Molecular Epidemiology, Evolution and Reemergence of Chikungunya Virus in South Asia

Molecular and serological evidence of chikungunya virus among dengue suspected patients in Sri Lanka

BACKGROUND

Chikungunya virus (CHIKV), transmitted by Aedes mosquitoes, causes significant morbidity characterized by acute febrile illness to chronic and permanent disability in some patients. Despite its potential for severe long-term effects, surveillance for CHIKV remains limited, especially in dengue-endemic region like Sri Lanka. To address the gap in surveillance, this study aimed to determine the prevalence of CHIKV among patients suspected of dengue fever during the 2017-2019 DENV outbreak in Sri Lanka.

METHODS

Serum samples were collected from 295 patients at Kandy National Hospital and 300 patients at Negombo Hospitals, presenting with dengue-like symptoms such as fever, rash, and arthralgia. We performed quantitative real-time RT-PCR (RT-qPCR) to detect the CHIKV genome and conducted serological tests for anti-CHIKV IgM and IgG antibodies on all samples. Serology-positive samples were further validated with neutralization assays to confirm CHIKV-specific antibodies.

RESULTS

The prevalence of recent CHIKV infection (IgM or RT-qPCR positive) was 2.4 % and 7.0 %, while past CHIKV infection (IgG-positive) was 16.3 % and 12.3 % with neutralizing antibody (NAb) in Kandy and Negombo Hospitals, respectively. All IgG-positive samples exhibited NAb with titers of 10 or higher. The NAb geometric mean titer in the Kandy and Negombo areas does not show a significant difference. In the Kandy area, the majority of CHIKV infections occurred in young adults aged 13-24 years, accounting for 57.1 % of recent infections and 52.1 % of past infections.

CONCLUSION

CHIKV circulates alongside DENV outbreaks, with a higher prevalence of recent infections in Negombo compared to Kandy, while past infections are more common in Kandy than in Negombo. Neutralization assays confirmed the presence of CHIKV-specific antibodies, emphasizing the need for enhanced surveillance for proper patient care and management. These findings underscore the importance of public health interventions, including surveillance programs and vaccine development, to mitigate the burden of CHIKV in Sri Lanka.

Unmasking the chik sign: A case report on nasal hyperpigmentation as a diagnostic clue for chikungunya fever

Macular hyperpigmentation of the nasal region, often referred to as the 'chik sign', constitutes a distinctive physical manifestation associated with chikungunya fever. Chikungunya, a mosquito-borne viral illness, presents with acute febrile symptoms, intense arthralgia and cutaneous eruptions. The chik sign serves as a valuable clinical marker for discerning chikungunya from other febrile illnesses with analogous presentations, such as dengue fever and malaria. This differentiation is particularly crucial in endemic regions. Recognition of the chik sign underscores the significance of clinical acumen in diagnosing chikungunya. In conjunction with confirmatory laboratory testing, identification of this sign can augment diagnostic accuracy and guide appropriate therapeutic strategies. Herein, we present the case of a 44-year-old woman with chikungunya virus infection who exhibited acute febrile symptoms, severe polyarthralgia and hyperpigmentation of the nasal region. In conclusion, the chik sign is a crucial clinical marker for identifying chikungunya fever. Its identification can improve diagnostic precision and enable timely care, particularly in places with limited access to laboratory testing. Healthcare professionals should thus be vigilant for this skin pigmentation in patients who exhibit joint pain and feverish symptoms that are indicative of chikungunya virus infection. To further understand the clinical spectrum of chikungunya, more research into the presentation of this pigmentation would be helpful.

Novel peptide inhibitor for the Chikungunya virus nsP2 protease: Identification and characterization

Chikungunya virus (CHIKV) is an emerging pathogen affecting populations worldwide, with rapidly increasing infection rates. CHIKV, an arbovirus of the alphavirus genus, is predominantly found in tropical regions and transmitted by Aedes mosquitoes. Climate change has accelerated the global spread of these vectors, leading to outbreaks in non-tropical regions, including parts of Europe. The absence of antiviral therapies and the potential for co-infections with other viruses make CHIKV a significant public health concern. CHIKV replication relies on nsP2 cysteine protease activity to cleave its viral polyprotein into functional nonstructural and structural proteins. Targeting the nsP2 protease represents a promising strategy for antiviral therapy development. In this study, phage display was used to screen a library of peptides for potential binders of the target protease. Biophysical and biochemical analyses of the identified peptides assessed their inhibitory potential. Among the six identified peptides (named as P1-P6), four demonstrated inhibitory effects on the nsP2 protease (nsP2pro). Peptide P1 exhibited the strongest inhibitory effect, with a half-maximal inhibitory concentration (IC50) of 4.6 ± 1.9 µM, and a low cytotoxicity. The secondary structure analysis through CD spectroscopy and homology modelling revealed that P1 adopts an alpha-helical conformation. Finally, molecular dynamics simulations enabled us to investigate the dynamics of the nsP2pro active site and molecular docking was employed to predict the orthosteric binding mode of P1, providing insights into protein-peptide interaction. These findings underscore the potential of peptide P1 as a lead compound for further investigation in the context of CHIKV research.

