Different Serotypes Of Dengue Virus Research Articles

The costs of transgenerational immune priming for homologous and heterologous infections with different serotypes of dengue virus in Aedes aegypti mosquitoes.

The immune system is a network of molecules, signaling pathways, transcription, and effector modulation that controls, mitigates, or eradicates agents that may affect the integrity of the host. In mosquitoes, the innate immune system is highly efficient at combating foreign organisms but has the capacity to tolerate vector-borne diseases. These implications lead to replication, dissemination, and ultimately the transmission of pathogenic organisms when feeding on a host. In recent years, it has been discovered that the innate immune response of mosquitoes can trigger an enhanced immunity response to the stimulus of a previously encountered pathogen. This phenomenon, called immune priming, is characterized by a molecular response that prevents the replication of viruses, parasites, or bacteria in the body. It has been documented that immune priming can be stimulated through homologous organisms or molecules, although it has also been documented that closely related pathogens can generate an enhanced immune response to a second stimulus with a related organism. However, the cost involved in this immune response has not been characterized through the transmission of the immunological experience from parents to offspring by transgenerational immune priming (TGIP) in mosquitoes. Here, we address the impact on the rates of oviposition, hatching, development, and immune response in Aedes aegypti mosquitoes, the mothers of which were stimulated with dengue virus serotypes 2 and/or 4, having found a cost of TGIP on the development time of the progeny of mothers with heterologous infections, with respect to mothers with homologous infections. Our results showed a significant effect on the sex ratio, with females being more abundant than males. We found a decrease in transcripts of the siRNA pathway in daughters of mothers who had been exposed to an immune challenge with DV. Our research demonstrates that there are costs and benefits associated with TGIP in Aedes aegypti mosquitoes exposed to DV. Specifically, priming results in a lower viral load in the offspring of mothers who have previously been infected with the virus. Although some results from tests of two dengue virus serotypes show similarities, such as the percentage of pupae emergence, there are differences in the percentage of adult emergence, indicating differences in TGIP costs even within the same virus with different serotypes. This finding has crucial implications in the context of dengue virus transmission in endemic areas where multiple serotypes circulate simultaneously.

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.

Dengue and natural remedies for its prevention and control: A review

Dengue virus is the most common mosquito borne viral infection and is caused by four different serotypes of dengue virus, named DENV-1, DENV-2, DENV-3 and DENV-4, which belongs to Flaviviridae family and Flavivirus genus. It is transmitted by the Aedes mosquito from one infected person to another healthy person. A frontal headache, retro-orbital pain, body aches, rashes, nausea, vomiting, weakness and a high body temperature are the main symptoms of dengue infection. Dengue haemorrhagic fever and dengue shock syndrome can result in death in severe cases if proper treatment is not given. Several medical technologies, such as monoclonal antibodies, tetravalent subunits, inactivated and live attenuated vaccines have been adopted globally, but developing and under developed countries cannot afford them due to high costs. Various developing countries use herbal and natural remedies to prevent and control dengue. In this review, we are discussing about various plant species that have antiviral, ovicidal, larvicidal and mosquito repellent properties, as well as compound that can be used to treat dengue fever. Following species of plants Momordica charantia, Alternanthera philoxeroides, Andrographis paniculata, Cladosiphon okamuranus, Carica papaya, Momordica charantia, Andropogon citratum, Curcuma longa, Piper longum, Piper ribesoides, Piper sarmentosum, Eupatorium perfoliatum, Kaempferia parviflora, Solanum villosum, Azadirachta indica, Pongamia glabra, Eupatorium odoratum, Catharanthus roseus, Nyctanthes arbortistis, Acalypha alnifolia, Delonix elata, Ocimum sanctum, Tinospora rumphii, Citrus grandis, Jatropha curcas, Ageratum houstonianum, Albizia lebbeck, Aristolochia bracteata, Houttuynia cordata, Hippophae rhamnoides, Kaempferia parvifora, Leucaena leucocephala, Mimosa scabrella, Piper sarmentosum, Psidium guajava, Rhizophora apiculata, Boesenbergia rotunda and Quercus lusitanica are widely used for treatment and control of dengue. Plant products and herbal remedies provided alternative of medicine for cure and recovery of various diseases including dengue fever.

