Dengue Virus Serotypes Research Articles

Molecular differentiation of dengue virus serotypes using RT-PCR and estimation of their effect on liver function

Dengue is one of the common and leading cause of mortality and morbidity in tropical countries specially in India. Its hepatotoxic effects have been demonstrated by the researchers over a long time. Dengue virus is a RNA virus, and known to have four serotypes and recently a fifth variant is also demonstrated in India. The effect of the different serotypes is seldomely investigated by the researchers. So we try to estimate the effect on Liver due to infection via different serotypes of Dengue virus. After taking the ethical clearance, from the ethical committee, A hospital based prospective study was conducted from August 2017 to November 2018, on patients attending OPD and IPD, of Medicine Department at Shri Mahant Indiresh Hospital Dehradun. 60 Dengue Positive cases were selected. RNA gets extracted using Reverse Transcriptase PCR, Conventional PCR and Real Time PCR techniques and further visualized using Agarose gel electrophoresis techniques at the CMRL (Central Molecular Research Laboratory), and liver Enzymes SGPT, SGOT, ALP, GGT were analyzed at Central Clinical Laboratory of SMI Hospital using the vitros 5600 fully autoanlyzer of the Orthoclinical diagnostics. Results were analyzed using suitable statistical tools.

Arbovirus Antibody Seroprevalence in the Human Population from Cauca, Colombia.

Several arboviruses have emerged or reemerged into the New World during the past several decades, causing outbreaks of significant proportion. In particular, the outbreaks of Dengue virus (DENV), Zika virus, and Chikungunya virus (CHIKV) have been explosive and unpredictable, and have led to significant adverse health effects. These viruses are considered the leading cause of acute undifferentiated febrile illnesses in Colombia. However, Venezuelan equine encephalitis virus (VEEV) is endemic in Colombia, and arboviruses such as the Mayaro virus (MAYV) and the Oropouche virus (OROV) cause febrile illnesses in neighboring countries. Yet, evidence of human exposure to MAYV and OROV in Colombia is scarce. In this study, we conducted a serosurvey study in healthy individuals from the Cauca Department in Colombia. We assessed the seroprevalence of antibodies against multiple arboviruses, including DENV serotype 2, CHIKV, VEEV, MAYV, and OROV. Based on serological analyses, we found that the overall seroprevalence for DENV serotype 2 was 30%, 1% for MAYV, 2.6% for CHIKV, 4.4% for VEEV, and 2% for OROV. This study provides evidence about the circulation of MAYV and OROV in Colombia, and suggests that they-along with VEEV and CHIKV-might be responsible for cases of acute undifferentiated febrile illnesses that remain undiagnosed in the region. The study results also highlight the need to strengthen surveillance programs to identify outbreaks caused by these and other vector-borne pathogens.

Differential critical residues on the overlapped region of the non-structural protein-1 recognized by flavivirus and dengue virus cross-reactive monoclonal antibodies

The non-structural protein-1 (NS1) of dengue virus (DENV) contributes to several functions related to dengue disease pathogenesis as well as diagnostic applications. Antibodies against DENV NS1 can cross-react with other co-circulating flaviviruses, which may lead to incorrect diagnosis. Herein, five anti-DENV NS1 monoclonal antibodies (mAbs) were investigated. Four of them (1F11, 2E3, 1B2, and 4D2) cross-react with NS1 of all four DENV serotypes (pan-DENV mAbs), whereas the other (2E11) also reacts with NS1 of other flaviviruses (flavi-cross-reactive mAb). The binding epitopes recognized by these mAbs were found to overlap a region located on the disordered loop of the NS1 wing domain (amino acid residues 104 to 123). Fine epitope mapping employing phage display technology and alanine-substituted DENV2 NS1 mutants indicates the critical binding residues W115, K116, and K120 for the 2E11 mAb, which are conserved among flaviviruses. In contrast, the critical binding residues of four pan-DENV mAbs include both flavi-conserved residues (W115 to G119) and DENV-conserved flanking residues (K112, Y113, S114 and A121, K122). Our results highlight DENV-conserved residues in cross-reactive epitopes that distinguish pan-DENV antibodies from the flavi-cross-reactive antibody. These antibodies can be potentially applied to differential diagnosis of DENV from other flavivirus infections.

