Investigating a Library of Flavonoids as Potential Inhibitors of a Cancer Therapeutic Target MEK2 Using in Silico Methods.

The second leading cause of death in the world is cancer. Mitogen-activated protein kinase (MAPK) and extracellular signal-regulated protein kinase (ERK) 1 and 2 (MEK1/2) stand out among the different anticancer therapeutic targets. Many MEK1/2 inhibitors are approved and widely used as anticancer drugs. The class of natural compounds known as flavonoids is well-known for their therapeutic potential. In this study, we focus on discovering novel inhibitors of MEK2 from flavonoids using virtual screening, molecular docking analyses, pharmacokinetic prediction, and molecular dynamics (MD) simulations. A library of drug-like flavonoids containing 1289 chemical compounds prepared in-house was screened against the MEK2 allosteric site using molecular docking. The ten highest-scoring compounds based on docking binding affinity (highest score: -11.3 kcal/mol) were selected for further analysis. Lipinski's rule of five was used to test their drug-likeness, followed by ADMET predictions to study their pharmacokinetic properties. The stability of the best-docked flavonoid complex with MEK2 was examined for a 150 ns MD simulation. The proposed flavonoids are suggested as potential inhibitors of MEK2 and drug candidates for cancer therapy.

Computational Design and Experimental Evaluation of MERS-CoV siRNAs in Selected Cell Lines.

Middle East respiratory syndrome coronavirus (MERS-CoV) is caused by a well-known coronavirus first identified in a hospitalized patient in the Kingdom of Saudi Arabia. MERS-CoV is a serious pathogen affecting both human and camel health globally, with camels being known carriers of viruses that spread to humans. In this work, MERS-CoV genomic sequences were retrieved and analyzed by multiple sequence alignment to design and predict siRNAs with online software. The siRNAs were designed from the orf1ab region of the virus genome because of its high sequence conservation and vital role in virus replication. The designed siRNAs were used for experimental evaluation in selected cell lines: Vero cells, HEK-293-T, and Huh-7. Virus inhibition was assessed according to the cycle threshold value during a quantitative real-time polymerase chain reaction. Out of 462 potential siRNAs, we filtered out 21 based on specific selection criteria without off-target effect. The selected siRNAs did not show any cellular toxicity in the tested cell lines at various concentrations. Based on our results, it was obvious that the combined use of siRNAs exhibited a reduction in MERS-CoV replication in the Vero, HEK-293-T, and Huh-7 cell lines, with the highest efficacy displayed in the Vero cells.

Bacillus Species as Direct-Fed Microbial Antibiotic Alternatives for Monogastric Production.

Antibiotic growth promoters have been utilized for long time at subtherapeutic levels as feed supplements in monogastric animal rations. Because of their side-effects such as antibiotic resistance, reduction of beneficial bacteria in the gut, and dysbiosis, it is necessary to look for non-therapeutic alternatives. Probiotics play an important role as the key substitutes to antibacterial agents due to their many beneficial effects on the monogastric animal host. For instance, enhancement of the gut microbiota balance can contribute to improvement of feed utilization efficiency, nutrients absorption, growth rate, and economic profitability of livestock. Probiotics are defined as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host." They are available in diverse forms for use as feed supplements. Their utilization as feed additives assists in good digestion of feed ingredients and hence, making the nutrients available for promoting growth. Immunity can also be enhanced by supplementing probiotics to monogastrics diets. Moreover, probiotics can help in improving major meat quality traits and countering a variety of monogastric animals infectious diseases. A proper selection of the probiotic strains is required in order to confer optimal beneficial effects. The present review focuses on the general functional, safety, and technological screening criteria for selection of ideal Bacillus probiotics as feed supplements as well as their mechanism of action and beneficial effects on monogastric animals for improving production performance and health status.

Future Prospects, Approaches, and the Government's Role in the Development of a Hepatitis C Virus Vaccine.

