Persistence of IgG and neutralizing antibodies in Crimean-Congo hemorrhagic fever survivors.

The World Health Organization classified Crimean-Congo hemorrhagic fever (CCHF) as a high-priority infectious disease and emphasized the performance of research studies and product development against it. Little information is available about the immune response due to natural CCHF virus (CCHFV) infection in humans. Here, we investigated the persistence of IgG and neutralizing antibodies in serum samples collected from 61 Iranian CCHF survivors with various time points after recovery (<12, 12-60, and >60 months after disease). The ELISA results showed IgG seropositivity in all samples while a pseudotyped based neutralization assay findings revealed the presence of neutralizing antibody in 29 samples (46.77%). For both IgG and neutralizing antibodies, a decreasing trend of titer was observed with the increase in the time after recovery. Not only the mean titer of IgG (772.80 U/mL) was higher than mean neutralizing antibody (25.64) but also the IgG persistence was longer. In conclusion, our findings provide valuable information about the long-term persistence of humoral immune response in CCHF survivors indicating that IgG antibody can be detected at least 8 years after recovery and low titers of neutralizing antibody can be detected in CCHF survivors.

Structure-based evaluation of the envelope domain III-nonstructural protein 1 (EDIII-NS1) fusion as a dengue virus vaccine candidate.

The lack of effective medicines or vaccines, combined with climate change and other environmental factors, annually subjects a significant proportion of the world's inhabitants to the risk of dengue virus (DENV) infection. These conditions increase the likelihood of exposure to mosquito-borne diseases such as dengue fever. Hence, many research approaches tend to develop efficient vaccine candidates against the dengue virus. Therefore, we used immunoinformatics and bioinformatics to design a construction for developing a candidate vaccine against dengue virus serotypes. In this study, the in silico structure, containing the non-structural protein 1 region (NS1) (consensus and epitope), the envelope domain III protein (EDIII) as the structural part of the virus construction, and the bc-loop of envelope domain II (EDII) as the neutralizing and protected epitope, were employed. We utilized in silico tools to enhance the immunogenicity and effectiveness of dengue virus vaccine candidates. Evaluations included refining and validating physicochemical characteristics, B and T-cell epitopes, homology modeling, and the three-dimensional structure to assess the designed vaccine's quality. In silico results for tertiary structure prediction and validation revealed high-quality modeling for all vaccine constructs. Additionally, the instructed model demonstrated stability throughout molecular dynamics simulation. The results of the immune simulation suggested that the titers of IgG and IgM could be raised to desirable values following injection into in vivo models. It can be concluded that the designed construct effectively induce humoral and cellular immunity and can be proposed as effective vaccine candidate against four dengue serotypes.Communicated by Ramaswamy H. Sarma.

Clinical and genomic evaluations of a persistent fatal SARS-CoV-2 infection in a goods syndrome patient: a case report.

The coronavirus disease of 2019 (COVID-19) resulted from an infection by severe acute respiratory syndrome coronavirus 2 (SARS­CoV­2) which is the main cause of acute respiratory distress syndrome (ARDS) in global population from 2019 on. It may contribute to higher rate of death among the patients with immunodeficiency based on recent reports. In addition, Good syndrome (GS) as a result of thymoma removal might cause in some long-lasting microbial infections. We described clinical aspects and viral mutations on a case of GS suffering from COVID-19. A 46-year-old man with fever, common respiratory disease symptoms and positive COVID-19 polymerase chain reaction (PCR) test, with the history of thymoma removal surgery was admitted to Masih Daneshvari Hospital, Tehran, Iran. Lung radiographs and oxygen saturation measurement disclosed considerable implication resulted in application of several anti-microbial medication. The delta variant (B.1.617.2 (21 J Clade)) was the strain isolated from the patient by sequencing methods done by the COVID-19 National Reference Laboratory (CNRL), Pasteur Institute of Iran, while the dominant strain circulated mostly among population was Omicron (B.1.1.529) at the time of sampling. Unfortunately, the patient had passed away a month later by sudden respiratory failure progressed in refractory septic shock. Despite the fact that opportunistic infections may lead the GS patients to a major health problematic condition, unusual persistent of infections such as non-dominant variant of SARS-Cov-2 could be observed through the disease timeline. Therefore, a fully screening of thymoma plus intra-host evolution monitoring of SARS-CoV-2 is highly recommended in immunocompromised patients.

