Chikungunya virus: recent advances in epidemiology, host pathogen interaction and vaccine strategies

Comparative analysis of midgut bacterial communities in Chikungunya virus-infected and non-infected Aedes aegypti Thai laboratory strain mosquitoes

Chikungunya virus (CHIKV) poses a significant global health threat, re-emerging as a mosquito-transmitted pathogen that caused high fever, rash, and severe arthralgia. In Thailand, a notable CHIKV outbreak in 2019-2020 affected approximately 20,000 cases across 60 provinces, underscoring the need for effective mosquito control protocols. Previous studies have highlighted the role of midgut bacteria in the interaction between mosquito vectors and pathogen infections, demonstrating their ability to protect the insect from invading pathogens. However, research on the midgut bacteria of Aedes (Ae.) aegypti, the primary vector for CHIKV in Thailand remains limited. This study aims to characterize the bacterial communities in laboratory strains of Ae. aegypti, both infected and non-infected with CHIKV. Female mosquitoes from a laboratory strain of Ae. aegypti were exposed to a CHIKV-infected blood meal through membrane feeding, while the control group received a non-infected blood meal. At 7 days post-infection (dpi), mosquito midguts were dissected for 16S rRNA gene sequencing to identify midgut bacteria, and CHIKV presence was confirmed by E1-nested RT-PCR using mosquito carcasses. The study aimed to compare the bacterial communities between CHIKV-infected and non-infected groups. The analysis included 12 midgut bacterial samples, divided into three groups: CHIKV-infected (exposed and infected), non-infected (exposed but not infected), and non-exposed (negative control). Alpha diversity indices and Bray-Curtis dissimilarity matrix revealed significant differences in bacterial profiles among the three groups. The infected group exhibited an increased abundance of bacteria genus Gluconobacter, while Asaia was prevalent in both non-infected and negative control groups. Chryseobacterium was prominent in the negative control group. These findings highlight potential alterations in the distribution and abundance of gut microbiomes in response to CHIKV infection status. This study provides valuable insights into the dynamic relationship between midgut bacteria and CHIKV, underscoring the potential for alterations in bacterial composition depending on infection status. Understanding the relationships between mosquitoes and their microbiota holds promise for developing new methods and tools to enhance existing strategies for disease prevention and control. This research advances our understanding of the circulating bacterial composition, opening possibilities for new approaches in combating mosquito-borne diseases.

HR-MAS NMR Metabolomics Profile of Vero Cells under the Influence of Virus Infection and nsP2 Inhibitor: A Chikungunya Case Study

The arbovirus Chikungunya (CHIKV) is transmitted by Aedes mosquitoes in urban environments, and in humans, it triggers debilitating symptoms involving long-term complications, including arthritis and Guillain-Barré syndrome. The development of antiviral therapies is relevant, as no efficacious vaccine or drug has yet been approved for clinical application. As a detailed map of molecules underlying the viral infection can be obtained from the metabolome, we validated the metabolic signatures of Vero E6 cells prior to infection (CC), following CHIKV infection (CV) and also upon the inclusion of the nsP2 protease inhibitor wedelolactone (CWV), a coumestan which inhibits viral replication processes. The metabolome groups evidenced significant changes in the levels of lactate, myo-inositol, phosphocholine, glucose, betaine and a few specific amino acids. This study forms a preliminary basis for identifying metabolites through HR-MAS NMR (High Resolution Magic Angle Spinning Nuclear Magnetic Ressonance Spectroscopy) and proposing the affected metabolic pathways of cells following viral infection and upon incorporation of putative antiviral molecules.

Importation of a novel Indian Ocean lineage carrying E1-K211E and E2-V264A of Chikungunya Virus in Zhejiang Province, China, in 2019

The chikungunya virus (CHIKV) is widespread. In Zhejiang province, China, CHIKV infection is often associated with travelers from tropical and subtropical countries. In the present study, three CHIKV isolates from serum samples of travelers in Zhejiang province in 2019 were sequenced, and phylogenetically analyzed to study their molecular characteristics. Sequence analysis showed that the non-structural protein and the structural protein had 37 and 28 amino acid mutations, respectively; no mutation site was found at the E1-A226 residue, which could increase the adaptability of CHIKV to Aedes albopictus. All three samples carried two mutations, namely, E1-K211E and E2-V264A, which were introduced to Bangladesh around late 2015 and Thailand in early 2017. Phylogenetic analysis revealed that these three CHIKVs were Indian Ocean lineage of the East Africa/Central/South Africa genotype (ECSA) and that the MF773566 strain from Bangladesh (Australia/Bangladesh 2017) had the closest evolutionary relationship. The three CHICKs imported into Zhejiang province in 2019 belonged to the ECSA genotype and had multiple amino acid variation sites. The variation in the three samples provides a certain reference for the subsequent research on CHIKV evolution.

