Incidence of articular pain and arthritis after chikungunya fever in the Americas: A systematic review of the literature and meta-analysis

Post-Viral Pain, Fatigue, and Sleep Disturbance Syndromes: Current Knowledge and Future Directions

Background

Post-viral pain syndrome, also known as post-viral syndrome, is a complex condition characterized by persistent pain, fatigue, musculoskeletal pain, neuropathic pain, neurocognitive difficulties, and sleep disturbances that can occur after an individual has recovered from a viral infection.

Aims

This narrative review provides a summary of the sequelae of post-viral syndromes, viral agents that cause it, and the pathophysiology, treatment, and future considerations for research and targeted therapies.

Methods

Medline, PubMed, and Embase databases were used to search for studies on viruses associated with post-viral syndrome.

Conclusion

Much remains unknown regarding the pathophysiology of post-viral syndromes, and few studies have provided a comprehensive summary of the condition, agents that cause it, and successful treatment modalities. With the COVID-19 pandemic continuing to affect millions of people worldwide, the need for an understanding of the etiology of post-viral illness and how to help individuals cope with the sequalae is paramount.

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.

Advances in mRNA vaccines for viral diseases

Since the onset of the pandemic caused by severe acute respiratory syndrome coronavirus 2, messenger RNA (mRNA) vaccines have demonstrated outstanding performance. mRNA vaccines offer significant advantages over conventional vaccines in production speed and cost-effectiveness, making them an attractive option against other viral diseases. This article reviewed recent advances in viral mRNA vaccines and their delivery systems to provide references and guidance for developing mRNA vaccines for new viral diseases.

A phase 1, randomized, placebo-controlled, dose-ranging study to evaluate the safety and immunogenicity of an mRNA-based chikungunya virus vaccine in healthy adults

BACKGROUND

Chikungunya, a mosquito-borne viral disease caused by the chikungunya virus (CHIKV), causes a significant global health burden, and there is currently no approved vaccine to prevent chikungunya disease. In this study, the safety and immunogenicity of a CHIKV mRNA vaccine candidate (mRNA-1388) were evaluated in healthy participants in a CHIKV-nonendemic region.

METHODS

This phase 1, first-in-human, randomized, placebo-controlled, dose-ranging study enrolled healthy adults (ages 18-49 years) between July 2017 and March 2019 in the United States. Participants were randomly assigned (3:1) to receive 2 intramuscular injections 28 days apart with mRNA-1388 in 3 dose-level groups (25 μg, 50 μg, and 100 μg) or placebo and were followed for up to 1 year. Safety (unsolicited adverse events [AEs]), tolerability (local and systemic reactogenicity; solicited AEs), and immunogenicity (geometric mean titers [GMTs] of CHIKV neutralizing and binding antibodies) of mRNA-1388 versus placebo were evaluated.

RESULTS

Sixty participants were randomized and received ≥ 1 vaccination; 54 (90 %) completed the study. mRNA-1388 demonstrated favorable safety and reactogenicity profiles at all dose levels. Immunization with mRNA-1388 induced substantial and persistent humoral responses. Dose-dependent increases in neutralizing antibody titers were observed; GMTs (95 % confidence intervals [CIs]) at 28 days after dose 2 were 6.2 (5.1-7.6) for mRNA-1388 25 μg, 53.8 (26.8-108.1) for mRNA-1388 50 μg, 92.8 (43.6-197.6) for mRNA-1388 100 μg, and 5.0 (not estimable) for placebo. Persistent humoral responses were observed up to 1 year after vaccination and remained higher than placebo in the 2 higher mRNA-1388 dose groups. The development of CHIKV-binding antibodies followed a similar trend as that observed with neutralizing antibodies.

CONCLUSIONS

mRNA-1388, the first mRNA vaccine against CHIKV, was well tolerated and elicited substantial and long-lasting neutralizing antibody responses in healthy adult participants in a nonendemic region.

CLINICALTRIALS

gov: NCT03325075.

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.

Viral infections in orthopedics: A systematic review and classification proposal

BACKGROUND

Although the impact of microbial infections on orthopedic clinical outcomes is well recognized, the influence of viral infections on the musculoskeletal system might have been underestimated.

AIM

To systematically review the available evidence on risk factors and musculoskeletal manifestations following viral infections and to propose a pertinent classification scheme.

METHODS

We searched MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), the Reference Citation Analysis (RCA), and Scopus for completed studies published before January 30, 2021, to evaluate risk factors and bone and joint manifestations of viral infection in animal models and patient registries. Quality assessment was performed using SYRCLE's risk of bias tool for animal studies, Moga score for case series, Wylde score for registry studies, and Newcastle-Ottawa Scale for case-control studies.

