Arthritogenic alphaviruses--an overview

VCP/p97 Is a Proviral Host Factor for Replication of Chikungunya Virus and Other Alphaviruses

The evolutionarily conserved AAA+ ATPase valosin-containing protein (VCP) was previously shown to be a proviral host factor for several viruses from different viral families such as Flaviviridae, Picornaviridae, and Herpesviridae. VCP was shown to affect trafficking of Sindbis virus receptor and functions as a component of Semliki Forest virus (SFV) replicase compartment. However, the role of this cellular protein was not evaluated during replication of alphaviruses including chikungunya virus (CHIKV). Using siRNA, chemical inhibitors, and trans-replication assays, we show here that VCP is a proviral factor involved in the replication of CHIKV. Immunofluorescence assays confirmed that VCP co-localized with non-structural replicase proteins but not with dsRNA foci possibly due to VCP epitope unavailability. VCP pro-viral role is also observed with other alphaviruses such as o’nyong’nyong virus (ONNV) and SFV in different human cell lines. VCP proviral roles on several viral families now extend to replication of alphaviruses CHIKV and ONNV, emphasizing the pivotal role of VCP in virus–host interaction biology.

Complete Coding Sequence of a Chikungunya Virus Strain Imported into Slovenia from Thailand in Late 2018

A case of chikungunya virus infection was imported from Thailand into Slovenia in late 2018. The infection was diagnosed using real-time reverse transcription-PCR, the virus was isolated in cell culture, and the whole genome was sequenced. Phylogenetic analysis of the nearly complete viral genome indicated that the virus belongs to the Indian Ocean lineage but does not possess the A226V mutation in the envelope protein E1.

A case of chikungunya virus infection was imported from Thailand into Slovenia in late 2018. The infection was diagnosed using real-time reverse transcription-PCR, the virus was isolated in cell culture, and the whole genome was sequenced. Phylogenetic analysis of the nearly complete viral genome indicated that the virus belongs to the Indian Ocean lineage but does not possess the A226V mutation in the envelope protein E1.

Chikungunya chronic disease: a systematic review and meta-analysis

Background

Chikungunya is a mosquito-borne disease caused by an arthritogenic alphavirus, with four genotypes: East Central South African (ECSA), West African, ECSA-diverged or Indian Ocean Lineage (IOL) and Asian lineage. Overall, the disease is self-limited; however, in some patients, joint pain and other non-specific symptoms can last for months or years. This systematic review and meta-analysis aims to estimate the proportion of people that self-report chikungunya-related chronic non-specific symptoms.

Methods

Medline, EMBASE, Global Health Library and Scopus were searched for articles published before March 2017. Case-control, cohort, cross-sectional, clinical trials studies and outcome-independent case series were eligible. It was estimated that the proportion of patients who did not recover, by virus genotype, and by the time between disease onset and assessment of chronic symptoms.

Results

A total of 38 studies were included in the review and 34 in the meta-analysis. Of 6532 chikungunya patients, 3157 did not recover fully after 3 months. The overall no recovery rate associated with chikungunya was 43% (95% CI, 35-52%); Inter-genotype group heterogeneity was observed, the highest prevalence in the ECSA-diverged genotype: 50% (95% CI; 40-60%), followed by the Asian lineage genotype: 36% (95% CI; 20-52%). After 12 months follow-up, the overall no-recovery rate was 21% (95% CI; 19-22%).

Conclusion

The evidence suggests that the prevalence of chronic discomfort associated with chikungunya illness varies by virus lineage. The proportion of people that do not fully recovered after chikungunya was high and, therefore, health authorities must prepare to treat patients with symptoms of long-lasting chikungunya adequately addressing the physical, psychological and social needs.

Immunoinformatics and structural vaccinology driven prediction of multi-epitope vaccine against Mayaro virus and validation through in-silico expression

The Mayaro virus (MAYV) belongs to genus "Alphavirus" and family "Togaviridae". MAYV has distribution in the Amazonia, Central and Northeastern regions of Brazil. The abundance of mosquito vector Haemagogus janthinomys has major role in the outbreaks of arthralgia disease in Brazil. Vaccination or immunization is an alternative approach for the protection against this disease. To search the effective candidate for vaccine against Mayaro virus, various immunoinformatics tools were used to predict both the B and T cell epitopes from five structural polyproteins (capsid, E2, 6K, E3and E1). A multi subunit vaccine was designed and the final sequence was modeled for docking with TLR-3. Human b defensin based on previous studies was used as linker. The docked complexes of vaccine-TLR-3 were then subjected to dynamics stability and RMSD and RMSF results suggested that the complexes are stable. Further, to validate our final vaccine construct, in silico cloning was carried out using E. coli as host. The CAI value of 0.96 suggests that the vaccine construct properly expresses in the host. The current findings will be useful for the future experimental validations to ratify the immunogenicity and safety of the supposed structure of vaccine, and ultimately to treat the Mayaro virus, associated infections.

Sindbis virus polyarthritis outbreak signalled by virus prevalence in the mosquito vectors

Polyarthritis and rash caused by Sindbis virus (SINV), was first recognised in northern Europe about 50 years ago and is known as Ockelbo disease in Sweden and Pogosta disease in Finland. This mosquito-borne virus occurs mainly in tropical and sub-tropical countries, and in northern Europe it is suggested to cause regularly reoccurring outbreaks. Here a seven-year cycle of SINV outbreaks has been referred to in scientific papers, although the hypothesis is based solely on reported human cases. In the search for a more objective outbreak signal, we evaluated mosquito abundance and SINV prevalence in vector mosquitoes from an endemic area in central Sweden. Vector mosquitoes collected in the River Dalälven floodplains during the years before, during, and after the hypothesised 2002 outbreak year were assayed for virus on cell culture. Obtained isolates were partially sequenced, and the nucleotide sequences analysed using Bayesian maximum clade credibility and median joining network analysis. Only one SINV strain was recovered in 2001, and 4 strains in 2003, while 15 strains were recovered in 2002 with significantly increased infection rates in both the enzootic and the bridge-vectors. In 2002, the Maximum Likelihood Estimated infection rates were 10.0/1000 in the enzootic vectors Culex torrentium/pipiens, and 0.62/1000 in the bridge-vector Aedes cinereus, compared to 4.9/1000 and 0.0/1000 in 2001 and 0.0/1000 and 0.32/1000 in 2003 Sequence analysis showed that all isolates belonged to the SINV genotype I (SINV-I). The genetic analysis revealed local maintenance of four SINV-I clades in the River Dalälven floodplains over the years. Our findings suggest that increased SINV-I prevalence in vector mosquitoes constitutes the most valuable outbreak marker for further scrutinising the hypothesized seven-year cycle of SINV-I outbreaks and the mechanisms behind.