Antiviral activity of myricetin glycosylated compounds isolated from Marcetia taxifolia against chikungunya virus

The chikungunya virus (CHIKV) has produced epidemic outbreaks of significant public health impact. The clinical symptoms of this disease are fever, polyarthralgia, and skin rash, generally self-limiting, although patients may develop a chronic disabling condition or suffer lethal complications. Unfortunately, there is no specific treatment or vaccine available. Thus, the search for effective therapies to control CHIKV infection is an urgent need. This study evaluated the antiviral activity of flavonoids isolated from Marcetia taxifolia by in vitro and in silico analysis. Cytotoxicity of compounds was determined by MTT assay and viral load was assessed in cell substrates supernatants by plaque-forming and RT-qPCR assays. Selected molecules were analyzed by molecular docking assays. Myricetin 3-rhamnoside (MR) and myricetin 3-(6-rhamnosylgalactoside) (MRG) were tested for antiviral assays and analyzed by the TCID50 method and RT-qPCR. MR exhibited dose-dependent antiviral activity, reducing viral titer at concentrations of 150-18.8 μg/mL by at least 1-log. Similarly, MRG showed a significant decrease in viral titer at concentrations of 37.5, 9.4, and 2.3 μg/mL. RT-qPCR analysis also displayed a substantial reduction of CHIKV RNA for both flavonoids. Furthermore, molecular docking of the selected flavonoids proposed the nsP3 macrodomain as a possible target of action. Our study reveals that MR and MRG could be considered promising anti-CHIKV therapeutic agents. Molecular modeling studies showed MR and MRG ligands with a high affinity for the N-terminal region of the nsP3 macrodomain, postulating them as a potential target of action for the CHIKV control.

Increased platelet activation and platelet-inflammasome engagement during chikungunya infection

Chikungunya fever is a viral disease transmitted by mosquitoes of the genus Aedes. The infection is usually symptomatic and most common symptoms are fever accompanied by joint pain and swelling. In most cases symptoms subside within a week. However, severe prolonged and disabling joint pain, that may persist for several months, even years, are reported. Although the pathogenesis of Chikungunya infection is not fully understood, the evolution to severe disease seems to be associated with the activation of immune mechanisms and the action of inflammatory mediators. Platelets are recognized as inflammatory cells with fundamental activities in the immune response, maintenance of vascular stability and pathogenicity of several inflammatory and infectious diseases. Although the involvement of platelets in the pathogenesis of viral diseases has gained attention in recent years, their activation in Chikungunya has not been explored. The aim of this study was to analyze platelet activation and the possible role of platelets in the amplification of the inflammatory response during Chikungunya infection. We prospectively included 132 patients attended at the Quinta D’Or hospital and 25 healthy volunteers during the 2016 epidemic in Rio de Janeiro, Brazil. We observed increased expression of CD62P on the surface of platelets, as well as increased plasma levels of CD62P and platelet-derived inflammatory mediators indicating that the Chikungunya infection leads to platelet activation. In addition, platelets from chikungunya patients exhibit increased expression of NLRP3, caspase 4, and cleaved IL-1β, suggestive of platelet-inflammasome engagement during chikungunya infection. In vitro experiments confirmed that the Chikungunya virus directly activates platelets. Moreover, we observed that platelet activation and soluble p-selectin at the onset of symptoms were associated with development of chronic forms of the disease. Collectively, our data suggest platelet involvement in the immune processes and inflammatory amplification triggered by the infection.

Atypical skin manifestation in severe acute chikungunya infection in a pregnant woman: a case report

Introduction

Patients with chikungunya virus infection commonly present with fever, skin rash, and severe joint pain. The vesiculobullous rash is rare in adults but common in infants. In addition, septic shock and acute respiratory distress syndrome are rare complications of atypical and severe acute chikungunya infection.

