Long-term sequelae of chikungunya virus disease: A systematic review

Cytokine and T cell responses in post-chikungunya viral arthritis: A cross-sectional study

OBJECTIVE

To define the relationship between chronic chikungunya post-viral arthritis disease severity, cytokine response and T cell subsets in order to identify potential targets for therapy.

METHODS

Participants with chikungunya arthritis were recruited from Colombia from 2019-2021. Arthritis disease severity was quantified using the Disease Activity Score-28 and an Arthritis-Flare Questionnaire adapted for chikungunya arthritis. Plasma cytokine concentrations (interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, interferon-γ and tumor necrosis factor (TNF)) were measured using a Meso Scale Diagnostics assay. Peripheral blood T cell subsets were measured using flow cytometry.

RESULTS

Among participants with chikungunya arthritis (N = 158), IL-2 levels and frequency of regulatory T cells (Tregs) were low. Increased arthritis disease activity was associated with higher levels of inflammatory cytokines (IL-6, TNF and CRP) and immunoregulatory cytokine IL-10 (p<0.05). Increased arthritis flare activity was associated with higher Treg frequencies (p<0.05) without affecting T effector (Teff) frequencies, Treg/Teff ratios and Treg subsets. Finally, elevated levels of IL-2 were correlated with increased Treg frequency, percent Tregs out of CD4+ T cells, and Treg subsets expressing immunosuppressive markers, while also correlating with an increased percent Teff out of live lymphocytes (p<0.05).

CONCLUSION

Chikungunya arthritis is characterized by increased inflammatory cytokines and deficient IL-2 and Treg responses. Greater levels of IL-2 were associated with improved Treg numbers and immunosuppressive markers. Future research may consider targeting these pathways for therapy.

Environmental factors and their impact on chronic pain development and maintenance

It is more than recognized and accepted that the environment affects the physiological responses of all living things, from bacteria to superior vertebrates, constituting an important factor in the evolution of all species. Environmental influences range from natural processes such as sunlight, seasons of the year, and rest to complex processes like stress and other mood disorders, infections, and air pollution, being all of them influenced by how each creature deals with them. In this chapter, it will be discussed how some of the environmental elements affect directly or indirectly neuropathic pain, a type of chronic pain caused by a lesion or disease of the somatosensory nervous system. For that, it was considered the edge of knowledge in translational research, thus including data from human and experimental animals as well as the applicability of such findings.

Adaptive coping strategies among individuals living with long-term chikungunya disease: a qualitative study in Curaçao

OBJECTIVE

Long-term chikungunya disease is characterised by persistent rheumatic symptoms following chikungunya virus infection. As there is no specific treatment available, affected individuals need strategies to adapt. However, research on these is scarce. This study aimed to explore which adaptive coping strategies are employed to manage persistent rheumatic symptoms in daily life.

SETTING

The study was conducted in Curaçao.

DESIGN AND PARTICIPANTS

An explorative qualitative study was conducted between September and October 2020, among a purposive sample of adults, 19 women and 4 men affected by long-term chikungunya disease. In-depth interviews were semi-structured and transcribed verbatim. The data were analysed using inductive thematic analysis.

RESULTS

The disease duration for all participants ranged between 68 and 74 months (6 years). In narrating their experiences of coping with long-term chikungunya disease, four themes were identified: (1) learning to live with the disease; (2) resilience for dealing with pain; (3) maintaining positive self-image and attitude; and (4) coping through spirituality.

CONCLUSION

To live with long-term chikungunya disease with dignity in spite of physical pain and discomfort, participants tried to retain a sense of control of oneself and one's lives, to not let the disease take over, focusing on the positive in their lives, and finding strength and remain hopeful. Interventions such as cognitive-behavioural therapy and mindfulness exercises may be effective in strengthening or regain affected individual's sense of competence and control by fostering adaptive coping skills and resilience. Subsequently, these interventions may improve health-related quality of life when rheumatic symptoms persist following chikungunya virus infection.

Longitudinal analysis of post-acute chikungunya-associated arthralgia in children and adults: A prospective cohort study in Managua, Nicaragua (2014-2018)

Chikungunya can result in debilitating arthralgia, often presenting as acute, self-limited pain, but occasionally manifesting chronically. Little is known about differences in chikungunya-associated arthralgia comparing children to adults over time. To characterize long-term chikungunya-associated arthralgia, we recruited 770 patients (105 0-4 years old [y/o], 200 5-9 y/o, 307 10-15 y/o, and 158 16+ y/o) with symptomatic chikungunya virus infections in Managua, Nicaragua, during two consecutive chikungunya epidemics (2014-2015). Participants were assessed at ~15 days and 1, 3, 6, 12, and 18 months post-fever onset. Following clinical guidelines, we defined participants by their last reported instance of arthralgia as acute (≤10 days post-fever onset), interim (>10 and <90 days), or chronic (≥90 days) cases. We observed a high prevalence of arthralgia (80-95%) across all ages over the study period. Overall, the odds of acute arthralgia increased in an age-dependent manner, with the lowest odds of arthralgia in the 0-4 y/o group (odds ratio [OR]: 0.27, 95% confidence interval [CI]: 0.14-0.51) and the highest odds of arthralgia in the 16+ y/o participants (OR: 4.91, 95% CI: 1.42-30.95) relative to 10-15 y/o participants. Females had higher odds of acute arthralgia than males (OR: 1.63, 95% CI: 1.01-2.65) across all ages. We found that 23-36% of pediatric and 53% of adult participants reported an instance of post-acute arthralgia. Children exhibited the highest prevalence of post-acute polyarthralgia in their legs, followed by the hands and torso - a pattern not seen among adult participants. Further, we observed pediatric chikungunya presenting in two distinct phases: the acute phase and the subsequent interim/chronic phases. Thus, differences in the presentation of arthralgia were observed across age, sex, and disease phase in this longitudinal chikungunya cohort. Our results elucidate the long-term burden of chikungunya-associated arthralgia among pediatric and adult populations.

Monoclonal antibody applications in travel medicine

For decades, immunoglobulin preparations have been used to prevent or treat infectious diseases. Since only a few years, monoclonal antibody applications (mAbs) are taking flight and are increasingly dominating this field. In 2014, only two mAbs were registered; end of October 2023, more than ten mAbs are registered or have been granted emergency use authorization, and many more are in (pre)clinical phases. Especially the COVID-19 pandemic has generated this surge in licensed monoclonal antibodies, although multiple phase 1 studies were already underway in 2019 for other infectious diseases such as malaria and yellow fever. Monoclonal antibodies could function as prophylaxis (i.e., for the prevention of malaria), or could be used to treat (tropical) infections (i.e., rabies, dengue fever, yellow fever). This review focuses on the discussion of the prospects of, and obstacles for, using mAbs in the prevention and treatment of (tropical) infectious diseases seen in the returning traveler; and provides an update on the mAbs currently being developed for infectious diseases, which could potentially be of interest for travelers.

Quality of Life and Disability in Chikungunya Arthritis

BACKGROUND

Chikungunya virus infection, transmitted by Aedes mosquito vectors, causes outbreaks of chikungunya fever (CHIKF), throughout the tropical and subtropical world. Following acute infection, many CHIKF patients develop a second phase, chronic and disabling arthritis.

OBJECTIVE

To evaluate the impact of chikungunya arthritis (CHIKA) on quality of life and disability in a cohort of Brazilian CHIKA patients.

METHODS

We conducted a descriptive, non-interventionist, retrospective cross-sectional study analysing data collected from the medical records of chikungunya virus-infected patients treated between June 1, 2022, and June 30, 2022, in the Brazilian rheumatology clinic of one of us (JKA). To assess disability, quality of life, and pain, patients were evaluated using the Health Assessment Questionnaire Disability Index (HAQ-DI), 12-Item Short-Form Health Survey (SF-12), and Visual Analog Scale (VAS) pain.

