Stiffness, pain, and joint counts in chronic chikungunya disease: relevance to disability and quality of life

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.

The Natural History of Post-Chikungunya Viral Arthritis Disease Activity and T-cell Immunology: A Cohort Study

Background

Chikungunya virus (CHIKV) is an alphavirus spread by mosquitos that causes arthralgias and arthritis that may last for years. The objective of this study was to describe the arthritis progression and T cell immunology over a two-year period.

Methods

A cohort of 40 cases of serologically confirmed CHIKV from Magdalena and Atlántico, Colombia were followed in 2019 and again in 2021. Arthritis disease severity, disability, pain, stiffness, physical function, mobility, fatigue, anxiety, sleep disturbances and depression were assessed. Serum cytokines and T-cell subsets were measured and tested for change. Correlations within each of the 2 time periods for laboratory parameters were also examined.

Results

Although, arthritis disease severity, as measured by the Disease Activity Score-28 (DAS-28) did not change significantly over a two-year period, a new metric- the Chikungunya Disease Activity Score (CHIK-DAS)- was more sensitive to detect changes in disease severity than the Disease Activity Score-28 (DAS-28) and showed some improvement in average disease severity from moderate to mild over two years. Cases were characterized by moderate disability, pain, and stiffness with mild alterations of physical function, mobility, fatigue, anxiety, sleep disturbances and depression that did not change significantly over time. Small joints including the fingers and wrists were most affected without significant change over time. The percentage of effector T cells (Teffs) and regulatory T cells (Tregs) of CD4+ T cells both decreased over time. Teff percentages decreased more significantly resulting in a halving of the Teff/Treg ratio two years later. Furthermore, markers of Treg immunosuppressive function such as CTLA4, Helios, CD28, CD45RA and 41bb decreased over time. Cytokines did not change significantly over time.

Conclusions

The presented data suggest that arthritis persists almost seven years after chikungunya infection in some patients with waning Teff and Treg numbers and activation markers over time. Treg activation may be a promising therapeutic target for further investigation.

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.

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.

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.

The impact of Chikungunya chronic arthralgia on women’s upper limbs motor function: a cross-sectional study

ABSTRACT Post-Chikungunya chronic arthralgia (PCCA) may lead to musculoskeletal repercussions and functional loss. The objective was to assess the upper limb physical disability and symptoms during daily, work, and leisure activities of women presenting PCCA compared to healthy controls (HC). This was a cross-sectional study conducted with 52 women. The participants were divided into PCCA (37) and HC (15) groups. Handgrip strength, range of motion, level of pain (numerical rating scale), and participants’ physical disability and symptoms (Disabilities of the Arm, Shoulder, and Hand Questionnaire - DASH) were evaluated. Differences between groups were evaluated using the Students t-test and Pearson’s correlations. The chi-square test was applied for categorical variables. The significance was set at α=0.05. The disease duration was 19.5±13.1 months. We found no differences between groups for peak force (PCAA:23.6±7.4kgf; HC: 24.5±6.2kgf; p=0.676). The results showed a significant difference between groups regarding range of motion (PCCA: 63.5±17.3o; HC: 77.2±9.6o), level of hand pain (PCCA: 5.8±2.2; HC: 0.4±1.5), and upper limbs functional levels (PCCA: 44.5±17.4; HC: 16.2±20.5). Participants related severe difficulty or inability to perform tasks such as opening a jar (78.4%), placing objects above head height (48.7%), doing heavy household chores (56.8%), and gardening (51.4%). Impairment in the upper limb physical function in daily, work, and leisure activities shows the higher prevalence in the long-term.

Determinants of Health-Related Quality of Life in Chronic Chikungunya Disease in Guadeloupe

Chronic chikungunya disease is associated with a poor quality of life and a variety of symptoms, not restricted to the musculoskeletal system. Patients with chronic chikungunya disease in Guadeloupe were evaluated in order to identify the main factors determining the quality of life. Patients were followed up at a mean of 36 months after chikungunya infection, undergoing detailed clinical examination for musculoskeletal involvement, with assessment of subjective symptoms and the impact on mood, physical activity, and quality of life (SF12). Patients had extensive musculoskeletal involvement shown by tenderness in 9 ± 4 joints and stiffness in 5 ± 4 joints. SF12 physical and mental component scores showed a poor health-related quality of life. Measures of joint pain, stiffness, and inflammation contributed to impaired quality of life scores. In addition, fatigue and interrupted sleep appeared to be important predictors for physical aspects of quality of life. The emergence of anxiodepressive syndromes post-chikungunya infection was associated with both physical and mental component scores of SF12. These data confirm that musculoskeletal symptoms are not the only determinants of quality of life in chronic chikungunya disease. Follow-up of patients should include assessment and management of fatigue, poor sleep quality, and anxiodepressive syndromes.