In Silico Elucidation of Potent Inhibitors from Natural Products for Nonstructural Proteins of Dengue Virus

Medicinal plants have been used from the beginning of human civilization against various health complications. Dengue virus (DENV) has emerged as one of the most widespread viruses in tropical and subtropical countries. Yet no clinically approved antiviral drug is available to combat DENV infection. Consequently, the search for novel antidengue agents from medicinal plants has assumed more insistence than in previous days. This study has focused on 31 potential antidengue molecules from secondary metabolites to examine their inhibitory activity against DENV nonstructural proteins through molecular docking and pharmacokinetics studies. In this research, the wet lab experiments were tested on a computational platform. Agathisflavone and pectolinarin are the top-scored inhibitors of DENV NS2B/NS3 protease and NS5 polymerase, respectively. Epigallocatechin gallate, Pinostrobin, Panduratin A, and Pectolinarin could be potential lead compounds against NS2B/NS3 protease, while acacetin-7-O-rutinoside against NS5 polymerase. Moreover, agathisflavone (LD50= 1430 mg/kg) and pectolinarin (LD50= 5000 mg/kg) exhibited less toxicity than nelfinavir (LD50= 600 mg/kg) and balapiravir (LD50 = 824 mg/kg), and the reference drugs. Further research on clinical trials is required to analyze the therapeutic efficacy of these metabolites to develop new potential drug candidates against different serotypes of DENV.

Neurological Complications of Dengue Fever.

Purpose of ReviewTo discuss the neurological complications of dengue virus (DENV) infection and their pathogenesis.Recent FindingsInclude recognition of the four different serotypes of DENV and their epidemiology as well as recognition of the expanded dengue syndrome encompassing multisystem involvement in the severe form of the disease including involvement of the central nervous system (CNS). DENV is a neurotropic virus with the ability to infect the supporting cells of the CNS. Neural injury during the acute stage of the infection results from direct neuro-invasion and/or the phenomenon of antibody-dependent enhancement, resulting in plasma leakage and coagulopathy. Immune mechanisms have been implicated in the development of the delayed neurological sequelae through molecular mimicry. A myriad of neurological syndromes has been described as a result of the involvement of the CNS, the peripheral nervous system (PNS), or both.SummaryNeurological manifestations in DENV infection are increasingly being recognized, some of which are potentially fatal if not treated promptly. DENV encephalopathy and encephalitis should be considered in the differential diagnosis of other acute febrile encephalopathies, autoimmune encephalitides, and in cases of encephalopathy/encephalitis related to SARS-CoV2 infection, especially in dengue-endemic areas. Acute disseminated encephalomyelitis (ADEM) may be occasionally encountered. Clinicians should be knowledgeable of the expanded dengue syndrome characterized by the concurrent compromise of cardiac, neurological, gastrointestinal, renal, and hematopopoietic systems. Isolated cranial nerve palsies occur rather uncommonly and are often steroid responsive. These neuropathies may result from the direct involvement of cranial nerve nuclei or nerve involvement or may be immune-mediated. Even if the diagnosis of dengue is confirmed, it is absolutely imperative to exclude other well-known causes of isolated cranial nerve palsies. Ischemic and hemorrhagic strokes may occur following dengue fever. The pathogenesis may be beyond the commonly observed thrombocytopenia and include cerebral vasculitis. Involvement of ocular blood vessels may cause maculopathy or retinal hemorrhages. Posterior reversible encephalopathy syndrome (PRES) is uncommon and possibly related to dysregulated cytokine release phenomena. Lastly, any patient developing acute neuromuscular weakness during the course or within a fortnight of remission from dengue fever must be screened for acute inflammatory demyelinating polyneuropathy (AIDP), hypokalemic paralysis, or acute myositis. Rarely, a Miller–Fisher-like syndrome with negative anti-GQ1b antibody may develop.

Cross-Reactive Immunity among Five Medically Important Mosquito-Borne Flaviviruses Related to Human Diseases.