Inhibition of Chikungunya Virus Replication in Primary Human Fibroblasts by Liver X Receptor Agonist

The mosquito-borne chikungunya virus (CHIKV) causes acute pain and joint inflammation, and in recent years the virus has caused large epidemics in previously CHIKV-free geographic areas. To advance the understanding of host factors that antagonize CHIKV, we show that synthetic agonist of liver X receptor (LXR-623) inhibits CHIKV replication by upregulating the cholesterol exporter ABCA1 and that endogenous and pharmacological activation of interferon signaling pathway partners with LXR-623 to generate a superior antiviral state.

Association of IL1RN VNTR polymorphism with chikungunya infection: A study from Western India

Chikungunya, caused by the chikungunya virus (CHIKV) mostly presents as acute and chronic articular inflammatory manifestations. Interleukin 1 receptor antagonist (IL-1RN) is a potent endogenous competitive inhibitor of IL-1α and 1β and has an anti-inflammatory role. The present study evaluated the possible association of IL1RN variable number tandem-repeat (VNTR) alleles and genotypes, and CHIKV stimulated IL-1RN cytokine production with resistance and/or susceptibility to chikungunya infection and disease state in 224 patients with chikungunya (61 patients with acute chikungunya and 163 patients with chronic chikungunya) and 355 healthy controls. Polymerase chain reaction, CHIKV stimulated cytokine assay and luminex platform were used for assessing polymorphism and protein levels respectively. The study revealed a significant association of IL1RN*1/*1 genotype under recessive genetic model with the risk of developing chikungunya infection. Our findings also indicated that IL1RN *2 allele under dominant mode was associated with protection to chronic chikungunya. The results also revealed a higher production of IL-1 RN protein in patients with chronic chikungunya. To conclude, the results suggest the association of ILRN VNTR polymorphism and IL-RN protein levels with chronic chikungunya.

Bioluminescent Ross River Virus Allows Live Monitoring of Acute and Long-Term Alphaviral Infection by In Vivo Imaging

Arboviruses like chikungunya and Ross River (RRV) are responsible for massive outbreaks of viral polyarthritis. There is no effective treatment or vaccine available against these viruses that induce prolonged and disabling arthritis. To explore the physiopathological mechanisms of alphaviral arthritis, we engineered a recombinant RRV expressing a NanoLuc reporter (RRV-NLuc), which exhibited high stability, near native replication kinetics and allowed real time monitoring of viral spread in an albino mouse strain. During the acute phase of the disease, we observed a high bioluminescent signal reflecting viral replication and dissemination in the infected mice. Using Bindarit, an anti-inflammatory drug that inhibits monocyte recruitment, we observed a reduction in viral dissemination demonstrating the important role of monocytes in the propagation of the virus and the adaptation of this model to the in vivo evaluation of treatment strategies. After resolution of the acute symptoms, we observed an increase in the bioluminescent signal in mice subjected to an immunosuppressive treatment 30 days post infection, thus showing active in vivo replication of remnant virus. We show here that this novel reporter virus is suitable to study the alphaviral disease up to the chronic phase, opening new perspectives for the evaluation of therapeutic interventions.

Pilates method in the treatment of patients with Chikungunya fever: a randomized controlled trial

Objective:

The aim of this study was to evaluate the effects of the Pilates method on the reduction of pain, improvement of joint function, and quality of life of patients with chronic Chikungunya fever.

Design:

This is a randomized, controlled, blind trial for the evaluators.

Setting:

The study was conducted at the Advanced Laboratory in Physical Education and Health at Federal University of Pernambuco, Brazil.

Subjects:

A total of 51 patients were allocated randomly and divided into 2 groups: a Pilates group (26 patients) and a control group (25 patients). After 12 weeks, 4 patients in the Pilates group and 5 in the control group were lost to follow-up.

Intervention:

The Pilates group performed 24 Pilates method intervention sessions; the control group continued to receive standard clinical treatment at the outpatient clinic.

Main measures:

The main measures were as follows: visual analogue scale (VAS) for pain, functional capacity evaluated by Health Assessment Questionaire (HAQ), quality of life measured by the 12-Item Short-Form Health Survey (SF-12), and range of joint motion by goniometry.

Results:

After 12 weeks, patients in the Pilates group presented lower VAS ( P < 0.001), lower HAQ scores ( P < 0.001), and higher quality-of-life scores ( P < 0.001) compared with the control group. We found statistically significant results for the Pilates group in the range of movement for shoulder, knee, ankle, and lumbar spine ( P < 0.001). In the intragroup analysis, there was a significant improvement in all outcomes evaluated.

Conclusion:

In this study, patients undertaking Pilates method for 12 weeks had less pain, better function and quality of life, and increased range of joint movement.

Development of a Specific CHIKV-E2 Monoclonal Antibody for Chikungunya Diagnosis

Chikungunya fever is a vector-borne viral disease transmitted to humans by chikungunya virus (CHIKV)-infected mosquitoes. There have been many outbreaks of CHIKV infection worldwide, and the virus poses ongoing risks to global health. To prevent and control CHIKV infection, it is important to improve the current CHIKV diagnostic approaches to allow for the detection of low CHIKV concentrations and to correctly distinguish CHIKV infections from those due to other mosquito-transmitted viruses, including dengue virus (DENV), Japanese encephalitis virus (JEV), and Zika virus (ZIKV). Here, we produced monoclonal antibodies (mAbs) against the CHIKV envelope 2 protein (CHIKV-E2) and compared their sensitivity and specificity with commercially available mAbs using enzyme-linked immunosorbent assays (ELISA). Two anti-CHIKV-E2 mAbs, 19-1 and 21-1, showed higher binding affinities to CHIKV-E2 protein than the commercial mAbs did. In particular, the 19-1 mAb had the strongest binding affinity to inactivated CHIKV. Moreover, the 19-1 mAb had very little cross-reactivity with other mosquito-borne viruses, such as ZIKV, JEV, and DENV. These results suggest that the newly produced anti-CHIKV-E2 mAb, 19-1, could be used for CHIKV diagnostic approaches.