Case presentation

We report the presence of an 18-year-old Thai female, at 31 weeks gestation, with fever, maculopapular rash, and polyarthritis. The rash later progressed to a vesiculobullous pattern, and she developed septic shock and acute respiratory distress syndrome. Skin biopsy and blood were positive for chikungunya virus RNA. The patient was intubated with a mechanical ventilator and subsequently fully recovered.

Conclusion

Atypical skin manifestation and severe acute disease is likely due to immune response attenuation in pregnancy. The possibility of progression to severe or atypical disease in pregnant women suffering chikungunya should always be considered.

Ultrastructural insights into the replication cycle of salmon pancreas disease virus (SPDV) using salmon cardiac primary cultures (SCPCs)

Salmon pancreas disease virus (SPDV) has been affecting the salmon farming industry for over 30 years, but despite the substantial amount of studies, there are still a number of recognized knowledge gaps, for example in the transmission of the virus. In this work, an ultrastructural morphological approach was used to describe observations after infection by SPDV of an ex vivo cardiac model generated from Atlantic salmon embryos. The observations in this study and those available on previous ultrastructural work on SPDV are compared and contrasted with the current knowledge on terrestrial mammalian and insect alphaviral replication cycles, which is deeper than that of SPDV both morphologically and mechanistically. Despite their limitations, morphological descriptions remain an excellent way to generate novel hypotheses, and this has been the aim of this work. This study has used a target host, ex vivo model and resulted in some previously undescribed features, including filopodial membrane projections, cytoplasmic stress granules or putative intracytoplasmic budding. The latter suggests a new hypothesis that warrants further mechanistic research: SPDV in salmon may have retained the capacity for non-cytolytic (persistent) infections by intracellular budding, similar to that noted in arthropod vectors of other alphaviruses. In the notable absence of a known intermediate host for SPDV, the presence of this pattern suggests that both cytopathic and persistent infections may coexist in the same host. It is our hope that the ultrastructural comparison presented here stimulates new research that brings the knowledge on SPDV replication cycle up to a similar level to that of terrestrial alphaviruses.

Pain related viral infections: a literature review

Pain is a common health problem all around the world. The pain symptoms are various depending on the underlying disease or the direct cause of pain itself. Viral infection could cause arthralgia or acute-onset arthritis, moreover in pandemic era of SARS-CoV-2 infection. The patients might experience arthritis, arthralgia, joint pain, or musculoskeletal pain. Viral infection including parvovirus B19, hepatitis virus, human immunodeficiency virus, arthropod-borne virus, and coronavirus could cause various types of pain. The pathogenesis of these symptoms is similar to each other despite of different causative organism. This review will discuss about pain caused by various causative organisms.

IL-18: a suggested target for immunomodulation in chikungunya virus infection

Chronic joint pain is the most common pathology found in chikungunya virus (CHIKV)-infected patients. Eight cytokines were compared in CHIKV patients with and without joint pain. IL-4 and IL-13 levels were significantly lower in patients with joint pain (p = 0.006 and p < 0.0001, respectively). IL-18 levels were higher in the group of patients with joint pain (p < 0.0001) and were significantly higher on days 3 and 4 after onset (p = 0.0012 and p = 0.003, respectively). Moreover, TNF-α levels were significantly higher in patients with joint pain on day 3 (p = 0.028). This study demonstrated that cytokines, particularly IL-18, may be candidates for immunomodulation.

Global transmission and evolutionary dynamics of the Chikungunya virus

Chikungunya virus (CHIKV) is a re-emerging pathogen of global importance. We attempted to gain an insight into the organisation, distribution and mutational load of the virus strains reported from different parts of the world. We describe transmission dynamics and genetic characterisation of CHIKV across the globe during the last 65 years from 1952 to 2017. The evolutionary pattern of CHIKV was analysed using the E1 protein gene through phylogenetic, Bayesian and Network methods with a dataset of 265 sequences from various countries. The time to most recent common ancestor of the virus was estimated to be 491 years ago with an evolutionary rate of 2.78 × 10-4 substitutions/site/year. Genetic characterisation of CHIKV strains was carried out in terms of variable sites, selection pressure and epitope mapping. The neutral selection pressure on the E1 gene of the virus suggested a stochastic process of evolution. We identified six potential epitope peptides in the E1 protein showing substantial interaction with human MHC-I and MHC-II alleles. The present study augments global epidemiological and population dynamics of CHIKV warranting undertaking of appropriate control measures. The identification of epitopic peptides can be useful in the development of epitope-based vaccine strategies against this re-emerging viral pathogen.