RESULTS

Forty-two women with a mean (± SD) age of 57.83 (± 13.05) years had CHIKF confirmed by chikungunya-specific serology. The mean (± SD) time between the onset of chikungunya symptoms and the first clinic visit was 55.19 (± 25.88) days. At this visit, the mean (± SD) VAS pain score and DAS28-ESR were 77.26 (± 23.71) and 5.8 (± 1.29), respectively. The mean (± SD) HAQDI score was 1.52 (± 0.67). The mean (± SD) SF-12 PCS-12 was 29.57 (± 8.62) and SF-12 MCS-12 was 38.42 (± 9.85).

CONCLUSION

CHIKA is often highly disabling. As the mosquito vectors that transmit this illness have spread to every continent except Antarctica, there is a potential for widespread public health impact from CHIKA and the need for more effective, early intervention to prevent CHIKA.

Mucocutaneous manifestations of chikungunya fever: an update

Chikungunya is a viral disease transmitted by female Aedes mosquitoes that has been increasingly reported in many parts of the world across the geographical borders. In addition to fever and joint pain, mucocutaneous manifestations of chikungunya have been reported in 40-75% of infected patients. Dermatological manifestations of chikungunya are often under-recognized and misdiagnosed as clinicians are not sensitized or educated regarding these. The early-onset cutaneous manifestations of chikungunya fever, occurring within 1 month of the fever, include maculopapular rashes, vesiculobullous eruptions, Steven-Johnson syndrome/toxic epidermal necrolysis-like eruptions, flagellate lesions, scrotal dermatitis, oro-genital ulcers, and exacerbation of preexisting dermatoses like psoriasis. Hyperpigmentation, lichenoid eruptions, diffuse hair fall, and exacerbation of acne usually occur as a late manifestation. Diagnosis of these mucocutaneous manifestations can be challenging as they often resemble other common dermatoses. This review article elaborates on various mucocutaneous manifestations of chikungunya fever, based on literature review and authors' clinical experience.

"It's very saddening, you keep on wondering when the symptoms will be over": A qualitative study exploring the long-term chikungunya disease impact on daily life and well-being, 6 years after disease onset

BACKGROUND

Long-term chikungunya is a mosquito-borne disease, characterized by disabling rheumatic symptoms persisting for years, after infection with the chikungunya virus. Previous studies focused on assessing the well-being of affected individuals from a quantitative perspective using generic instruments, and have reported physical and psychological impairment. However, a common critique is that generic instrument's structured responses and pre-defined health domains selected by health professionals, may not capture the full extent of well-being impairment experienced by patients. This study aimed to explore in-depth to which extent long-term chikungunya disease impacts daily living and the physical, psychological, and social well-being from the experiences and perspective of affected individuals.

METHODOLOGY/PRINCIPAL FINDINGS

Using open-ended questions, in-depth interviews were conducted with 20 purposively selected individuals with long-term chikungunya disease, in Curaçao. Interview audio-recordings were transcribed verbatim. The data were thematically analyzed. Living with persistent rheumatic symptoms affected the participant's daily living and well-being in several ways: experience of physical impact (restricted physical functioning and limitations in activities of daily life); experience of psychological impact (altered emotional state, fear of walking and running, psychosocial aspects of footwear adaptations, and uncertainty about disease progression and future health); and experience of social impact (social isolation and impaired relational maintenance, social dependency, challenges of social support, at-work productivity loss, and giving up leisure activities after work).

CONCLUSIONS/SIGNIFICANCE

This study, the first of its kind, indicated that the adverse impact of long-term chikungunya disease is currently underreported. The persistent rheumatic symptoms had a negative effect on functional ability, which in turn impacted broad aspects of daily life and well-being, beyond what is captured by generic instruments. In the view of the findings, physical exercise programs including manual therapy, aerobics, resistance and stretching exercises, and orthopaedic footwear interventions in a multidisciplinary patient-centred approach may improve physical function and subsequently overall well-being.

"What will the doctor give me, the same painkiller?": a qualitative study exploring health-care seeking and symptoms self-management among patients for the treatment of long-term chikungunya disease, in Curaçao

BACKGROUND

Long-term chikungunya disease, characterized by persistent disabling rheumatic symptoms, including poly-arthralgia/arthritis of severe pain intensity, can persist for years after infection with the re-emerging mosquito-borne chikungunya virus. Although persistent symptoms and pain severity are important determinants of health-care seeking and self-management of symptoms, research on these in relation to long-term chikungunya disease is scarce. This study aimed to explore the perceived benefits and perceived barriers concerning health-care seeking, based on the Health Belief Model, and the symptoms self-management strategies used for health outcome improvement among individuals affected by long-term chikungunya disease.

METHODS

An exploratory qualitative descriptive study was conducted with 20 purposively selected adults (17 females and 3 males) with persistent rheumatic symptoms, recruited from an ongoing longitudinal chikungunya cohort, in Curaçao. Semi-structured interviews were carried out, audio-recorded, and transcribed. An iterative coding process was used for themes identification through inductive thematic analyses.

RESULTS

No perceived benefits in health-care seeking were reported. Identified themes in relation to perceived barriers were: (1) health-care seeking at disease onset; (2) general practitioners (GPs) perceptions and awareness of persistent symptoms; (3) challenges for medical referrals and support; (4) no validation of symptoms and challenges accessing therapy; (5) health system restrictions; and (6) social stigmatization of psychological help. These perceived barriers have led participants to self-manage persistent symptoms. Over-the-counter pharmacological and/or non-pharmacological treatments were used without consulting GPs. Identified themes were: (1) self-medication of symptoms; and (2) self-management true non-pharmacological treatments.

CONCLUSIONS

To promote the benefits of long-term health-care seeking and subsequently reduce the possible harmful use of analgesics, a collaborative physician-patient therapeutic relationship need to be encouraged. To facilitate this, important shifts may be needed in chikungunya sequalae education of both patients and health-care professionals, and policy makers need to revise health systems for the long-term provision of multidisciplinary care to achieve beneficial health outcomes in long-term chikungunya disease.

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.

Modelling lifespan reduction in an exogenous damage model of generic disease

We model the effects of disease and other exogenous damage during human aging. Even when the exogenous damage is repaired at the end of acute disease, propagated secondary damage remains. We consider both short-term mortality effects due to (acute) exogenous damage and long-term mortality effects due to propagated damage within the context of a generic network model (GNM) of individual aging that simulates a U.S. population. Across a wide range of disease durations and severities we find that while excess short-term mortality is highest for the oldest individuals, the long-term years of life lost are highest for the youngest individuals. These appear to be universal effects of human disease. We support this conclusion with a phenomenological model coupling damage and mortality. Our results are consistent with previous lifetime mortality studies of atom bomb survivors and post-recovery health studies of COVID-19. We suggest that short-term health impact studies could complement lifetime mortality studies to better characterize the lifetime impacts of disease on both individuals and populations.

Incidence and factors associated with chronic chikungunya arthritis following chikungunya virus infection

OBJECTIVES

Chikungunya virus infection is a mosquito-borne illness. First-phase symptoms include fever, malaise, rash, and arthritis (self-limiting). Some patients can have chronic-phase symptoms, including chronic tenosynovitis, bursitis, and arthritis. This study aimed to determine the incidence and risk factors of chronic arthritis in patients with chikungunya infection.

METHODS

This retrospective cohort study analysed all adults diagnosed with chikungunya infection between 2015 and 2020 at our centre. Baseline and follow-up symptoms were evaluated in serologically confirmed cases. Chronic chikungunya arthritis was persistent arthritis >3 months after the onset. Patients who had preexisting chronic inflammatory arthritis and were lost to follow-up before 3 months from diagnosis were excluded.

RESULTS

This study enrolled 120 patients. The median age was 51 (IQR 14) years, and 78% were female. The median number of joints with arthritis was 4 (IQR 8). The initial visual analog scale (VAS) score was 50 mm (IQR 40). Small joints of the hands, wrist, and knee (44.2%, 43.3%, and 42.3%, respectively) were the most affected. The incidence of chronic chikungunya arthritis was 40.4%. From the multivariable logistic regression, the initial number of joints with arthritis, initial VAS scores, and female sex were independently associated with chronic chikungunya arthritis with odds ratios of 1.09 (95% confidence interval [CI] 1.01-1.18), 1.03 (95% CI 1.01-1.06), and 4.17 (95% CI, 1.05-16.67), respectively.