Arthritogenic Alphaviruses: A Worldwide Emerging Threat?

Arthritogenic alphaviruses are responsible for a dengue-like syndrome associated with severe debilitating polyarthralgia that can persist for months or years and impact life quality. Chikungunya virus is the most well-known member of this family since it was responsible for two worldwide epidemics with millions of cases in the last 15 years. However, other arthritogenic alphaviruses that are as of yet restrained to specific territories are the cause of neglected tropical diseases: O'nyong'nyong virus in Sub-Saharan Africa, Mayaro virus in Latin America, and Ross River virus in Australia and the Pacific island countries and territories. This review evaluates their emerging potential in light of the current knowledge for each of them and in comparison to chikungunya virus.

Molecular Basis of Arthritogenic Alphavirus Receptor MXRA8 Binding to Chikungunya Virus Envelope Protein

Arthritogenic alphaviruses, such as Chikungunya virus (CHIKV), cause severe and debilitating rheumatic diseases worldwide, resulting in severe morbidity and economic costs. Recently, MXRA8 was reported as an entry receptor. Here, we present the crystal structures of the mouse MXRA8, human MXRA8 in complex with the CHIKV E protein, and the cryo-electron microscopy structure of human MXRA8 and CHIKV virus-like particle. MXRA8 has two Ig-like domains with unique structural topologies. This receptor binds in the "canyon" between two protomers of the E spike on the surface of the virion. The atomic details at the interface between the two binding entities reveal that both the two domains and the hinge region of MXRA8 are involved in interaction with CHIKV E1-E2 residues from two protomers. Notably, the stalk region of MXRA8 is critical for CHIKV virus entry. This finding provides important information regarding the development of therapeutic countermeasures against those arthritogenic alphaviruses.

Animal model of arthritis and myositis induced by the Mayaro virus

BACKGROUND

The Mayaro virus (MAYV) is an endemic arbovirus in South American countries, where it is responsible for sporadic outbreaks of Mayaro fever. Clinical manifestations include fever, headache, ocular pain, rash, myalgia, and debilitating and persistent polyarthralgia. Understanding the mechanisms associated with MAYV-induced arthritis is of great importance due to the potential for its emergence, urbanization and dispersion to other regions.

METHODS

15-day old Balb/c mice were infected by two distinct pathways, below the forelimb and in the rear footpad. Animals were observed for a period of 21 days. During this time, they were monitored every 24 hours for disease signs, such as weight loss and muscle weakness. Histological damage in the muscles and joints was evaluated 3, 7, 10, 15 and 20 days post-infection. The cytokine profile in serum and muscles during MAYV infection was evaluated by flow cytometry at different post-infection times. For pain analysis, the animals were submitted to the von Frey test and titre in different organs was evaluated throughout the study to obtain viral kinetics.

FINDINGS

Infection by two distinct pathways, below the forelimb and in the rear footpad, resulted in a homogeneous viral spread and the development of acute disease in animals. Clinical signs were observed such as ruffled fur, hunched posture, eye irritation and slight gait alteration. In the physical test, both groups presented loss of resistance, which was associated with histopathological damage, including myositis, arthritis, tenosynovitis and periostitis. The immune response was characterized by a strong inflammatory response mediated by the cytokines TNF-α, IL-6 and INF-γ and chemokine MCP-1, followed by the action of IL-10 and IL-4 cytokines.

INTERPRETATION

The results showed that Balb/c mice represent a promising model to study mechanisms involved in MAYV pathogenesis and for future antiviral testing.

Emergence and treatment of chikungunya arthritis

PURPOSE OF REVIEW

To review the emergence, clinical features, pathogenesis, and treatment of acute chikungunya (CHIK) fever and chronic CHIK arthritis.

RECENT FINDINGS

Since 2004, CHIK, an arboviral infection, has spread throughout the world, infecting millions of people. The illness occurs in two phases: an acute viremic infection followed by chronic arthritis. In less developed countries, there are limited resources and effective treatment. For acutely ill CHIK fever patients, management is symptomatic. The treatment of chronic CHIK arthritis should be determined by an understanding of pathogenesis. Is chronic CHIK arthritis a persistent viral infection or a postinfectious inflammatory process? Multiple proinflammatory cytokines, chemokines, and growth factors have been identified in chronic CHIK arthritis. Attempts to isolate CHIK virus from synovial fluid have been unsuccessful. Given pathogenetic similarities (as well as differences) compared with rheumatoid arthritis and the painful, disabling nature of the arthritis, it is not surprising that disease-modifying antirheumatic drugs such as methotrexate have begun to be used.

SUMMARY

CHIK infection has emerged with major arthritic epidemics for which evidence-based therapy is limited. But there is an opportunity to improve the treatment of chronic CHIK arthritis and, from this disease, to gain understanding of the pathogenesis and treatment of inflammatory arthritis more generally.

In Vivo Evaluation of Withania somnifera-Based Indian Traditional Formulation ( Amukkara Choornam), Against Chikungunya Virus-Induced Morbidity and Arthralgia

Chikungunya viral fever results in extreme morbidity and arthralgia in affected individuals. Currently, modern medicines providing symptomatic relief for the acute febrile phase and the chronic arthritic phase are only options available. Traditional Indian medical system, however, uses specific formulations for treatment of this infection; one such polyherbal formulation used to treat the postpyretic phase of chikungunya is amukkara choornam. The current study was undertaken to study the efficacy of amukkara choornam in the treatment of chikungunya in C57BL/6J mice. The formulation when administered to chikungunya-infected mice relieved morbidity and joint swelling. Analysis of virus clearance in brain and joint tissues on formulation treatment revealed a direct correlation of viral load in brain to morbidity during infection; likewise, joint swelling receded prior to complete viral clearance explaining possible immunomodulatory effect of amukkara choornam. This study provides insight into the possible mode of action of amukkara choornam during chikungunya.