Lessons from COVID-19 Pandemic: A Successful Policy and Practice by Pasteur Institute of Iran.

The present study aims to provide an insight to the comprehensive efforts of Pasteur Institute of Iran (PII) regarding COVID-19 management, research, achievements, and vaccine production, though there are many challenges. The relevant literature review was investigated through national and international database and also reports from the related research departments. Six strategies were taken by PII to manage the pandemic of COVID-19. While this pandemic has been hopefully controlled, SARS-CoV-2 could still be a potential threat. Therefore, COVID-19 data management and updated studies, as well as long-term safety and efficacy of the SARS-CoV-2 vaccines are still on the agenda.

Role of Laboratory in Emerging Infectious Disease Control in Iran, Pasteur Institute of Iran, and national laboratory network.

Strengthening surveillance systems is a key aspect of outbreak response and was particularly important during the COVID-19 pandemic. Respiratory pathogens spread rapidly, and laboratory capacity is key to monitoring the spread. Prior to the pandemic, Iran had established a rapid response team and laboratory network to provide identification, monitoring, and detection of emerging infectious diseases, but did not have the laboratory capacity to respond to COVID-19. Following the announcement of the COVID-19 pandemic, the rapid response team diverted all attention to supporting COVID-19 surveillance. Iran built on the existing national laboratory infrastructure to incorporate SARS-CoV-2 surveillance into the response network. Based on existing international protocols, in-house molecular diagnosis capacity was operationalized, and commercial controls and assays were acquired and validated to national standards. The first COVID-19 laboratory was operational by January 25, less than 4 weeks before the initial detection of SARS-CoV-2 was announced. Assays and support were expanded and rolled out to form the COVID-19 National Laboratory Network, which consists of 560 multi-sectoral laboratories covering all provinces of Iran. The national laboratory network supports a wide range of operational capacities, including assay validation and protocol development, quality assurance, respiratory pathogen diagnosis and surveillance, and variant identification and assessment using multiple sequencing platforms. This network has supported the testing of over 55 million samples over the past 36 months using RT-qPCR and has sequenced approximately 2200 samples across the country, contributing the data to international databases, including GISAID.

Epidemiological surveillance of respiratory viral infections in SARS-CoV-2-negative samples during COVID-19 pandemic in Iran.

BACKGROUND: To improve the patient care, public health surveillance, and infection control, it is crucial to identify the presence and frequency of the common respiratory infections in individuals with COVID-19 symptoms but tested negative for SARS-CoV-2. This study aimed to shed light on this during the COVID-19 pandemic in Iran. METHODS: In this cross-sectional study, a total of 1,002 patients with acute respiratory infection who had negative SARS-CoV-2 test results and referred to Valfajr Health Center, the National Collaborating Laboratory of Influenza and COVID-19 National Reference Laboratory at Pasteur Institute of Iran were recruited between January 2020 and January 2022. Nasopharyngeal and oropharyngeal swab samples were collected to detect 17 common respiratory viruses via TaqMan one-step real-time multiplex PCR. Demographic and clinical data of the participants were obtained from their electronic medical records. RESULTS: In total, 218 samples (21.8%) were tested positive for at least one respiratory virus infection. Most of the common investigated respiratory viruses belonged to the years 2020 and 2022. The number of investigated patients in 2021 was few, which highlights the impact of health measures following the COVID-19 pandemic in Iran. Influenza A was the most common virus (5.8%), while adenovirus had the lowest prevalence (0.1%). Although the rate of respiratory virus infection was higher in men (24%) compared to women (19.3%), this difference was not statistically significant (P = 0.069). The prevalence of respiratory viruses had an inverse association with increasing age, with the highest rate (55.6%) observed in the age group below 2 years and the lowest rate (12.7%) in those above 65 years. CONCLUSION: Our findings underscore the significance of adopting a comprehensive approach to respiratory infections detection and management. These results can be employed for the development of syndromic surveillance systems and implementation of the effective infection control measures. Furthermore, the results contribute to better understanding of the dynamics of respiratory viruses, both during pandemic periods and in non-pandemic contexts.

Immunogenicity and safety of heterologous boost immunization with PastoCovac Plus against COVID-19 in ChAdOx1-S or BBIBP-CorV primed individuals.