Discomfort, pain and stiffness: what do these terms mean to patients? A cross-sectional survey with lexical and qualitative analyses

BACKGROUND

While pain is often the focus of clinical interventions, other clinical outcomes (e.g., discomfort, stiffness) might also contribute to patients' functionality and well-being. Although researchers and clinicians may view discomfort, pain and stiffness as different constructs, it remains unclear how patients perceive and differentiate between these constructs. Therefore, the purpose of this study was to explore patients' perceptions of pain, discomfort, and stiffness.

METHODS

Chiropractic patients were invited to complete an online cross-sectional survey and describe what 'discomfort', 'pain' and 'stiffness' meant to them using their own words. Lexical and inductive qualitative content analyses were conducted independently and then triangulated.

RESULTS

Fifty-three chiropractic patients (47.2% female, mean age: 39.1 ± 15.1 years) responded. The most common combinations of words to describe discomfort were "can be ignored" and "less severe than". "Cannot be ignored" and "sharp shooting" were used to describe pain. "Limited range of motion" was used to describe stiffness. Qualitatively, five themes were developed: impact, character, feeling, intensity and temporality. Stiffness was described as limited movement/mobility. Although discomfort and stiffness impacted patients' activities, patients remained functional; pain was described as stopping/limiting activities. Discomfort was described as dull and tingling, pain as sharp and shooting, and stiffness as tight and restricted. Patients felt displeased and annoyed when experiencing discomfort and stiffness but hurt and in danger of harm when experiencing pain. Discomfort and stiffness were described as less intense than pain, with shorter/intermittent duration; however, all constructs could be experienced constantly.

CONCLUSION

Patients perceived discomfort, pain and stiffness as different, yet overlapping constructs. This preliminary work advances our knowledge of how patients conceptualize these constructs, contributing to better understanding of what patients mean when reporting these experiences, potentially improving the clinician-patient communication.

Long-term Chikungunya sequelae and quality of life 2.5 years post-acute disease in a prospective cohort in Curaçao

Background

Little is known about the persistence and impact of non-rheumatic symptoms after acute chikungunya disease. We have studied the clinical presentation and long-term impact of rheumatic and non-rheumatic symptoms on health related quality of life (QoL) 2.5 years after disease onset. Additionally, the validity of the Curaçao Long-Term Chikungunya Sequelae (CLTCS) score in classifying disease severity over time was evaluated.

Methodology/Principal findings

This prospective cohort study followed 248 chikungunya patients. Symptoms and SF-36 QoL were evaluated during baseline and follow-up at 2.5 years using questionnaires. Chikungunya disease status was classified using the CLTCS-score. At 2.5 years after disease onset patients were classified as being recovered (43%), mildly (35%) or highly (22%) affected. In comparison to mildly affected, highly affected patients reported the highest prevalence of ongoing rheumatic and non-rheumatic/psychological symptoms, with increased prevalence of arthralgia in the lower extremities (p = .01) and fatigue (p = .049) over time, and higher pain intensity (p < .001). Compared to mildly affected, being highly affected was associated with weakness in the lower extremities (OR: 1.90; CI: 1.29–2.80, p = .001) and worsened physical and mental QoL impairment.

Conclusions

Patients are both physically and psychologically affected by rheumatic and non-rheumatic symptoms of long-term chikungunya disease.

The CLTCS-score is an easy to use instrument for classifying long-term chikungunya disease severity and impact and can facilitate health care providers in identifying highly affected patients who are prone to develop severe QoL impairment. Highly affected patients are recommended to be treated in a multidisciplinary setting to improve physical and psychological functioning, and QoL.