CONCLUSIONS

Chronic chikungunya arthritis is common in patients with chikungunya virus infection. Its predictive factors include the initial number of joints with arthritis, initial VAS scores, and female sex.

Physical virology: how physics is enabling a better understanding of recent viral invaders

The world is frequently afflicted by several viral outbreaks that bring diseases and health crises. It is vital to comprehend how viral assemblies' fundamental components work to counteract them. Determining the ultrastructure and nanomechanical characteristics of viruses from a physical standpoint helps categorize their mechanical characteristics, offers insight into new treatment options, and/or shows weak spots that can clarify methods for medication targeting. This study compiles the findings from studies on the ultrastructure and nanomechanical behavior of SARS-CoV-2, ZIKV (Zika virus), and CHIKV (Chikungunya virus) viral particles. With results that uncovered aspects of the organization and the spatial distribution of the proteins on the surface of the viral particle as well as the deformation response of the particles when applied a recurring loading force, this review aims to provide further discussion on the mechanical properties of viral particles at the nanoscale, offering new prospects that could be employed for designing strategies for the prevention and treatment of viral diseases.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12551-023-01075-4.

Global geotemporal distribution of chikungunya disease, 2011-2022

BACKGROUND

Chikungunya virus is a mosquito-borne alphavirus, transmitted by Aedes mosquitoes. Humans serve as the primary reservoir. Chikungunya infections typically appear with an abrupt onset of fever, rash, and severe joint pain. Some 40% of cases develop chronic rheumatologic complications that can persist months to years.

OBJECTIVES

To improve precision of risk characterization by analyzing cases of chikungunya by year and by country and depicting this geotemporal distribution in map form.

METHOD

Chikungunya case counts by year were compiled from national or regional health authorities from 2011 to 2022. These data were augmented by published reviews plus the Program for Monitoring Emerging Diseases (ProMED). Country-level distribution was categorized into four groups based on recency and magnitude. Data for India were mapped on a per-state basis.

RESULTS

The global map depicts distribution of chikungunya disease from 2011 through 2022. Most cases are reported in tropical and subtropical areas, but notable exceptions include the northern coast of the Mediterranean Sea. Countries of high recency and frequency include India, Brazil, Sudan, and Thailand. Countries with high frequency, but few cases reported in 2019-22 include many Latin American and Caribbean countries. Subnational foci are discussed in general and mapped for India. The range of Aedes mosquitoes is broader than the geography where chikungunya infection is typically diagnosed.

CONCLUSIONS

These maps help identify geographical regions where residents or travelers are at greatest risk of chikungunya. Once vaccines are licensed to help prevent chikungunya, maps like these can help guide future vaccine decision-making.

Longitudinal Analysis of the Burden of Post-Acute Chikungunya-Associated Arthralgia in Children and Adults: A Prospective Cohort Study in Managua, Nicaragua (2014-2019)

Chikungunya can result in debilitating arthralgia, often presenting as acute, self-limited pain, but occasionally manifesting chronically. Little is known about differences in chikungunya-associated arthralgia comparing children to adults over time. To characterize long-term chikungunya-associated arthralgia, we recruited 770 patients (105 0-4 year olds [y/o], 200 5-9 y/o, 307 10-15 y/o, and 158 16+ y/o) with symptomatic chikungunya virus infections in Managua, Nicaragua, during two chikungunya epidemics (2014-2015). Participants were assessed at ~15 days and 1, 3, 6, 12, and 18 months post-fever onset. Following clinical guidelines, we defined participants by their last reported instance of arthralgia as acute (≤10 days post-fever onset), interim (>10 and <90 days), or chronic (≥90 days) cases. We observed a high prevalence of arthralgia (80-95%) across all ages over the study period. Overall, the odds of acute arthralgia increased in an age-dependent manner, with the lowest odds of arthralgia in the 0-4 y/o group (odds ratio [OR]: 0.27, 95% confidence interval [CI]: 0.14-0.51) and the highest odds of arthralgia in the 16+ y/o participants (OR: 4.91, 95% CI: 1.42-30.95) relative to 10-15 y/o participants. Females had a higher odds of acute arthralgia than males (OR: 1.63, 95% CI: 1.01-2.65) across all ages. We found that 23-36% of pediatric and 53% of adult participants reported an instance of post-acute arthralgia. Children exhibited the highest prevalence of post-acute polyarthralgia in their legs, followed by the hands and torso - a pattern not seen among adult participants. Further, we observed pediatric chikungunya presenting in two distinct phases: the acute phase and the associated interim and chronic phases. Differences in the presentation of arthralgia were observed across age, sex, and disease phase in this longitudinal chikungunya cohort. Our results elucidate the long-term burden of chikungunya-associated arthralgia among pediatric and adult populations.

Evolution and immunopathology of chikungunya virus informs therapeutic development

Chikungunya virus (CHIKV), a mosquito-borne alphavirus, is an emerging global threat identified in more than 60 countries across continents. The risk of CHIKV transmission is rising due to increased global interactions, year-round presence of mosquito vectors, and the ability of CHIKV to produce high host viral loads and undergo mutation. Although CHIKV disease is rarely fatal, it can progress to a chronic stage, during which patients experience severe debilitating arthritis that can last from several weeks to months or years. At present, there are no licensed vaccines or antiviral drugs for CHIKV disease, and treatment is primarily symptomatic. This Review provides an overview of CHIKV pathogenesis and explores the available therapeutic options and the most recent advances in novel therapeutic strategies against CHIKV infections.

The Host Non-Coding RNA Response to Alphavirus Infection

Alphaviruses are important human and animal pathogens that can cause a range of debilitating symptoms and are found worldwide. These include arthralgic diseases caused by Old-World viruses and encephalitis induced by infection with New-World alphaviruses. Non-coding RNAs do not encode for proteins, but can modulate cellular response pathways in a myriad of ways. There are several classes of non-coding RNAs, some more well-studied than others. Much research has focused on the mRNA response to infection against alphaviruses, but analysis of non-coding RNA responses has been more limited until recently. This review covers what is known regarding host cell non-coding RNA responses in alphavirus infections and highlights gaps in the knowledge that future research should address.

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.

Chikungunya: risks for travellers

RATIONALE FOR REVIEW

Chikungunya outbreaks continue to occur, with changing epidemiology. Awareness about chikungunya is low both among the at-risk travellers and healthcare professionals, which can result in underdiagnosis and underreporting. This review aims to improve awareness among healthcare professionals regarding the risks of chikungunya for travellers.

KEY FINDINGS

Chikungunya virus transmission to humans occurs mainly via daytime-active mosquitoes, Aedes aegypti and Aedes albopictus. The areas where these mosquitoes live is continuously expanding, partly due to climate changes. Chikungunya is characterized by an acute onset of fever with joint pain. These symptoms generally resolve within 1-3 weeks but at least one-third of the patients suffer from debilitating rheumatologic symptoms for months to years. Large outbreaks in changing regions of the world since the turn of the 21st century (e.g. Caribbean, La Réunion; currently Brazil, India) have resulted in growing numbers of travellers importing chikungunya, mainly to Europe and North America. Viremic travellers with chikungunya infection have seeded chikungunya clusters (France, United States of America) and outbreaks (Italy in 2007 and 2017) in non-endemic countries where Ae. albopictus mosquitoes are present. Community preventive measures are important to prevent disease transmission by mosquitoes. Individual preventive options are limited to personal protection measures against mosquito bites, particularly the daytime-active mosquitos that transmit the chikungunya virus. Candidate vaccines are on the horizon and regulatory authorities will need to assess environmental and host risk factors for persistent sequelae, such as obesity, age (over 40 years), and history of arthritis or inflammatory rheumatologic disease to determine which populations should be targeted for these chikungunya vaccines.