BACKGROUND: This study aimed at evaluation and comparison of PastoCovac Plus protein-subunit vaccine in parallel with ChAdOx1-S (AstraZeneca) and BBIBP-CorV (Sinopharm) in primarily vaccinated volunteers with two doses of ChAdOx1-S or BBIBP-CorV. MATERIALS AND METHODS: 194 volunteers enrolled the study who were previously primed with 2 doses of ChAdOx1-S or BBIBP-CorV vaccines. They were divided into two heterologous regimens receiving a third dose of PastoCovac Plus, and two parallel homologous groups receiving the third dose of BBIBP-CorV or ChAdOx1-S. Serum samples were obtained just before and 4 weeks after booster dose. Anti-spike IgG and neutralizing antibodies were quantified and the conventional live-virus neutralization titer, (cVNT50) assay was done against Omicron BA.5 variant. Moreover, the adverse events data were recorded after receiving booster doses. RESULTS: ChAdOx1-S/PastoCovac Plus group reached 73.0 units increase in anti-Spike IgG rise compared to the ChAdOx1-S/ ChAdOx1-S (P: 0.016). No significant difference was observed between the two groups regarding neutralizing antibody rise (P: 0.256), indicating equivalency of both booster types. Adjusting for baseline titers, the BBIBP-CorV/PastoCovac Plus group showed 135.2 units increase (P<0.0001) in anti-Spike IgG, and 3.1 (P: 0.008) unit increase in mean rise of neutralizing antibodies compared to the homologous group. Adjustment for COVID-19 history, age, underlying diseases, and baseline antibody titers increased the odds of anti-Spike IgG fourfold rise both in the ChAdOx1-S (OR: 1.9; P: 0.199) and BBIBP CorV (OR: 37.3; P< 0.0001) heterologous groups compared to their corresponding homologous arms. The odds of neutralizing antibody fourfold rise, after adjustment for the same variables, was 2.4 (P: 0.610) for the ChAdOx1-S heterologous group and 5.4 (P: 0.286) for the BBIBP CorV heterologous groups compared to their corresponding homologous groups. All the booster types had the potency to neutralize BA.5 variant with no significant difference. The highest rate of adverse event incidence was recorded for ChAdOx1-S homologous group. CONCLUSIONS: PastoCovac Plus booster application in primed individuals with BBIBP-CorV or ChAdOx1-S successfully increased specific antibodies' levels without any serious adverse events. This vaccine could be administrated in the heterologous regimen to effectively boost humoral immune responses.

Comparison of a Multiplex Real-Time PCR Technique with Oxford Nanopore Technologies Next-Generation Sequencing for Identification of SARS-CoV-2 Variants of Concern.

INTRODUCTION: The rapid emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and their potential to endangering the global health has increased the demand for a fast-tracking method in comparison to the next-generation sequencing (NGS) as a gold standard assay, particularly in developing countries. This study was designed to evaluate the performance of a commercial multiplex real-time PCR technique (GA SARS-CoV-2 OneStep RT-PCR Kit, Iran) for identification of SARS-CoV-2 variants of concern (VOCs) compared to the Oxford Nanopore NGS assay. METHODS: A total of 238 SARS-CoV-2-positive respiratory samples from different waves of COVID-19 in Iran were randomly selected in this study. To determine the SARS-CoV-2 VOC, the samples were analyzed via the commercial triple target assay, GA SARS-CoV-2 OneStep RT-PCR Kit, and NGS as well. RESULTS: The results revealed good concordance between GA SARS-CoV-2 OneStep RT-PCR Kit and NGS for identification of SARS-CoV-2 VOCs. GA SARS-CoV-2 OneStep RT-PCR Kit identified Wuhan, Alpha, and Delta variants with 100% relative sensitivity and specificity. Regarding Omicron subvariants of BA.1, BA.2, and BA.4/5, the relative sensitivity of 100%, 100%, and 81.5% and the relative specificity of 95.3%, 93.5%, and 100% were observed. CONCLUSION: Overall, GA SARS-CoV-2 OneStep RT-PCR Kit can be used as a rapid and cost-effective alternative to NGS for identification of SARS-CoV-2 VOCs.

Metagenomics Characterization of Ixodes ricinus Intestinal Microbiota as Major Vector of Tick-Borne Diseases in Domestic Animals.