Tropism of the Chikungunya Virus

Chikungunya virus (CHIKV) is a re-emerging mosquito-borne virus that displays a large cell and organ tropism, and causes a broad range of clinical symptoms in humans. It is maintained in nature through both urban and sylvatic cycles, involving mosquito vectors and human or vertebrate animal hosts. Although CHIKV was first isolated in 1953, its pathogenesis was only more extensively studied after its re-emergence in 2004. The unexpected spread of CHIKV to novel tropical and non-tropical areas, in some instances driven by newly competent vectors, evidenced the vulnerability of new territories to this infectious agent and its associated diseases. The comprehension of the exact CHIKV target cells and organs, mechanisms of pathogenesis, and spectrum of both competitive vectors and animal hosts is pivotal for the design of effective therapeutic strategies, vector control measures, and eradication actions.

Temperature dependent transmission potential model for chikungunya in India

Chikungunya is a major public health problem in tropical and subtropical countries of the world. During 2016, the National Capital Territory of Delhi experienced an epidemic caused by chikungunya virus with >12,000 cases. Similarly, other parts of India also reported a large number of chikungunya cases, highest incidence rate was observed during 2016 in comparison with last 10 years of epidemiological data. In the present study we exploited R₀ mathematical model to understand the transmission risk of chikungunya virus which is transmitted by Aedes vectors. This mechanistic transmission model is climate driven and it predicts how the probability and transmission risk of chikungunya occurs in India. The gridded temperature data from 1948 to 2016 shows that the mean temperatures are gradually increasing in South India from 1982 to 2016 when compared with data of 1948-1981 time scale. During 1982-2016 period many states have reported gradual increase in risk of chikungunya transmission when compared with the 1948-1981 period. The highest transmission risk of chikungunya in India due to favourable ecoclimatic conditions, increasing temperature leads to low extrinsic incubation period, mortality rates and high biting rate were predicted for the year 2016. The epidemics in 2010 and 2016 are also strongly connected to El Nino conditions which favours transmission of chikungunya in India. The study shows that transmission of chikungunya occurs between 20 and 34 °C but the peak transmission occurs at 29 °C. The infections of chikungunya in India are due to availability of vectors and optimum temperature conditions influence chikungunya transmission faster in India. This climate based empirical model helps the public health authorities to assess the risk of chikungunya and one can implement necessary control measures before onset of disease outbreak.

Global prevalence and distribution of coinfection of malaria, dengue and chikungunya: a systematic review

BACKGROUND

Malaria, Dengue and Chikungunya are vector borne diseases with shared endemic profiles and symptoms. Coinfections with any of these diseases could have fatal outcomes if left undiagnosed. Understanding the prevalence and distribution of coinfections is necessary to improve diagnosis and designing therapeutic interventions.

METHODS

We have carried out a systematic search of the published literature based on PRISMA guidelines to identify cases of Malaria, Dengue and Chikungunya coinfections. We systematically reviewed the literature to identify eligible studies and extracted data regarding cases of coinfection from cross sectional studies, case reports, retrospective studies, prospective observational studies and surveillance reports.

RESULTS

Care full screening resulted in 104 publications that met the eligibility criteria and reported Malaria/Dengue, Dengue/Chikungunya, Malaria/Chikungunya and Malaria/Dengue/Chikungunya coinfections. These coinfections were spread over six geographical locations and 42 different countries and are reported more frequently in the last 15 years possibly due to expanding epidemiology of Dengue and Chikungunya. Few of these reports have also analysed distinguishing features of coinfections. Malaria/Dengue coinfections were the most common coinfection followed by Dengue/Chikungunya, Malaria/Chikungunya and Malaria/Dengue/Chikungunya coinfections. P. falciparum and P. vivax were the commonest species found in cases of malaria coinfections and Dengue serotype-4 commonest serotype in cases of dengue coinfections. Most studies were reported from India. Nigeria and India were the only two countries from where all possible combinations of coinfections were reported.

