Chikungunya Infection: A Re-emerging Epidemic

The global health and economic burden of chikungunya from 2011 to 2020: a model-driven analysis on the impact of an emerging vector-borne disease

INTRODUCTION

Chikungunya is a mosquito-borne arboviral disease posing an emerging global public health threat. Understanding the global burden of chikungunya is critical for designing effective prevention and control strategies. However, current estimates of the economic and health impact of chikungunya remain limited and are potentially underestimated. This study aims to provide a comprehensive overview of the chikungunya burden worldwide.

METHODS

We analysed the global burden of chikungunya between 2011 and 2020 and calculated disability-adjusted life years (DALYs) and direct and indirect costs using a data-driven simulation model. The main outcomes were the number of cases, the total DALY burden, and the direct and indirect costs of acute and chronic chikungunya between 2011 and 2020.

RESULTS

Our study revealed a total of 18.7 million chikungunya cases in 110 countries between 2011 and 2020, causing 1.95 million DALYs. Most of this burden was found in the Latin American and Caribbean region. The total economic burden caused by chikungunya over these 10 years was estimated at $2.8 billion in direct costs and $47.1 billion in indirect costs worldwide. Long-term chronic illness was the source of most costs and DALYs.

CONCLUSION

Chikungunya has a higher disease burden than was previously estimated and costs related to the disease are substantial. Especially in combination with its unpredictable nature, chikungunya could significantly impact local health systems. Insights from this study could inform decision makers on the impact of chikungunya on population health and help them to appropriately allocate resources to protect vulnerable populations from this debilitating disease.

From bench to clinic: the development of VLA1553/IXCHIQ, a live-attenuated chikungunya vaccine

BACKGROUND

Over the past 20 years, over 5 million cases of chikungunya, a mosquito-transmitted viral disease, have been reported in over 110 countries. Until recently, preventative strategies for chikungunya were largely ineffective, relying on vector control and individual avoidance of mosquito bites.

METHODS

This review outlines the preclinical and clinical efficacy and safety data that led to the approval of VLA1553 (IXCHIQ®), a live-attenuated vaccine against chikungunya disease. It also describes the innovative development pathway of VLA1553, based on an immunological surrogate of protection, and discusses ongoing and future post-licensure studies.

RESULTS

In mice and non-human primate models, VLA1553 elicited high titres of neutralizing antibodies, conferred protection against wild-type chikungunya virus challenge and raised no safety concerns. A Phase 1 clinical trial of VLA1553 demonstrated 100% seroconversion among 120 healthy participants, with sustained neutralizing antibody titres after 12 months. These results and determination of a surrogate marker of protection led to advancement of VLA1553 directly into Phase 3 clinical development, as agreed with the US Food and Drug Administration (FDA) and the European Medicines Agency. The pivotal Phase 3 trial met its primary immunogenicity endpoint, achieving seroprotective levels based on immuno-bridging in baseline seronegative participants 28 days post-vaccination. These findings enabled submission of a Biologics Licence Application to the FDA for accelerated approval of VLA1553 in the US for adults aged ≥18 years. Ongoing and planned studies will confirm the clinical efficacy/effectiveness and safety of VLA1553 in adults and younger individuals, and will generate data in chikungunya endemic countries that have the highest unmet need.

CONCLUSION

VLA1553 is the first vaccine approved for the prevention of chikungunya disease in adults, following accelerated development based on a serological surrogate marker of protection. VLA1553 adds to strategies to reduce the spread and burden of chikungunya in endemic populations and travellers.

Nifuroxazide Prevents Chikungunya Virus Infection Both In Vitro and In Vivo via Suppressing Viral Replication

Chikungunya virus (CHIKV) is a reemerging arbovirus causing disease on a global scale, and the potential for its epidemics remains high. CHIKV has caused millions of cases and heavy economic burdens around the world, while there are no available approved antiviral therapies to date. In this study, nifuroxazide, an FDA-approved antibiotic for acute diarrhea or colitis, was found to significantly inhibit a variety of arboviruses, although its antiviral activity varied among different target cell types. Nifuroxazide exhibited relatively high inhibitory efficiency in yellow fever virus (YFV) infection of the hepatoma cell line Huh7, tick-borne encephalitis virus (TBEV) and west nile virus (WNV) infection of the vascular endothelial cell line HUVEC, and CHIKV infection of both Huh7 cells and HUVECs, while it barely affected the viral invasion of neurons. Further systematic studies on the action stage of nifuroxazide showed that nifuroxazide mainly inhibited in the viral replication stage. In vivo, nifuroxazide significantly reduced the viral load in muscles and protected mice from CHIKV-induced footpad swelling, an inflammation injury within the arthrosis of infected mice. These results suggest that nifuroxazide has a potential clinical application as an antiviral drug, such as in the treatment of CHIKV infection.