Background: Understanding the microbiota of disease vectors can help for developing new strategies to prevent the transmission of vector pathogens. Ixodes ricinus is one of the most notorious tick vectors with increasing importance in Iran and other parts of the world while there is limited data on its microbiota. This study aimed to use metagenomics for identifying the I. ricinus tick's microbiota of Iran. Methods: A total of 39 adult ticks were collected from Mazandaran (21 females), Gilan (17 females), and Golestan (1 male). Five tick pools prepared from 39 adults of I. ricinus were subjected to metagenomics analysis. The data were analyzed by targeting the V6 region of the 16S rRNA gene by Illumina 4000 Hiseq sequencing. Results: Among hundreds of intestinal microbiota identified by metagenomics, various pathogenic microorganisms distributed in 30 genera and species including those responsible for tick-borne diseases resided in the genera Coxiella, Rickettsia, and Burkholderia were found. Conclusion: Our results indicated that metagenomics identifies bacteria genera and species which cannot be easily recognized by routine methods. The presence of such pathogenic bacteria indicates the importance of possible zoonotic diseases in this region which could affect public health. These results further substantiate the importance of advanced metagenomics analyses to identify neglected tick-borne pathogens which enable researchers to provide efficient mapping roads for the management of emerging and re-emerging infectious diseases.

Evaluation of PastoCovac plus vaccine as a booster dose on vaccinated individuals with inactivated COVID-19 vaccine.

COVID-19 pandemic has been managed through global vaccination programs. However, the antibody waning in various types of vaccines came to notice. Hereby, PastoCovac Plus as a protein subunit vaccine was investigated in immunized health care workers by COVAXIN (BBV152). The booster vaccine was recommended at least three months post the second dose of COVAXIN. Sera collection was done before and after each injection. SARS-CoV-2 PCR test was done monthly to detect any asymptomatic and symptomatic vaccine breakthrough. 47.9 and 24.3% of the participants were seronegative for anti-N and anti-S antibodies three months after the second dose of COVAXIN, respectively. On average, fold-rises of 70, 93, 8 and mean-rises of 23.32, 892.4, 5.59 were recorded regarding neutralizing antibody, quantitative and semi-quantitative anti-Spike antibody, respectively. Anti-Spike and neutralizing antibodies seroconversion was seen 59.3% and 45.7%, respectively. The vaccine breakthrough assessment showed that all the isolated samples belonged to SARS-CoV-2 Delta variant. PastoCovac Plus boosting is strongly recommended in combination with inactivated vaccine platforms against SARS-CoV-2.

Molecular detection of SARS-CoV-2 in domestic cats in close contact with positively-infected owners in Tehran, Iran in 2021.

Objectives: In 2019, COVID-19 emerged in China and has since spread worldwide. Owing to the virus's ability to adhere to specific receptors, cats are susceptible to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The popularity of pet cats in Iran has sparked fears of human-cat-human transmission of the virus. This study aimed to identify positive cases in cats owned by people infected with SARS-CoV-2, to determine if they remained positive for >3 weeks and to examine the virus genome isolated from a number of cats and one of their owners. Methods: A total of 30 cats were sampled approximately 3 days after their owners tested positive (day 1), and 3 weeks later, in strict accordance with health regulations. Rectal and oropharyngeal samples were collected. All samples were subjected to a qualitative PCR and reverse transcription PCR. The S-gene region was partially sequenced in positive samples and the results were used to create a phylogenetic tree. Results: SARS-CoV-2 was detected in 7/30 (23.3%) cats examined. In the third week, every cat tested negative. The sequence data of positive cats and one of their owners revealed that the retrieved RNAs belonged to the alpha variation. The genetic distance between the samples and the reference sequence (20I/B.1.1.7: OM003849, MZ344997) was minimal, with a 99% similarity. Positive samples of cats had four mutations in gene S. Amino acid substitutions in the spike glycoprotein at positions N501Y, A570D, D614G and P681H were recorded in the isolates compared with 780 other sequences of Iranian strains. Conclusions and relevance: This study confirmed the presence of SARS-CoV-2-infected cats living in close contact with infected owners. Despite cats' susceptibility to COVID-19, the risk of severe infection in these animals is low, as evidenced by the lack of clinical signs in positive cats.

Efficacy and Safety of a Protein-Based SARS-CoV-2 Vaccine: A Randomized Clinical Trial.