Protocol for Screening Host-Targeting Antivirals (HTAs) Using Human PBMCs and pDCs

This protocol offers an ex vivo method for screening host-targeting antivirals (HTAs) using human peripheral blood mononuclear cells (PBMCs) or plasmacytoid dendritic cells (pDCs). Unlike virus-targeting antivirals (VTAs), HTAs provide advantages in overcoming drug resistance and offering broad-spectrum protection, especially against rapidly mutating or newly emerging viruses. By focusing on PBMCs or pDCs, known for their high production of humoral factors such as Type I interferons (IFNs), the protocol enables the screening of antivirals that modulate immune responses against viruses. Targeting host pathways, especially innate immunity, allows for species-independent antiviral activity, reducing the likelihood of viral escape mutations. Additionally, the protocol's versatility makes it a powerful tool for testing potential antivirals against various viral pathogens, including emerging viruses, positioning it as an essential resource in both pandemic preparedness and broad-spectrum antiviral research. This approach differentiates itself from existing protocols by focusing on host immune modulation through pDCs, offering a novel avenue for HTA discovery. Key features • Optimized protocol for screening HTAs against dengue virus (DENV), chikungunya virus (CHIKV), and Zika virus (ZIKV). • This protocol is ideal for screening soluble or intravenous-formulated compounds for evaluating their efficacy in experimental settings. • This protocol builds upon the method developed by Tsuji et al. [1] and extends its application to PBMCs and testing against DENV, CHIKV, and ZIKV.

Clinical Epidemiology of Dengue and COVID-19 Co-infection Among the Residents in Dhaka, Bangladesh, 2021-2023: A Cross-sectional Study

Background

Co-infection of dengue and COVID-19 has increased the health burden worldwide. We found a significant knowledge gap in epidemiology and risk factors of co-infection in Bangladesh.

Methods

This study included 2458 participants from Dhaka city from 1 December 2021 to November 30 2023. We performed the Kruskal-Wallis test and χ2 test. Multivariable logistic regression was also performed.

Results

Co-infection of dengue and COVID-19 was found among 31% of the participants. Coprevalence of dengue and COVID-19 was found in higher frequency in Jatrabari (14%) and Motijhil (11%). Severe (65%, P = .001) and very severe (78%, P = .005) symptoms were prevalent among the participants aged >50 years. Long-term illness was prevalent among the participants with co-infection (35%; 95% confidence interval [CI], 33-36) and COVID-19 (28%; 95% CI, 26-30). Co-infected participants had a higher frequency of heart damage (31.6%, P = .005), brain fog (22%, P = .03), and kidney damage (49.3%, P = .001). Fever (100%) was the most prevalent symptom followed by weakness (89.6%), chills (82.4%), fatigue (81.4%), headache (80.6%), feeling thirsty (76.3%), myalgia (75%), pressure in the chest (69.1%), and shortness of breath (68.3%), respectively. Area of residence (odds ratio [OR], 2.26; 95% CI, 1.96-2.49, P = .01), number of family members (OR, 1.45; 95% CI ,1.08-1.87; P <.001), and population density (OR, 2.43; 95% CI, 2.15-3.01; P = .001) were associated with higher odds of co-infection. We found that coinfected participants had a 4 times higher risk of developing severe health conditions (OR, 4.22; 95% CI, 4.11-4.67; P = .02).

Conclusions

This is one of the early epidemiologic studies of co-infection of dengue and COVID-19 in Bangladesh.