Drugs targeting structural and nonstructural proteins of the chikungunya virus: A review

Chikungunya virus (CHIKV) is a single positive-stranded RNA virus of the Togaviridae family and Alphavirus genus, with a typical lipid bilayer envelope structure, and is the causative agent of human chikungunya fever (CHIKF). The U.S. Food and Drug Administration has recently approved the first chikungunya vaccine, Ixchiq; however, vaccination rates are low, and CHIKF is prevalent owing to its periodic outbreaks. Thus, developing effective anti-CHIKV drugs in clinical settings is imperative. Viral proteins encoded by the CHIKV genome play vital roles in all stages of infection, and developing therapeutic agents that target these CHIKV proteins is an effective strategy to improve CHIKF treatment efficacy and reduce mortality rates. Therefore, in the present review article, we aimed to investigate the basic structure, function, and replication cycle of CHIKV and comprehensively outline the current status and future advancements in anti-CHIKV drug development, specifically targeting nonstructural (ns) proteins, including nsP1, nsP2, nsP3, and nsP4 and structural proteins such as capsid (C), E3, E2, 6K, and E1.

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.

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

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

Experience with a triplex arbovirus nucleic acid test (NAT) at a Canadian Public Health Laboratory

BACKGROUND

Dengue, chikungunya and zika infections occur in tropical and subtropical regions of the world. We describe the utilization of an in-house nucleic acid test (NAT) targeting all three viruses for febrile returning travelers in Alberta, Canada.

METHODS

NAT was performed until 40 days from symptom onset or exposure due to the prolonged duration of zika virus RNA detection. From Sept 1, 2017 to August 31, 2019, 2552 specimens from 1932 patients were tested.

RESULTS

Approximately 2% of patients tested were NAT positive for dengue virus (n = 42), chikungunya virus (n = 4), and zika virus (n = 1). The majority presented with fever, myalgia and rash. Regions with the most frequent travel included SouthEast Asia (68.5%), South America (25%) and the Caribbean (6.5%). Ct values were stronger (~ 1.5 logs) for patients within 1-3 days following onset of clinical symptoms than those presenting later. Nineteen patients had urine and plasma submitted; 5 were positive for both specimens and 2 were positive only for dengue virus in the urine. Also, Ct values were lower for plasma when compared to the corresponding urine. RNA was detected until 10 days and 5 days post-exposure in plasma and urine respectively for dengue virus.

CONCLUSIONS

Owing to dengue viremia detected beyond the conventional 7 days and low levels of circulating zika virus globally, a cutoff of 14 days from symptom onset to NAT is sufficient to diagnose acute cases. Inclusion of a zoonotic history form that collects appropriate clinical history results in improved test utilization.

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.

Early warning systems (EWSs) for chikungunya, dengue, malaria, yellow fever, and Zika outbreaks: What is the evidence? A scoping review

BACKGROUND

Early warning systems (EWSs) are of increasing importance in the context of outbreak-prone diseases such as chikungunya, dengue, malaria, yellow fever, and Zika. A scoping review has been undertaken for all 5 diseases to summarize existing evidence of EWS tools in terms of their structural and statistical designs, feasibility of integration and implementation into national surveillance programs, and the users' perspective of their applications.

METHODS

Data were extracted from Cochrane Database of Systematic Reviews (CDSR), Google Scholar, Latin American and Caribbean Health Sciences Literature (LILACS), PubMed, Web of Science, and WHO Library Database (WHOLIS) databases until August 2019. Included were studies reporting on (a) experiences with existing EWS, including implemented tools; and (b) the development or implementation of EWS in a particular setting. No restrictions were applied regarding year of publication, language or geographical area.

FINDINGS

Through the first screening, 11,710 documents for dengue, 2,757 for Zika, 2,706 for chikungunya, 24,611 for malaria, and 4,963 for yellow fever were identified. After applying the selection criteria, a total of 37 studies were included in this review. Key findings were the following: (1) a large number of studies showed the quality performance of their prediction models but except for dengue outbreaks, only few presented statistical prediction validity of EWS; (2) while entomological, epidemiological, and social media alarm indicators are potentially useful for outbreak warning, almost all studies focus primarily or exclusively on meteorological indicators, which tends to limit the prediction capacity; (3) no assessment of the integration of the EWS into a routine surveillance system could be found, and only few studies addressed the users' perspective of the tool; (4) almost all EWS tools require highly skilled users with advanced statistics; and (5) spatial prediction remains a limitation with no tool currently able to map high transmission areas at small spatial level.