Synthesis, Anti-Influenza H1N1 and Anti-Dengue Activity of A-Ring Modified Oleanonic Acid Polyamine Derivatives

A series of sixteen A-ring modified (2,3-indolo-, 2-benzylidene) oleanonic acid derivatives, holding some cyclic amines, linear polyamines and benzylaminocarboxamides at C28, has been synthesized and screened for antiviral activity against influenza A/PuertoRico/8/34 (H1N1) and Dengue virus serotypes of DENV-1, -2, -3, -4. It was found that 28-homopiperazine 2 and 3-N-phthalyl 22 amides of oleanonic acid demonstrated high potency with selectivity index SI 27 (IC50 21 μM) and 42 (IC50 12 μM). Oleanonic acid aminoethylpiperazine amide 6 and C-azepano-erythrodiol 23 appeared to be the most effective compounds against DENV-1 (IC50's 67 and 107 μM) and -2 (IC50's 86 and 68 μM correspondingly) serotypes.

Dengue infection in Agra region, Uttar Pradesh: An observational study of seroprevalence, clinicoepidemiological profile, and serotype of dengue virus from tertiary care center

Background: Dengue is the most widespread mosquito-borne viral infection, found in tropical and subtropical climates worldwide. The World Health Organization has included dengue as one of the 10 threats to global health in 2019 with rapidly evolving epidemiology. Aims and Objectives: Given the limitation of data in regard to dengue burden, we have planned the present study with the objectives to provide a comprehensive overview of the seroprevalence, clinicoepidemiological profile, and serotype of dengue virus in Agra region of Uttar Pradesh. Materials and Methods: We conducted an observational study at viral diagnostic and research laboratory, Sarojini Naidu Medical College, Agra, Uttar Pradesh, from August to December 2021. Our study included all blood specimens received at virology laboratory from clinically suspected cases of dengue infection. For the identification of serotype, NS1-positive samples were sent to King Georges Medical University, Lucknow. For clinical-epidemiological profile of dengue positive patients, data were obtained from records of 203 patients from our hospital. Results: We received total of 5457 serum samples from suspected patients for dengue serology during the study period. In total, positivity rate was 27.29% (1489/5457) and peak of cases was reported in month of October. Median age of dengue positive cases was 17 years. Dengue hemorrhagic fever (DHS) was diagnosed in almost 41% of patients of 203 patients admitted in our hospital. DEN-2 was reported to be most common serotype (97.1%). In our analsyis, we found that in most patients fall in platelets levels below 50,000 happened during the 5th and 6th day in Dengue fever. Conclusion: We conclude that our study showed higher seroprevalence of dengue in Agra region with the age group of 0–20 years being infected most. DEN-2 was most prevalent circulating strain, which leads to more severe dengue infection.

Spatial-temporal distribution of dengue in Banjarmasin, Indonesia from 2016 to 2020

Dengue hemorrhagic fever (DHF) is an acute febrile disease caused by four serotypes of dengue virus (DENV) and transmitted by the <em>Aedes aegypti</em> mosquito. This article aims to analyze monthly trends in cases and climates as well as spatial analysis and autocorrelation in 52 urban villages of Banjarmasin city. Laboratory-confirmed dengue cases from 2016 to 2020 were analyzed for trends in malaria cases. Decomposition analysis was performed to assess seasonality. The annual spatial grouping of incidents, identified by Moran's I. The result shows the annual dengue incidence decreased significantly to 72% in 2017 and lasted until 2020. Dengue infection is more common in men with an age range of 15-64 years. The monthly dengue season is highest from January to May along with increased rainfall. The high incidence is spatially clustered which is identified in the east and borders neighboring districts, especially six urban villages. A trend and spatially explicit decision support system are needed to support surveillance and control programs in identified high-risk areas to succeed in dengue eradication goals.

The dengue virus 4 component of NIAID's tetravalent TV003 vaccine drives its innate immune signature.