CONCLUSIONS/RECOMMENDATIONS

Travellers planning to visit destinations with active CHIKV circulation should be advised about the risk for chikungunya, prevention strategies, the disease manifestations, possible chronic rheumatologic sequelae, and if symptomatic, seek medical evaluation and report potential exposures.

Clinical markers of post-Chikungunya chronic inflammatory joint disease: A Brazilian cohort

BACKGROUND

Chikungunya-fever (CHIKF) remains a public health major issue. It is clinically divided into three phases: acute, post-acute and chronic. Chronic cases correspond to 25-40% individuals and, though most of them are characterized by long-lasting arthralgia alone, many of them exhibit persistent or recurrent inflammatory signs that define post-Chikungunya chronic inflammatory joint disease (pCHIKV-CIJD). We aimed to identify early clinical markers of evolution to pCHIKV-CIJD during acute and post-acute phases.

METHODOLOGY/PRINCIPAL FINDINGS

We studied a prospective cohort of CHIKF-confirmed volunteers with longitudinal clinical data collection from symptoms onset up to 90 days, including a 21-day visit (D21). Of 169 patients with CHIKF, 86 (50.9%) completed the follow-up, from whom 39 met clinical criteria for pCHIKV-CIJD (45.3%). The relative risk of chronification was higher in women compared to men (RR = 1.52; 95% CI = 1.15-1.99; FDR = 0.03). None of the symptoms or signs presented at D0 behaved as an early predictor of pCHIKV-CIJD, while being symptomatic at D21 was a risk factor for chronification (RR = 1.31; 95% CI = 1.09-1.55; FDR = 0.03). Significance was also observed for joint pain (RR = 1.35; 95% CI = 1.12-1.61; FDR = 0.02), reported edema (RR = 3.61; 95% CI = 1.44-9.06; FDR = 0.03), reported hand and/or feet small joints edema (RR = 4.22; 95% CI = 1.51-11.78; FDR = 0.02), and peri-articular edema observed during physical examination (RR = 2.89; 95% CI = 1.58-5.28; FDR = 0.002). Furthermore, patients with no findings in physical examination at D21 were at lower risk of chronic evolution (RR = 0.41, 95% CI = 0.24-0.70, FDR = 0.01). Twenty-nine pCHIKV-CIJD patients had abnormal articular ultrasonography (90.6% of the examined). The most common findings were synovitis (65.5%) and joint effusion (58.6%).

CONCLUSION

This cohort has provided important insights into the prognostic evaluation of CHIKF. Symptomatic sub-acute disease is a relevant predictor of evolution to chronic arthritis with synovitis, drawing attention to joint pain, edema, multiple articular involvement including small hand and feet joints as risk factors for chronification beyond three months, especially in women. Future studies are needed to accomplish the identification of accurate and early biomarkers of poor clinical prognosis, which would allow better understanding of the disease's evolution and improve patients' management, modifying CHIKF burden on global public health.

The clinical manifestation and the influence of age and comorbidities on long-term chikungunya disease and health-related quality of life: a 60-month prospective cohort study in Curaçao

BACKGROUND

Persistent rheumatic symptoms and its impact on health-related quality of life (QoL), induced by the Indian Ocean Lineage (IOL) chikungunya virus (CHIKV) genotype have been widely studied. In 2014, a major CHIKV outbreak of the Asian genotype occurred in Curaçao, after which we established a longitudinal cohort in 2015, to follow the long-term CHIKV sequalae. Currently, the long-term clinical manifestations and its impact on QoL induced by the Asian CHIKV genotype, followed prospectively through time, and the association of age and comorbidities with rheumatic symptoms persistence, 60 months (M60) after disease onset is unknown.

METHODS

The cohort of 304 laboratory confirmed patients were followed prospectively in time at 3-16 months (M3-16), 30 months (M30), and M60 after disease onset. Demographic and clinical characteristics, and the 36-item short-form survey (SF-36) QoL status were collected through questionnaires. At M60, QoL scores were compared to general population (CHIK-) norms.

RESULTS

A total of 169 (56%) patients participated (74.6% female, mean age 56.1 years) at all time points, 107 (63%) were classified as recovered and 62 (37%) as affected. The affected patients reported an increase in the prevalence of arthralgia (P .001) and arthralgia in the lower extremities (P < .001), at M30 compared to M3-16. At M60, in comparison to recovered patients, affected patients reported a higher prevalence of recurrent rheumatic symptoms of moderate to severe pain, irrespective of age and comorbidities, and a higher prevalence of non-rheumatic symptoms (P < .001). Arthralgia in the upper (odds ratio (OR): 4.79; confidence interval (CI): 2.01-11.44; P < .001) and lower (OR: 8.68; CI: 3.47-21.69; P < .001) extremities, and headache (OR: 3.85; CI: 1.40-10.54; P = .009) were associated with being affected. The SF-36 QoL scores of the recovered patients were less impaired over time compared to the QoL scores of the affected patients. At M60, the QoL scores of the recovered patients were comparable to the CHIK- QoL scores.

CONCLUSIONS

Rheumatic and non-rheumatic symptoms, and QoL impairment may persist, 60 months following infection with the Asian CHIKV genotype, similar to the IOL genotype disease sequelae. Further research is needed to follow the clinical manifestations and QoL impact of each CHIKV genotype.

Chikungunya: An Emerging Public Health Concern

Purpose of Review

The worldwide spread of chikungunya over the past two decades calls for greater knowledge and awareness of the virus, its route of transmission, methods of diagnosis, and the use of available treatment and prevention measures.

Recent Findings

Chikungunya virus infection, an Aedes mosquito-borne febrile disease, has spread from Africa and Asia to Europe and the Americas and from the tropics and subtropics to temperate regions. International travel is a pivotal influence in the emergence of chikungunya as a global public health threat, as evidenced by a growing number of published reports on travel-related chikungunya infections. The striking features of chikungunya are arthralgia and arthritis, and the disease is often mistaken for dengue. Although mortality is low, morbidity can be profound and persistent. Current treatment for chikungunya is supportive; chikungunya vaccines and therapeutics are in development. Travelers planning to visit areas where the mosquito vectors are present should be advised on preventive measures.

Summary

Chikungunya is an emerging disease in the Americas. Frequent travel, the presence of at least two competent mosquito species, and a largely naïve human population in the Western Hemisphere create a setting conducive to future outbreaks. Awareness of the disease and its manifestations is critical to effectively and safely manage and limit its impact. Vaccines in late-stage clinical trials offer a new pathway to prevention.

Ten sessions of transcranial direct current stimulation for chronic chikungunya arthralgia: study protocol for a randomised clinical trial

INTRODUCTION

The chikungunya virus infection is still an epidemic in Brazil with an incidence of 59.4 cases per 100 000 in the Northeast region. More than 60% of the patients present relapsing and remitting chronic arthralgia with debilitating pain lasting for years. Transcranial direct current stimulation (tDCS) appears promising as a novel neuromodulation approach for pain-related networks to alleviate pain in several pain syndromes. Our objective is to evaluate the effectiveness of tDCS (C3/Fp2 montage) on pain, muscle strength, functionality and quality of life in chronic arthralgia.

METHODS AND ANALYSIS

This protocol is a single-centre, parallel-design, double-blind, randomised, sham-controlled trial. Forty participants will be randomised to either an active or sham tDCS. A total of 10 sessions will be administered over 2 weeks (one per weekday) using a monophasic continuous current with an intensity of 2 mA for 20 min. Participants will be evaluated at baseline, after the 10th session, 2 weeks and 4 weeks after intervention.

PRIMARY OUTCOME

pain assessed using numeric rating scale and algometry.

SECONDARY OUTCOMES

muscle strength, functionality and quality of life. The effects of stimulation will be calculated using a mixed analysis of variance model.

ETHICS AND DISSEMINATION

The study was approved by the ethics committee of the Faculty of Health Sciences of Trairí, Federal University of Rio Grande do Norte (No. 2.413.851) and registered on the Brazilian Registry of Clinical Trials. Study results will be disseminated through presentations at conferences and publications in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

RBR-469yd6.