CONCLUSIONS

In view of the escalating infectious diseases as global threats, gaps and challenges are significantly present within the EWS applications. While some advanced EWS showed high prediction abilities, the scarcity of tool assessments in terms of integration into existing national surveillance systems as well as of the feasibility of transforming model outputs into local vector control or action plans tends to limit in most cases the support of countries in controlling disease outbreaks.

Maternal and perinatal outcomes during a Chikungunya outbreak in Kassala, eastern Sudan

BACKGROUND

Arboviruses (dengue, Zika, and chikungunya) have recently emerged as an important public health issue and can lead to adverse obstetrics outcomes. The current study was conducted to assess maternal and perinatal outcomes following chikungunya fever/infection and to compare adverse pregnancy outcomes with data from the community collected in a previous study.

METHODS

This study was performed during a chikungunya infection epidemic in Kassala, Sudan by recruiting all pregnant women with a confirmed chikungunya fever diagnosis by using antibodies/detection viral RNA using reverse transcriptase-polymerase chain reaction.

RESULTS

Ninety-three pregnant women with confirmed chikungunya infection were enrolled. Their mean (standard deviation) age and parity were 31.6 (3.4) years and 3.5 (1.4), respectively. Of the 93 women, 58 (62.4%) delivered a live infant at term and 18 (19.4%), 13 (13.9%), and 4 (4.3%) women experienced miscarriage, preterm birth, and stillbirth, respectively. In the logistic regression model, severe thrombocytopenia (platelets < 50,000 cells/mm³ (odds ratio [OR] = 5.1; confidence interval [CI] 1.8-14; P = 0.001) and leukopenia (OR = 4.5; CI 2.2-8.8; P < 0.001) were predictors for poor obstetric outcomes in pregnant women with chikungunya fever. The rates of miscarriage (18/93 [19.3%] vs. 1/71 [1.4%], P < 0.001) and preterm birth (13/93 [13.9%] vs. 2/71 [2.8%], P = 0.003) were significantly higher in the current study compared with the rate in the community.

CONCLUSION

Chikungunya infections during pregnancy were associated with miscarriage and preterm birth. Women with severe thrombocytopenia and leukopenia were at higher risk of poor obstetric outcomes. Women with severe thrombocytopenia and leukopenia were at higher risk of poor obstetric outcomes.

Neonatal consequences of maternal exposure to the chikungunya virus: Case reports

RATIONALE

The chikungunya virus (CHIKV) was first isolated in a Tanzanian epidemic area between 1952 and 1953. The best description of the CHIKV transmission during pregnancy can be found in a well-documented epidemic in 2005, in the "La Reunion" island, a French territory located in the Indian Ocean, in which about one-third of the population was infected. Reports of arbovirus infections in pregnancy are increasing over time, but the spectrum of clinical findings remains an incognita among researchers, including CHIKV.

PATIENT CONCERNS

In this report, it was possible to verify 2 cases exposed to CHIKV during foetal period and the possible implications of the infection on gestational structures and exposed children after the birth.

DIAGNOSIS

In both cases, the mothers were positive by laboratory tests in serologic analysis for CHIKV, as ezyme-linked immunossorbent assay (ELISA), plaque reduction neutralisation testing (PRNT) and immunofluorescence (IF); but there were no positive tests in quantitative polymerase chain reaction (qPCR) for mothers or children.

INTERVENTIONS

The exposed children were followed up in a paediatrics clinic in order not only to provide the medical assistance, but also to verify child development and the possible implications and neurocognitive changes caused by gestational infection.

OUTCOMES

There were neurological and developmental changes in one of the children followed up on an outpatient basis. There was an improvement in the neurological situation and symptoms only 3 years and 1 month after birth.

LESSONS

Based on the cases presented, we can conclude that clinical symptoms of CHIKV maternal infection may occur late in new-borns and can affect their development.

Chronic Joint Pain 3 Years after Chikungunya Virus Infection Largely Characterized by Relapsing-remitting Symptoms

OBJECTIVE

To determine the frequency of chronic joint pain and stiffness 3 years after infection with chikungunya virus (CHIKV) in a Latin American cohort.