RESULTS

Six human and four animal studies were eligible for inclusion in the qualitative synthesis. Hepatitis C virus was implicated in several peri- and post-operative complications in patients without cirrhosis after major orthopedic surgery. Herpes virus may affect the integrity of lumbar discs, whereas Ross River and Chikungunya viruses provoke viral arthritis and bone loss.

CONCLUSION

Evidence of moderate strength suggested that viruses can cause moderate to severe arthritis and osteitis. Risk factors such as pre-existing rheumatologic disease contributed to higher disease severity and duration of symptoms. Therefore, based on our literature search, the proposed clinical and pathogenetic classification scheme is as follows: (1) Viral infections of bone or joint; (2) Active bone and joint inflammatory diseases secondary to viral infections in other organs or tissues; and (3) Viral infection as a risk factor for post-surgical bacterial infection.

Annexin A1-FPR2/ALX Signaling Axis Regulates Acute Inflammation during Chikungunya Virus Infection

Chikungunya (CHIKV) is an arthritogenic alphavirus that causes a self-limiting disease usually accompanied by joint pain and/or polyarthralgia with disabling characteristics. Immune responses developed during the acute phase of CHIKV infection determine the rate of disease progression and resolution. Annexin A1 (AnxA1) is involved in both initiating inflammation and preventing over-response, being essential for a balanced end of inflammation. In this study, we investigated the role of the AnxA1-FPR2/ALX pathway during CHIKV infection. Genetic deletion of AnxA1 or its receptor enhanced inflammatory responses driven by CHIKV. These knockout mice showed increased neutrophil accumulation and augmented tissue damage at the site of infection compared with control mice. Conversely, treatment of wild-type animals with the AnxA1 mimetic peptide (Ac_2–26) reduced neutrophil accumulation, decreased local concentration of inflammatory mediators and diminished mechanical hypernociception and paw edema induced by CHIKV-infection. Alterations in viral load were mild both in genetic deletion or with treatment. Combined, our data suggest that the AnxA1-FPR2/ALX pathway is a potential therapeutic strategy to control CHIKV-induced acute inflammation and polyarthralgia.

Epidemiological burden of Chikungunya fever in Brazil, 2016 and 2017

OBJECTIVES

To describe Chikungunya fever (CHIKF) cases and estimate the burden of the disease in Brazil between 2016 and 2017.

METHODS

The first stage of this study consisted of a descriptive epidemiological study with estimations of incidence, mortality and case-fatality rates for each Brazilian state. The second stage provided estimates of the disease burden using DALY, an indicator that aggregates measures of morbidity (years lived with disability - YLD) and mortality (years of life lost - YLL) into a single value.

RESULTS

In Brazil, the incidence rate in 2016 was 114.70 per 100,000 inhabitants, while the mortality rate was 0.15 per 100,000, for a case-fatality rate of 0.13%. In 2017, these figures were 87.59 and 0.12 per 100,000 inhabitants and 0.14%, respectively. The estimated CHIKF burden for Brazil in 2016 was 77,422.61 DALY or 0.3757 per 1000 inhabitants. In 2016, the YLL share of DALY was 10.04%, with YLD accounting for the remaining 89.96%. In 2017, the estimated burden was 59,307.59 DALY or 0.2856 per 1000 inhabitants, with YLL accounting for 9.65% of the total and YLD for 90.35%.

CONCLUSION

CHIKF causes a significant disease burden in Brazil. The chronic phase of CHIKF is responsible for the largest portion of DALY. Deaths from CHIKF are a significant component of the disease burden, with YLL accounting for approximately 10% of the total DALY value.

Rediscovering the chikungunya virus

El virus de chikunguña (CHIKV) es un Alfavirus perteneciente al grupo denominado del Viejo Mundo; estos son virus artritogénicos que causan una enfermedad febril caracterizada por artralgias y mialgias. Aunque la muerte por CHIKV es poco frecuente, la enfermedad puede llegar a ser incapacitante y generar un amplio espectro de manifestaciones atípicas, como complicaciones cardiovasculares, respiratorias, oculares, renales y dérmicas, entre otras. Cuando el dolor articular persiste por tres o más meses, da lugar a la forma crónica de la enfermedad denominada reumatismo inflamatorio crónico poschikunguña, el cual es la principal secuela de la enfermedad. Se considera que este virus no es neurotrópico, sin embargo, puede afectar el sistema nervioso central y generar secuelas graves y permanentes, principalmente, en niños y ancianos.