Developing a safe and effective vaccine against the hepatitis C virus (HCV) remains a top priority for global health. Despite recent advances in antiviral therapies, the high cost and limited accessibility of these treatments impede their widespread application, particularly in resource-limited settings. Therefore, the development of the HCV vaccine remains a necessity. This review article analyzes the current technologies, future prospects, strategies, HCV genomic targets, and the governmental role in HCV vaccine development. We discuss the current epidemiological landscape of HCV infection and the potential of HCV structural and non-structural protein antigens as vaccine targets. In addition, the involvement of government agencies and policymakers in supporting and facilitating the development of HCV vaccines is emphasized. We explore how vaccine development regulatory channels and frameworks affect research goals, funding, and public health policy. The significance of international and public-private partnerships in accelerating the development of an HCV vaccine is examined. Finally, the future directions for developing an HCV vaccine are discussed. In conclusion, the review highlights the urgent need for a preventive vaccine to fight the global HCV disease and the significance of collaborative efforts between scientists, politicians, and public health organizations to reach this important public health goal.

Gene Expression Profiling of Early Acute Febrile Stage of Dengue Infection and Its Comparative Analysis With Streptococcus pneumoniae Infection.

Infectious diseases are the disorders caused by organisms such as bacteria, viruses, fungi, or parasites. Although many of them are permentantly hazardous, a number of them live in and on our bodies and they are normally harmless or even helpful. Under certain circumstances, some organisms may cause diseases and these infectious diseases may be passed directly from person to person or via intermediate vectors including insects and other animals. Dengue virus and Streptococcus pneumoniae are the critical and common sources of infectious diseases. So, it is critical to understand the gene expression profiling and their inferred functions in comparison to the normal and virus infected conditions. Here, we have analyzed the gene expression profiling for dengue hemorrhagic fever, dengue fever, and normal human dataset. Similar to it, streptococcus pneumoniae infectious data were analyzed and both the outcomes were compared. Our study leads to the conclusion that the dengue hemorrhagic fever arises in result to potential change in the gene expression pattern, and the inferred functions obviously belong to the immune system, but also there are some additional potential pathways which are critical signaling pathways. In the case of pneumoniae infection, 19 pathways were enriched, almost all these pathways are associated with the immune system and 17 of the enriched pathways were common with dengue infection except platelet activation and antigen processing and presentation. In terms of the comparative study between dengue virus and Streptococcus pneumoniae infection, we conclude that cell adhesion molecules (CAMs), MAPK signaling pathway, natural killer cell mediated cytotoxicity, regulation of actin cytoskeleton, and cytokine-cytokine receptor interaction are commonly enriched in all the three cases of dengue infection and Streptococcus pneumoniae infection, focal adhesion was enriched between classical dengue fever - dengue hemorrhagic fever, dengue hemorrhagic fever-normal samples, and SP, and antigen processing and presentation and Leukocyte transendothelial migration were enriched in classical dengue fever -normal samples, dengue hemorrhagic fever-normal samples, and Streptococcus pneumoniae infection.

A Reliable Indirect ELISA Protocol for Detection of Human Antibodies Directed to SARS-CoV-2 NP Protein.

A few months ago, the availability of a reliable and cost-effective testing capacity for COVID-19 was a concern for many countries. With the emergence and circulation of new SARS-CoV-2 variants, another layer of challenge can be added for COVID-19 testing at both molecular and serological levels. This is particularly important for the available tests principally designed to target the S gene/protein where multiple mutations have been reported. Herein, the SARS-CoV-2 NP recombinant protein was utilized to develop a simple and reliable COVID-19 NP human IgG ELISA. The optimized protocol was validated against a micro-neutralization (MN) assay, in-house S-based ELISA, and commercial chemiluminescence immunoassay (CLIA). The developed assay provides 100% sensitivity, 98.9% specificity, 98.9% agreement, and high overall accuracy with an area under curve equal to 0.9998 ± 0.0002 with a 95% confidence interval of 0.99 to 1.00. The optical density values of positive samples significantly correlated with their corresponding MN titers. The assay specifically detects IgG antibodies to the SARS-CoV-2 NP protein and does not cross-detect IgG to the viral S protein. Moreover, it does not cross-react with antibodies related to other coronaviruses (e.g., the Middle East respiratory syndrome coronavirus or human coronavirus HKU1). The availability of this reliable COVID-19 NP IgG ELISA protocol is highly valuable for its diagnostic and epidemiological applications.

Immunotherapeutic Efficacy of IgY Antibodies Targeting the Full-Length Spike Protein in an Animal Model of Middle East Respiratory Syndrome Coronavirus Infection.