CONCLUSION

We have comprehensively reviewed the literature associated with cases of coinfections of three important vector borne diseases to present a clear picture of their prevalence and distribution across the globe. The frequency of coinfections presented in the study suggests proper diagnosis, surveillance and management of cases of coinfection to avoid poor prognosis of the underlying etiology.

The mixture of cashew nut shell liquid and castor oil results in an efficient larvicide against Aedes aegypti that does not alter embryo-fetal development, reproductive performance or DNA integrity

Dengue fever, chikungunya fever and Zika virus are epidemics in Brazil that are transmitted by mosquitoes, such as Aedes aegypti or Aedes albopictus. The liquid from shells of cashew nuts is attractive for its important biological and therapeutic activities, which include toxicity to mosquitoes of the genus Aedes. The present study evaluated the effects of a mixture of surfactants from natural cashew nutshell liquid and castor oil (named TaLCC-20) on the mortality of larvae and on the reproductive performance, embryonic and fetal development and genetic stability of Swiss mice. A total of 400 Ae. aegypti larvae (third larval stage) were treated with TaLCC-20 concentrations of 0.05 mg/L, 0.5 mg/L, or 5 mg/L (ppm). Twenty pregnant female mice were also orally administered TaLCC-20 at doses of 5 mg/kg and 50 mg/kg body weight (b.w.), and 10 animals were given only drinking water at 0.1 mL/10 g b.w. (orally). The results of a larvicide test demonstrated that 5 mg/mL TaLCC-20 killed 100% of larvae within three hours, which is comparable to the gold standard indicated by the Ministry of Health. Overall, these results show that TaLCC-20 is an efficient larvicide that does not induce genetic damage. In addition, changes in reproductive performance and embryo-fetal development appear positive, and the formulation is cost effective. Therefore, TaLCC-20 is an important product in the exploration of natural larvicides and can assist in fighting mosquitos as vectors for dengue fever, chikungunya fever and Zika virus, which are emerging/re-emerging and require proper management to ensure minimal harm to the human population. Therefore, TaLCC-20 can be considered a key alternative to commercial products, which are effective yet toxigenic.

A clinical report on mixed infection of malaria, dengue and chikungunya from New Delhi, India

Arthropod-borne infections like malaria, dengue and chikungunya fever are transmitted by mosquitoes. The present report describes an unusual case of mixed infection with malaria, dengue and chikungunya viruses in a 21 year old male patient from New Delhi, India during monsoon season of 2016. The malarial fever was diagnosed by thin slide microscopy and antigen test. Chikungunya virus IgM was detected in the sample by the card test. Dengue and chikungunya viruses were further confirmed by RT-PCR for CprM and E1 gene respectively. Phylogenetic analysis clustered the study dengue virus serotype 3 sequence in the genotype III. Thus, the mono infections can not be differentiated from concurrent infections on the basis of clinical symptoms, the appropriate laboratory diagnosis is essential for the accurate pathogen confirmation. Precise and appropriate identification of the multiple pathogens in such clinical cases will assist in the effective management of these arthropod mediated infections.

Evaluation of a range of mammalian and mosquito cell lines for use in Chikungunya virus research

Chikungunya virus (CHIKV) is becoming an increasing global health issue which has spread across the globe and as far north as southern Europe. There is currently no vaccine or anti-viral treatment available. Although there has been a recent increase in CHIKV research, many of these in vitro studies have used a wide range of cell lines which are not physiologically relevant to CHIKV infection in vivo. In this study, we aimed to evaluate a panel of cell lines to identify a subset that would be both representative of the infectious cycle of CHIKV in vivo, and amenable to in vitro applications such as transfection, luciferase assays, immunofluorescence, western blotting and virus infection. Based on these parameters we selected four mammalian and two mosquito cell lines, and further characterised these as potential tools in CHIKV research.

Atypical Clinical Presentations of Acute Phase Chikungunya Virus Infection in Older Adults

OBJECTIVES

We aimed to determine whether the presentation of Chikungunya virus (CHIKV) infection differs between older and younger adults with regard to clinical form during the acute phase defined by the World Health Organization: acute clinical, atypical, and severe acute.

DESIGN

Cross-sectional, retrospective.

SETTING

University Hospital of Martinique.

PARTICIPANTS

Individuals aged 65 and older (n = 267, mean age 80.4 ± 87.9) who attended the emergency department with a positive biological diagnosis of CHIKV (reverse transcriptase polymerase chain reaction) between January and December 2014 and a randomly selected sample of individuals younger than 65 (n = 109, mean age 46.2 ± 12.7).