Chikungunya virus infection in the skin: histopathology and cutaneous immunological response

Alphavirus chikungunya virus (CHIKV) is an arbovirus, belonging to the Togaviridae family. The disease caused by CHIKV generally evolves with spontaneous resolution in a few weeks; however, progression to a chronic disease may occur. The most common symptoms are fever, myalgia, and arthralgia; however, skin manifestations may occur in 40 to 80% of infected individuals. Morbilliform and maculopapular erythematous eruptions, vesiculobullous lesions, generalized erythema, maculopapular eruption and skin peeling, hypermelanosis, painful oral lesions, and urticarial lesions have been reported. Usually, these manifestations disappear, but they can become sequelae. Since the skin is the first line of defense against CHIKV infection, in this study, we aimed to investigate the immunohistopathological aspects of the skin of infected individuals during the acute phase of the disease by performing histopathological and ultrastructural analysis, detection and quantification of the viral genome, detection of viral antigen and immune cells, and cytokines/chemokines' characterization. The main histopathological findings were perivascular and inflammatory infiltrates, blood capillary ectasia, and interstitial edema. The immunohistochemistry revealed CHIKV antigen in the epidermis, endothelial cells, fibroblasts, and macrophages in the reticular and papillary dermis; inflammatory cells infiltrate; arrector pili muscle; sweat and sebaceous glands; and hair follicle. Moreover, inflammatory infiltrates were composed of lymphocytes (CD4+ and CD8+) and macrophages (CD68+) in the dermis and perivascular infiltrate. TNF-α, IL-6, RANTES, and VEGFR2 were expressed in the epidermis, blood vessels, sweat glands, and migrating cells. Loss of contact among adjacent keratinocytes, epidermis presenting necrotic cells, and fibroblasts with dilated cisternae in the endoplasmic reticulum and mitochondria with few cristae was observed by transmission electron microscopy. Studies involving skin immunopathogenesis during CHIKV infection are still scarce; therefore, the findings presented here can contribute to a better understanding of the disease immunopathogenesis.

Spatial heterogeneity in the potential distribution of Aedes mosquitoes in India under current and future climatic scenarios

Aedes is the most globally distributed mosquito genus in the 21st century and transmits various arboviral diseases. The rapid expansion of Ae. Aegypti and Ae. albopictus breeding habitats is a significant threat to global public health, driven by temperature and precipitation changes. In this study, bioclimatic variables were employed to predict the spatial distribution of Ae. aegypti and Ae. albopictus in India. The reference coordinate points of (n = 583) Aedes occurrences at a scale of ∼1 km and nineteen bioclimatic factors were retrieved to train SDM (Species Distribution Models) for both species. Maximum entropy modelling was used to predict the species' fundamental climatic niche distributions. Future projections were made using global climate models for 2021-2040 and 2081-2100 separately. The models performed reasonably well (AUC > 0.77). Both species thrived in reduced diurnal temperature and higher annual mean temperatures, with suitability increasing alongside precipitation. Ae. aegypti's projected present and future distribution was broader than that of Ae. Albopictus. The expansion of Aedes suitability varied under different future climatic scenarios. Suitability for Ae. aegypti could expand from between 17.6 and 41.1 % in 2100 under SSP (shared socioeconomic pathways) scenarios 1 and 3, respectively, whereas for Ae. albopictus suitability increased from between 10.2 and 25 % under SSP scenarios 1 and 3 respectively. Preparing for future epidemics and outbreaks requires robust vector distribution models to identify high-risk areas, allocate resources for surveillance and control, and implement prevention strategies.

The Antiviral Effects of Heat-Killed Lactococcus lactis Strain Plasma Against Dengue, Chikungunya, and Zika Viruses in Humans by Upregulating the IFN-α Signaling Pathway

The growing risk of contracting viral infections due to high-density populations and ecological disruptions, such as climate change and increased population mobility, has highlighted the necessity for effective antiviral treatment and preventive measures against Dengue virus (DENV), Chikungunya virus (CHIKV), and Zika virus (ZIKV). Recently, there has been increasing attention on the use of probiotics as a potential antiviral option to reduce virus infections. The present study aimed to assess the immunomodulatory effects of heat-killed Lactococcus lactis strain plasma (LC-Plasma) on peripheral blood mononuclear cells (PBMCs) and its subsequent antiviral response against DENV, CHIKV, and ZIKV. To evaluate the immunomodulatory effects of LC-Plasma on PBMCs isolated from healthy individuals, PBMCs were cultured at a density of 2 × 105 cells/well and stimulated with 10 µg/mL of LC-Plasma. LC-plasma-stimulated PBMCs demonstrated elevated interferon-alpha (IFN-α) production and cluster of differentiation 86 (CD86) and human leukocyte antigen-DR isotype (HLA-DR) upregulation, potentially linked to plasmacytoid dendritic cell (pDC) activation. The replication of DENV, CHIKV, and ZIKV was dose-dependently inhibited when Huh-7 cells were stimulated with LC-Plasma-stimulated PBMC supernatant (LCP Sup). IFN-stimulated gene (ISG) expression, including IFN-stimulated gene 15 (ISG15), IFN-stimulated exonuclease gene 20 (ISG20), IFN-induced transmembrane protein 1 (IFITM-1), myxovirus resistance protein A (MxA), and radical S-adenosyl methionine domain-containing protein 2 (RSAD2), was significantly upregulated in LCP Sup-stimulated Huh-7 cells. Findings from this study indicate that LC-Plasma has the potential to induce IFN-α production, leading to an enhancement in the expression of ISGs and contributing to a broad-spectrum antiviral response. Thus, LC-Plasma may serve as a rational adjunctive treatment to ameliorate viral diseases, warranting future clinical trials.