Identified in 2012, the Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe and often fatal acute respiratory illness in humans. No approved prophylactic or therapeutic interventions are currently available. In this study, we developed chicken egg yolk antibodies (IgY Abs) specific to the MERS-CoV spike (S) protein and evaluated their neutralizing efficiency against MERS-CoV infection. S-specific IgY Abs were produced by injecting chickens with the purified recombinant S protein of MERS-CoV at a high titer (4.4 mg/mL per egg yolk) at week 7 post immunization. Western blotting and immune-dot blot assays demonstrated specific binding to the MERS-CoV S protein. In vitro neutralization of the generated IgY Abs against MERS-CoV was evaluated and showed a 50% neutralizing concentration of 51.42 µg/mL. In vivo testing using a human-transgenic mouse model showed a reduction of viral antigen positive cells in treated mice, compared to the adjuvant-only controls. Moreover, the lung cells of the treated mice showed significantly reduced inflammation, compared to the controls. Our results show efficient neutralization of MERS-CoV infection both in vitro and in vivo using S-specific IgY Abs. Clinical trials are needed to evaluate the efficiency of the IgY Abs in camels and humans.

Evaluation of a Pseudovirus Neutralization Assay for SARS-CoV-2 and Correlation with Live Virus-Based Micro Neutralization Assay.

The unusual cases of pneumonia outbreak were reported from Wuhan city in late December 2019. Serological testing provides a powerful tool for the identification of prior infection and for epidemiological studies. Pseudotype virus neutralization assays are widely used for many viruses and applications in the fields of serology. The accuracy of pseudotype neutralizing assay allows for its use in low biosafety lab and provides a safe and effective alternative to the use of wild-type viruses. In this study, we evaluated the performance of this assay compared to the standard microneutralization assay as a reference. The lentiviral pseudotype particles were generated harboring the Spike gene of SARS-CoV-2. The generated pseudotype particles assay was used to evaluate the activity of neutralizing antibodies in 300 human serum samples from a COVID-19 sero-epidemiological study. Testing of these samples resulted in 55 positive samples and 245 negative samples by pseudotype viral particles assay while microneutralization assay resulted in 64 positive and 236 negative by MN assay. Compared to the MN, the pseudotyped viral particles assay showed a sensitivity of 85.94% and a specificity of 100%. Based on the data generated from this study, the pseudotype-based neutralization assay showed a reliable performance for the detection of neutralizing antibodies against SARS-CoV-2 and can be used safely and efficiently as a diagnostic tool in a biosafety level 2 laboratory.

Seroprevalence of neutralizing antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among healthcare workers in Makkah, Saudi Arabia.

OBJECTIVE: The new coronavirus disease 2019 (COVID-19) is a major health problem worldwide. The surveillance of seropositive individuals serves as an indicator to the extent of infection spread and provides an estimation of herd immunity status among population. Reports from different countries investigated this issue among healthcare workers (HCWs) who are "at risk" and "sources of risk" for COVID-19. This study aims to investigate the seroprevalence of COVID-19 among HCWs in one of the COVID-19 referral centers in Makkah, Saudi Arabia using three different serological methods. METHODS: In-house developed enzyme-linked immunoassay (ELISA), commercially available electro-chemiluminescence immunoassay (ECLIA), and microneutralization (MN) assay were utilized to determine the seroprevalence rate among the study population. 204 HCWs participated in the study. Both physicians and nurses working in the COVID-19 and non COVID-19 areas were included. Twelve out of 204 were confirmed cases of COVID-19 with variable disease severity. Samples from recovered HCWs were collected four weeks post diagnosis. RESULTS: The overall seroprevalence rate was 6.3% (13 out of 204) using the in-house ELISA and MN assay and it was 5.8% (12 out of 204) using the commercial ECLIA. Among HCWs undiagnosed with COVID-19, the seroprevalence was 2% (4 out 192). Notably, neutralizing antibodies were not detected in 3 (25%) out 12 confirmed cases of COVID-19. CONCLUSIONS: Our study, similar to the recent national multi-center study, showed a low seroprevalence of SARS-Cov-2 antibodies among HCWs. Concordance of results between the commercial electro-chemiluminescence immunoassay (ECLIA), in-house ELISA and MN assay was observed. The in-house ELISA is a promising tool for the serological diagnosis of SARS-CoV-2 infection. However, seroprevalence studies may underestimate the extent of COVID-19 infection as some cases with mild disease did not have detectable antibody responses.

