a more ordered sequence organization. It is apparent that the increased sequence order, particularly in the spike region, endowed some early variants with a more efficient mechanism to spreading, replicating and infecting. Overall, the results showed that the DFA provides a suitable framework to assess long-term correlations hidden in the internal organization of the SARS-CoV-2 genome sequence.

Molecular characterization of SARS-CoV-2 from Bangladesh: implications in genetic diversity, possible origin of the virus, and functional significance of the mutations.

In a try to understand the pathogenesis, evolution and epidemiology of the SARS-CoV-2 virus, scientists from all over the world are tracking its genomic changes in real-time. Genomic studies can be helpful in understanding the disease dynamics. We have downloaded 324 complete and near complete SARS-CoV-2 genomes submitted in GISAID database from Bangladesh which were isolated between 30 March to 7 September, 2020. We then compared these genomes with Wuhan reference sequence and found 4160 mutation events including 2253 missense single nucleotide variations, 38 deletions and 10 insertions. The C>T nucleotide change was most prevalent (41% of all mutations) possibly due to selective mutation pressure to reduce CpG sites to evade CpG targeted host immune response. The most frequent mutation that occurred in 98% isolates was 3037C>T which is a synonymous change that usually accompanied 3 other mutations that include 241C>T, 14408C>T (P323L in RdRp) and 23403A>G (D614G in spike protein). The P323L was reported to increase mutation rate and D614G is associated with increased viral replication and currently most prevalent variant circulating all over the world. We identified multiple missense mutations in B-cell and T-cell predicted epitope regions and/or PCR target regions (including R203K and G204R that occurred in 86% of the isolates) that may impact immunogenicity and/or RT-PCR based diagnosis. Our analysis revealed 5 large deletion events in ORF7a and ORF8 gene products that may be associated with less severity of the disease and increased viral clearance. Our phylogeny analysis identified most of the isolates belonged to the Nextstrain clade 20B (86%) and GISAID clade GR (88%). Most of our isolates shared common ancestors either directly with European countries or jointly with middle eastern countries as well as Australia and India. Interestingly, the 19B clade (GISAID S clade) was unique to Chittagong, which was originally prevalent in China. This reveals possible multiple introductions of the virus in Bangladesh via different routes. Hence, more genome sequencing and analysis with related clinical data is needed to interpret functional significance and better predict the disease dynamics that may be helpful for policy makers to control the COVID-19 pandemic.