RESULTS

Typical presentation was present in 8.2% of older adults and 59.6% of younger individuals (P < .001), atypical presentation in 29.6% of older adults and 5.6% of younger individuals (P < .001), and severe presentation in 19.5% of older adults and 17.4% of younger individuals (P = .65). One hundred fourteen (42.7%) of the older group and 19 (17.4%) of the younger group could not be classified in any category (absence of fever, absence of joint pain, or both) (P < .001).

CONCLUSION

Only 8.2% of the older adults presenting in the acute phase of CHIKV have typical forms, suggesting that the most-frequent clinical presentation of CHIKV in older adults differs from that in younger individuals.

Emerging Causes of Arbovirus Encephalitis in North America: Powassan, Chikungunya, and Zika Viruses

Arboviruses are arthropod-borne viruses transmitted by the bite of mosquitoes, ticks, or other arthropods. Arboviruses are a common and an increasing cause of human illness in North America. Powassan virus, Chikungunya virus, and Zika virus are arboviruses that have all recently emerged as increasing causes of neurologic illness. Powassan virus almost exclusively causes encephalitis, but cases are rare, sporadic, and restricted to portions of North America and Russia. Chikungunya virus has spread widely across the world, causing millions of infections. Encephalitis is a rare manifestation of illness but is more common and severe in neonates and older adults. Zika virus has recently spread through much of the Americas and has been associated mostly with microcephaly and other congenital neurologic complications. Encephalitis occurring in infected adults has also been recently reported. This review will discuss the neuropathogenesis of these viruses, their transmission and geographic distribution, the spectrum of their neurologic manifestations, and the appropriate method of diagnosis.

Evolution and Emergence of Pathogenic Viruses: Past, Present, and Future

Incidences of emerging/re-emerging deadly viral infections have significantly affected human health despite extraordinary progress in the area of biomedical knowledge. The best examples are the recurring outbreaks of dengue and chikungunya fever in tropical and sub-tropical regions, the recent epidemic of Zika in the Americas and the Caribbean, and the SARS, MERS, and influenza A outbreaks across the globe. The established natural reservoirs of human viruses are mainly farm animals, and, to a lesser extent, wild animals and arthropods. The intricate "host-pathogen-environment" relationship remains the key to understanding the emergence/re-emergence of pathogenic viruses. High population density, rampant constructions, poor sanitation, changing climate, and the introduction of anthropophilic vectors create selective pressure on host-pathogen reservoirs. Nevertheless, the knowledge and understanding of such zoonoses and pathogen diversity in their known non-human reservoirs are very limited. Prevention of arboviral infections using vector control methods has not been very successful. Currently, new approaches to protect against food-borne infections, such as consuming only properly cooked meats and animal products, are the most effective control measures. Though significant progress in controlling human immunodeficiency virus and hepatitis viruses has been achieved, the unpredictable nature of evolving viruses and the rare occasions of outbreaks severely hamper control and preventive modalities.

Dengue Chikungunya co-infection: A live-in relationship??

Dengue and Chikungunya are viral infections that are a major public health hazard in recent times. Both these infections are caused by RNA viruses termed arboviruses owing to their requirement of an arthropod vector to get transmitted to vertebrate hosts. Apart from sharing a common vector, namely Aedes mosquitoes, these infections are also characterized by overlapping clinical presentations and are known to exist as co-infection. The present review traces the history and evolution of co-infection across the globe and provides specific compilation of the scenario in India. Furthermore, clinical manifestations during co-infection are discussed. Lastly, up-to-date information with respect to vector behaviour during co-infection both under laboratory conditions and in natural Aedes populations is reviewed.