In Silico Prediction and Designing of Potential siRNAs to be used as Antivirals Against SARS-CoV-2.

BACKGROUND: The unusual pneumonia outbreak that originated in the city of Wuhan, China in December 2019 was found to be caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), or COVID-19. METHODS: In this work, we have performed an in silico design and prediction of potential siRNAs based on genetic diversity and recombination patterns, targeting various genes of SARS-CoV-2 for antiviral therapeutics. We performed extensive sequence analysis to analyze the genetic diversity and phylogenetic relationships, and to identify the possible source of virus reservoirs and recombination patterns, and the evolution of the virus as well as we designed the siRNAs which can be used as antivirals against SARS-CoV-2. RESULTS: The sequence analysis and phylogenetic relationships indicated high sequence identity and closed clusters with many types of coronavirus. In our analysis, the full-genome of SARS-CoV-2 showed the highest sequence (nucleotide) identity with SARS-bat-ZC45 (87.7%). The overall sequence identity ranged from 74.3% to 87.7% with selected SARS viruses. The recombination analysis indicated the bat SARS virus is a potential recombinant and serves as a major and minor parent. We have predicted 442 siRNAs and finally selected only 19 functional, and potential siRNAs. CONCLUSION: The siRNAs were predicted and selected based on their greater potency and specificity. The predicted siRNAs need to be validated experimentally for their effective binding and antiviral activity.

Lack of Antibodies to SARS-CoV-2 among Blood Donors during COVID-19 Lockdown: A Study from Saudi Arabia.

In response to the coronavirus disease 2019 (COVID-19), Saudi Arabia have imposed timely restrictions to minimize the infection spread, lower the risk for vulnerable groups, and reduce the pressure on healthcare services. The effectiveness of these measures has not been assessed comprehensively and, thereby, remains uncertain. Besides monitoring the number of COVID-19 cases diagnosed by molecular assays, the seroprevalence can serve as an indicator for the incidence rate among the general population. This study aimed to evaluate seroprevalence status of all healthy blood donors who attended one of the main largest hospital located in the western region of Saudi Arabia from 1 January to 31 May 2020. The study period covered two months prior to reporting the first COVID-19 case in the country on 2 March 2020. Importantly, it covered the period when "lock-down type" measures have been enforced. Samples were subjected to in-house enzyme-linked immunosorbent assay (ELISA), chemiluminescence immunoassay (CLIA), and microneutralization (MN). The sero statuses of all samples were confirmed negative, demonstrating the lack of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among blood donors during COVID-19 lockdown period. This study supports the hypothesis that COVID-19 restrictions have potential for limiting the extent of the infection.

Natural Products Homoharringtonine and Emetine Alkaloids as SARS-CoV-2 Treatment Options.

BACKGROUND: Viruses are known as the major causative agents for infectious diseases globally. The coronaviruses are one of the serious pathogens to cause serious diseases in humans. Recently identified SARSCoV- 2 from Wuhan City, China, has emerged as a serious threat to human health and caused a global pandemic. Bats have been confirmed as a primary source of infection. The vaccination of the human population and animals serving as a potential reservoir is a straightforward strategy to control the transmission of any pathogen to humans. Natural products from many herbal plants are well known to have novel antiviral properties and evaluated against various viral diseases. There are many alkaloids that have shown to be effective against coronaviruses. METHODS: Recently, the antiviral efficacy of natural alkaloids known as Homoharringtonine (HTT) and Emetine has been evaluated and provided promising results against coronaviruses, including SARS-CoVs. These alkaloids may be very useful and can be used as antivirals against SARS-CoV-2 because they have already been reported to inhibit the replication of SASRS-CoV and other viruses in cell lines. CONCLUSION: This review specifically focuses on the recent findings of these alkaloids against coronaviruses and possible treatment options for SARS-CoV-2. It is expected that natural products as alkaloids from herbal plants could be considered as novel and valuable candidates for the new antiviral drugs against SARS-CoV-2.

Development and Optimization of In-house ELISA for Detection of Human IgG Antibody to SARS-CoV-2 Full Length Spike Protein.