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.

Structural insights into the inhibition of the nsP2 protease from Chikungunya virus by molecular modeling approaches

Chikungunya virus (CHIKV) is the etiological agent of the Chikungunya fever which has spread worldwide. Clinically, this disease may lead to prolonged incapacitating joint pain that can compromise remarkably the patients' quality of life. However, there are no licensed vaccines or specific drugs to fight this infection yet, making the search for novel therapies an imperative need. In this scenario, the CHIKV nsP2 protease emerged as an attractive therapeutic target once this protein plays a pivotal role in viral replication and pathogenesis. Hence, we investigated the structural basis for the inhibition of this enzyme by using molecular docking and dynamics simulations. Compounds with inhibitory activities against CHIKV nsP2 protease determined experimentally were selected from the literature. Docking studies with a set of stereoisomers showed that trans isomers, but not cis ones, bound close to the catalytic dyad which may explain isomerism requirements to the enzyme's inhibition. Further, binding mode analyses of other known inhibitors revealed highly conserved contacts between inhibitors and enzyme residues like N1011, C1013, A1046, Y1079, N1082, W1084, L1205, and M1242. Molecular dynamics simulations reinforced the importance of some of these interactions and pointed to nonpolar interactions as the main forces for inhibitors' binding. Finally, we observed that true inhibitors exhibited lower structural fluctuation, higher ligand efficiency and did not induce significant changes in protein correlated motions. Collectively, our findings might allow discerning true inhibitors from false ones and can guide drug development efforts targeting the nsP2 protease to fight CHIKV infections in the future.

Safety and immunogenicity of PXVX0317, an aluminium hydroxide-adjuvanted chikungunya virus-like particle vaccine: a randomised, double-blind, parallel-group, phase 2 trial

BACKGROUND

Chikungunya virus (CHIKV) disease is an ongoing public health threat. We aimed to evaluate the safety and immunogenicity of PXVX0317, an aluminium hydroxide-adjuvanted formulation of a CHIKV virus-like particle (VLP) vaccine.

METHODS

This randomised, double-blind, parallel-group, phase 2 trial was conducted at three clinical trial centres in the USA. Eligible participants were healthy CHIKV-naïve adults aged 18-45 years. Participants were stratified by site and randomly assigned (1:1:1:1:1:1:1:1) to one of the eight vaccination groups using a block size of 16. Group 1 received two doses of unadjuvanted PXVX0317 28 days apart (2 × 20 μg; standard); all other groups received adjuvanted PXVX0317: groups 2-4 received two doses 28 days apart (2 × 6 μg [group 2], 2 × 10 μg [group 3], or 2 × 20 μg [group 4]; standard); group 4 also received a booster dose 18 months after the first active injection (40 μg; standard plus booster); groups 5-7 received two doses 14 days apart (2 × 6 μg [group 5], 2 × 10 μg [group 6], or 2 × 20 μg [group 7]; accelerated); and group 8 received one dose (1 × 40 μg; single). The primary endpoint was the geometric mean titre of anti-CHIKV neutralising antibody on day 57 (28 days after the last vaccination), assessed in the immunogenicity-evaluable population. Additionally, we assessed safety. This trial is registered at ClinicalTrials.gov, NCT03483961.

FINDINGS

This trial was conducted from April 18, 2018, to Sept 21, 2020; 468 participants were assessed for eligibility. Of these, 415 participants were randomly assigned to eight groups (n=53 in groups 1, 5, and 6; n=52 in groups 2 and 8; n=51 in groups 3 and 7; and n=50 in group 4) and 373 were evaluable for immunogenicity. On day 57, serum neutralising antibody geometric mean titres were 2057·0 (95% CI 1584·8-2670·0) in group 1, 1116·2 (852·5-1461·4; p=0·0015 vs group 1 used as a reference) in group 2, 1465·3 (1119·1-1918·4; p=0·076) in group 3, 2023·8 (1550·5-2641·7; p=0·93) in group 4, 920·1 (710·9-1190·9; p<0·0001) in group 5, 1206·9 (932·4-1562·2; p=0·0045) in group 6, 1562·8 (1204·1-2028·3; p=0·14) in group 7, and 1712·5 (1330·0-2205·0; p=0·32) in group 8. In group 4, a booster dose increased serum neutralising antibody geometric mean titres from 215·7 (95% CI 160·9-289·1) on day 547 to 10 941·1 (7378·0-16 225·1) on day 575. Durability of the immune response (evaluated in groups 1, 4, and 8) was shown up to 2 years. The most common solicited adverse event was pain at the injection site, reported in 12 (23%) of 53 participants who received the unadjuvanted vaccine (group 1) and 111 (31%) of 356 who received the adjuvanted vaccine. No vaccine-related serious adverse events were reported.

INTERPRETATION

PXVX0317 was well tolerated and induced a robust and durable serum neutralising antibody immune response against CHIKV up to 2 years. A single 40 μg injection of adjuvanted PXVX0317 is being further investigated in phase 3 clinical trials (NCT05072080 and NCT05349617).

FUNDING

Emergent BioSolutions.

Chikungunya Virus Shedding in Semen: A Case Series

Background: Chikungunya is a viral disease that is transmitted by mosquitoes. It is characterized by an acute onset of fever and severe arthralgia. Methods: We describe six cases of acute and post-acute chikungunya in which viral RNA was detected in semen. Conclusions: The most prolonged detection period was 56 days after illness onset. We attempted to cultivate positive semen samples, but virus isolation was unsuccessful in all cases.

A diversified role for γδT cells in vector-borne diseases

Vector-borne diseases have high morbidity and mortality and are major health threats worldwide. γδT cells represent a small but essential subpopulation of T cells. They reside in most human tissues and exert important functions in both natural and adaptive immune responses. Emerging evidence have shown that the activation and expansion of γδT cells invoked by pathogens play a diversified role in the regulation of host-pathogen interactions and disease progression. A better understanding of such a role for γδT cells may contribute significantly to developing novel preventative and therapeutic strategies. Herein, we summarize recent exciting findings in the field, with a focus on the role of γδT cells in the infection of vector-borne pathogens.

Chikungunya Immunopathology as It Presents in Different Organ Systems

Chikungunya virus (CHIKV) is currently an urgent public health problem as high morbidity from the virus leaves populations with negative physical, social, and economic impacts. CHIKV has the potential to affect every organ of an individual, leaving patients with lifelong impairments which negatively affect their quality of life. In this review, we show the importance of CHIKV in research and public health by demonstrating the immunopathology of CHIKV as it presents in different organ systems. Papers used in this review were found on PubMed, using “chikungunya and [relevant organ system]”. There is a significant inflammatory response during CHIKV infection which affects several organ systems, such as the brain, heart, lungs, kidneys, skin, and joints, and the immune response to CHIKV in each organ system is unique. Whilst there is clinical evidence to suggest that serious complications can occur, there is ultimately a lack of understanding of how CHIKV can affect different organ systems. It is important for clinicians to understand the risks to their patients.

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.

The Impact of COVID Vaccination on Symptoms of Long COVID: An International Survey of People with Lived Experience of Long COVID

Long COVID is a multi-system syndrome following SARS-CoV-2 infection with persistent symptoms of at least 4 weeks, and frequently for several months. It has been suggested that there may be an autoimmune component. There has been an understandable caution amongst some people experiencing long COVID that, by boosting their immune response, a COVID vaccine may exacerbate their symptoms. We aimed to survey people living with long COVID, evaluating the impact of their first COVID vaccination on their symptoms. Methods: Patients with long COVID were invited to complete a web-based questionnaire through postings on social media and direct mailing from support groups. Basic demographics, range and severity of long COVID symptoms, before and after their vaccine, were surveyed. Results: 900 people participated in the questionnaire, of whom 45 had pre-existing myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) but no evidence of COVID infection, and a further 43 did not complete the survey in full. The demographics and symptomology of the remaining 812 people were similar to those recorded by the UK Office of National Statistics. Following vaccination, 57.9% of participants reported improvements in symptoms, 17.9% reported deterioration and the remainder no change. There was considerable individual variation in responses. Larger improvements in symptom severity scores were seen in those receiving the mRNA vaccines compared to adenoviral vector vaccines. Conclusions: Our survey suggests COVID-19 vaccination may improve long COVID patients, on average. The observational nature of the survey limits drawing direct causal inference, but requires validation with a randomised controlled trial.