Potential entry inhibitors of the envelope protein (E2) of Chikungunya virus: in silico structural modeling, docking and molecular dynamic studies

Chikungunya fever is an arboviral infection caused by the Chikungunya virus (CHIKV) and is transmitted by Aedes mosquito. The envelope protein (E2) of Chikungunya virus is involved in attachment of virion with the host cell. The present study was conceptualized to determine the structure of E2 protein of CHIKV and to identify the potential viral entry inhibitors. The secondary and tertiary structure of E2 protein was determined using bioinformatics tools. The mutational analysis of the E2 protein suggested that mutations may stabilize or de-stabilize the structure which may affect the structure-function relationship. In silico screening of various compounds from different databases identified two lead molecules i.e. phenothiazine and bafilomycin. Molecular docking and MD simulation studies of the E2 protein and compound complexes was carried out. This analysis revealed that bafilomycin has high docking score and thus high binding affinity with E2 protein suggesting stable protein-ligand interaction. Further, MD simulations suggested that both the compounds were stabilizing E2 protein. Thus, bafilomycin and phenothiazine may be considered as the lead compounds in terms of potential entry inhibitor for CHIKV. Further, these results should be confirmed by comprehensive cell culture, cytotoxic assays and animal experiments. Certain derivatives of phenothiazines can also be explored in future studies for entry inhibitors against CHIKV. The present investigation thus provides insight into protein structural dynamics of the envelope protein of CHIKV. In addition the study also provides information on the dynamics of interaction of E2 protein with entry inhibitors that will contribute towards structure based drug design.

Zika Virus-Induced Microcephaly and Its Possible Molecular Mechanism

Zika virus is an arthropod-borne re-emerging pathogen associated with the global pandemic of 2015-2016. The devastating effect of Zika viral infection is reflected by its neurological manifestations such as microcephaly in newborns. This scenario evoked our interest to uncover the neurotropic localization, multiplication of the virus, and the mechanism of microcephaly. The present report provides an overview of a possible molecular mechanism of Zika virus-induced microcephaly based on recent publications. Transplacental transmission of Zika viral infection from mother to foetus during the first trimester of pregnancy results in propagation of the virus in human neural progenitor cells (hNPCs), where entry is facilitated by the receptor (AXL protein) leading to the alteration of signalling and immune pathways in host cells. Further modification of the viral-induced TLR3-mediated immune network in the infected hNPCs affects viral replication. Downregulation of neurogenesis and upregulation of apoptosis in hNPCs leads to cell cycle arrest and death of the developing neurons. In addition, it is likely that the environmental, physiological, immunological, and genetic factors that determine in utero transmission of Zika virus are also involved in neurotropism. Despite the global concern regarding the Zika-mediated epidemic, the precise molecular mechanism of neuropathogenesis remains elusive.

Estimating and mapping the incidence of dengue and chikungunya in Honduras during 2015 using Geographic Information Systems (GIS)

Geographical information systems (GIS) use for development of epidemiological maps in dengue has been extensively used, however not in other emerging arboviral diseases, nor in Central America. Surveillance cases data (2015) were used to estimate annual incidence rates of dengue and chikungunya (cases/100,000 pop) to develop the first maps in the departments and municipalities of Honduras. The GIS software used was Kosmo Desktop 3.0RC1^®. Four thematic maps were developed according departments, municipalities, diseases incidence rates. A total of 19,289 cases of dengue and 85,386 of chikungunya were reported (median, 726 cases/week for dengue and 1460 for chikungunya). Highest peaks were observed at weeks 25th and 27th, respectively. There was association between progression by weeks (p<0.0001). The cumulated crude national rate was estimated in 224.9 cases/100,000 pop for dengue and 995.6 for chikungunya. The incidence rates ratio between chikungunya and dengue is 4.42 (ranging in municipalities from 0.0 up to 893.0 [San Vicente Centenario]). Burden of both arboviral diseases is concentrated in capital Central District (>37%, both). Use of GIS-based epidemiological maps allow to guide decisions-taking for prevention and control of diseases that still represents significant issues in the region and the country, but also in emerging conditions.

Three atypical lethal cases associated with acute Zika virus infection in Suriname

Acute Zika virus infection usually presents with a self-limiting triad of fever, rash and arthritis. There is limited information on severe or lethal cases. We report three cases of lethal acute Zika infection, confirmed with polymerase chain reaction, in adult patients with some co-morbidities. The patients showed rapid clinical deterioration with hemorrhagic and septic shock, and exaggerated acute and innate inflammatory responses with pronounced coagulopathy, and died soon after admission to the hospital. It remains unclear whether the fatal outcomes were due to acute Zika virus infection alone or to the combination with exacerbated underlying prior disease or co-infection. Nonetheless, the severity of these cases implies that increased awareness for atypical presentations of Zika virus infection, and careful clinical assessment of patients with symptoms of Zika, is warranted during current and future outbreaks.