The ongoing coronavirus disease 19 (COVID-19) pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), poses a threat to human health. Despite this, many affected countries are now in the process of gradual lifting of COVID-19 restrictions that were initially implemented in response to the pandemic. The success of the so-called "exit strategy" requires continued surveillance of virus circulation in the community and evaluation of the prevalence of protective immunity among population. Serology tests are valuable tools for these purposes. Herein, SARS-CoV-2 full-length spike (S) recombinant protein was utilized to develop and optimize an indirect enzyme-linked immunoassay (ELISA) that enables a reliable detection of virus-specific IgG antibody in human sera. Importantly, the performance of this assay was evaluated utilizing micro-neutralization (MN) assay as a reference test. Our developed ELISA offers 100% sensitivity, 98.4% specificity, 98.8% agreement, and high overall accuracy. Moreover, the optical density (OD) values of positive samples significantly correlated with their MN titers. The assay specifically detects human IgG antibodies directed against SARS-CoV-2, but not those to Middle East respiratory syndrome coronavirus (MERS-CoV) or human coronavirus HKU1 (HCoV-HKU1). The availability of this in-house ELISA protocol would be valuable for various diagnostic and epidemiological applications.

The Emergence of Human Pathogenic Coronaviruses: Lectins as Antivirals for SARS-CoV-2.

BACKGROUND: Human coronaviruses (HCoV) are common viruses and known to be associated with respiratory diseases, including pneumonia. Currently, seven human coronaviruses have been identified and known to cause upper and lower respiratory infections as well as nosocomial viral infections in humans. The bats, palm civets, and camels are identified as the reservoir of human coronaviruses. In 2002-2003, the emergence of SARS-CoV resulted in an outbreak and led towards the more awareness and importance of scientific research and medical urgency. METHODS: The recently identified SARS-CoV-2 was identified from the seafood market of the city Wuhan, China, in December 2019 and caused a global pandemic. This virus has now spread to more than 213 countries. This is the third highly pathogenic human coronavirus after SARS and MERS-CoV. The coronaviruses have RNA as genetic material and are known to have frequent recombination and mutations in their genome, which lead to the emergence and re-emergence of new virus strains and isolates with novel properties and extended hosts. The genetic mutations and suitable environmental conditions result in the emergence and re-emergence of pathogenic coronaviruses and cause a serious issue to human health and the economy globally. Lectins are the ubiquitous group of proteins that bind to glycosylated molecules. CONCLUSION: The plant lectins are known to have significant antiviral activities against coronaviruses. Additionally, the plant lectins can be used as potential therapeutics against bacteria, fungus, yeast, and protozoa. In this review, we have discussed the current status of human pathogenic coronavirus emergence and the use of plant lectins as antivirals against SARS-CoV-2.

Genetic diversity of MERS-CoV spike protein gene in Saudi Arabia.

BACKGROUND: Middle East respiratory syndrome coronavirus (MERS-CoV) was primarily detected in 2012 and still causing disease in human and camel. Camel and bats have been identified as a potential source of virus for disease spread to human. Although, significant information related to MERS-CoV disease, spread, infection, epidemiology, clinical features have been published, A little information is available on the sequence diversity of Spike protein gene. The Spike protein gene plays a significant role in virus attachment to host cells. Recently, the information about recombinant MERS-CoV has been published. So, this work was designed to identify the emergence of any another recombinant virus in Jeddah, Saudi Arabia. METHODS: In this study samples were collected from both human and camels and the Spike protein gene was amplified and sequenced. The nucleotide and amino acid sequences of MERS-CoV Spike protein gene were used to analyze the recombination, genetic diversity and phylogenetic relationship with selected sequences from Saudi Arabia. RESULTS: The nucleotide sequence identity ranged from 65.7% to 99.8% among all the samples collected from human and camels from various locations in the Kingdom. The lowest similarity (65.7%) was observed in samples from Madinah and Dammam. The phylogenetic relationship formed different clusters with multiple isolates from various locations. The sample collected from human in Jeddah hospital formed a closed cluster with human samples collected from Buraydah, while camel sample formed a closed cluster with Hufuf isolates. The phylogenetic tree by using Aminoacid sequences formed closed cluster with Dammam, Makkah and Duba isolates. The amino acid sequences variations were observed in 28/35 samples and two unique amino acid sequences variations were observed in all samples analyzed while total 19 nucleotides sequences variations were observed in the Spike protein gene. The minor recombination events were identified in eight different sequences at various hotspots in both human and camel samples using recombination detection programme. CONCLUSION: The generated information from this study is very valuable and it will be used to design and develop therapeutic compounds and vaccine to control the MERS-CoV disease spread in not only in the Kingdom but also globally.