Rheumatic symptoms following COVID-19: a chronic post COVID-19 condition

Background

Detailed characteristics of rheumatic symptoms of coronavirus disease 2019 (COVID-19) were still unknown. We aim to investigate the proportions, characteristics, and risk factors of this condition.

Methods

In this prospective, longitudinal cohort study, discharged patients with COVID-19 were interviewed face-to-face at 12 months after symptom onset. Rheumatic symptoms following COVID-19 included newly occurring joint pain and/or joint swelling. The risk factors of developing rheumatic symptoms were identified by multivariable logistic regression analysis.

Results

In total, 1296 of 2469 discharged patients with COVID-19 were enrolled in this study. Among them, 160 (12.3% [95% confidence interval {CI}, 10.6%–14.3%]) suffered from rheumatic symptoms following COVID-19 at 12-month follow-up. The most frequently involved joints were the knee joints (38%), followed by hand (25%) and shoulder (19%). Rheumatic symptoms were independent of the severity of illness and corticosteroid treatment during the acute phase, while elderly age (odds ratio [OR], 1.22 [95% CI, 1.06–1.40]) and female sex (OR, 1.58 [95% CI, 1.12–2.23]) were identified as the risk factors for this condition.

Conclusions

Our investigation showed a considerable proportion of rheumatic symptoms following COVID-19 in discharged patients, which highlights the need for continuing attention. Notably, rheumatic symptoms following COVID-19 were independent of the severity of illness and corticosteroid treatment during the acute phase.

Post-chikungunya arthritis: a longitudinal study in a tertiary care hospital in Bangladesh

Background and objective

To identify the clinical patterns and consequences of post-chikungunya arthritis was the study's objective.

Methods

This longitudinal study was carried out among 143 Chikungunya virus (CHIKV) infected adult patients at the rheumatology department, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh, during the outbreak of CHIKV infection in 2017. The disease was categorized into three phases: acute or febrile (lasting up to 10 days), subacute (11–90 days), and chronic (> 90 days). Patients who progressed towards the chronic phase were followed up to 1-year. Post-CHIKV de novo chronic inflammatory rheumatisms (CIRs) were characterized by persistent mono or oligoarthritis, undifferentiated polyarthritis, or meet the criteria rheumatoid arthritis (RA) or Spondyloarthritis (SpA). In addition, functional status was assessed by the validated Bangla version of the Health Assessment Questionnaire (HAQ).

Results

Mean age was 43.3 ± 11.5 years, and 51.0% were male. Within 1-year follow-up, 60 (41.9%) patients were suffering from arthralgia/ arthritis. Of them 52 patients did not have any pre-existing arthralgia/arthritis. 35 (65.3%) had undifferentiated arthritis, 10 (19.2%) had SpA, and 7 (13.5%) had RA. Patients with pre-existing rheumatological disorders, 6(4.2%) had SpA, 1(0.7%) had RA and 1(0.7%) had osteoarthritis. Polyarthralgia (n = 33, 55.0%) and polyarthritis (n = 20, 33.3%) were the main presentations. Female gender (OR: 0.45; CI: 0.21–0.96), positive IgG (OR: 0.30; CI: 0.12–0.76), and moderate to severe functional disability (OR: 3.46; CI: 1.62–7.40) were independent predictors of developing chronic post-CHIKV rheumatism.

Conclusions

At 1-year follow-up, more than one-third of the patients remained symptomatic. Female gender, positive IgG, and moderate to severe functional disability contributed to the development of chronicity.

Interleukin-17 contributes to Ross River virus-induced arthritis and myositis

Arthritogenic alphaviruses are mosquito-borne viruses that are a major cause of infectious arthropathies worldwide, and recent outbreaks of chikungunya virus and Ross River virus (RRV) infections highlight the need for robust intervention strategies. Alphaviral arthritis can persist for months after the initial acute disease, and is mediated by cellular immune responses. A common strategy to limit inflammation and pathology is to dampen the overwhelming inflammatory responses by modulating proinflammatory cytokine pathways. Here, we investigate the contribution of interleukin-17 (IL-17), a cytokine involved in arthropathies such as rheumatoid arthritis, in the development RRV-induced arthritis and myositis. IL-17 was quantified in serum from RRV-infected patients, and mice were infected with RRV and joints and muscle tissues collected to analyse cellular infiltrates, tissue mRNA, cytokine expression, and joint and muscle histopathology. IL-17 expression was increased in musculoskeletal tissues and serum of RRV-infected mice and humans, respectively. IL-17–producing T cells and neutrophils contributed to the cellular infiltrate in the joint and muscle tissue during acute RRV disease in mice. Blockade of IL-17A/F using a monoclonal antibody (mAb) reduced disease severity in RRV-infected mice and led to decreased proinflammatory proteins, cellular infiltration in synovial tissues and cartilage damage, without affecting viral titers in inflamed tissues. IL-17A/F blockade triggered a shift in transcriptional profile of both leukocyte infiltrates and musculoskeletal stromal cells by downregulating proinflammatory genes. This study highlights a previously uncharacterized role for an effector cytokine in alphaviral pathology and points towards potential therapeutic benefit in targeting IL-17 to treat patients presenting with RRV-induced arthropathy.

Some viruses transmitted by mosquitoes cause painful and debilitating arthritis, which manifests both as an acute form shortly following infection, and a chronic form long after the initial symptoms have subsided. These viruses, termed arboviruses, are difficult to control and there are currently no specific treatments to alleviate the pain and loss of mobility. Arthritis caused by arboviruses shares similarities with a non-infectious, autoimmune form of arthritis called rheumatoid arthritis (RA). In RA, an immune molecule termed interleukin-17, or IL-17, has been shown to drive arthritis and treatments that target or block IL-17 are being developed to treat RA. Here, we asked whether arthritis caused by an arbovirus, Ross River virus (RRV), was also associated with elevated IL-17 in humans and mice. Disease severity in mice was associated with high IL-17 expression in the feet and muscle, and blocking IL-17 using an anti-IL-17 monoclonal antibody ameliorated disease in mice infected with RRV. Our study provides new information on a molecule that is implicated in arthritic inflammation, and could be targeted to treat disease caused by arthritogenic arboviruses.

Nervous System Manifestations of Arboviral Infections

Purpose of Review

Complex environmental factors and human intervention influence the spread of arthropod vectors and the cycle of transmission of arboviruses. The spectrum of clinical manifestations is diverse, ranging from serious presentations like viral hemorrhagic fever (e.g., dengue, yellow fever, rift valley fever) or shock syndromes (e.g., dengue virus) to organ-specific illness like meningoencephalitis.

Recent Findings

A spectrum of clinical neurologic syndromes with potential acute devastating consequences or long-term sequelae may result from some arboviral infections.

Summary

In this review, we describe some of the most frequent and emerging neuro-invasive arboviral infections, spectrum of neurologic disorders including encephalitis, meningitis, myelitis or poliomyelitis, acute demyelinating encephalomyelitis, Guillain-Barré syndrome, and ocular syndromes.