Flaviviruses cause a spectrum of potentially severe diseases. Most flaviviruses are transmitted by mosquitoes or ticks and are widely distributed all over the world. Among them, several mosquito-borne flaviviruses are co-epidemic, and the similarity of their antigenicity creates abundant cross-reactive immune responses which complicate their prevention and control. At present, only effective vaccines against yellow fever and Japanese encephalitis have been used clinically, while the optimal vaccines against other flavivirus diseases are still under development. The antibody-dependent enhancement generated by cross-reactive immune responses against different serotypes of dengue virus makes the development of the dengue fever vaccine a bottleneck. It has been proposed that the cross-reactive immunity elicited by prior infection of mosquito-borne flavivirus could also affect the outcome of the subsequent infection of heterologous flavivirus. In this review, we focused on five medically important flaviviruses, and rearranged and recapitulated their cross-reactive immunity in detail from the perspectives of serological experiments in vitro, animal experiments in vivo, and human cohort studies. We look forward to providing references and new insights for the research of flavivirus vaccines and specific prevention.

Multiplexed Diagnosis of Four Serotypes of Dengue Virus by Real-time RT-PCR

The number of people at risk for dengue viral infection is about 50% of the worlds population. Dengue viral infection is classified as dengue fever and severe dengue depending on the severity. Severe dengue may be associated with infection by the different serotype from the primary infected serotype. The circulating epidemic serotypes have changed continuously and periodically. It is very important to diagnose dengue viral infection as early as possible to be treated adequately. The purpose of this study was the development of a simultaneous detection method for all the serotypes of dengue virus in a single sample. The consensus primers and four different fluorescein-tagged probes that specifically binds to each serotype of dengue virus were designed from the multiple alignment data of full-length dengue viral sequences, which were retrieved from GenBank. They were located between the 5’ untranslated region and the capsid gene of the dengue viruses. Each serotype of dengue viruses isolated in Korea was detected correctly with the established multiplex real time RT-PCR at the level of 5-10 copies/reaction. Other RNA viruses such as the Japanese encephalitis virus, Zika virus, yellow fever virus, and Chikungunya virus were not amplified with this method. The results of the inter-assays and intra-assays were within the acceptable variation ranges. Conclusively, the developed method can detect each serotype of dengue virus specifically and quantitatively even when different serotypes of dengue virus are present in a sample.

Experimental study of dengue virus infection in Aedes aegypti and Aedes albopictus: A comparative analysis on susceptibility, virus transmission and reproductive success

Epidemiology of dengue fever has substantially changed over the years with respect to prevalent strains, affected geographical locations and severity of disease. Mosquito vectors show variable response in terms of susceptibility to four different serotypes of dengue virus. Although studies have postulated that, the vectors Ae. aegypti and Ae. albopictus are crucial for transmission of dengue virus, comparative efficacy of these species for viral transmission and tolerance is still enigmatic. In this study, these two vectors were infected orally with four serotypes of the dengue virus viz. DENV-1 to DENV-4 and their co-infection. It was observed that Ae. aegypti harbors multiple serotype infections more efficiently than Ae. albopictus. We suggest that transovarial transmission is of low importance in the epidemiology of the virus due to low infection rates in the filial generation, and also that reduced fecundity and fertility in both vectors after dengue virus infection affect the ecology of the pathogen.

Improved detection of dengue and Zika viruses using multiplex RT-qPCR assays

Dengue virus (DENV) and Zika virus (ZIKV) are important viral pathogens, known to cause human infections with similar symptoms, are transmitted by common vectors and co-circulate in intertropical regions. Moreover, dengue fever results from infection with one of four different serotypes of dengue virus. Considering the recent ZIKV emergence, multiplex and up-to-date assays are more preferable for detection of both viruses in a single reaction. This study aimed to develop: (i) an one-step duplex real-time reverse transcription polymerase chain reaction (RT-qPCR) assay to efficiently and simultaneously detect and quantify DENV and ZIKV; (ii) a fourplex RT-qPCR to differentiate and quantify the four DENV serotypes. The detection limit of the duplex assay was 0.028 and 0.065 FFU (focus forming unit)/ml for DENV and ZIKV respectively. The lower limit of analytical sensitivity of fourplex assay was 0.01 FFU/ml for DENV-1 and 0.1 FFU/ml for DENV-2,-3 and -4. The assessment of specificity indicated both assays were highly specific to targeted viruses with negative results for other Flaviviridae such as Japanese encephalitis, West Nile, Yellow fever or Hepatitis C viruses. The newly developed RT-qPCRs were shown to be more sensitive than a previously described assay in detecting DENV in clinical samples and are suitable for the routine diagnosis.