Annually, roughly 2.5 billion people are at risk for dengue virus (DENV) infection, and the incidence of infection has increased 30-fold since its discovery in the 1900s. At present, there are no globally licensed antiviral treatments or vaccines that protect against all four of the DENV serotypes. The NIAID Live Attenuated Tetravalent Vaccine (LATV) dengue vaccine candidate is composed of variants of three DENV serotypes attenuated by a 30 nucleotide (Δ30) deletion in the 3' untranslated region and a fourth component that is a chimeric virus in which the prM and E genes of DENV-2 replace those of DENV-4 on the rDEN4Δ30 backbone. The vaccine candidate encodes the non-structural proteins of DENV-1, DENV-3, and DENV-4, which could be of critical importance in the presentation of DENV-specific epitopes in a manner that facilitates antigen presentation and confers higher protection. Our findings demonstrate that the attenuation mechanism (Δ30) resulted in decreased viral infectivity and replication for each vaccine virus in monocyte-derived dendritic cells but were able to generate a robust innate immune response. When tested as monovalent viruses, DEN-4Δ30 displayed the most immunogenic profile. In addition, we found that the tetravalent DENV formulation induced a significantly greater innate immune response than the trivalent formulation. We demonstrate that the presence of two components with a DENV-4Δ30 backbone is necessary for the induction of RANTES, CD40, IP-10, and Type I IFN by the tetravalent formulation. Finally, we found that the DEN-4Δ30 backbone in the DENV-2 component of the vaccine enhanced its antigenic properties, as evidenced by enhanced ability to induce IP-10 and IFNα2 in monocyte-derived dendritic cells. In sum, our study shows that the Δ30 and Δ30/Δ31 mutations attenuate the DENV vaccine strains in terms of replication and infectivity while still allowing the induction of a robust innate immune response.

Neutralization fingerprinting technology for characterizing polyclonal antibody responses to dengue vaccines

Dengue is a major public health threat. There are four dengue virus (DENV) serotypes; therefore, efforts are focused on developing safe and effective tetravalent DENV vaccines. While neutralizing antibodies contribute to protective immunity, there are still important gaps in understanding of immune responses elicited by dengue infection and vaccination. To that end, here, we develop a computational modeling framework based on the concept of antibody-virus neutralization fingerprints in order to characterize samples from clinical studies of TAK-003, a tetravalent vaccine candidate currently in phase 3 trials. Our results suggest a similarity of neutralizing antibody specificities in baseline-seronegative individuals. In contrast, amplification of pre-existing neutralizing antibody specificities is predicted for baseline-seropositive individuals, thus quantifying the role of immunologic imprinting in driving antibody responses to DENV vaccines. The neutralization fingerprinting analysis framework presented here can contribute to understanding dengue immune correlates of protection and help guide further vaccine development and optimization.

No room for complacency to control dengue in Nepal.

Dengue is a febrile disease caused by the dengue virus (Flaviviridae Family) transmitted by Aedes mosquitoes (Aedes aegypti and Aedes albopictus). Symptoms include headache, nausea, vomiting, rash, eye, joint, bone and muscle pain. Dengue symptoms typically last for 2–7 days, most people will recover within a week and one in every 20 people may develop severe dengue, which can lead to death.1 Four serotypes of dengue virus (DENV-1, DENV-2, DENV-3 and DENV-4) are capable of infection, and there is no specific treatment for this disease.2 Dengue fever was first recorded in Nepal in 2004, and it has since grown endemic, with outbreaks occurring every year except in 2005. In 2019, there were 17 992 cases and six death cases were reports in Nepal which were the highest for 2019. As of 15 October 2022, 40 029 dengue cases and 48 deaths were reported, which are the highest for the country since the first outbreak in 2004 (Figure 1).3 There was a surge in cases from the first week of August, peaked in September and started to decline since the beginning of October. The outbreaks of Dengue could have occurred due to high humidity and associated favorable environmental conditions that favor the growth, development and transmission of Aedes mosquitoes.4

Unbiased Identification of Dengue Virus Non-Structural Protein 1 Peptides for Use in Vaccine Design.

Dengue virus (DENV) is a global health problem, with over half of the world's population at risk for infection. Despite this, there is only one licensed vaccine available to prevent infection and safety concerns limit immunization to only a subset of individuals. Most dengue virus vaccine efforts attempt to evoke broadly neutralizing antibodies against structural proteins. However, eliciting antibodies to block the activity of viral proteins involved in pathogenesis could be a useful complementary approach. Studies suggest that non-structural protein 1, which participates in disruption of the endothelial barrier and is hypothesized to play a significant role in the progression to severe dengue, could be a promising target for vaccine efforts. Here, we used an unbiased approach to identify peptide epitopes of dengue virus non-structural protein 1 that could evoke antibodies that bind to NS1 from all 4 serotypes and also bind to DENV-infected cells. DENV-2 NS1 peptides were generated such that 35 overlapping 15 amino acid peptides represented the entire NS1 protein. These peptides were each chemically conjugated to bacteriophage virus-like particles (VLP) and used to immunize mice. Sera were then screened for IgG to cognate peptide as well as binding to recombinant hexameric NS1 from all four DENV serotypes as well as binding to DENV-2 infected cells by microscopy. From these data, we identified several peptides that were able to elicit antibodies that could bind to infected cells as well as DENV NS1. These peptides and their homologues in the corresponding NS1 of other DENV serotypes could be used as potential immunogens to elicit binding antibodies to NS1. Future studies will investigate the functional and protective capacities of antibodies elicited by these immunogens against DENV NS1.