A Highly Immunogenic, Protective, and Safe Adenovirus-Based Vaccine Expressing Middle East Respiratory Syndrome Coronavirus S1-CD40L Fusion Protein in a Transgenic Human Dipeptidyl Peptidase 4 Mouse Model.

BACKGROUND: Infection control measures have played a major role in limiting human/camel-to-human transmission of Middle East respiratory syndrome coronavirus (MERS-CoV); however, development of effective and safe human or camel vaccines is warranted. METHODS: We extended and optimized our previous recombinant adenovirus 5 (rAd5)-based vaccine platform characterized by in vivo amplified and CD40-mediated specific responses to generate MERS-CoV S1 subunit-based vaccine. We generated rAd5 constructs expressing CD40-targeted S1 fusion protein (rAd5-S1/F/CD40L), untargeted S1 (rAd5-S1), and Green Fluorescent Protein (rAd5-GFP), and evaluated their efficacy and safety in human dipeptidyl peptidase 4 transgenic (hDPP4 Tg+) mice. RESULTS: Immunization of hDPP4 Tg+ mice with a single dose of rAd5-S1/F/CD40L elicited as robust and significant specific immunoglobulin G and neutralizing antibodies as those induced with 2 doses of rAd5-S1. After MERS-CoV challenge, both vaccines conferred complete protection against morbidity and mortality, as evidenced by significantly undetectable/reduced pulmonary viral loads compared to the control group. However, rAd5-S1- but not rAd5-S1/F/CD40L-immunized mice exhibited marked pulmonary perivascular hemorrhage post-MERS-CoV challenge despite the observed protection. CONCLUSIONS: Incorporation of CD40L into rAd5-based MERS-CoV S1 vaccine targeting molecule and molecular adjuvants not only enhances immunogenicity and efficacy but also prevents inadvertent pulmonary pathology after viral challenge, thereby offering a promising strategy to enhance safety and potency of vaccines.

Boosting Alfalfa (Medicago sativa L.) Production With Rhizobacteria From Various Plants in Saudi Arabia.

This study focused on rhizobacteria to promote sustainable crop production in arid regions of Saudi Arabia. The study isolated 17 tightly root-adhering rhizobacteria from various plants at Hada Al Sham in Saudi Arabia. All 17 rhizobacterial isolates were confirmed as plant growth promoting rhizobacteria by classical biochemical tests. Using 16S rDNA gene sequence analyses, the strains were identified as Bacillus, Acinetobacter and Enterobacter. Subsequently, the strains were assessed for their ability to improve the physiology, nutrient uptake, growth, and yield of alfalfa plants grown under desert agriculture conditions. The field trials were conducted in a randomized complete block design. Inoculation of alfalfa with any of these 17 strains improved the relative water content; chlorophyll a; chlorophyll b; carotenoid contents; nitrogen (N), phosphorus, and potassium contents; plant height; leaf-to-stem ratio; and fresh and dry weight. Acinetobacter pittii JD-14 was most effective to increase fresh and dry weight of alfalfa by 41 and 34%, respectively, when compared to non-inoculated control plants. Nevertheless, all strains enhanced crop traits when compared to controls plants, indicating that these desert rhizobacterial strains could be used to develop an eco-friendly biofertilizer for alfalfa and possibly other crop plants to enhance sustainable production in arid regions.

Diversity of dengue virus-3 genotype III in Jeddah, Saudi Arabia.