Seroprevalence of Dengue Virus in Hidalgo County from 2005-2017

We report the testing results for Dengue in Hidalgo County, Texas from 2005-2017. Serology and PCR testing of submitted samples confirmed that, out of 121 submitted samples, 18 (~15%) were positive for Dengue virus. The highest number of positive samples were from Edinburg and Weslaco, Texas. Dengue virus (DENV) is single-stranded, positive-sense arbovirus that belongs to the family Flaviviridae. This family includes other medically significant viruses such as West Nile virus and Zika virus. There are four antigenically different serotypes of DENV: DENV-1, DENV-2, DENV-3, and DENV-4. All four serotypes can be found worldwide, posing a threat to one-third of the global population and causing an estimated 390 million new infections every year [1]. DENV has historically been transmitted throughout northern Mexico, but few studies have been conducted near the northern Mexico-south Texas border. There is an extreme disparity between reported cases of dengue virus in the northern border states of Mexico, and in the border regions of South Texas [2].

Suppression of µ1 subunit of the adaptor protein complex 2 reduces dengue virus release.

Dengue virus (DENV) requires clathrin-mediated endocytosis for its entry into the cells where the adaptor protein complex (AP) is vital for the clathrin-coated vesicle formation. The role of AP-2 was previously examined in the early stages of DENV infection; however, the role of AP-2 in the late stage of DENV infection was not determined. The µ1 subunit of AP-2 (AP2M1) is one of the most important cytoplasmic carrier domains in clathrin-mediated endocytosis and the phosphorylation of this subunit by the kinase enzyme, AP-2 associated protein kinase 1 (AAK1), stimulates clathrin and supports the cell surface receptor incorporation. In the present study, we primarily aimed to investigate the role of AP2M1 by gene silencing approach as well as using naked DENV RNA transfection into AP2M1 knockdown cells. Secondarily, an inhibitor of AAK1, sunitinib was used to investigate whether AAK1 could influence the virus production in DENV-infected Huh7 cells. The knockdown of AP2M1 in the DENV-infected Huh7 cells displayed a reduction in the viral titer at 24h post-infection. Furthermore, experiments were conducted to bypass the DENV internalization using a naked DENV RNA transfection into the AP2M1 knockdown cells. Higher intracellular DENV RNA, DENV E protein, and intracellular virion were observed, whereas the extracellular virion production was comparably less than that of control. Treatment with sunitinib in DENV-infected Huh7 cells was able to reduce extracellular virion production and was consistent with all four serotypes of DENV. Therefore, our findings demonstrate the role of AP2M1 in the exocytosis step of DENV replication leading to infectious DENV production and the efficacy of sunitinib in suppressing virus production during the infection with different serotypes of DENV.