METHODS

A cross-sectional followup of 120 patients from an initial cohort of 500 patients who reported joint pain 2 years after infection from the Atlántico Department, Colombia. Patients were clinically diagnosed as having CHIKV during the 2014-2015 epidemic, and baseline and followup symptoms at 40 months were evaluated in serologically confirmed cases.

RESULTS

Of the initial 500 patients enrolled in the study, 482 had serologically confirmed chikungunya infection. From this group, 123 patients reported joint pain 20 months after infection, and 54% of those patients reported continued joint pain 40 months after infection. Therefore, 1 out of every 8 people who tested serologically positive for CHIKV infection had persistent joint pain 3 years after infection. Participants who followed up in person were predominantly adult (mean ± SD age 51 ± 14 yrs) and female (86%). The most common type of pain reported in these patients at 40 months post-infection was pain with periods of relief and subsequent reoccurrence, and over 75% reported stiffness after immobility, with 39% experiencing morning stiffness.

CONCLUSION

To our knowledge, this is the first report to describe persistent joint pain and stiffness 40 months after viral infection. The high frequency of chronic disease highlights the need to develop prevention and treatment methods. Further studies should be conducted to understand the similarities between post-chikungunya joint pain and rheumatoid arthritis.

Epidemiologic Characteristics of Imported and Domestic Chikungunya Cases in Taiwan: A 13-Year Retrospective Study

Background: Chikungunya fever is caused by the chikungunya virus. Numerous factors affect the risk of chikungunya transmission. This study explored the epidemiological characteristics, differences, and trends in domestic and imported cases of chikungunya fever in Taiwan in terms of patient sex, age, month of confirmation, and area of residence from 2007 to 2019. Methods: Public annual chikungunya data from Taiwan’s Centers for Disease Control (CDC) were analyzed. In total, 21 confirmed domestic and 198 imported cases of chikungunya were reported. Of the domestic cases, one was sporadic and reported in July 2019, and 20 were attributed to a cluster event during August and September 2019. Results: In a comparison between domestic and imported cases reported from July to October 2019, differences in sex were nonsignificant (p = 0.555), whereas significant differences were observed for age (p < 0.001), month of confirmation (p = 0.005), and place of residence (p = 0.001). An age of 69–69 years (odds ratio (OR) = 6.66, 95% confidence interval (95%CI) = 2.15–20.65), month of confirmation of September (OR = 5.25, 95%CI = 1.89–14.61) and place of residence of New Taipei City (OR = 48.70, 95%CI = 6.17–384.44) were identified as potential risk factors. Additionally, domestic cases in August and September 2019 increased in proportion to the increase in imported cases during July and August 2019. Increased domestic patients may have been caused by the domestic mosquitoes that transmitted the virus by biting the imported patients to Taiwan. This is the first report comparing domestic and imported cases of chikungunya from surveillance data from the Taiwan CDC from 2007 to 2019. Conclusion: This study highlights the importance of longitudinal and geographically extended studies to understand the implications of zoonotic disease transmission on Taiwan’s population. Critical data were identified to inform future surveillance and research efforts in Taiwan.

Disease Resolution in Chikungunya-What Decides the Outcome?

Chikungunya disease (CHIKD) is a viral infection caused by an alphavirus, chikungunya virus (CHIKV), and triggers large outbreaks leading to epidemics. Despite the low mortality rate, it is a major public health concern owing to high morbidity in affected individuals. The complete spectrum of this disease can be divided into four phases based on its clinical presentation and immunopathology. When a susceptible individual is bitten by an infected mosquito, the bite triggers inflammatory responses attracting neutrophils and initiating a cascade of events, resulting in the entry of the virus into permissive cells. This phase is termed the pre-acute or the intrinsic incubation phase. The virus utilizes the cellular components of the innate immune system to enter into circulation and reach primary sites of infection such as the lymph nodes, spleen, and liver. Also, at this point, antigen-presenting cells (APCs) present the viral antigens to the T cells thereby activating and initiating adaptive immune responses. This phase is marked by the exhibition of clinical symptoms such as fever, rashes, arthralgia, and myalgia and is termed the acute phase of the disease. Viremia reaches its peak during this phase, thereby enhancing the antigen-specific host immune response. Simultaneously, T cell-mediated activation of B cells leads to the formation of CHIKV specific antibodies. Increase in titres of neutralizing IgG/IgM antibodies results in the clearance of virus from the bloodstream and marks the initiation of the post-acute phase. Immune responses mounted during this phase of the infection determine the degree of disease progression or its resolution. Some patients may progress to a chronic arthritic phase of the disease that may last from a few months to several years, owing to a compromised disease resolution. The present review discusses the immunopathology of CHIKD and the factors that dictate disease progression and its resolution.