[Virus-associated arthritis]

Epidemiological studies suggest a viral etiology in approximately 1% of patients presenting with acute arthritis. The arthritogenic effect of viral infections may be related to viral invasion of synovial cells, the cellular and humoral immune response to viral antigens or by induction of autoimmunity. Viral arthritis can mimic rheumatoid arthritis by presenting as a symmetrical polyarticular disease often accompanied by a rash and influenza-like symptoms. Serological testing for pathogen-specific IgM and IgG antibodies is frequently performed for establishing a viral etiology of arthritis. Virus isolation from the joints or detection of viral nucleic acids in the synovium or synovial fluid is only rarely successful and does not always provide proof of a viral origin of arthritis. While viral arthritis in most cases is self-limiting, protracted disease can occur.

Protective immunity by an engineered DNA vaccine for Mayaro virus

Mayaro virus (MAYV) of the genus alphavirus is a mosquito-transmitted emerging infectious disease that causes an acute febrile illness, rash, headaches, and nausea that may turn into incapacitating, persistent arthralgias in some victims. Since its discovery in Trinidad in 1954, cases of MAYV infection have largely been confined there and to the northern countries of South America, but recently, MAYV cases have been reported in some island nations in the Caribbean Sea. Accompanying these reports is evidence that new vectors, including Aedes spp. mosquitos, recently implicated in the global spread of Zika and chikungunya viruses, are competent for MAYV transmission, which, if true, could facilitate the spread of MAYV beyond its current range. Despite its status as an emerging virus, there are no licensed vaccines to prevent MAYV infection nor therapeutics to treat it. Here, we describe the development and testing of a novel DNA vaccine, scMAYV-E, that encodes a synthetically-designed consensus MAYV envelope sequence. In vivo electroporation-enhanced immunization of mice with this vaccine induced potent humoral responses including neutralizing antibodies as well as robust T-cell responses to multiple epitopes in the MAYV envelope. Importantly, these scMAYV-E-induced immune responses protected susceptible mice from morbidity and mortality following a MAYV challenge.

Arbovirus-Mosquito Vector-Host Interactions and the Impact on Transmission and Disease Pathogenesis of Arboviruses

Hundreds of viruses, designated as arboviruses, are transmitted by arthropod vectors in complex transmission cycles between the virus, vertebrate host, and the vector. With millions of human and animal infections per year, it is critical to improve our understanding of the interactions between the biological and environmental factors that play a critical role in pathogenesis, disease outcomes, and transmission of arboviruses. This review focuses on mosquito-borne arboviruses and discusses current knowledge of the factors and underlying mechanisms that influence infection and transmission of arboviruses and discusses critical factors and pathways that can potentially become targets for intervention and therapeutics.

A potent prolyl tRNA synthetase inhibitor antagonizes Chikungunya and Dengue viruses

Arboviruses represent a group of pathogens that can spread efficiently throughout human populations by hematophagous arthropod vectors. The mosquito-borne (re)emerging Chikungunya and Dengue viruses belong to the alphavirus and flavivirus genus, respectively, with no approved therapeutics or safe vaccines for humans. Transmitted by the same vector Aedes spp., these viruses cause significant morbidity and mortality in endemic areas. Due to the increasing likelihood of co-circulation and co-infection with viruses, we aimed to identify a pharmacologically targetable host factor that can inhibit multiple viruses and show that a potent antagonist of prolyl tRNA synthetase (halofuginone) suppresses both Chikungunya and Dengue viruses. Host tRNA synthetase inhibition may signify an additional approach to combat present and future epidemic pathogens.

Rev-erb Agonist Inhibits Chikungunya and O'nyong'nyong Virus Replication

Chikungunya virus (CHIKV), an alphavirus spread by Aedes spp. mosquitos, causes severe inflammation and joint pain, progressing to a chronic arthralgic state in a subset of patients. Due to recent global epidemics of CHIKV and the potential for related viruses to cause outbreaks, multiple approaches to combat these pathogens are of interest. We report that SR9009, a synthetic agonist of nuclear receptors Rev-erb α/β, inhibits replication of multiple alphaviruses (CHIKV and O'nyong'nyong virus) mainly by suppressing structural protein synthesis, although viral RNA accumulation is relatively unimpeded. Furthermore, SR9009 reduces the inflammatory response in cultured murine macrophages exposed to alphavirus-infected cells.

Autoimmunity Mimics: Infection and Malignancy

Musculoskeletal rheumatic syndromes are commonly encountered in the primary care setting. A plethora of commonly encountered and rare infectious agents can produce osteoarticular and soft tissue manifestations. Likewise, malignancies may manifest rheumatic symptoms via direct tumor invasion or paraneoplastic effects. Awareness of these diseases and their clinical risk factors should result in improved screening and earlier recognition and intervention, leading to improved long-term outcomes and overall patient care.

Pain, balance, grip strength and gait parameters of older adults with and without post-chikungunya chronic arthralgia

OBJECTIVE

To compare the levels of pain, grip strength, balance and gait in older adults with and without post-Chikungunya chronic arthralgia (PCCA).

METHODS

Sixty-two older adults, 30 with and 32 without PCCA participated in the study. Pain level was assessed using a Visual Analogue Scale (VAS). Gait during a 10-m walk was assessed using inertial sensors. Semi-static balance was assessed during an eyes-closed bipedal balance test on a force platform, and grip strength was assessed using a hand dynamometer.

RESULTS

Participants with PCCA presented severe levels of pain (VAS > 7.5), poorer balance, lower grip strength, walked slower, with lower cadence and stride length and higher stride time and stride length variability than participants without PCCA (P < 0.001 for all variables).

CONCLUSIONS

Older adults with PCCA had high levels of pain, impaired balance and gait and lower grip strength compared to older adults without PCCA.