Clinical spectrum of dengue at a tertiary care hospital in Eastern India

Background: Dengue is a vector borne disease by four different serotypes of dengue virus transmitted by bite of female Aedes mosquito. It is an acute febrile illness characterised by myalgia, joint pain, gastrointestinal manifestations. Complications like dengue hemorrhagic fever (DHF) and Dengue shock syndrome (DSS) , Extended Dengue Syndrome(EDS) may be fatal for patients. Authors analyse different clinical spectrum of of manifestations, complications and correlation bleeding to platelet level.Methods: This study conducted from July 2017 to December 2018 comprising of 100 dengue patients of age more than 15 years in IMS & SUM Hospital.Result: Out of 100 dengue patients’ males 73% and females 27%. From the patients 57% were NS1 Antigen positive, 29% IgM positive, 9% NS1 and IgM positive, 4% IgM and IgG positive and 2 % with all NS1, IgM, IgG positive. In our series in clinical manifestations, all cases (100%) presented with fever, myalgia (78%), headache (53%), rashes (14%), nausea, pain abdomen (21%) loose motion (17%), and Retro-orbital pain (6%). Bleeding manifestations in any form was seen in 39% cases like Purpura or Petechie (23%), malena (18%), hematemesis ( 2% ), epixtasis (6%), Gum bleeding (2%), Hematuria (1%), and Ophthalmic bleeding like sub conjunctival hemorrhage, intra-vitreal hemorrhage in 8% cases. Complications detected e.g. hepatopathy in 53%, nephropathy. 4%, ascites 8%, pneumonia 7%, DSS (4%), Multi Organ Dysfunction (MODS) (4%), DHF (8%) and EDS in 2% cases. It was observed that 95.8% of patients with platelet counts between 20,000-50,000/cu.mm and 61% of patients less than 25000 had bleeding manifestations.Conclusion: Wide clinical spectrum of manifestations and complications makes it common differential diagnosis of acute febrile illnesses and bleeding manifestation does not always corelate with lower platelet count.

Differences in the Transmission of Dengue Fever by Different Serotypes of Dengue Virus.

Dengue fever is the most common arbovirus in the world, and all four serotypes are infectious and pathogenic, but dengue virus (DENV)-1 and DENV-2 are the most prevalent in Guangdong Province. To investigate the differences in serotypes, we evaluated the replication, pathogenicity, and NS1 expression of DENV-2 and DENV-3 in cells, and further investigated the effects of NS1 on viral replication and transmission. The results of this study indicated that DENV-2 replicated faster and was more pathogenic than DENV-3. In Vero cells, DENV-2 secreted more NS1 protein than DENV-3, and NS1 protein promoted the infection of Aedes albopictus and A. aegypti by DENV. The spread of DENV and the severity of the disease depend on many factors. Further research on the differences between different serotypes of DENV will help us understand the epidemiology of DENV infection. This will provide a scientific basis for the prevention and control of the dengue epidemic.

Increased serum ferritin and interleukin-18 levels in children with dengue.

Activated monocytes/macrophages that produce a cytokine storm play an important role in the pathogenesis of dengue. Interleukin-18 (IL-18) is a proinflammatory cytokine produced by monocyte/macrophages that is increased during dengue. Ferritin is an acute-phase reactant and expressed by cells of the reticulo-endothelial system in response to infection by dengue virus. The aims of this study were to analyze the simultaneous expression of both IL-18 and ferritins in children infected by diverse serotypes of dengue virus (DENV) and determine their association with dengue severity. In this regard, children with dengue (n = 25) and healthy controls with similar age and sex (n = 20) were analyzed for circulating ferritin and cytokines. Monocytes were isolated by Hystopaque gradient and co-cultured with DENV-2. IL-18 and ferritin contents in blood, and IL-18 in culture supernatants were determined by ELISA. Increased levels of ferritin and IL-18 (p < 0.0001) were observed in dengue patients, not associated to NS1expression or type of infection (primary or secondary). Highest values of both molecules (p < 0.001) were observed in dengue with warning signs and severe dengue. Differential effect on IL-18/ferritin production was observed associated to viral serotype infection. There were no correlations between ferritin vs. IL-18 production, ferritin vs. NS1 status, and IL-18 vs. NS1 status. Viral-infected monocyte cultures showed increased production of IL-18 (p < 0.001). In conclusion, increased circulating ferritin and IL-18 are expressed in children infected by different serotypes of DENV associated with dengue severity.

Dengue Underestimation in Guangzhou, China: Evidence of Seroprevalence in Communities With No Reported Cases Before a Large Outbreak in 2014.