Vaccine value profile for Chikungunya

Chikungunya virus (CHIKV) a mosquito-borne alphavirus is the causative agent of Chikungunya (CHIK), a disease with low mortality but high acute and chronic morbidity resulting in a high overall burden of disease. After the acute disease phase, chronic disease including persistent arthralgia is very common, and can cause fatigue and pain that is severe enough to limit normal activities. On average, around 40% of people infected with CHIKV will develop chronic arthritis, which may last for months or years. Recommendations for protection from CHIKV focus on infection control through preventing mosquito proliferation. There is currently no licensed antiviral drug or vaccine against CHIKV. Therefore, one of the most important public health impacts of vaccination would be to decrease burden of disease and economic losses in areas impacted by the virus, and prevent or reduce chronic morbidity associated with CHIK. This benefit would particularly be seen in Low and Middle Income Countries (LMIC) and socio-economically deprived areas, as they are more likely to have more infections and more severe outcomes. This 'Vaccine Value Profile' (VVP) for CHIK is intended to provide a high-level, holistic assessment of the information and data that are currently available to inform the potential public health, economic and societal value of vaccines in the development pipeline and vaccine-like products.This VVP was developed by a working group of subject matter experts from academia, non-profit organizations, public private partnerships, and multi-lateral organizations. All contributors have extensive expertise on various elements of the CHIK VVP and collectively aimed to identify current research and knowledge gaps.The VVP was developed using only existing and publicly available information.

Molecular characterization of Chikungunya virus recovered from patients in the Maranhão state, Brazil

BACKGROUND

Chikungunya virus (CHIKV) is an arbovirus from the Togaviridae family which has four genotypes: West African (WA), East/Central/South African (ECSA) and Asian/Caribbean lineage (AL) and Indian Ocean Lineage (IOL). The ECSA genotype was first registered in Brazil in Feira de Santana and spread to all Brazilian regions. This study reports the characterization of CHIKV isolates recovered from sera samples of fifty patients from seventeen cities in Maranhão, a state from Brazilian northeast region and part of the Legal Amazon area.

METHODS AND RESULTS

Primers were developed to amplify the partial regions coding structural proteins (E1, E3, E2, 6 K, and Capsid C). The consensus sequences have 2871 bp, covering approximately 24% of the genome. The isolates were highly similar (> 99%) to the ECSA isolate from Feira de Santana (BHI3734/H804698), presenting 30 non-synonymous mutations in E1 (5.95%), 18 in E2 (4.46%), and 1 in E3 (3.03%), taking the BHI3734/H804698 isolate as standard. Although the mutations described have not previously been related to increased infectivity or transmissibility of CHIKV, in silico analysis showed changes in physicochemical characteristics, antigenicity, and B cell epitopes of E1 and E2.

CONCLUSIONS

These findings demonstrate the importance of molecular approaches for monitoring the viral adaptations undergone by CHIKV and its geographic distribution.

Isolation and molecular detection of dengue and chikungunya virus from field-collected adult mosquitoes in Kelantan, Malaysia

BACKGROUND OBJECTIVES

Dengue and chikungunya infections are one of the major health problems that have plagued the human population globally. All dengue virus (DENV) serotypes circulate within Malaysia with particular serotypes dominating in different years/outbreaks. In the state of Kelantan, an increasing number of DENV and chikungunya virus (CHIKV) new cases have been reported, including several deaths. This study aimed to isolate and detect these arboviruses from adult mosquitoes in Kelantan.