Cutaneous features of Zika virus infection: a clinicopathological overview

Zika virus (ZIKV) is an emerging mosquito-borne flavivirus transmitted mainly by Aedes species of mosquitos. Although the infection is usually mild and self-limiting, it is emerging as a public health challenge in tropical and subtropical countries owing to its unprecedented pathogenicity and increased risk for fetal malformations and neurological symptoms. Cutaneous manifestations as for other mosquito-borne viruses remain a hallmark of the disease. This article provides a detailed overview on ZIKV infection, including its varied cutaneous clinical manifestations and diagnostic aspects, and also provides detailed insights into its pathogenesis in human skin.

Mayaro: an emerging viral threat?

Mayaro virus (MAYV), an enveloped RNA virus, belongs to the Togaviridae family and Alphavirus genus. This arthropod-borne virus (Arbovirus) is similar to Chikungunya (CHIKV), Dengue (DENV), and Zika virus (ZIKV). The term “ChikDenMaZika syndrome” has been coined for clinically suspected arboviruses, which have arisen as a consequence of the high viral burden, viral co-infection, and co-circulation in South America. In most cases, MAYV disease is nonspecific, mild, and self-limited. Fever, arthralgia, and maculopapular rash are among the most common symptoms described, being largely indistinguishable from those caused by other arboviruses. However, severe manifestations of the infection have been reported, such as chronic polyarthritis, neurological complications, hemorrhage, myocarditis, and even death. Currently, there are no specific commercial tools for the diagnosis of MAYV, and the use of serological methods can be affected by cross-reactivity and the window period. A diagnosis based on clinical and epidemiological data alone is still premature. Therefore, new entomological research is warranted, and new highly specific molecular diagnostic methods should be developed. This comprehensive review is intended to encourage public health authorities and scientific communities to actively work on diagnosing, preventing, and treating MAYV infection.

Plasmodium co-infection protects against chikungunya virus-induced pathologies

Co-infection with Plasmodium and chikungunya virus (CHIKV) has been reported in humans, but the impact of co-infection on pathogenesis remains unclear. Here, we show that prior exposure to Plasmodium suppresses CHIKV-associated pathologies in mice. Mechanistically, Plasmodium infection induces IFNγ, which reduces viraemia of a subsequent CHIKV infection and suppresses tissue viral load and joint inflammation. Conversely, concomitant infection with both pathogens limits the peak of joint inflammation with no effect on CHIKV viraemia. Reduced peak joint inflammation is regulated by elevated apoptosis of CD4+ T-cells in the lymph nodes and disrupted CXCR3-mediated CD4+ T-cell migration that abolishes their infiltration into the joints. Virus clearance from tissues is delayed in both infection scenarios, and is associated with a disruption of B cell affinity-maturation in the spleen that reduces CHIKV-neutralizing antibody production.

Human CD8 T-cell activation in acute and chronic chikungunya infection

There is a need for more detailed elucidation of T-cell immunity in chikungunya infection. CD8 T cells are one of main actors against viruses. Here, we analysed CD8⁺ T lymphocytes from patients in the acute and chronic phases of chikungunya disease (CHIKD). Our results demonstrate that CD8⁺ T cells expressed higher ex vivo granzyme B, perforin and CD107A expression in patients in the acute phase of CHIKD compared with healthy individuals and higher ex vivo expression of CD69, interleukin-17A, interleukin-10 and CD95 ligand, and co-expression of CD95/CD95 ligand. These results elucidate the importance of these lymphocytes, demonstrating immune mechanisms mediated in human chikungunya infection.

Comprehensive innate immune profiling of chikungunya virus infection in pediatric cases

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes global epidemics of debilitating disease worldwide. To gain functional insight into the host cellular genes required for virus infection, we performed whole-blood RNA-seq, 37-plex mass cytometry of peripheral blood mononuclear cells (PBMCs), and serum cytokine measurements of acute- and convalescent-phase samples obtained from 42 children naturally infected with CHIKV Semi-supervised classification and clustering of single-cell events into 57 sub-communities of canonical leukocyte phenotypes revealed a monocyte-driven response to acute infection, with the greatest expansions in "intermediate" CD14++CD16+ monocytes and an activated subpopulation of CD14+ monocytes. Increases in acute-phase CHIKV envelope protein E2 expression were highest for monocytes and dendritic cells. Serum cytokine measurements confirmed significant acute-phase upregulation of monocyte chemoattractants. Distinct transcriptomic signatures were associated with infection timepoint, as well as convalescent-phase anti-CHIKV antibody titer, acute-phase viremia, and symptom severity. We present a multiscale network that summarizes all observed modulations across cellular and transcriptomic levels and their interactions with clinical outcomes, providing a uniquely global view of the biomolecular landscape of human CHIKV infection.

The Methyltransferase-Like Domain of Chikungunya Virus nsP2 Inhibits the Interferon Response by Promoting the Nuclear Export of STAT1