ObjectiveDengue has become a serious public health problem in southern China particularly with a record-breaking outbreak in 2014. Serological evidence from areas with no known dengue cases reported prior to 2014 could provide information on possible unrecognized circulation of dengue virus (DENV) before this outbreak.MethodBetween March and May 2015, we performed a cross-sectional serosurvey using a stratified random sampling method among individuals aged 1–84 years-old in 7 communities in Guangzhou with no reported dengue cases before 2014. Sera of subjects were initially screened with the indirect DENV IgG enzyme-linked immunosorbent assay, and positive samples were further tested by the indirect immunofluorescence assay to identify specific serotypes.ResultsA total of 850 subjects had complete information available. The overall seroprevalence against DENV was 6.59% (56 of 850; 95% CI, 4.92%–8.26%). The seroprevalence increased with age in general (3.86%, 4.58%, 8.72%, 7.22%, and 10.69% among participants in ≤14, 15–29, 30–44, 45–59 and ≥60 years age group, respectively). Living in rural or peri-urban communities and longer years of residence therein were risk factors for higher seroprevalence, whereas wearing long sleeves and pants when outdoors was associated with lower seroprevalence. Of the total subjects, 55.36% (31 of 56) sera were successfully identified with specific serotypes, with 12.90% (4 of 31) being coinfected with 2 serotypes.ConclusionsDengue transmission in the study communities had occurred prior to the 2014 massive outbreak, possibly for many years, but went undiagnosed and unreported. A proportion of the study population experienced secondary infection as different serotypes of DENV increased the risk for severe diseases. Active surveillance and education of both healthcare providers and the general population should be conducted in areas at risk for dengue emergence in order to better reduce disease burden.

Japanese encephalitis virus prM-E antigen immunization conferred protection against challenge by four different serotypes of Dengue viruses in mice.

Dengue virus (DENV) and Japanese encephalitis virus (JEV) are closely related mosquito-borne flaviviruses. Together, they caused most arthropod-borne diseases in the world. Previously, we had demonstrated that both live attenuated and inactivated JE vaccines elicited cross-protection against DENV infection, and a DNA vaccine candidate expressing JEV prM-E protein (named pCAG-JME) could provide effective protection against JEV infection in mice. In this study, we examined whether the same pCAG-JME could elicit cross-protection against DENV infection. Our results showed that pCAG-JME indeed induced cross-reactive antibodies and cross-protection against four different serotypes of DENV in mice. Interestingly, pCAG-JME-immunized mice also generated both Th1 and Th2 responses when stimulated by all four different serotypes of DENV antigens. Moreover, cross-primed CD8+ T cell response was also detected following the stimulation of DENV proteins using intracellular cytokine staining. In addition, sera from pCAG-JME-immunized mice significantly reduced the mortality caused by DENV2 infection in severe combination immunodeficiency mouse. These results suggest that both JE and DENV cross-reactive antibodies and cross-primed T cells might play important roles in the cross-protection. The findings of this study also indicate a possibility of developing novel multivalent genetically engineered vaccines against both JEV and DENV.

Avocado (Persea americana) fruit extract (2R,4R)-1,2,4-trihydroxyheptadec-16-yne inhibits dengue virus replication via upregulation of NF-\u03baB\u2013dependent induction of antiviral interferon responses

Dengue virus (DENV) caused millions of infections around the world annually. Co-infection with different serotypes of DENV is associated with dengue hemorrhagic shock syndrome, leading to an estimate of 50% death rate. No approved therapies are currently available for the treatment of DENV infection. Hence, novel anti-DENV agents are urgently needed for medical therapy. Here we demonstrated that a natural product (2 R,4 R)-1,2,4-trihydroxyheptadec-16-yne (THHY), extracted from avocado (Persea americana) fruit, can inhibit DENV-2 replication in a concentration-dependent manner and efficiently suppresses replication of all DENV serotypes (1–4). We further reveal that the NF-κB-mediated interferon antiviral response contributes to the inhibitory effect of THHY on DENV replication. Using a DENV-infected ICR suckling mouse model, we found that THHY treatment caused an increased survival rate among mice infected with DENV. Collectively, these findings support THHY as a potential agent to control DENV infection.

Epitope resurfacing on dengue virus-like particle vaccine preparation to induce broad neutralizing antibody.