Importance: The protein-based SARS-CoV-2 vaccines FINLAY-FR-2 (Soberana 02) and FINLAY-FR-1A (Soberana Plus) showed good safety and immunogenicity in phase 1 and 2 trials, but the clinical efficacy of the vaccine remains unknown. Objective: To evaluate the efficacy and safety of a 2-dose regimen of FINLAY-FR-2 (cohort 1) and a 3-dose regimen of FINLAY-FR-2 with FINLAY-FR-1A (cohort 2) in Iranian adults. Design, Setting, and Participants: A multicenter, randomized, double-blind, placebo-controlled, phase 3 trial was conducted at 6 cities in cohort 1 and 2 cities in cohort 2. Participants included individuals aged 18 to 80 years without uncontrolled comorbidities, coagulation disorders, pregnancy or breastfeeding, recent immunoglobulin or immunosuppressive therapy, and clinical presentation or laboratory-confirmed COVID-19 on enrollment. The study was conducted from April 26 to September 25, 2021. Interventions: In cohort 1, 2 doses of FINLAY-FR-2 (n = 13 857) or placebo (n = 3462) were administered 28 days apart. In cohort 2, 2 doses of FINLAY-FR-2 plus 1 dose of FINLAY-FR-1A (n = 4340) or 3 placebo doses (n = 1081) were administered 28 days apart. Vaccinations were administered via intramuscular injection. Main Outcomes and Measures: The primary outcome was polymerase chain reaction-confirmed symptomatic COVID-19 infection at least 14 days after vaccination completion. Other outcomes were adverse events and severe COVID-19. Intention-to-treat analysis was performed. Results: In cohort 1 a total 17 319 individuals received 2 doses and in cohort 2 5521 received 3 doses of the vaccine or placebo. Cohort 1 comprised 60.1% men in the vaccine group and 59.1% men in the placebo group; cohort 2 included 59.8% men in the vaccine group and 59.9% in the placebo group. The mean (SD) age was 39.3 (11.9) years in cohort 1 and 39.7 (12.0) years in cohort 2, with no significant difference between the vaccine and placebo groups. The median follow-up time in cohort 1 was 100 (IQR, 96-106) days and, in cohort 2, 142 (137-148) days. In cohort 1, 461 (3.2%) cases of COVID-19 occurred in the vaccine group and 221 (6.1%) in the placebo group (vaccine efficacy: 49.7%; 95% CI, 40.8%-57.3%) vs 75 (1.6%) and 51 (4.3%) in cohort 2 (vaccine efficacy: 64.9%; 95% CI, 49.7%-59.5%). The incidence of serious adverse events was lower than 0.1%, with no vaccine-related deaths. Conclusions and Relevance: In this multicenter, randomized, double-blind, placebo-controlled, phase 3 trial of the efficacy and safety of FINLAY-FR-2 and FINLAY-FR-1A, 2 doses of FINLAY-FR-2 plus the third dose of FINLAY-FR-1A showed acceptable vaccine efficacy against symptomatic COVID-19 as well as COVID-19-related severe infections. Vaccination was generally safe and well tolerated. Therefore, Soberana may have utility as an option for mass vaccination of the population, especially in resource-limited settings, because of its storage condition and affordable price. Trial Registration: isrctn.org Identifier: IRCT20210303050558N1.

PastoCovac and PastoCovac Plus as protein subunit COVID-19 vaccines led to great humoral immune responses in BBIP-CorV immunized individuals.

The optimal booster vaccine schedule against COVID-19 is still being explored. The present study aimed at assessment of the immunogenicity and antibody persistency of inactivated-virus based vaccine, BBIP-CorV and protein-subunit based vaccines, PastoCovac/Plus through heterologous and homologous prime-boost vaccination. Totally, 214 individuals who were previously primed with BBIBP-CorV vaccines were divided into three arms on their choice as heterologous regimens BBIBP-CorV/PastoCovac (n = 68), BBIBP-CorV/PastoCovac Plus (n = 72) and homologous BBIBP-CorV (n = 74). PastoCovac booster recipients achieved the highest rate of anti-Spike IgG titer rise with a fourfold rise in 50% of the group. Anti-RBD IgG and neutralizing antibody mean rise and fold rise were almost similar between the PastoCovac and PastoCovac Plus booster receivers. The antibody durability results indicated that the generated antibodies were persistent until day 180 in all three groups. Nevertheless, a higher rate of antibody titer was seen in the heterologous regimen compared to BBIP-CorV group. Furthermore, no serious adverse event was recorded. The protein subunit-based booster led to a stronger humoral immune response in comparison with the BBIP-CorV booster receivers. Both the protein subunit boosters neutralized SARS-CoV-2 significantly more than BBIP-CorV. Notably, PastoCovac protein subunit-based vaccine could be successfully applied as a booster with convenient immunogenicity and safety profile.