Immune-Mediated Pathogenesis in Dengue Virus Infection.

Dengue virus (DENV) infection is one of the major public health concerns around the globe, especially in the tropical regions of the world that contribute to 75% percent of dengue cases. While the majority of DENV infections are mild or asymptomatic, approximately 5% of the cases develop a severe form of the disease that is mainly attributed to sequential infection with different DENV serotypes. The severity of dengue depends on many immunopathogenic mechanisms involving both viral and host factors. Emerging evidence implicates an impaired immune response as contributing to disease progression and severity by restricting viral clearance and inducing severe inflammation, subsequently leading to dengue hemorrhagic fever and dengue shock syndrome. Moreover, the ability of DENV to infect a wide variety of immune cells, including monocytes, macrophages, dendritic cells, mast cells, and T and B cells, further dysregulates the antiviral functions of these cells, resulting in viral dissemination. Although several risk factors associated with disease progression have been proposed, gaps persist in the understanding of the disease pathogenesis and further investigations are warranted. In this review, we discuss known mechanisms of DENV-mediated immunopathogenesis and its association with disease progression and severity.

In silico and in vitro arboviral MHC class I-restricted-epitope signatures reveal immunodominance and poor overlapping patterns.

The present work sought to identify MHC-I-restricted peptide signatures for arbovirus using in silico and in vitro peptide microarray tools. First, an in-silico analysis of immunogenic epitopes restricted to four of the most prevalent human MHC class-I was performed by identification of MHC affinity score. For that, more than 10,000 peptide sequences from 5 Arbovirus and 8 different viral serotypes, namely Zika (ZIKV), Dengue (DENV serotypes 1-4), Chikungunya (CHIKV), Mayaro (MAYV) and Oropouche (OROV) viruses, in addition to YFV were analyzed. Haplotype HLA-A*02.01 was the dominant human MHC for all arboviruses. Over one thousand HLA-A2 immunogenic peptides were employed to build a comprehensive identity matrix. Intending to assess HLAA*02:01 reactivity of peptides in vitro, a peptide microarray was designed and generated using a dimeric protein containing HLA-A*02:01. The comprehensive identity matrix allowed the identification of only three overlapping peptides between two or more flavivirus sequences, suggesting poor overlapping of virus-specific immunogenic peptides amongst arborviruses. Global analysis of the fluorescence intensity for peptide-HLA-A*02:01 binding indicated a dose-dependent effect in the array. Considering all assessed arboviruses, the number of DENV-derived peptides with HLA-A*02:01 reactivity was the highest. Furthermore, a lower number of YFV-17DD overlapping peptides presented reactivity when compared to non-overlapping peptides. In addition, the assessment of HLA-A*02:01-reactive peptides across virus polyproteins highlighted non-structural proteins as "hot-spots". Data analysis supported these findings showing the presence of major hydrophobic sites in the final segment of non-structural protein 1 throughout 2a (Ns2a) and in nonstructural proteins 2b (Ns2b), 4a (Ns4a) and 4b (Ns4b). To our knowledge, these results provide the most comprehensive and detailed snapshot of the immunodominant peptide signature for arbovirus with MHC-class I restriction, which may bring insight into the design of future virus-specific vaccines to arboviruses and for vaccination protocols in highly endemic areas.

Preparedness for the Dengue Epidemic: Vaccine as a Viable Approach.