Dengue fever is caused by four different serotypes of dengue virus (DENV) which is the leading cause of worldwide arboviral diseases in humans. Virus-like particles (VLPs) containing flavivirus prM/E proteins have been demonstrated to be a potential vaccine candidate; however, the structure of dengue VLP is poorly understood. Herein VLP derived from DENV serotype-2 were engineered becoming highly matured (mD2VLP) and showed variable size distribution with diameter of ~31 nm forming the major population under cryo-electron microscopy examination. Furthermore, mD2VLP particles of 31 nm diameter possess a T = 1 icosahedral symmetry with a groove located within the E-protein dimers near the 2-fold vertices that exposed highly overlapping, cryptic neutralizing epitopes. Mice vaccinated with mD2VLP generated higher cross-reactive (CR) neutralization antibodies (NtAbs) and were fully protected against all 4 serotypes of DENV. Our results highlight the potential of 'epitope-resurfaced' mature-form D2VLPs in inducing quaternary structure-recognizing broad CR NtAbs to guide future dengue vaccine design.

Tick-Borne Encephalitis Virus Vaccine-Induced Human Antibodies Mediate Negligible Enhancement of Zika Virus Infection InVitro and in a Mouse Model.

Recent reports in the scientific literature have suggested that anti-dengue virus (DENV) and anti-West Nile virus (WNV) immunity exacerbates Zika virus (ZIKV) pathogenesis in vitro and in vivo in mouse models. Large populations of immune individuals exist for a related flavivirus (tick-borne encephalitis virus [TBEV]), due to large-scale vaccination campaigns and endemic circulation throughout most of northern Europe and the southern Russian Federation. As a result, the question of whether anti-TBEV immunity can affect Zika virus pathogenesis is a pertinent one. For this study, we obtained 50 serum samples from individuals vaccinated with the TBEV vaccine FSME-IMMUN (Central European/Neudörfl strain) and evaluated their enhancement capacity in vitro using K562 human myeloid cells expressing CD32 and in vivo using a mouse model of ZIKV pathogenesis. Among the 50 TBEV vaccinee samples evaluated, 29 had detectable reactivity against ZIKV envelope (E) protein by enzyme-linked immunosorbent assay (ELISA), and 36 showed enhancement of ZIKV infection in vitro. A pool of the most highly reacting and enhanced samples resulted in no significant change in the morbidity/mortality of ZIKV disease in immunocompromised Stat2-/- mice. Our results suggest that humoral immunity against TBEV is unlikely to enhance Zika virus pathogenesis in humans. No clinical reports indicating that TBEV vaccinees experiencing enhanced ZIKV disease have been published so far, and though the epidemiological data are sparse, our findings suggest that there is little reason for concern. This study also displays a clear relationship between the phylogenetic distance between two flaviviruses and their capacity for pathogenic enhancement. IMPORTANCE The relationship between serial infections of two different serotypes of dengue virus and more severe disease courses is well-documented in the literature, driven by so-called antibody-dependent enhancement (ADE). Recently, studies have shown the possibility of ADE in cells exposed to anti-DENV human plasma and then infected with ZIKV and also in mouse models of ZIKV pathogenesis after passive transfer of anti-DENV human plasma. In this study, we evaluated the extent to which this phenomenon occurs using sera from individuals immunized against tick-borne encephalitis virus (TBEV). This is highly relevant, since large proportions of the European population are vaccinated against TBEV or otherwise seropositive.

Multiplex polymerase chain reaction-based serotype analysis of dengue virus during 2015 dengue outbreak in Pakistan.

Dengue is one of the most important arthropod-borne viral diseases. It is endemic in > 125 countries including Pakistan, with a global incidence of 50-200 million. We determined the frequency of different serotypes of dengue virus to highlight its hyperendemicity in Rawalpindi, Pakistan. Between May and October 2015 we analysed the serum samples of 140 patients with a suspicion of dengue, using ELISA and multiplex polymerase chain reaction. One hundred and eight were infected with serotype 2, 16 with serotype 3, 7 with serotype 4 and 3 with serotype 1. Three patients were infected with serotypes 1 and 2, and 1 each with serotypes 1 and 4 and serotypes 2 and 3. Incidence of dengue has increased many fold in the past 50 years and has expanded to areas that were previously free from the disease. Serotype 2 was predominant in our population followed by serotype 3. There is currently no specific treatment for dengue, and vector control and vaccination are the only effective methods to prevent future outbreaks.