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that has evolved effective mechanisms to counteract the type I interferon (IFN) response. Upon recognition of the virus, cells secrete IFNs, which signal through transmembrane receptors (IFNAR) to phosphorylate STAT proteins (pSTAT). pSTAT dimers are transported into the nucleus by importin-α5 and activate the transcription of IFN-stimulated genes (ISGs), increasing cellular resistance to infection. Subsequently, STAT proteins are shuttled back into the cytoplasm by the exportin CRM1. CHIKV nonstructural protein 2 (nsP2) reduces ISG expression by inhibiting general host cell transcription and by specifically reducing the levels of nuclear pSTAT1 via an unknown mechanism. To systematically examine where nsP2 acts within the JAK/STAT signaling cascade, we used two well-characterized mutants of nsP2, P718S and KR649AA. Both mutations abrogate nsP2's ability to shut off host transcription, but only the KR649AA mutant localizes exclusively to the cytoplasm and no longer specifically inhibits JAK/STAT signaling. These mutant nsP2 proteins did not differentially affect IFNAR expression levels or STAT1 phosphorylation in response to IFNs. Coimmunoprecipitation experiments showed that in the presence of nsP2, STAT1 still effectively bound importin-α5. Chemically blocking CRM1-mediated nuclear export in the presence of nsP2 additionally showed that nuclear translocation of STAT1 is not affected by nsP2. nsP2 putatively has five domains. Redirecting the nsP2 KR649AA mutant or just nsP2's C-terminal methyltransferase-like domain into the nucleus strongly reduced nuclear pSTAT in response to IFN stimulation. This demonstrates that the C-terminal domain of nuclear nsP2 specifically inhibits the IFN response by promoting the nuclear export of STAT1.IMPORTANCE Chikungunya virus is an emerging pathogen associated with large outbreaks on the African, Asian, European, and both American continents. In most patients, infection results in high fever, rash, and incapacitating (chronic) arthralgia. CHIKV effectively inhibits the first line of defense, the innate immune response. As a result, stimulation of the innate immune response with interferons (IFNs) is ineffective as a treatment for CHIKV disease. The IFN response requires an intact downstream signaling cascade called the JAK/STAT signaling pathway, which is effectively inhibited by CHIKV nonstructural protein 2 (nsP2) via an unknown mechanism. The research described here specifies where in the JAK/STAT signaling cascade the IFN response is inhibited and which protein domain of nsP2 is responsible for IFN inhibition. The results illuminate new aspects of antiviral defense and CHIKV counterdefense strategies and will direct the search for novel antiviral compounds.

Immunomodulatory drug methotrexate used to treat patients with chronic inflammatory rheumatisms post-chikungunya does not impair the synovial antiviral and bone repair responses

Chikungunya virus (CHIKV) is a mosquito-transmitted RNA alphavirus causing major outbreaks of infectious chronic inflammatory rheumatisms (CIR). Recently, methotrexate (MTX), a disease modifying anti-rheumatic drug has been used successfully to treat patients suffering from rheumatoid-like arthritis post-CHIK but its immunomodulatory activity in the context of viral persistence has been a matter of concerns. We herein used a model of primary human synovial fibroblasts (HSF) and the synthetic molecule polyriboinosinic:polyribocytidylic acid (PIC) to mimic chronic infectious settings in the joints of CHIKV infected patients. The innate antiviral immune and inflammatory responses were investigated in response to MTX used at the therapeutic concentration of 1 μM. We found that MTX did not affect cellular viability as indicated by the LDH release assay. By quantitative RT-PCR, we observed that HSF responded robustly to PIC by increasing ISG15 and IFNβ mRNA levels. Furthermore, PIC upregulated the mRNA expression of two of the major pattern recognition receptors, RIG-I and MDA5 involved in the innate immune detection of viral RNA. MTX did not impact the antiviral response of PIC on ISG15, IFNβ, RIG-I and MDA5 mRNA expressions. MTX alone or combined with PIC did not affect the expression of proinflammatory CCL2 and CXCL8 chemokines. PIC strongly upregulated the mRNA and protein expression of osteoclastogenic factors (IL-6, GM-CSF but not RANKL). Critically, MTX treatment alone or combined with PIC did not affect the expression of all three tested osteoclastogenic cytokines. We found that MTX alone did not increase the capacity of CHIKV to infect and replicate in HSF. In conclusion, our study argues for a beneficial effect of MTX to treat CIR post-CHIKV given that it does not critically impact the antiviral, the proinflammatory and the bone tissue remodeling responses of synovial cells.

Chikungunya is a mosquito-borne virus (CHIKV) and has been incriminated in the development of arthralgia (pain of the joint) and arthritis particularly in elderly patients. Methotrexate (MTX) has been used widely to effectively treat these chronic rheumatic symptoms. Using a model of primary human joint fibroblasts (HSF), we investigated the capacity of the MTX immunosuppressive drug to affect the immune antiviral and inflammatory responses essential to clear the virus while allowing bone tissue repair. This study is important given that CHIKV and its RNA were shown to persist in the joint for months to years post infection and leading to injuries through ill-characterized mechanisms. The molecule PIC was used to mimic the effect of viral RNA. Interestingly, we found that MTX did not affect the expression of several proinflammatory and bone repair factors by HSF. Remarkably, MTX did not also impair the antiviral response of synovial fibroblasts. Our study revealed for the first time that MTX treatment should be considered as safe even in the context of viral persistence associated with chronic inflammation. MTX will not affect the capacity of the synovial tissue to maintain antiviral mechanism, to control inflammation and to promote bone tissue repair.

Repurposed FDA-Approved drug sorafenib reduces replication of Venezuelan equine encephalitis virus and other alphaviruses

The New World alphaviruses -Venezuelan, eastern, and western equine encephalitis viruses (VEEV, EEEV, and WEEV respectively) - cause a febrile disease that is often lethal in equines and children and leads to long-term neurological sequelae in survivors. Endemic to the Americas, epizootic outbreaks of the three viruses occur sporadically in the continental United States. All three viruses aerosolize readily, replicate to high titers in cell culture, and have low infectious doses. Additionally, there are no FDA-approved vaccines or therapeutics for human use. To address the therapeutic gap, a high throughput assay utilizing a luciferase reporter virus, TC83-luc, was performed to screen a library of commercially available, FDA-approved drugs for antiviral activity. From a group of twenty compounds found to significantly decrease luminescence, the carcinoma therapeutic sorafenib inhibited replication of VEEV-TC83 and TrD in vitro. Additionally, sorafenib inhibited replication of EEEV and two Old World alphaviruses, Sindbis virus and chikungunya virus, at 8 and 16 h post-infection. Sorafenib caused no toxicity in Vero cells, and coupled with a low EC₅₀ value, yielded a selectivity index of >19. Mechanism of actions studies suggest that sorafenib inhibited viral translation through dephosphorylation of several key proteins, including eIF4E and p70S6K, leading to a reduction in viral protein production and overall viral replication.

Full-Length Genome Sequence of a Sindbis Virus Strain Isolated from Culex cinereus in 1977 in Bozo, Central African Republic

We report here the complete genome sequence of a Sindbis virus (SINV) strain, ArB7761, isolated in 1977 in the Central African Republic. This strain, closely related to the Babanki virus, belongs to the SINV genotype I clade.