Dengue fever is one of the significant fatal mosquito-borne viral diseases and is considered to be a worldwide problem. Aedes mosquito is responsible for transmitting various serotypes of dengue viruses to humans. Dengue incidence has developed prominently throughout the world in the last ten years. The exact number of dengue cases is underestimated, whereas plenty of cases are misdiagnosed as alternative febrile sicknesses. There is an estimation that about 390 million dengue cases occur annually. Dengue fever encompasses a wide range of clinical presentations, usually with undefinable clinical progression and outcome. The diagnosis of dengue depends on serology tests, molecular diagnostic methods, and antigen detection tests. The therapeutic approach relies completely on supplemental drugs, which is far from the real approach. Vaccines for dengue disease are in various stages of development. The commercial formulation Dengvaxia (CYD-TDV) is accessible and developed by Sanofi Pasteur. The vaccine candidate Dengvaxia was inefficient in liberating a stabilized immune reaction toward different serotypes (1-4) of dengue fever. Numerous promising vaccine candidates are now being developed in preclinical and clinical stages even though different serotypes of DENV exist that worsen the situation for a vaccine to be equally effective for all serotypes. Thus, the development of an efficient dengue fever vaccine candidate requires time. Effective dengue fever management can be a multidisciplinary challenge, involving international cooperation from diverse perspectives and expertise to resolve this global concern.

Characteristics of imported cases of Dengue fever and hemorrhagic Dengue fever in 2009-2019

In Russia, the approved morbidity statistics system is represented by the International Classification of Diseases of the 10th revision (ICD-10). This classification provides two forms of dengue fever (DF): dengue fever (A90) and hemorrhagic dengue (A91). Official statistics on the ratio of forms of DF is not published in open sources and this lack of information about the real ratio of the forms of DF makes it difficult to objectively assess the factors that determine the severity of this disease. compare the clinical and epidemiological features of dengue fever and hemorrhagic dengue fever in patients hospitalized in 2009-2019 to the City Infectious Clinical Hospital No. 1, Moscow. A retrospective cohort study. We analyzed the patient database and reviewed 391 medical records of patients with diagnosed dengue fever. We compared gender, age characteristics, travel geography including information about previous visits of patients to endemic regions and dengue virus serotype. To determine the primary and re-infection rate, an analysis of IgG for the dengue virus was carried out on days 1-5 of the disease. To compare indicators, 95% confidence intervals for proportions, medians, and interquartile ranges were calculated. The significance of differences between independent samples for assessing qualitative characteristics was carried out using the criteria χ2, the odds ratio. To assess the quantitative characteristics, the Mann-Whitney test was used. Differences were considered statistically significant at p ≤ 0.05. The proportion of patients with dengue fever was 14.9% of all hospitalized with febrile illnesses that developed after international travel. Hemorrhagic dengue fever (DHF) was diagnosed in 15.7% of patients with dengue fever. DHF developed significantly more often in women, as well as in those who had history of repeated visits to endemic regions. However, DHF was also diagnosed in 10.9% of first-time travelers to tropical countries. We did not find significant differences in the rates of DHF development depending on age and dengue virus serotype. In a number of patients who had not previously traveled to endemic regions, IgG to the dengue virus were detected, which may indicate a previous infection with related flaviviruses. It has been established that in the regions most visited by Russians, there is a circulation of all serotypes of the dengue virus with an annual change in the predominant serotype.

All-Serotype Dengue Virus Detection through Multilayered Origami-Based Paper/Polymer Microfluidics.

The dengue virus (DENV) infection commonly triggers threatening seasonal outbreaks all around the globe (estimated yearly infections are in the order of 100 million, combining all the viral serotypes), testifying the need for early detection to facilitate disease management and patient recovery. The laboratory-based testing procedures for detecting DENV infection early enough are challenged by the need of resourced settings that result in inevitable cost penalty and unwarranted delay in obtaining the test results due to distance-related factors with respect to the patient's location. Recognizing that the introduction of alternative extreme point-of-care technologies for early detection may potentially mitigate this challenge largely, we develop here a multiplex paper/polymer-based detection strip that interfaces with an all-in-one simple portable device, synchronizing the pipeline of nucleic acid isolation, isothermal amplification, and colorimetric analytics as well as readout for detecting all the four serotypes of dengue viruses in around 30 min from about 50 μL of human blood serum with high specificity and sensitivity. Aligned with the mandatory guidelines of the World Health Organization, the ultralow-cost test is ideal for dissemination at different community centers via a user-friendly device interface, not only as a critical surveillance measure in recognizing the potential cocirculation of the infection across regions that are hyperendemic for all four DENV serotypes but also for facilitating effective monitoring of patients infected by any one of the particular viral serotypes as well as timely administration of life-saving measures on need.