METHODS

Adult mo squito samples were collected from January to August 2019 and were identified according to gender, species and locality. The isolation of the virus was done in C6/36 cells. Dengue NS1 antigen was carried out using direct mosquito lysate and mosquito culture supernatant. Detection and serotyping of the DENV was performed using multiplex RT-PCR and CHIKV detection using a one-step RT-PCR assay.

RESULTS

Of 91 mosquito pools, four were positive for NS1 antigen comprising two pools (2.2%) of male Ae. albopictus (Pulau Melaka and Kubang Siput) and two pools (2.2%) of Ae. aegypti (Kampung Demit Sungai). DENV 1 was detected in one pool (0.9%) of female Ae. albopictus among 114 tested Aedes pools. Two pools of 114 pools (1.7%) from both male Aedes species were positive with double serotypes, DENV 1 and DENV 2 (Pulau Melaka). However, no pool was positive for CHIKV.

INTERPRETATION CONCLUSION

The presence of DENV and the main vectors of arboviruses in Kelantan are pertinent indicators of the need to improve vector controls to reduce arbovirus infections among people in the localities.

Tropism and immune response of chikungunya and zika viruses: An overview

Zika virus (ZIKV) and chikungunya virus (CHIKV) are two medically important vector-borne viruses responsible for causing significant disease burden in humans, including neurological sequelae/complications. Besides sharing some common clinical features, ZIKV has major shares in causing microcephaly and brain malformations in developing foetus, whereas CHIKV causes chronic joint pain/swelling in infected individuals. Both viruses have a common route of entry to the host body. i.e., dermal site of inoculation through the bite of an infected mosquito and later taken up by different immune cells for further dissemination to other areas of the host body that lead to a range of immune responses via different pathways. The immune responses generated by both viruses have similar characteristics with varying degrees of inflammation and activation of immune cells. However, the overall response of immune cells is not fully explored in the context of ZIKV and CHIKV infection. The knowledge of cellular tropism and the immune response is the key to understanding the mechanisms of viral immunity and pathogenesis, which may allow to develop novel therapeutic strategies for these viral infections. This review aims to discuss recent advancements and identify the knowledge gaps in understanding the mechanism of cellular tropism and immune response of CHIKV and ZIKV.

Antiviral evaluation of 1,4-disubstituted-1,2,3-triazole derivatives against Chikungunya virus

Aim

This work aimed to investigate the antiviral activity of two 1,4-disubstituted-1,2,3-triazole derivatives (1 and 2) against Chikungunya virus (CHIKV) replication.

Materials & methods

Cytotoxicity was analyzed using colorimetric assays and the antiviral potential was evaluated using plaque assays and computational tools.

Results

Compound 2 showed antiviral activity against CHIKV 181-25 in BHK-21 and Vero cells. Also, this compound presented a higher activity against CHIKV BRA/RJ/18 in Vero cells, like compound 1. Compound 2 exhibited virucidal activity and inhibited virus entry while compound 1 inhibited virus release. Molecular docking suggested that these derivatives inhibit nsP1 protein while compound 1 may also target capsid protein.

Conclusion

Both compounds exhibit promising antiviral activity against CHIKV by blocking different steps of virus replication.

Arboviral Risk Associated with Solid Organ and Hematopoietic Stem Cell Grafts: The Prophylactic Answers Proposed by the French High Council of Public Health in a National Context

Diseases caused by arboviruses are on the increase worldwide. In addition to arthropod bites, most arboviruses can be transmitted via accessory routes. Products of human origin (labile blood products, solid organs, hematopoietic stem cells, tissues) present a risk of contamination for the recipient if the donation is made when the donor is viremic. Mainland France and its overseas territories are exposed to a complex array of imported and endemic arboviruses, which differ according to their respective location. This narrative review describes the risks of acquiring certain arboviral diseases from human products, mainly solid organs and hematopoietic stem cells, in the French context. The main risks considered in this study are infections by West Nile virus, dengue virus, and tick-borne encephalitis virus. The ancillary risks represented by Usutu virus infection, chikungunya, and Zika are also addressed more briefly. For each disease, the guidelines issued by the French High Council of Public Health, which is responsible for mitigating the risks associated with products of human origin and for supporting public health policy decisions, are briefly outlined. This review highlights the need for a "One Health" approach and to standardize recommendations at the international level in areas with the same viral epidemiology.