Predictive Value Alteration of Laboratory Routine and Ferritin/Transferrin Ratio in Monitoring of COVID-19 Patients.

BACKGROUND: Inflammatory processes activated by rapid viral replication of SARS-CoV-2 can play a key role in the pathogenesis of multiple organ damage and be responsible for the COVID-19 patients' dramatic outcomes and common abnormal laboratory findings. The aim of this study was to assess the correlation between various laboratory biomarkers, ferritin/transferrin ratio (FTR) and receiver operating characteristic (ROC) analysis in monitoring COVID-19 patients. METHODS: This observational study was conducted in three groups: healthy participants, non COVID-19 patients with COVID-19-like clinical signs, and COVID-19 patients (severe and non-severe). Biochemical (CRP, ferritin, transferrin and albumin) and hematological (WBC, lymphocytes) parameters were assessed by automated methods. Moreover, FTR and NLR markers were calculated in the three groups mentioned. Statistical analyses were done using R (version 4.1.0). ROC curve was used to validate the predictive value of parameters. RESULTS: The COVID-19 positive group had significantly higher NEU, CRP, ferritin, FTR values, while it's WBC, absolute counts of lymphocytes and albumin were significantly lower compared to the non-COVID-19 patients (p < 0.001). Serum ferritin and FTR level of the severe group was significantly higher than that of the non-severe group (p = 0.006 and (p = 0.011, respectively). The strongest correlation in all subjects showed between lymphocytopenia and increased NEU (r = -0.99, p < 0.001). The AUC values of WBC (0.95), lymphocytes (0.89), NEU (0.88), and NLR (0.88) were higher than CRP (0.64) or Ferritin (0.81). CONCLUSIONS: We recommend using FTR, WBC, and NLR changes as simple, useful, and inexpensive indicators in early detection of COVID-19 patients.

Investigation of Rickettsia conorii in Patients Suspected of Having Crimean-Congo Hemorrhagic Fever.

Rickettsia conorii is the causative agent of Mediterranean spotted fever (MSF). Misdiagnosis of MSF may occur with febrile syndromes associated with rash and thrombocytopenia, such as Crimean-Congo hemorrhagic fever (CCHF). This study aimed to determine the prevalence of R. conorii among serum samples obtained from 260 suspected CCHF patients with features of MSF in Iran (2018-2020). The quantitative polymerase chain reaction (qPCR) method detected three (1.15%) positive 16S rDNA Rickettsia spp. samples that were classified as R. conorii subsp. conorii, R. conorii subsp. Israelensis, and R. helvetica using the sequencing of gltA, ompA, and 17kDa genes. Furthermore, R. conorii IgM antibodies presented in 38 (14.62%) patients by the enzyme-linked immunosorbent assay (ELISA) method. Out of 97 MSF patients with available paired serum samples, IgM seroconversion and a four-fold increase were observed in 14 (14.43%) and 12 (12.37%) patients, respectively. We concluded that rickettsial agents are present in Iran and may be misdiagnosed with other febrile syndromes.

Rapid, label-free and low-cost diagnostic kit for COVID-19 based on liquid crystals and machine learning.

We report a label-free method for detection of the SARS-CoV-2 virus in nasopharyngeal swab samples without purification steps and multiplication of the target which simplifies and expedites the analysis process. The kit consists of a textile grid on which liquid crystals (LC) are deposited and the grid is placed in a crossed polarized microscopy. The swab samples are subsequently placed on the LCs. In the presence of a particular biomolecule, the direction of LCs changes locally based on the properties of the biomolecule and forms a particular pattern. As the swab samples are not perfectly purified, image processing and machine learning techniques are employed to detect the presence of specific molecules or quantify their concentrations in the medium. The method can differentiate negative and positive COVID-19 samples with an accuracy of 96% and also differentiate COVID-19 from influenza types A and B with an accuracy of 93%. The kit is portable, simple to manufacture, convenient to operate, cost effective, rapid and sensitive. The simplicity of the specimen processing, the speed of image acquisition, and fast diagnostic operations enable the deployment of the proposed technique for performing extensive on-spot screening of COVID-19 in public places.