Acute-Phase Levels of CXCL8 as Risk Factor for Chronic Arthralgia Following Chikungunya Virus Infection

The immunopathogenesis of chikungunya virus (CHIKV) infection and the role of acute-phase immune response on joint pain persistence is not fully understood. We investigated the profile of serum chemokine and cytokine in CHIKV-infected patients with acute disease, compared the levels of these biomarkers to those of patients with other acute febrile diseases (OAFD) and healthy controls (HC), and evaluated their role as predictors of chronic arthralgia development. Chemokines and cytokines were measured by flow Cytometric Bead Array. Patients with CHIKV infection were further categorized according to duration of arthralgia (≤ 3 months vs >3 months), presence of anti-CHIKV IgM at acute-phase sample, and number of days of symptoms at sample collection (1 vs 2-3 vs ≥4). Patients with acute CHIKV infection had significantly higher levels of CXCL8, CCL2, CXCL9, CCL5, CXCL10, IL-1β, IL-6, IL-12, and IL-10 as compared to HC. CCL2, CCL5, and CXCL10 levels were also significantly higher in patients with CHIKV infection compared to patients with OAFD. Patients whose arthralgia lasted > 3 months had increased CXCL8 levels compared to patients whose arthralgia did not (p<0.05). Multivariable analyses further indicated that high levels of CXCL8 and female sex were associated with arthralgia lasting >3 months. Patients with chikungunya and OAFD had similar cytokine kinetics for IL-1β, IL-12, TNF, IFN-γ, IL-2, and IL-4, although the levels were lower for CHIKV patients. This study suggests that chemokines may have an important role in the immunopathogenesis of chronic chikungunya-related arthralgia.

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.

Tender and swollen joint counts are poorly associated with disability in chikungunya arthritis compared to rheumatoid arthritis

Chronic rheumatological manifestations similar to those of rheumatoid arthritis (RA) are described after chikungunya virus infection. We aimed to compare the relevance of joint counts and symptoms to clinical outcomes in RA and chronic chikungunya disease. Forty patients with chronic chikungunya arthralgia and 40 patients with RA were enrolled in a cross-sectional study. The association of tenderness and swelling, clinically assessed in 28 joints, and patient evaluations of pain and musculoskeletal stiffness with modified Health Assessment Questionnaire (HAQ) and quality of life (QoL) assessments were investigated. Tender and swollen joint counts, pain and stiffness scores were all associated with the HAQ disability index in RA (all r > 0.55, p ≤ 0.0002), but only stiffness was significantly associated with disability in chikungunya (r = 0.38, p = 0.02). Joint counts, pain and stiffness were also associated with most QoL domains in RA patients. In contrast, in chikungunya disease, tender joint counts were associated only with one QoL domain and swollen joints for none, while pain and stiffness were associated with several domains. Our results confirm the relevance of joint counts in RA, but suggest that in chronic chikungunya disease, joint counts have more limited value. Stiffness and pain score may be more important to quantify chikungunya arthritis impact.

Arthralgia resolution rate following chikungunya virus infection

•

This study investigated the duration of persistence of chikungunya-related arthralgia.

•

Statisticalanalysis of multiple cohorts of chikungunya patients was performed.

•

First estimates of the average rate of chronic chikungunya virus arthralgia resolution were calculated.

•

Varying rates of arthralgia resolution are associated with age and other factors.

Background

Arthralgia, persistent pain or stiffness of the joints, is the hallmark symptom of chronic chikungunya virus (CHIKV) disease. Associated with significant disability and reduced quality of life, arthralgia can persist for many months following CHIKV infection. Understanding the expected duration of arthralgia persistence is important for managing clinical expectations at the individual-level as well as for estimating long-term burdens on population health following a CHIKV epidemic.

Methods

A review of cohort studies reporting the prevalence of arthralgia post-CHIKV infection over multiple time points was conducted. Generalized linear models were used to estimate the average rate of arthralgia resolution following CHIKV infection.

Results

Sixteen cohort studies matching the inclusion criteria were identified and included in the analysis. An average rate of arthralgia resolution of 10.85% (95% confidence interval (CI) 9.05–12.66%) per month was estimated across studies, corresponding to an expected median time to arthralgia resolution of 6.39 months (95% CI 5.48–7.66 months) and an expected arthralgia prevalence of 72.21% (95% CI 68.40–76.23%) at 3 months post-CHIKV infection.

Conclusions

Estimates of the average rate of arthralgia resolution and the expected prevalence of arthralgia over time post-CHIKV infection were derived. These can help inform expectations regarding the long-term public health burdens associated with CHIKV epidemics.

Implications of Innate Immunity in Post-Acute Sequelae of Non-Persistent Viral Infections

Non-persistent viruses classically cause transient, acute infections triggering immune responses aimed at the elimination of the pathogen. Successful viruses evolved strategies to manipulate and evade these anti-viral defenses. Symptoms during the acute phase are often linked to dysregulated immune responses that disappear once the patient recovers. In some patients, however, symptoms persist or new symptoms emerge beyond the acute phase. Conditions resulting from previous transient infection are termed post-acute sequelae (PAS) and were reported for a wide range of non-persistent viruses such as rota-, influenza- or polioviruses. Here we provide an overview of non-persistent viral pathogens reported to be associated with diverse PAS, among them chronic fatigue, auto-immune disorders, or neurological complications and highlight known mechanistic details. Recently, the emergence of post-acute sequelae of COVID-19 (PASC) or long COVID highlighted the impact of PAS. Notably, PAS of non-persistent infections often resemble symptoms of persistent viral infections, defined by chronic inflammation. Inflammation maintained after the acute phase may be a key driver of PAS of non-persistent viruses. Therefore, we explore current insights into aberrant activation of innate immune signaling pathways in the post-acute phase of non-persistent viruses. Finally, conclusions are drawn and future perspectives for treatment and prevention of PAS are discussed.

Mode-Dependent Antiviral Activity of Medicinal Plant Extracts against the Mosquito-Borne Chikungunya Virus

The lack of specific treatment for chikungunya fever makes the need for anti-chikungunya virus agents more crucial. This study was conducted to evaluate 132 extracts obtained by sequential solvent extraction from 21 medicinal plants for cytopathic effect inhibitory activity using virus-infected Vero cells in two different sample introduction modes. Among the extracts, 42 extracts (31.8%) from 12 plants in the concurrent mode and three extracts (2.3%) from a plant in the non-concurrent mode displayed strong cytopathic effect inhibitory activity (cell viability ≥70%). Viral load quantification analysis unveiled that the extracts of Clinacanthus nutans (chloroform, ethyl acetate, and ethanol), Hydrocotyle sibthorpioides (ethanol), and Ocimum americanum (ethanol and methanol) hindered the release of viral progeny from the infected cells while the extracts of Ficus deltoidea (ethanol), Gynura bicolor (water), H. sibthorpioides (water), and O. americanum (chloroform and ethyl acetate) blocked the entry of virus into the cells. The extracts of Diodella sarmentosa (ethyl acetate), Diplazium esculentum (chloroform, ethyl acetate, and ethanol), and G. bicolor (ethanol) possessed virucidal effect and caused 5.41-log to 6.63-log reductions of viral load compared to the virus control. The results indicate that these medicinal plants are potential sources of anti-chikungunya virus agents that have varied modes of action.

Targeting Chikungunya Virus Entry: alternatives for new inhibitors in drug discovery

Chikungunya virus (CHIKV) is an Alphavirus (Togaviridae) responsible for Chikungunya fever (CHIKF) that is mainly characterized by a severe polyarthralgia, in which it is transmitted by the bite of infected Aedes aegypti and Ae. albopictus mosquitoes. Nowadays, there no licensed vaccines or approved drugs to specifically treat this viral disease. Structural viral proteins participate in key steps of its replication cycle, such as viral entry, membrane fusion, nucleocapsid assembly, and virus budding. In this context, envelope E3-E2-E1 glycoproteins complex could be targeted for designing new drug candidates. In this review, aspects of the CHIKV entry process are discussed to provide insights to assist the drug discovery process. Moreover, several natural, nature-based and synthetic compounds, as well as repurposed drugs and virtual screening, are also explored as alternatives for developing CHIKV entry inhibitors. Finally, we provided a complimentary analysis of studies involving inhibitors that were not explored by in silico methods. Based on this, Phe118, Val179, and Lys181 were found to be the most frequent residues, being present in 89.6, 82.7, and 93.1% of complexes, respectively. Lastly, some chemical aspects associated with interactions of these inhibitors and mature envelope E3-E2-E1 glycoproteins' complex were discussed to provide data for scientists worldwide, supporting their search for new inhibitors against this emerging arbovirus.