We report here the complete genome sequence of a Sindbis virus (SINV) strain, ArB7761, isolated in 1977 in the Central African Republic. This strain, closely related to the Babanki virus, belongs to the SINV genotype I clade. However, it differs from the Egyptian prototype strain AR339 by several indels in the nsP3 gene.

A compendium of small molecule direct-acting and host-targeting inhibitors as therapies against alphaviruses

Alphaviruses were amongst the first arboviruses to be isolated, characterized and assigned a taxonomic status. They are globally widespread, infecting a large variety of terrestrial animals, birds, insects and even fish. Moreover, they are capable of surviving and circulating in both sylvatic and urban environments, causing considerable human morbidity and mortality. The re-emergence of Chikungunya virus (CHIKV) in almost every part of the world has caused alarm to many health agencies throughout the world. The mosquito vector for this virus, Aedes, is globally distributed in tropical and temperate regions and capable of thriving in both rural and urban landscapes, giving the opportunity for CHIKV to continue expanding into new geographical regions. Despite the importance of alphaviruses as human pathogens, there is currently no targeted antiviral treatment available for alphavirus infection. This mini-review discusses some of the major features in the replication cycle of alphaviruses, highlighting the key viral targets and host components that participate in alphavirus replication and the molecular functions that were used in drug design. Together with describing the importance of these targets, we review the various direct-acting and host-targeting inhibitors, specifically small molecules that have been discovered and developed as potential therapeutics as well as their reported in vitro and in vivo efficacies.

Molecular characterization and phylogenetic analysis of Chikungunya virus from Delhi, India

Background

Chikungunya virus is an alpha virus with high similarity to Dengue and Zika viruses, both in transmission cycle and in clinical presentation. Chikungunya is a re-emerging mosquito-borne infection known to cause small to very large outbreaks/epidemics at frequent intervals. In 2016, India witnessed a large outbreak of Chikungunya infection affecting more than 58,000 people. This study was undertaken to look at the genotypic phylogeny to know the relatedness with previously reported strains.

Methods

During the 2016 outbreak, samples from all patients clinically suspected to have Chikungunya were collected and subjected to testing for IgM antibody by ELISA and viral RNA detection by RT-PCR. Sequencing of the E1 gene segment was done to create a phylogenetic tree comparison with other strains.

Results

Serum samples were collected from 142 patients of clinically suspected Chikungunya infection. Majority of the patients were in the age group of 31-50 years accounting for more than 35% of the total cases. Twenty eight samples were positive for IgM antibody. Thirty seven samples were positive for viral RNA by RT-PCR. Only 06 cases were positive by both tests. Mutations in the amino acids K211E, M269V and D284E in the E1 gene segment of the Chikungunya virus were observed in the seven strains that were sequenced. On phylogeny tree, all the strains were found to belong to the ECSA genotype.

Conclusion

Actively searching for the potential epidemic causing mutations and reporting of novel mutations may help in better understanding and probably forecasting of future CHIKV outbreaks and its nature.

In vitro comparison of three common essential oils mosquito repellents as inhibitors of the Ross River virus

BACKGROUND

The essential oils of Cymbopogon citratus (CC), Pelargonium graveolens (PG) and Vetiveria zizanioides (VZ) are commonly used topically to prevent mosquito bites and thus the risk of infection by their vectored pathogens such as arboviruses. However, since mosquito bites are not fully prevented, the effect of these products on the level of viral infection remains unknown.

OBJECTIVES

To evaluate in vitro the essentials oils from Reunion Island against one archetypal arbovirus, the Ross River virus (RRV), and investigate the viral cycle step that was impaired by these oils.

METHODS

The essential oils were extracted by hydrodistillation and analyzed by a combination of GC-FID and GC×GC-TOF MS techniques. In vitro studies were performed on HEK293T cells to determine their cytotoxicity, their cytoprotective and virucidal capacities on RRV-T48 strain, and the level of their inhibitory effect on the viral replication and residual infectivity prior, during or following viral adsorption using the reporter virus RRV-renLuc.

RESULTS

Each essential oil was characterized by an accurate quantification of their terpenoid content. PG yielded the least-toxic extract (CC50 > 1000 μg.mL-1). For the RRV-T48 strain, the monoterpene-rich CC and PG essential oils reduced the cytopathic effect but did not display virucidal activity. The time-of-addition assay using the gene reporter RRV-renLuc showed that the CC and PG essential oils significantly reduced viral replication and infectivity when applied prior, during and early after viral adsorption. Overall, no significant effect was observed for the low monoterpene-containing VZ essential oil.

CONCLUSION

The inhibitory profiles of the three essential oils suggest the high value of the monoterpene-rich essential oils from CC and PG against RRV infection. Combined with their repellent activity, the antiviral activity of the essential oils of CC and PG may provide a new option to control arboviral infection.

Structural divergence creates new functional features in alphavirus genomes

Alphaviruses are mosquito-borne pathogens that cause human diseases ranging from debilitating arthritis to lethal encephalitis. Studies with Sindbis virus (SINV), which causes fever, rash, and arthralgia in humans, and Venezuelan equine encephalitis virus (VEEV), which causes encephalitis, have identified RNA structural elements that play key roles in replication and pathogenesis. However, a complete genomic structural profile has not been established for these viruses. We used the structural probing technique SHAPE-MaP to identify structured elements within the SINV and VEEV genomes. Our SHAPE-directed structural models recapitulate known RNA structures, while also identifying novel structural elements, including a new functional element in the nsP1 region of SINV whose disruption causes a defect in infectivity. Although RNA structural elements are important for multiple aspects of alphavirus biology, we found the majority of RNA structures were not conserved between SINV and VEEV. Our data suggest that alphavirus RNA genomes are highly divergent structurally despite similar genomic architecture and sequence conservation; still, RNA structural elements are critical to the viral life cycle. These findings reframe traditional assumptions about RNA structure and evolution: rather than structures being conserved, alphaviruses frequently evolve new structures that may shape interactions with host immune systems or co-evolve with viral proteins.