Generation of a Large Repertoire of Monoclonal Antibodies against Dengue Virus NS1 Antigen and the Development of a Novel NS1 Detection Enzyme-Linked Immunosorbent Assay.

Commercial dengue virus (DENV) nonstructural-1 (NS1) Ag detection immunoassays often perform poorly, particularly in secondary DENV infection. To develop a highly sensitive NS1 ELISA, we generated a large repertoire of anti-DENV NS1 mouse mAbs (n = 95) that falls into 36 mAb classes based on binding specificities. The identified mAb pair, capable of efficiently detecting NS1 from four DENV serotypes in an immunoassay, was selected based on multiparametric analysis. The selected mAbs have subnanomolar affinities for NS1 with recognition sites outside the immunodominant wing domain. The assay was converted to an ELISA kit, which showed higher analytical sensitivity (3-fold to 83-fold) for NS1 from four DENV serotypes than commercial Platelia NS1 ELISA (Bio-Rad Laboratories). Compared to RT-PCR, the developed NS1 ELISA showed 78.57% (66 of 84) sensitivity, whereas Platelia NS1 ELISA showed a sensitivity of 60.71% (51 of 84). In a subgroup of RT-PCR-positive secondary dengue samples, our ELISA showed a sensitivity of 70.18% (40 of 57), whereas Platelia ELISA detected only 47.37% (27 of 57) samples. Furthermore, unlike Platelia ELISA, our test equally detected NS1 from four serotypes; Platelia ELISA performed poorly for the DENV-2 serotype, in which only 8 of 21 (38.10%) samples were detected compared with 17 of 21 (80.95%) in our ELISA. Moreover, our ELISA showed 100% specificity in 342 challenging dengue-negative samples. The large and diverse mAb repertoire generated against DENV NS1 and the appropriate selection of mAbs allowed us to establish an ELISA that can efficiently detect NS1 Ag even in secondary dengue and without serotype level bias.

To estimate the prevailing Serotype of dengue virus and IgM antibody in suspected dengue fever cases

Dengue virus infection a vector borne disease affecting more than 50 million people worldwide annually. It is distributed in tropical and subtropical regions of the world, abundant in urban and semi-urban areas. It is the disease that spreads by bite of Aedes aegypti and Aedes albopictus mosquitoes. The virus being a RNA virus belongs to Flaviviridae family. The four serotypes of Dengue virus are DENV-1, DENV-2, DENV-3, and DENV-4 which have distinct antigenicity complex.This study was conducted in Microbiology Department, Government Stanley Medical College, Chennai, during the period Jan 2018 to Dec 2018 with 120 blood samples from patients of suspected dengue fever. Samples were selected by stratified random sampling method into three strata and each strata consisting of 40 samples based on duration of fever. All the samples were subjected to procedure for both NS1 antigen and IgM antibodies.15 NS1 positives samples with duration of fever less than 5 days were serotyped by PCR. : A total of 18 cases had NS1 antigen, 26 cases had IgM antibodies and 27 cases had both. A combination of the two tests detected a total of 44 cases. The chance of detection of NS1antigen decreased with duration of fever and IgM antibodies increased with duration of fever. The serotyping detected were DENV1 and DENV3 NS1 antigen detection by ELISA is useful in early phase of infection. A combination of NS1 ELISA and IgM ELISA have high sensitivity depending upon the duration of illness. Detection of DENV1 and DENV3 by PCR procedure helps to know the presence of prevailing serotype in this particular region which would be a good guide to predict the recurrence of outbreak and for efficient prevention and management.

Major Histocompatibility Complex Class I and Dengue Hemorrhagic Fever: A Meta-Analysis of Human Leukocyte Antigens A*24 and B*44.