En África, Asia y Europa se habían reportado anteriormente brotes epidémicos por CHIKV, pero solo hasta finales del 2013 se documentó la introducción del virus a las Américas; desde entonces, el virus se ha propagado a 45 países o territorios del continente y el número de casos acumulados ascendió a cerca de dos millones en dos años.

Esta revisión describe de manera general la biología molecular del virus, sus manifestaciones clínicas, su patogénesis y las principales complicaciones posteriores a la infección. Además, reúne la información de la epidemia en Colombia y el continente americano publicada entre el 2014 y el 2020.

Clinical Manifestations and Outcomes in Disease-Modifying Antirheumatic Drug-Naive Adult Patients with Chronic Chikungunya Arthritis

Most studies on chronic chikungunya virus (CHIKV) arthritis include patients treated with disease-modifying antirheumatic drugs (DMARDs), likely altering the expression of clinical manifestations and outcome. Therefore, we sought to evaluate the clinical features and correlates in DMARD-naive patients with chronic CHIKV arthritis. We conducted a case-control study in adult patients with serologically confirmed CHIKV infection in Puerto Rico. Demographic features, clinical manifestations, comorbidities, disease activity (per Clinical Disease Activity Index [CDAI]), functional status (per Health Assessment Questionnaire Disability Index [HAQ-DI]), and pharmacologic treatment were ascertained. Patients with and without chronic CHIKV arthritis were compared. Furthermore, a sub-analysis was performed among patients with chronic CHIKV who presented with mild disease activity versus moderate-to-high disease activity at study visit. In total, 61 patients were studied; 33 patients had chronic arthritis and 28 had resolved arthritis. Patients with chronic arthritis had significantly more diabetes mellitus, chronic back pain, and fever, tiredness, and myalgias on the acute phase. The mean (SD) HAQ score was 0.95 (0.56), and 57.6% had moderate-to-high disease activity. Patients with moderate-to-high disease activity had higher scores in overall HAQ-DI and HAQ-DI categories (dressing and grooming, arising, hygiene, reaching, and activities) than in those with mild activity. In conclusion, in this group of DMARD-naive patients with chronic CHIKV arthritis, nearly 58% had moderate-to-high disease activity and had substantial functional disability. Diabetes mellitus, chronic back pain, and some manifestations on acute infection were associated with chronic CHIKV arthritis.

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.

A phase 1 trial of lipid-encapsulated mRNA encoding a monoclonal antibody with neutralizing activity against Chikungunya virus

Chikungunya virus (CHIKV) infection causes acute disease characterized by fever, rash and arthralgia, which progresses to severe and chronic arthritis in up to 50% of patients. Moreover, CHIKV infection can be fatal in infants or immunocompromised individuals and has no approved therapy or prevention. This phase 1, first-in-human, randomized, placebo-controlled, proof-of-concept trial conducted from January 2019 to June 2020 evaluated the safety and pharmacology of mRNA-1944, a lipid nanoparticle-encapsulated messenger RNA encoding the heavy and light chains of a CHIKV-specific monoclonal neutralizing antibody, CHKV-24 ( NCT03829384 ). The primary outcome was to evaluate the safety and tolerability of escalating doses of mRNA-1944 administered via intravenous infusion in healthy participants aged 18-50 years. The secondary objectives included determination of the pharmacokinetics of mRNA encoding for CHKV-24 immunoglobulin heavy and light chains and ionizable amino lipid component and the pharmacodynamics of mRNA-1944 as assessed by serum concentrations of mRNA encoding for CHKV-24 immunoglobulin G (IgG), plasma concentrations of ionizable amino lipid and serum concentrations of CHKV-24 IgG. Here we report the results of a prespecified interim analysis of 38 healthy participants who received intravenous single doses of mRNA-1944 or placebo at 0.1, 0.3 and 0.6 mg kg^-1, or two weekly doses at 0.3 mg kg^-1. At 12, 24 and 48 h after single infusions, dose-dependent levels of CHKV-24 IgG with neutralizing activity were observed at titers predicted to be therapeutically relevant concentrations (≥1 µg ml^-1) across doses that persisted for ≥16 weeks at 0.3 and 0.6 mg kg^-1 (mean t_1/2 approximately 69 d). A second 0.3 mg kg^-1 dose 1 week after the first increased CHKV-24 IgG levels 1.8-fold. Adverse effects were mild to moderate in severity, did not worsen with a second mRNA-1944 dose and none were serious. To our knowledge, mRNA-1944 is the first mRNA-encoded monoclonal antibody showing in vivo expression and detectable ex vivo neutralizing activity in a clinical trial and may offer a treatment option for CHIKV infection. Further evaluation of the potential therapeutic use of mRNA-1944 in clinical trials for the treatment of CHIKV infection is warranted.