"Kankasha" in Kassala: A prospective observational cohort study of the clinical characteristics, epidemiology, genetic origin, and chronic impact of the 2018 epidemic of Chikungunya virus infection in Kassala, Sudan

Background

The public health impact of Chikungunya virus (CHIKV) is often underestimated. Usually considered a mild condition of short duration, recent outbreaks have reported greater incidence of severe illness, fatality, and longer-term disability. In 2018/19, Eastern Sudan experienced the largest epidemic of CHIKV in Africa to date, affecting an estimated 487,600 people. Known locally as Kankasha, this study examines clinical characteristics, risk factors, and phylogenetics of the epidemic in Kassala City.

Methodology/Principal findings

A prospective cohort of 102 adults and 40 children presenting with chikungunya-like illness were enrolled at Kassala Teaching Hospital in October 2018. Clinical information, socio-demographic data, and sera samples were analysed to confirm diagnosis, characterise illness, and identify viral strain. CHIKV infection was confirmed by real-time reverse transcription-PCR in 84.5% (120/142) of participants. Nine (7.5%) CHIKV-positive participants had concurrent Dengue virus (DENV) infection; 34/118 participants (28.8%) had a positive Rapid Diagnostic Test for Plasmodium falciparum; six (5.0%) had haemorrhagic symptoms including two children with life-threatening bleeding. One CHIKV-positive participant died with acute renal injury. Age was not associated with severity of illness although CHIKV-infected participants were younger (p = 0.003).

Two to four months post-illness, 63% of adults available for follow-up (30) were still experiencing arthralgia in one or more joints, and 11% remained moderately disabled on Rapid3 assessment. Phylogenetic analysis showed all CHIKV sequences from this study belonged to a single clade within the Indian Ocean Lineage (IOL) of the East/Central/South African (ECSA) genotype. History of contact with an infected person was the only factor associated with infection (p = 0.01), and likely related to being in the same vector environment.

Conclusions/Significance

Vulnerability to CHIKV remains in Kassala and elsewhere in Sudan due to widespread Aedes aegypti presence and mosquito-fostering household water storage methods. This study highlights the importance of increasing awareness of the severity and impact of CHIKV outbreaks, and the need for urgent actions to reduce transmission risk in households.

Chikungunya is an arboviral disease transmitted to humans by infected mosquitoes and characterised by fever and arthralgia. Although it is generally considered a short self-limiting infection, long term sequelae and severe disease are increasingly recognised. In 2018/19, Eastern Sudan experienced the largest epidemic of Chikungunya in Africa to date, affecting approximately 500,000 people. We undertook a prospective hospital-based cohort study of patients presenting with undifferentiated febrile illness in Kassala city, Sudan, supported by next-generation sequencing. We confirmed that CHIKV was the dominant pathogen, with positive CHIKV RT-PCR in 85% of patients presenting during the 7-day study period. Dengue virus was also circulating with nine CHIKV RT-PCR-positive patients co-infected, and we identified high rates of Plasmodium falciparum infection and CHIKV/P.falciparum co-infection. Genetic sequencing confirmed Indian Ocean Lineage of the East/Central/South African CHIKV genotype. A quarter of participants available for follow-up (16/60, 26.6%) reported being admitted to hospital including two children with haemorrhage, reflecting the severe phenotype linked to this genotype. Increased understanding of the health and economic burden of Chikungunya is needed, and recognition that severe and occasionally fatal infection exists. With widespread presence of Ae. aegypti and household water storage practices that encourage mosquito breeding, timely actions will be essential to prevent further large outbreaks.

Post-Chikungunya Virus Infection Musculoskeletal Disorders: Syndromic Sequelae after an Outbreak

The Chikungunya virus is a re-emerging mosquito-borne alphavirus. Outbreaks are unpredictable and explosive in nature. Fever, arthralgia, and rash are common symptoms during the acute phase. Diagnostic tests are required to differentiate chikungunya virus from other co-circulating arboviruses, as symptoms can overlap, causing a dilemma for clinicians. Arthritis is observed during the sub-acute and chronic phases, which can flare up, resulting in increased morbidity that adversely affects the activities of daily living. During the 2019 chikungunya epidemic in Thailand, cases surged in Bangkok in the last quarter of the year. Here, we demonstrate the chronic sequelae of post-chikungunya arthritis in one of our patients one year after the initial infection. An inflammatory process involving edema, erythema, and tenderness to palpation of her fingers' flexor surfaces was observed, with positive chikungunya IgG and negative IgM tests and antigen. The condition produced stiffness in the patient's fingers and limited their range of motion, adversely affecting daily living activities. Resolution of symptoms was observed with a short course of an anti-inflammatory agent. More research is required to determine whether sanctuaries enable chikungunya virus to evade the host immune response and remain latent, flaring up months later and triggering an inflammatory response that causes post-chikungunya arthritis.

Arthritogenic Alphavirus Capsid Protein

In the past two decades Old World and arthritogenic alphavirus have been responsible for epidemics of polyarthritis, causing high morbidity and becoming a major public health concern. The multifunctional arthritogenic alphavirus capsid protein is crucial for viral infection. Capsid protein has roles in genome encapsulation, budding and virion assembly. Its role in multiple infection processes makes capsid protein an attractive target to exploit in combating alphaviral infection. In this review, we summarize the function of arthritogenic alphavirus capsid protein, and describe studies that have used capsid protein to develop novel arthritogenic alphavirus therapeutic and diagnostic strategies.

Risk of chronic arthralgia and impact of pain on daily activities in a cohort of patients with chikungunya virus infection from Brazil

OBJECTIVES

To investigate risk factors for persistent arthralgia in patients with chikungunya, and describe its impact on daily activities.

METHODS

From September 2014 to July 2016, a surveillance study enrolled patients with acute febrile illness in Salvador, Brazil, and detected those with chikungunya virus infection using IgM enzyme-linked immunosorbent assay or reverse transcriptase polymerase chain reaction. Telephone follow-ups were performed to ascertain the progression of disease.

RESULTS

Of 153 followed cases, 65 (42.5%) reported chronic arthralgia that lasted >3 months, and 47 (30.7%) were still symptomatic at the time of the interview (approximately 1.5 years after symptom onset). Limitations in daily activities and mental distress were reported by 93.8% and 61.5% of those with chronic arthralgia, respectively. Female sex [risk ratio (RR) 1.79, 95% confidence interval (CI) 1.95-2.69] and age (RR 1.02 for each 1-year increase, 95% CI 1.01-1.03) were independent risk factors for chronic arthralgia. Chronic arthralgia was not associated with co-infection with dengue virus (RR 0.97, 95% CI 0.48-1.94) or chikungunya viral load at diagnosis (median chikungunya virus RNA of 5.60 and 5.52 log₁₀ copies/μL for those with and without chronic arthralgia, respectively; P = 0.75).

CONCLUSIONS

These findings reinforce the high frequency of chronic chikungunya arthralgia, and highlight the substantial disability associated with the persistence of pain. Development of novel strategies to mitigate the transmission of chikungunya virus and to provide long-term medical assistance for patients with chikungunya are needed urgently.

The CD147 Protein Complex Is Involved in Entry of Chikungunya Virus and Related Alphaviruses in Human Cells

Chikungunya virus (CHIKV) is an arbovirus with a global spread and significant public health impact. It is a positive stranded RNA alphavirus belonging to the Togaviridae family. However, many questions about the replication cycle of CHIKV remain unanswered. The entry process of CHIKV is not completely understood nor are the associated virus-receptor interactions fully identified. Here, we designed an affinity purification mass spectrometry coupled approach that allowed the identification of factors that facilitate entry of CHIKV in human cells. The identified entry factors were further validated using CRISPR/Cas9. In HEK293T cells we identified the CD147 protein complex as an entry factor for CHIKV. We further showed the involvement of the CD147 protein complex in the replication cycle of related alphaviruses. Interestingly, CD147 contains similar protein domains as the previously identified alphavirus entry factor MXRA8.