Emerging and re-emerging zoonotic viral diseases in Southeast Asia: One Health challenge

The ongoing significant social, environmental, and economic changes in Southeast Asia (SEA) make the region highly vulnerable to the emergence and re-emergence of zoonotic viral diseases. In the last century, SEA has faced major viral outbreaks with great health and economic impact, including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), arboviruses, highly pathogenic avian influenza (H5N1), and Severe Acute Respiratory Syndrome (SARS-CoV); and so far, imported cases of Middle East Respiratory Syndrome Coronavirus (MERS-CoV). Given the recent challenging experiences in addressing emerging zoonotic diseases, it is necessary to redouble efforts to effectively implement the "One Health" initiative in the region, which aims to strengthen the human-animal-plant-environment interface to better prevent, detect and respond to health threats while promoting sustainable development. This review provides an overview of important emerging and re-emerging zoonotic viral diseases in SEA, with emphasis on the main drivers behind their emergency, the epidemiological situation from January 2000 to October 2022, and the importance of One Health to promote improved intervention strategies.

Chikungunya fever

Chikungunya virus is widespread throughout the tropics, where it causes recurrent outbreaks of chikungunya fever. In recent years, outbreaks have afflicted populations in East and Central Africa, South America and Southeast Asia. The virus is transmitted by Aedes aegypti and Aedes albopictus mosquitoes. Chikungunya fever is characterized by severe arthralgia and myalgia that can persist for years and have considerable detrimental effects on health, quality of life and economic productivity. The effects of climate change as well as increased globalization of commerce and travel have led to growth of the habitat of Aedes mosquitoes. As a result, increasing numbers of people will be at risk of chikungunya fever in the coming years. In the absence of specific antiviral treatments and with vaccines still in development, surveillance and vector control are essential to suppress re-emergence and epidemics.

Dengue-chikungunya infection in the tertiary care hospital of northern India: Cross-sectional latent class cluster analysis in viral infection

Cases of dengue and chikungunya fever are escalating all over India. Both viruses share a common vector, the "Aedes" mosquito. Due to similar clinical symptoms, both the dengue (DENV) and chikungunya (CHIKV) virus can circulate as co-infection. There is very limited data available on dengue-chikungunya co-infection in Uttarakhand, India. The purpose of this study was to determine the seroprevalence of dengue and chikungunya virus infections, as well as their co-infection, in patients presenting with clinical symptoms. Serum samples of clinically suspected patients from the tertiary care hospital of Uttarakhand were collected, and Latent Class Cluster Analysis was performed for clinical profiling. ELISA was performed for DENV and CHIKV. 279 cases were enrolled, out of which 222 (79.5%) came positive for dengue NS1 Ag, 143 (51.2%) for dengue IgM, 98 (35.1%) for IgG followed by 16 (5.7%) of CHIKV IgM, and 4 (1.4%) were NS1 Ag with CHIKV IgM. Among the clinical features, fever (n = 270, 96.8%) was the most common symptom in all suspected dengue and chikungunya cases. Other symptoms like chills (n = 254, 91.0%), arthralgia (n = 241, 86.4%), and headache (n = 240, 86.0%) were present in a significant number. Results showed fewer odds of getting both DENV and CHIKV infection simultaneously, but the risk is still not negligible. This study explores the clinical presentation of the suspected dengue-chikungunya case. The increasing incidence of dengue and chikungunya and their co-infection necessitate the authorities' active surveillance of endemic regions and effective patient care management.

Growth in chikungunya virus-related research in ASEAN and South Asian countries from 1967 to 2022 following disease emergence: a bibliometric and graphical analysis

BACKGROUND

ASEAN (Association of Southeast Asian Nations) is composed of ten Southeast Asian countries bound by socio-cultural ties that promote regional peace and stability. South Asia, located in the southern subregion of Asia, includes nine countries sharing similarities in geographical and ethno-cultural factors. Chikungunya is one of the most significant problems in Southeast and South Asian countries. Much of the current chikungunya epidemic in Southeast Asia is caused by the emergence of a virus strain that originated in Africa and spread to Southeast Asia. Meanwhile, in South Asia, three confirmed lineages are in circulation. Given the positive correlation between research activity and the improvement of the clinical framework of biomedical research, this article aimed to examine the growth of chikungunya virus-related research in ASEAN and South Asian countries.

METHODS

The Scopus database was used for this bibliometric analysis. The retrieved publications were subjected to a number of analyses, including those for the most prolific countries, journals, authors, institutions, and articles. Co-occurrence mapping of terms and keywords was used to determine the current state, emerging topics, and future prospects of chikungunya virus-related research. Bibliometrix and VOSviewer were used to analyze the data and visualize the collaboration network mapping.