Chikungunya infection: First autochthonous cases in Taiwan

The first autochthonous case and the first outbreak of chikungunya in Taiwan occurred during July-October 2019, with a total of 21 cases confirmed. Genetic analysis revealed the strains belonged to East/Central/South African genotype and had 99.95%-100% identity with the strains from the imported cases from Myanmar in 2019. This event confirmed that the imported chikungunya cases has the potential to cause autochthonous transmission in Taiwan; intensified surveillance and vector control measures are essential to contain the outbreak.

Mosquito-Borne Diseases Emergence/Resurgence and How to Effectively Control It Biologically

Deadly pathogens and parasites are transmitted by vectors and the mosquito is considered the most threatening vector in public health, transmitting these pathogens to humans and animals. We are currently witnessing the emergence/resurgence in new regions/populations of the most important mosquito-borne diseases, such as arboviruses and malaria. This resurgence may be the consequence of numerous complex parameters, but the major cause remains the mismanagement of insecticide use and the emergence of resistance. Biological control programmes have rendered promising results but several highly effective techniques, such as genetic manipulation, remain insufficiently considered as a control mechanism. Currently, new strategies based on attractive toxic sugar baits and new agents, such as Wolbachia and Asaia, are being intensively studied for potential use as alternatives to chemicals. Research into new insecticides, Insect Growth Regulators, and repellent compounds is pressing, and the improvement of biological strategies may provide key solutions to prevent outbreaks, decrease the danger to at-risk populations, and mitigate resistance.

Liposomal Delivery of the RNA Genome of a Live-Attenuated Chikungunya Virus Vaccine Candidate Provides Local, but Not Systemic Protection After One Dose

Chikungunya virus (CHIKV) is the causative pathogen of chikungunya fever, a mosquito-borne viral disease causing highly debilitating arthralgia that can persist for months and progress to chronic arthritis. Our previous studies have identified the CHIKV live-attenuated vaccine candidate CHIKV-NoLS. Like most live-attenuated vaccines, attenuated replication of CHIKV-NoLS has the potential to limit scalable production. To overcome production limits, as well as other drawbacks of live-attenuated vaccines, we developed an in vivo liposome RNA delivery system to deliver the self-replicating RNA genome of CHIKV-NoLS directly into mice, allowing the recipients' body to produce the live-attenuated vaccine particles. CAF01 liposomes were able to deliver replication-competent CHIKV-NoLS RNA in vitro. Immunodeficient AG129 mice inoculated with liposome-delivered CHIKV-NoLS RNA developed viremia and disease signs representative of this lethal model of CHIKV infection, demonstrating de novo vaccine particle production in vivo. In immunocompetent C57BL/6 mice, liposome-delivered CHIKV-NoLS RNA inoculation was associated with reduced IgM and IgG levels with low antibody CHIKV-neutralizing capacity, compared to vaccination with the original live-attenuated vaccine CHIKV-NoLS. One dose of liposome-delivered CHIKV-NoLS RNA did not provide systemic protection from CHIKV wild-type (WT) challenge but was found to promote an early onset of severe CHIKV-induced footpad swelling. Liposome-delivered CHIKV-NoLS RNA inoculation did, however, provide local protection from CHIKV-WT challenge in the ipsilateral foot after one dose. Results suggest that in the presence of low CHIKV-specific neutralizing antibody levels, local inflammatory responses, likely brought on by liposome adjuvants, have a role in the protection of CHIKV-induced footpad swelling in the ipsilateral foot of mice inoculated with liposome-delivered CHIKV-NoLS RNA. Low IgG and CHIKV-specific neutralizing antibody levels may be responsible for early onset of severe swelling in the feet of CHIKV-WT-challenged mice. These results support previous studies that suggest CHIKV is vulnerable to antibody-mediated enhancement of disease. Further studies using booster regimes aim to demonstrate the potential for liposomes to deliver the self-replicating RNA genome of live-attenuated vaccines and offer a novel immunization strategy.

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

INTRODUCTION/OBJECTIVES

To characterize the importance of musculoskeletal stiffness in a cohort of chikungunya patients with chronic joint symptoms.