Chronic Chikungunya Arthritis and Rheumatoid Arthritis: What They Have in Common

Chikungunya virus (CHIKV) is a single-stranded RNA virus belonging to the family Togaviridae and genus Alphavirus that causes an acute febrile illness, chikungunya fever, which is transmitted to humans by Aedes species mosquitoes. During acute illness, patients have high fever, polyarthralgias or polyarthritis, maculopapular rash, headache, and myalgia that lasts for days to weeks. Following resolution of acute infection, a significant proportion of patients develop chronic chikungunya arthritis that can resemble rheumatoid arthritis. In this review, we first consider the historical background of infectious causes of inflammatory arthritis, and then the pathogenic and clinical manifestations of chronic chikungunya arthritis as a rheumatoid arthritis mimic. We believe that chronic chikungunya arthritis may be a postinfectious inflammatory process, and that an understanding of the parallels and differences between chronic chikungunya arthritis and rheumatoid arthritis may offer insights into better diagnosis and treatment of both diseases.

Dengue, Zika and chikungunya during pregnancy: pre- and post-travel advice and clinical management

RATIONALE FOR REVIEW

Young adults of childbearing age and pregnant women are travelling more frequently to tropical areas, exposing them to specific arboviral infections such as dengue, zika and chikungunya viruses, which may impact ongoing and future pregnancies. In this narrative review, we analyse their potential consequences on pregnancy outcomes and discuss current travel recommendations.

MAIN FINDINGS

Dengue virus may be associated with severe maternal complications, particularly post-partum haemorrhage. Its association with adverse fetal outcomes remains unclear, but prematurity, growth retardation and stillbirths may occur, particularly in cases of severe maternal infection. Zika virus is a teratogenic infectious agent associated with severe brain lesions, with similar risks to other well-known TORCH pathogens. Implications of chikungunya virus in pregnancy are mostly related to intrapartum transmission that may be associated with severe neonatal infections and long-term morbidity.

TRAVEL RECOMMENDATIONS

Few agencies provide specific travel recommendations for travelling pregnant patients or couples trying to conceive and discrepancies exist, particularly regarding Zika virus prevention. The risks significantly depend on epidemiological factors that may be difficult to predict. Prevention relies principally on mosquito control measures. Couples trying to conceive and pregnant women should receive adequate information about the potential risks. It seems reasonable to advise pregnant women to avoid unnecessary travel to Aedes spp. endemic regions. The current rationale to avoid travel and delay conception is debatable in the absence of any epidemic. Post-travel laboratory testing should be reserved for symptomatic patients.

Propriedades psicométricas do WHODAS para uso em pessoas com chikungunya no Brasil

RESUMO O objetivo deste estudo é validar um instrumento de aferição da funcionalidade segundo a proposta conceitual da Classificação Internacional de Funcionalidade, Incapacidade e Saúde, para uso em pessoas pós-chikungunya. Este é um estudo de validação com indivíduos >17 anos, de ambos os sexos, em atendimento para manejo clínico da chikungunya. A coleta de dados foi realizada por meio de entrevistas coletando informações sobre funcionalidade (WHODAS), qualidade de vida (WHOQOL-bref) e sociodemográficas. A análise estatística usou o coeficiente alfa de Cronbach (consistência interna) e coeficiente de correlação de Spearman (validade convergente), médias e desvios-padrão para a determinação do perfil de qualidade de vida, com nível de significância de 5%. A amostra foi composta por 68 indivíduos. Os valores médios das pontuações dos instrumentos foram: 45,4 (±16,38) para o WHODAS e 12,1 (±2,10) para o WHOQOL-bref. O alfa de Cronbach do valor total foi de α=0,93; todos os domínios do WHODAS apresentaram valores acima de 0,75. O valor total do WHODAS 2.0 apresentou forte correlação com o domínio físico (r=−0,74) e moderada correlação com os domínios psicológico (r=−0,68) e social (r=−0,42) do WHOQOL-bref. Os resultados indicam que o WHODAS 2.0 é um instrumento válido para a mensuração da autopercepção de alteração da funcionalidade em pacientes acometidos pela chikungunya, capaz de fornecer dados que podem ajudar a construir um perfil de impacto da doença no perfil de funcionalidade dessa população.