BACKGROUND: Dengue is the most important arboviral disease in tropical and subtropical countries. Dispersal of the vector and an increase in migratory flow between countries have led to large epidemics and severe clinical outcomes. Over the past 20 years, dengue epidemics have become more wide-spread and frequent. Previous studies have shown that dengue is endemic in Jeddah, Makkah and Al-Madinah in western Saudi Arabia as well as in Jazan region in the southern part of the country. The four serotypes of dengue virus (DENV) have been reported from western Saudi Arabia. It has been suggested that pilgrims could play a significant and unique role in DENV-1 and DENV-2 introduction into Saudi Arabia, especially in the cities of Jeddah, Makkah and Al-Madinah during Hajj and Umrah seasons. However, only limited data on DENV-3 in Saudi Arabia are available. METHODS: All available DENV-3 sequences published and unpublished from Saudi Arabia and other countries were retrieved from Genbank and gene sequence repository and phylogenetically analyzed to examine the diversity of DENV-3 into the city of Jeddah. RESULTS: Based on the analysis of the envelope gene and non-structural 1 (E/NS1) junction sequences, we show that there were at least four independent introductions of DENV-3, all from genotype III into Jeddah. The first introduction was most probably before 1997 as Saudi virus isolates from 1997 formed a cluster without any close relationship to other globally circulating isolates, suggesting their local circulation from previous introduction events. Two introductions were most probably in 2004 with isolates closely-related to isolates from Africa and India (Asia), in addition to another introduction in 2014 with isolates clustering with those from Singapore (Asia). CONCLUSIONS: Our data shows that only genotype III isolates of DENV-3 are circulating in Jeddah and highlights the potential role of pilgrims in DENV-3 importation into western Saudi Arabia and subsequent exportation to their home countries during Hajj and Umrah seasons. Therefore, it is highly recommended to establish DENV sentinel surveillance programs targeting clinical cases and the mosquito vector in the country to implement effective control measures and to minimize the burden of the disease in the kingdom.

Multiple Introductions of Dengue 2 Virus Strains into Saudi Arabia from 1992 to 2014.

INTRODUCTION: Dengue is a significant arboviral infection that represents a major public health concern worldwide. The infection is endemic in most parts of South East Asia, sub-Saharan Africa, and Latin America. Among the four dengue virus (DENV) serotypes, DENV-2 has been reported to be the predominant serotype in Saudi Arabia since 1992. However, virological and epidemiological data of DENV-2 from Saudi Arabia are severely deficient and require further investigations. METHODS: Full genome sequencing of a recent DENV-2 isolate and phylogenetic analysis of all available DENV-2 sequences from Saudi Arabia. RESULTS: Based on full genome and envelope (E) gene sequence, we show that a recent isolate (DENV-2-Jeddah-2014) belongs to the Indian subcontinent lineage of the Cosmopolitan genotype with close similarity to recent strains from Pakistan. Interestingly, the E gene sequence of DENV-2-Jeddah-2014 isolate was slightly divergent from those previously identified in Saudi Arabia between 1992 and 2004 with three to nine amino acid (aa) substitutions. While our data show that the Cosmopolitan genotype is still circulating in Saudi Arabia, they highlight four distinct genetic groups suggesting at least four independent introductions into the Kingdom. CONCLUSIONS: The close clustering of DENV-2 isolates reported from Saudi Arabia between 1992 and 2014 with strains from countries providing the highest numbers of pilgrims attending either Hajj or Umrah pilgrimages (Indonesia, Pakistan, India) clearly suggests a role for pilgrims or expatriates coming from DENV endemic countries in DENV-2 importation into Saudi Arabia. Accordingly, continuous monitoring of the circulation of DENVs in Saudi Arabia must be implemented to undertake effective control and management strategies in the Kingdom. Screening of the pilgrims coming to perform Hajj and Umrah might help prevent the introduction of new DENV strains, which is expected to increase the burden of the disease not only in Saudi Arabia but also in other countries.

Tackling dengue fever: Current status and challenges.

According to recent statistics, 96 million apparent dengue infections were estimated worldwide in 2010. This figure is by far greater than the WHO prediction which indicates the rapid spread of this disease posing a growing threat to the economy and a major challenge to clinicians and health care services across the globe particularly in the affected areas.This article aims at bringing to light the current epidemiological and clinical status of the dengue fever. The relationship between genetic mutations, single nucleotide polymorphism (SNP) and the pathophysiology of disease progression will be put into perspective. It will also highlight the recent advances in dengue vaccine development.Thus far, a significant progress has been made in unraveling the risk factors and understanding the molecular pathogenesis associated with the disease. However, further insights in molecular features of the disease and the development of animal models will enormously help improving the therapeutic interventions and potentially contribute to finding new preventive measures for population at risk.