Adenovirus vector-based vaccines as forefront approaches in fighting the battle against flaviviruses.

Flaviviruses are arthropod-borne viruses (arboviruses) that have been recently considered among the significant public health problems in defined geographical regions. In this line, there have been vaccines approved for some flaviviruses including dengue virus (DENV), Japanese encephalitis virus (JEV), yellow fever virus (YFV), and tick-borne encephalitis virus (TBEV), although the efficiency of such vaccines thought to be questionable. Surprisingly, there are no effective vaccine for many other hazardous flaviviruses, including West Nile and Zika viruses. Furthermore, in spite of approved vaccines for some flaviviruses, for example DENV, alternative prophylactic vaccines seem to be still needed for the protection of a broader population, and it originates from the unsatisfying safety, and the efficacy of vaccines that have been introduced. Thus, adenovirus vector-based vaccine candidates are suggested to be effective, safe, and reliable. Interestingly, recent widespread use of adenovirus vector-based vaccines for the COVID-19 pandemic have highlighted the importance and feasibility of their widespread application. In this review, the applicability of adenovirus vector-based vaccines, as promising approaches to harness the diseases caused by Flaviviruses, is discussed.

Designing vaccine candidates against dengue virus by in silico studies on structural and nonstructural domains.

One-third of the world's population is at risk of Dengue infection. Envelope domain 3 (EDIII) and nonstructural protein1 (NS1) proteins as the potent antigenicity regions for humoral immunity in addition to the bc loop region as a completely conserved region have been used for designing protective vaccines. We aimed to design vaccine candidates according to the bc loop, EDIII, and NS1 regions of Dengue serotype2 to be used as vaccine candidates for all serotypes of Dengue virus especially serotype 2. Firstly the bc loop region with EDII fragments at both ends as well as EDIII and NS1 regions were used which were linked with the GGGGS linker to the bc loop region. In two other strategies, the bc loop with EDII and NS1 fragments at both ends was used to increase its structural stability. Tertiary structure prediction and validation of vaccine constructs indicated that all vaccine constructs were modeled with high quality and stable structure during molecular dynamics simulation. B cell epitope mapping by Bepipred and ElliPro methods confirmed the existence of high potent epitopes in the bc loop, EDIII, and NS1 regions in both linear and conformational B cell epitopes. Furthermore, molecular docking for the bc loop region demonstrated that all designed vaccines have a higher affinity to interact with 1C19 monoclonal antibody than only the bc loop region or bc loop epitope in the protein EII. Our data of in silico studies indicated that the designed vaccines could effectively induce humoral immunity against four dengue serotypes.

SARS-CoV-2 in domestic cats (Felis catus) in the northwest of Iran: Evidence for SARS-CoV-2 circulating between human and cats.

This study aimed to investigate the prevalence of COVID-19 in domestic cats, focusing on the disease in the northwest of Iran and then showing the natural transmission of SARS-COV-2 circulating between domestic cats and humans. After receiving ethic codes from Tehran University of Medical Sciences (IR.TUMS.VCR.REC.1399.303) and confirmed by the Center of Communicable Diseases Control (CDC) of Iran, 124 domestic cats were collected from the homes and only one hospital of Meshkin -Shahr district from northwestern Iran where SARS-CoV-2 patients were hospitalized and quarantined during 2020. Samples were prepared from fluid materials of oropharynx and nasopharynx. All samples were tested by real-time PCR (RT-PCR) using specific genes N and ORF1ab in Pasteur Institute of Iran, and then partial sequence analyses of S gene were performed. All collected cats were kept in separated cages until SARS-COV-2 infection was confirmed with the RT-PCR. RT- PCR Ct values of 123 collected cats were ≥40; thus, all of them showed negative results, but one of the collected cats with close contact with its owner, whom confirmed SARS-CoV-2 showed positive results with gene N(Ct=30) and gene ORF1ab (Ct=32). Furthermore, the positive pet cat showed respiratory and gastro-intestinal clinical manifestations, and its owner was infected with SARS-CoV-2 two weeks ago. Cats are susceptible animals to SARS-CoV-2 infection. Epidemiological evidence showed that SARS-COV-2 is able to transmit to healthy cats due to having close contact with its owner as a reverse zoonosis.