Chikungunya disease manifestation is characterized by a sudden onset of non-rheumatic flu-like symptoms and debilitating rheumatic symptoms in the acute phase. Little is known about the persistence of non-rheumatic symptoms after acute disease. In this prospective cohort study we investigated the clinical manifestations and persistence of baseline rheumatic and non-rheumatic/psychological symptoms and their impact on health related quality of life (QoL) 2.5 years after disease onset. Moreover, we investigated the performance of the classification instrument the Curaçao Long-Term Chikungunya Sequelae (CLTCS) score in classifying chikungunya disease severity over time. We found that 57% of the patients were still affected 2.5 years after disease onset. An increase of mainly recurrent rheumatic and non-rheumatic/psychological symptoms including fatigue, insomnia, sombreness, and loss of vitality were reported, with a significantly higher symptom recurrence and pain intensity reported by highly affected patients. In addition, QoL assessment indicates that the disease burden impaired the physiological well-being of these patients. We also showed that the CLTCS-score can be used to easily identify highly affected patients. This study demonstrates that disease severity increases non-rheumatic symptoms and subsequent physiological impairments and suggests a multidisciplinary treatment approach to treat the psychological effects of long-term chikungunya disease.

Chikungunya virus infection: molecular biology, clinical characteristics, and epidemiology in Asian countries

Chikungunya virus (CHIKV) is a re-emerging mosquito-borne human pathogen that causes chikungunya fever, which is typically accompanied by severe joint pain. In Asia, serological evidence indicated that CHIKV first emerged in 1954. From the 1950’s to 2005, sporadic CHIKV infections were attributed to the Asian genotype. However, the massive outbreak of CHIKV in India and the Southwest Indian Ocean Islands in 2005 has since raised chikungunya as a worldwide public health concern. The virus is spreading globally, but mostly in tropical and subtropical regions, particularly in South and Southeast Asia. The emergence of the CHIKV East/Central/South African genotype-Indian Ocean lineage (ECSA-IOL) has caused large outbreaks in South and Southeast Asia affected more than a million people over a decade. Notably, the massive CHIKV outbreaks before 2016 and the more recent outbreak in Asia were driven by distinct ECSA lineages. The first significant CHIKV ECSA strains harbored the Aedes albopictus-adaptive mutation E1: A226V. More recently, another mass CHIKV ECSA outbreak in Asia started in India and spread beyond South and Southeast Asia to Kenya and Italy. This virus lacked the E1: A226V mutation but instead harbored two novel mutations (E1: K211E and E2: V264A) in an E1: 226A background, which enhanced its fitness in Aedes aegypti. The emergence of a novel ECSA strain may lead to a more widespread geographical distribution of CHIKV in the future. This review summarizes the current CHIKV situation in Asian countries and provides a general overview of the molecular virology, disease manifestation, diagnosis, prevalence, genotype distribution, evolutionary relationships, and epidemiology of CHIKV infection in Asian countries over the past 65 years. This knowledge is essential in guiding the epidemiological study, control, prevention of future CHIKV outbreaks, and the development of new vaccines and antivirals targeting CHIKV.

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

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

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Statisticalanalysis of multiple cohorts of chikungunya patients was performed.

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

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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.

Persistent Joint Pain Following Arthropod Virus Infections

PURPOSE OF REVIEW

Persistent joint pain is a common manifestation of arthropod-borne viral infections and can cause long-term disability. We review the epidemiology, pathophysiology, diagnosis, and management of arthritogenic alphavirus infection.

RECENT FINDINGS

The global re-emergence of alphaviral outbreaks has led to an increase in virus-induced arthralgia and arthritis. Alphaviruses, including Chikungunya, O'nyong'nyong, Sindbis, Barmah Forest, Ross River, and Mayaro viruses, are associated with acute and/or chronic rheumatic symptoms. Identification of Mxra8 as a viral entry receptor in the alphaviral replication pathway creates opportunities for treatment and prevention. Recent evidence suggesting virus does not persist in synovial fluid during chronic chikungunya infection indicates that immunomodulators may be given safely. The etiology of persistent joint pain after alphavirus infection is still poorly understood. New diagnostic tools along and evidence-based treatment could significantly improve morbidity and long-term disability.

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.

Musculoskeletal stiffness is common in healthy adults and increases with age

INTRODUCTION/OBJECTIVE

Musculoskeletal stiffness is a common feature in rheumatologic inflammatory diseases but little is known about background joint stiffness in the healthy population. The aim of this survey was to determine the variation in musculoskeletal stiffness with age in a cohort of healthy adults using a patient reported outcome instrument designed to assess stiffness in rheumatoid arthritis.

METHODS

Healthy subjects ≥18 years old were enrolled at two sites. Those with a diagnosis of rheumatological disease were excluded. Each subject completed a 21-item questionnaire designed to evaluate the severity of musculoskeletal stiffness, its physical impact and psychosocial impact, and to provide an overall stiffness score, expressed as a percentage. Scores were analyzed by age group.