RESULTS

The Scopus search engine identified 1280 chikungunya-related documents published by ASEAN and South Asian countries between 1967 and 2022. According to our findings, India was the most productive country in South Asia, and Thailand was the most productive country in Southeast Asia. In the early stages of the study, researchers investigated the vectors and outbreaks of the chikungunya virus. In recent years, the development of antivirus agents has emerged as a prominent topic.

CONCLUSIONS

Our study is the first to present the growth of chikungunya virus-related research in ASEAN and South Asian countries from 1967 to 2022. In this study, the evaluation of the comprehensive profile of research on chikungunya can serve as a guide for future studies. In addition, a bibliometric analysis may serve as a resource for healthcare policymakers.

In silico design and validation of a novel multi-epitope vaccine candidate against structural proteins of Chikungunya virus using comprehensive immunoinformatics analyses

Chikungunya virus (CHIKV) is an emerging viral infectious agent with the potential of causing pandemic. There is neither a protective vaccine nor an approved drug against the virus. The aim of this study was design of a novel multi-epitope vaccine (MEV) candidate against the CHIKV structural proteins using comprehensive immunoinformatics and immune simulation analyses. In this study, using comprehensive immunoinformatics approaches, we developed a novel MEV candidate using the CHIKV structural proteins (E1, E2, 6 K, and E3). The polyprotein sequence was obtained from the UniProt Knowledgebase and saved in FASTA format. The helper and cytotoxic T lymphocytes (HTLs and CTLs respectively) and B cell epitopes were predicted. The toll-like receptor 4 (TLR4) agonist RS09 and PADRE epitope were employed as promising immunostimulatory adjuvant proteins. All vaccine components were fused using proper linkers. The MEV construct was checked in terms of antigenicity, allergenicity, immunogenicity, and physicochemical features. The docking of the MEV construct and the TLR4 and molecular dynamics (MD) simulation were also performed to assess the binding stability. The designed construct was non-allergen and was immunogen which efficiently stimulated immune responses using the proper synthetic adjuvant. The MEV candidate exhibited acceptable physicochemical features. Immune provocation included prediction of HTL, B cell, and CTL epitopes. The docking and MD simulation confirmed the stability of the docked TLR4-MEV complex. The high-level protein expression in the Escherichia coli (E. coli) host was observed through in silico cloning. The in vitro, in vivo, and clinical trial investigations are required to verify the findings of the current study.

Low Transmission of Chikungunya Virus by Aedes aegypti from Vientiane Capital, Lao PDR

In 2012−2013, chikungunya virus (CHIKV) was the cause of a major outbreak in the southern part of Lao People’s Democratic Republic (Lao PDR). Since then, only a few imported cases, with isolates belonging to different lineages, were recorded between 2014 and 2020 in Vientiane capital and few autochthonous cases of ECSA-IOL lineage were detected in the south of the country in 2020. The CHIKV epidemiological profile contrasts with the continuous and intensive circulation of dengue virus in the country, especially in Vientiane capital. The study’s aim was to investigate the ability of the local field-derived Aedes aegypti population from Vientiane capital to transmit the Asian and ECSA-IOL lineages of CHIKV. Our results revealed that, for both CHIKV lineages, infection rates were low and dissemination rates were high. The transmission rates and efficiencies evidenced a low vector competence for the CHIKV tested. Although this population of Ae. aegypti showed a relatively modest vector competence for these two CHIKV lineages, several other factors could influence arbovirus emergence such as the longevity and density of female mosquitoes. Due to the active circulation of CHIKV in Southeast Asia, investigations on these factors should be done to prevent the risk of CHIKV emergence and spread in Lao PDR and neighboring countries.