METHOD

Eighty-two patients were followed up 3 years after chikungunya infection. Tender and swollen joint counts, a pain intensity scale, Health Assessment Questionnaire-Disability Index (HAQ-DI), and the EuroQol EQ-5D quality of life instrument were completed. A musculoskeletal stiffness questionnaire provided scores for overall stiffness and its components: stiffness severity, physical impact, and psychosocial impact.

RESULTS

Patients had a mean age 51 ± 14 years. Sixty-seven patients were still experiencing chronic arthralgia. Musculoskeletal stiffness was reported by 43/67 patients with arthralgia and 3/15 patients without arthralgia. A physical impact of stiffness was reported by 87% patients and psychosocial impact by 71% patients. Mean tender joint count in patients reporting arthralgia was 6 ± 7, mean pain intensity 65 ± 20 out of 100, mean HAQ-DI was 0.54 ± 0.52, and mean EQ-VAS global health perception was 68 ± 62 out of 100. Stiffness severity was correlated with tender joint counts (ρ = 0.46) and pain intensity (ρ = 0.40). All three measures were equally well correlated with the EuroQol-VAS global health perception. Pain and tender joints were better correlated with the HAQ-DI (ρ = 0.68 and ρ = 0.63), but stiffness was more strongly correlated with several quality of life domains, including mobility. Swollen joints were a poor predictor of outcomes.

CONCLUSIONS

Musculoskeletal stiffness following chikungunya infection is distinct from arthralgia. It does not always occur in the same patients or with a corresponding intensity. Joint pain and stiffness may be independently associated with disability and quality of life assessments.

Proinflammatory Cytokines and Chemokines as Biomarkers of Persistent Arthralgia and Severe Disease After Chikungunya Virus Infection: A 5-Year Follow-Up Study in Southern Thailand

Chikungunya fever is a re-emerging viral disease caused by chikungunya virus (CHIKV). The disease is generally self-limiting, but chronic arthralgia/arthritis may persist for months or years. We evaluated the expression of 12 cytokines/chemokines and matrix metalloproteinases (MMP)-1 and MMP-3 using enzyme-linked immunosorbent assays (ELISAs) and compared among patients who still had arthralgia (persistent arthralgia), patients who had fully recovered, and healthy controls. There was a significant increase in interleukin (IL)-1β, IL-6, IL-8, monocyte chemotactic protein-1 (MCP-1), MMP-1, and MMP-3 levels in patients with persistent arthralgia in comparison to healthy controls (p < 0.05) and a significant increase in tumor necrosis factor-alpha (TNF-α), MMP-1, and MMP-3 levels in patients with persistent arthralgia in comparison to patients who had fully recovered (p < 0.05). Interferon (IFN)-γ, IL-6, and transforming growth factor beta (TGF-β) levels tended to be increased in patients with chronic CHIKV-induced arthritis compared with fully recovered. TNF-α, IL-12, and MCP-1 levels were elevated (p < 0.05), whereas regulated on activation, normal T cell expressed and secreted (RANTES) levels were decreased in patients with severe pain compared with patients with nonsevere pain (p < 0.05). IFN-γ, IL-1β, IL-6, and IL-8 levels tended to be elevated in patients with severe pain compared with patients with nonsevere pain. We proposed a role played by TNF-α, IL-6, IL-8, and MCP-1 in persistent arthralgia or chronic disease through the activation of MMP-1 and MMP-3. The increase in TNF-α, IL-12, and MCP-1 levels (and the tendency toward an increase in IFN-γ, IL-1β, IL-6, and IL-8 levels) in patients with severe pain compared with patients with nonsevere pain suggests the role of these inflammatory markers in chronic disease and severity of the disease.

Beyond Fever and Pain: Diagnostic Methods for Chikungunya Virus

Chikungunya virus (CHIKV) is an alphavirus that is primarily transmitted by Aedes species mosquitoes. Though reports of an illness consistent with chikungunya date back over 200 years, CHIKV only gained worldwide attention during a massive pandemic that began in East Africa in 2004. Chikungunya, the clinical illness caused by CHIKV, is characterized by a rapid onset of high fever and debilitating joint pain, though in practice, etiologic confirmation of CHIKV requires the availability and use of specific laboratory diagnostics. Similar to infections caused by other arboviruses, CHIKV infections are most commonly detected with a combination of molecular and serological methods, though cell culture and antigen detection are reported. This review provides an overview of available CHIKV diagnostics and highlights aspects of basic virology and epidemiology that pertain to viral detection. Although the number of chikungunya cases has decreased since 2014, CHIKV has become endemic in countries across the tropics and will continue to cause sporadic outbreaks in naive individuals. Consistent access to accurate diagnostics is needed to detect individual cases and initiate timely responses to new outbreaks.