RESULTS

Two hundred eighty-two subjects were included with a mean age of 42 years (±17, range 18-85). More than 50% of subjects reported stiffness in each age group but with a low median overall stiffness score of 5.4% (IQR 0, 12.6). Scores were markedly higher in those aged ≥60 years, median 10.0% (IQR 2.6, 21.9), and only in this age group did the majority of subjects report a physical or psychosocial impact of stiffness. Scores in males and females were similar.

CONCLUSION

The prevalence of musculoskeletal stiffness in healthy subjects of all ages is not negligible, and the high frequency of stiffness and greater severity in the upper age cohort suggest that the background joint stiffness amongst older subjects should be considered when interpreting stiffness in rheumatologic patients.

Immunopathogenesis of alphaviruses

Alphaviruses, members of the enveloped, positive-sense, single-stranded RNA Togaviridae family, represent a reemerging public health threat as mosquito vectors expand into new geographic territories. The Old World alphaviruses, which include chikungunya virus, Ross River virus, and Sindbis virus, tend to cause a clinical syndrome characterized by fever, rash, and arthritis, whereas the New World alphaviruses, which consist of Venezuelan equine encephalitis virus, eastern equine encephalitis virus, and western equine encephalitis virus, induce encephalomyelitis. Following recovery from the acute phase of infection, many patients are left with debilitating persistent joint and neurological complications that can last for years. Clues from human cases and studies using animal models strongly suggest that much of the disease and pathology induced by alphavirus infection, particularly atypical and chronic manifestations, is mediated by the immune system rather than directly by the virus. This review discusses the current understanding of the immunopathogenesis of the arthritogenic and neurotropic alphaviruses accumulated through both natural infection of humans and experimental infection of animals, particularly mice. As treatment following alphavirus infection is currently limited to supportive care, understanding the contribution of the immune system to the disease process is critical to developing safe and effective therapies.

In-depth characterization of a novel live-attenuated Mayaro virus vaccine candidate using an immunocompetent mouse model of Mayaro disease

Mayaro virus (MAYV) is endemic in South American countries where it is responsible for sporadic outbreaks of acute febrile illness. The hallmark of MAYV infection is a highly debilitating and chronic arthralgia. Although MAYV emergence is a potential threat, there are no specific therapies or licensed vaccine. In this study, we developed a murine model of MAYV infection that emulates many of the most relevant clinical features of the infection in humans and tested a live-attenuated MAYV vaccine candidate (MAYV/IRES). Intraplantar inoculation of a WT strain of MAYV into immunocompetent mice induced persistent hypernociception, transient viral replication in target organs, systemic production of inflammatory cytokines, chemokines and specific humoral IgM and IgG responses. Inoculation of MAYV/IRES in BALB/c mice induced strong specific cellular and humoral responses. Moreover, MAYV/IRES vaccination of immunocompetent and interferon receptor-defective mice resulted in protection from disease induced by the virulent wt MAYV strain. Thus, this study describes a novel model of MAYV infection in immunocompetent mice and highlights the potential role of a live-attenuated MAYV vaccine candidate in host's protection from disease induced by a virulent MAYV strain.

Persistent chikungunya arthritis in Roraima, Brazil

BACKGROUND

The Amazon region of Brazil experienced a large epidemic of East Central South African (ECSA) chikungunya virus (CHIKV) in 2017 and continuous transmission of CHIKV persists. The impact of chronic arthritis caused by ECSA CHIKV is unknown.

OBJECTIVE

The study aim was to describe the duration, severity, and characteristics of CHIKV arthritis in Roraima, Brazil, in comparison with local controls to further understand the long-term rheumatologic impact of ECSA CHIKV infection.

METHODS

We performed a cross-sectional analysis comparing clinical arthritis outcomes among 40 cases with chronic (> 3 months) arthritis attributed to their CHIKV disease (n = 40) with control participants who were exposed to CHIKV but did not develop chronic arthritis (n = 40), rheumatoid arthritis controls (n = 40), and healthy controls lacking CHIKV exposure and arthritis (n = 40).

FINDINGS

Our primary finding is that over 2 years post-infection, patients report moderate arthritis disease severity comparable with rheumatoid arthritis with the most significant impact on decreased quality of life from pain.

MAIN CONCLUSIONS

These findings suggest that chronic arthritis caused by ECSA CHIKV infection has had a moderate impact in the Americas. Key Points • Chikungunya infection is responsible for moderate arthritis disease severity. • The East Central South African (ECSA) strain of CHIKV is a cause of persistent arthritis in Roraima, Brazil.