Multiple chikungunya virus introductions in Lao PDR from 2014 to 2020

The first documented chikungunya virus (CHIKV) outbreak in Lao People’s Democratic Republic (Lao PDR) occurred in 2012–2013. Since then, several imported and a few autochthonous cases were identified by the national arbovirus surveillance network. The present study aimed to summarize the main genetic features of the CHIKV strains detected in Lao PDR between 2014 and 2020. Samples from Lao patients presenting symptoms compatible with a CHIKV infection were centralized in Vientiane Capital city for real-time RT-PCR screening. Molecular epidemiology was performed by sequencing the E2-6K-E1 region. From 2014 to 2020, two Asian lineage isolates (e.g. French Polynesia; Indonesia), one ECSA-IOL lineage isolate (e.g. Thailand) and one unclassified (e.g. Myanmar) were imported in Vientiane Capital city. Sequences from the autochthonous cases recorded in the Central and Southern parts of the country between July and September 2020 belonged to the ECSA-IOL lineage and clustered with CHIKV strains recently detected in neighboring countries. These results demonstrate the multiple CHIKV introductions in Lao PDR since 2014 and provide evidence for sporadic and time-limited circulation of CHIKV in the country. Even if the circulation of CHIKV seems to be geographically and temporally limited in Lao PDR, the development of international tourism and trade may cause future outbreaks of CHIKV in the country and at the regional level.

Effectiveness of CHIKV vaccine VLA1553 demonstrated by passive transfer of human sera

Chikungunya virus (CHIKV) is a reemerging mosquito-borne alphavirus responsible for numerous outbreaks. Chikungunya can cause debilitating acute and chronic disease. Thus, the development of a safe and effective CHIKV vaccine is an urgent global health priority. This study evaluated the effectiveness of the live-attenuated CHIKV vaccine VLA1553 against WT CHIKV infection by using passive transfer of sera from vaccinated volunteers to nonhuman primates (NHP) subsequently exposed to WT CHIKV and established a serological surrogate of protection. We demonstrated that human VLA1553 sera transferred to NHPs conferred complete protection from CHIKV viremia and fever after challenge with homologous WT CHIKV. In addition, serum transfer protected animals from other CHIKV-associated clinical symptoms and from CHIKV persistence in tissue. Based on this passive transfer study, a 50% micro–plaque reduction neutralization test titer of ≥ 150 was determined as a surrogate of protection, which was supported by analysis of samples from a seroepidemiological study. In conclusion, considering the unfeasibility of an efficacy trial due to the unpredictability and explosive, rapidly moving nature of chikungunya outbreaks, the definition of a surrogate of protection for VLA1553 is an important step toward vaccine licensure to reduce the medical burden caused by chikungunya.

Chikungunya Encephalitis: an Inconsistently Reported Headache and Cause of Death in Patients with Pre-Existing Conditions

Chikungunya virus (CHIKV) is an alphavirus of the family Togaviridae with outbreaks occurring across Africa, Asia, parts of Europe, and South and Central America. There are three main lineages of CHIKV, including the West African lineage, the East Central South African (ECSA) lineage, and the Asian lineage. While CHIKV infection usually results in a self-limited febrile illness, there have been reports of concerning neurological manifestations, including encephalitis. Herein we discuss findings of over 700 cases of CHIKV encephalitis and risk factors for death. Additionally, we examined the genotypes of CHIKV associated with encephalitis and found that both the Asian and ECSA lineages were responsible for encephalitis but not the West African lineage. Protein analysis of consensus sequences of CHIKV strains associated with encephalitis identified mutations in the nsP1, nsP2, and nsP3 proteins. Reports and manuscripts of CHIKV encephalitis were inconsistent in reporting viral, demographic, and clinical features which complicated the delineation of risk factors associated with the disease and viral evolution. As climate change contributes to the range expansion of natural vectors, it is important for researchers and clinicians to consistently report patient and viral data to facilitate research and countermeasures for the ecology and epidemiology of CHIKV due to the lack of a targeted treatment or vaccine.

Chikungunya and arthritis: An overview

Chikungunya is caused by CHIKV (chikungunya virus), an emerging and re-emerging arthropod-vectored viral infection that causes a febrile disease with primarily long term sequelae of arthralgia and myalgia and is fatal in a small fraction of infected patients. Sporadic outbreaks have been reported from different parts of the world chiefly Africa, Asia, the Indian and Pacific ocean regions, Europe and lately even in the Americas. Currently, treatment is primarily symptomatic as no vaccine, antibody-mediated immunotherapy or antivirals are available. Chikungunya belongs to a family of arthritogenic alphaviruses which have many pathophysiological similarities. Chikungunya arthritis has similarities and differences with rheumatoid arthritis. Although research into arthritis caused by these alphaviruses have been ongoing for decades and significant progress has been made, the mechanisms underlying viral infection and arthritis are not well understood. In this review, we give a background to chikungunya and the causative virus, outline the history of alphavirus arthritis research and then give an overview of findings on arthritis caused by CHIKV. We also discuss treatment options and the research done so far on various therapeutic intervention strategies.