Dengue fever (DF) is a disease caused by dengue virus (DENV) from the family Flaviviridae. The role of human leukocyte antigens (HLAs) in dengue fever (DF) and its more severe manifestation, dengue hemorrhagic fever (DHF), has been a topic of great research interest. In addition to HLA profile, race, age, DENV serotype, infection while having certain chronic diseases, and secondary infection are risk factors for DHF susceptibility. Antibody-dependent enhancement (ADE) of dengue virus infection is a mechanism for DHF infection. Individual studies have examined the effects of HLA-A*24 and HLA-B*44 presence on DHF, butnone have analyzed these in a meta-analysis. The objective of this study was to determine the effects of HLA-A*24 and HLA-B*44 presence on DHF and DF susceptibility. A meta-analysis on DHF and DF susceptibility in patients with HLA-A*24 and HLA-B*44 was conducted. Google Scholar was used to find studies that contained patients with HLA-A*24 or HLA-B*44 that were diagnosed with DHF or DF. Studies containing patients diagnosed using the 1997 WHO guidelines and possessing HLA-A*24 or HLA-B*44 that were diagnosed with DHF or DF, including primary or secondary infection, and studies measuring odds ratios (ORs) were included. Patients diagnosed using the 2009 WHO guidelines and studies in a foreign language, using animals, or lacking odds ratios were excluded. The National Institutes of Health (NIH) quality assessment of the case-control study tool was used, and a Doi plot was generated using MetaXL to assess for risk of bias. Review Manager version 5.4 was used to generate odds ratios and forest plots with subgroup analysis from allele and phenotype frequency data. Ten studies from 2001 to 2015 met the inclusion criteria. The studies included 2837 DHF/DF patients and 4880 healthy control (HC) patients. HLA-A*24 was associated with a 1.39 times susceptibility to DHF while those possessing HLA-B*44 were 0.62 times susceptible to DHF (OR=1.39 and 95% CI=1.17-1.66; OR=0.62 and 95% CI=0.39-0.99). NeitherHLA-A*24 nor HLA-B*44 presence was associated with DF susceptibility (OR=1.04 and 95% CI=0.82-1.33; OR=0.88 and 95% CI=0.68-1.14). These results indicate that two different major histocompatibility complex (MHC) class I alleles, HLA-A*24 and HLA-B*44, have opposing effects on DHF susceptibility but none on DF susceptibility. The study's specificity is limited in that it examines HLA allele groups and not specific HLA proteins. The results of this study can be used clinically to identify patients that may be at a higher risk of developing DHF based on their HLA profile.

Molecular characterization of recombinant premembrane protein of dengue virus serotype-2 for development of diagnostic assay.

Dengue is an acute arboviral infection common in tropical and subtropical countries. Dengue has been highlighted as a public health concern in the last five decades, affecting almost 50% of the population in developing nations. Dengue infection results in a complex symptomatic disease that ranges from headache, fever, and skin rash to extreme hemorrhage fever and liver dysfunction. The diagnosis of the disease is essential for effective treatment. The early onset of the infection can be detected through viral structural peptides that act as markers for detection, including Pre-Membrane (Pre-M) protein. In the currently proposed research, the structural gene obtained from local isolates was targeted for studies. For this purpose, recombinant structural protein Pre-M was amplified, cloned, and expressed in the bacterial expression system. The expression of the structural protein (Pre-M) was scrutinized by Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and validated by western blot and dot blot, and afterwards, the antigen was purified. The purified Pre-M protein carries the potential for the development of in-house diagnostic assay as well as for vaccine production. This study aimed to develop a highly specific, sensitive, and cost-effective in-house enzyme-linked immunoassay (ELISA) for the detection of antibodies of Pakistani most prevalent dengue virus serotype 2 (DENV-2). The success of this research would also pave the way toward developing novel vaccines for the future prevention of dengue infection.

Multiplexed rapid antigen tests developed using multicolored nanoparticles and cross-reactive antibody pairs: Implications for pandemic preparedness

Global public health infrastructure is unprepared for emerging pathogen epidemics, in part because diagnostic tests are not developed in advance. The recent Zika, Ebola, and SARS-CoV-2 virus epidemics are cases in point. We demonstrate here that multicolored gold nanoparticles, when coupled to cross-reactive monoclonal antibody pairs generated from a single immunization regimen, can be used to create multiple diagnostics that specifically detect and distinguish related viruses. The multiplex approach for specific detection centers on immunochromatography with pairs of antibody-conjugated red and blue gold nanoparticles, coupled with clustering algorithms to detect and distinguish related pathogens. Cross-reactive antibodies were used to develop rapid tests for i) Dengue virus serotypes 1–4, ii) Zika virus, iii) Ebola and Marburg viruses, and iv) SARS-CoV and SARS-CoV-2 viruses. Multiplexed rapid antigen tests based on multicolored nanoparticles and cross-reactive antibodies and can be developed prospectively at low cost to improve preparedness for epidemic outbreaks.