High costs of infection: Alphavirus infection reduces digestive function and bone and feather growth in nestling house sparrows (Passer domesticus)

Increasingly, ecoimmunology studies aim to use relevant pathogen exposure to examine the impacts of infection on physiological processes in wild animals. Alphaviruses are arthropod-borne, single-stranded RNA (ssRNA) viruses ("arboviruses") responsible for millions of cases of human illnesses each year. Buggy Creek virus (BCRV) is a unique alphavirus that is transmitted by a cimicid insect, the swallow bug, and is amplified in two avian species: the house sparrow (Passer domesticus) and the cliff swallow (Petrochelidon pyrrhonota). BCRV, like many alphaviruses, exhibits age-dependent susceptibility where the young are most susceptible to developing disease and exhibit a high mortality rate. However, alphavirus disease etiology in nestling birds is unknown. In this study, we infected nestling house sparrows with Buggy Creek virus and measured virological, pathological, growth, and digestive parameters following infection. Buggy Creek virus caused severe encephalitis in all infected nestlings, and the peak viral concentration in brain tissue was over 34 times greater than any other tissue. Growth, tissue development, and digestive function were all significantly impaired during BCRV infection. However, based on histopathological analysis performed, this impairment does not appear to be the result of direct tissue damage by the virus, but likely caused by encephalitis and neuronal invasion and impairment of the central nervous system. This is the first study to examine the course of alphavirus diseases in nestling birds and these results will improve our understanding of age-dependent infections of alphaviruses in vertebrate hosts.

A vaccinia-based single vector construct multi-pathogen vaccine protects against both Zika and chikungunya viruses

Zika and chikungunya viruses have caused major epidemics and are transmitted by Aedes aegypti and/or Aedes albopictus mosquitoes. The “Sementis Copenhagen Vector” (SCV) system is a recently developed vaccinia-based, multiplication-defective, vaccine vector technology that allows manufacture in modified CHO cells. Herein we describe a single-vector construct SCV vaccine that encodes the structural polyprotein cassettes of both Zika and chikungunya viruses from different loci. A single vaccination of mice induces neutralizing antibodies to both viruses in wild-type and IFNAR^−/− mice and protects against (i) chikungunya virus viremia and arthritis in wild-type mice, (ii) Zika virus viremia and fetal/placental infection in female IFNAR^−/− mice, and (iii) Zika virus viremia and testes infection and pathology in male IFNAR^−/− mice. To our knowledge this represents the first single-vector construct, multi-pathogen vaccine encoding large polyproteins, and offers both simplified manufacturing and formulation, and reduced “shot burden” for these often co-circulating arboviruses.

Zika and chikungunya virus are co-circulating in many regions and currently there is no approved vaccine for either virus. Here, the authors engineer one vaccinia virus based vaccine for both, Zika and chikungunya, and show protection from infection and pathogenesis in mice.

Chikungunya Arthritis: Implications of Acute and Chronic Inflammation Mechanisms on Disease Management

In the past decade, arboviruses-arthropod-borne viruses-have been the focus of public health institutions worldwide following a spate of devastating outbreaks. Chikungunya virus, an arbovirus that belongs to the alphavirus genus, is a reemerging arthritogenic virus that has caused explosive outbreaks since 2006, notably on Réunion Island, and more recently in the Caribbean, South America, India, and Southeast Asia. The severity of arthritic disease caused by chikungunya virus has prompted public health authorities in affected countries to develop specific guidelines to tackle this pathogen. Chikungunya virus disease manifests first as an acute stage of severe joint inflammation and febrile illness, which later progresses to a chronic stage, during which patients may experience debilitating and persisting articular pain for extended periods. This review aims to provide a broad perspective on current knowledge of chikungunya virus pathogenesis by identifying key clinical and experimental studies that have contributed to our understanding of chikungunya virus to date. In addition, the review explores the practical aspects of treatment and management of both acute and chronic chikungunya virus based on clinical experience during chikungunya virus outbreaks. Finally, recent findings on potential therapeutic solutions-from antiviral agents to immunomodulators-are reviewed to provide both viral immunologists and clinical rheumatologists with a balanced perspective on the nature of a reemerging arboviral disease of significant public health concern, and insight into future therapeutic approaches to better address the treatment and management of chikungunya virus.

Frequency of Chronic Joint Pain Following Chikungunya Virus Infection: A Colombian Cohort Study

OBJECTIVE

To estimate the frequency of chronic joint pain after infection with chikungunya virus in a Latin American cohort.

METHODS

A cross-sectional follow-up of a prospective cohort of 500 patients from the Atlántico Department, Colombia who were clinically diagnosed as having chikungunya virus during the 2014-2015 epidemic was conducted. Baseline symptoms and follow-up symptoms at 20 months were evaluated in serologically confirmed cases.

RESULTS

Among the 500 patients enrolled, 485 had serologically confirmed chikungunya virus and reported joint pain status. Patients were predominantly adults (mean ± SD age 49 ± 16 years) and female, had an education level of high school or less, and were of Mestizo ethnicity. The most commonly affected joints were the small joints, including the wrists, ankles, and fingers. The initial virus symptoms lasted a median of 4 days (interquartile range [IQR] 3-8 days). Sixteen percent of the participants reported missing school or work (median 4 days [IQR 2-7 days]). After 20 months, one-fourth of the participants had persistent joint pain. A multivariable analysis indicated that significant predictors of persistent joint pain included college graduate status, initial symptoms of headache or knee pain, missed work, normal activities affected, ≥4 days of initial symptoms, and ≥4 weeks of initial joint pain.

CONCLUSION

This is the first report to describe the frequency of chikungunya virus-related arthritis in the Americas after a 20-month follow-up. The high frequency of chronic disease highlights the need for the development of prevention and treatment methods.

Macrophages as target cells for Mayaro virus infection: involvement of reactive oxygen species in the inflammatory response during virus replication

Alphaviruses among the viruses that cause arthritis, consisting in a public health problem worldwide by causing localized outbreaks, as well as large epidemics in humans. Interestingly, while the Old World alphaviruses are arthritogenic, the New World alphaviruses cause encephalitis. One exception is Mayaro virus (MAYV), which circulates exclusively in South America but causes arthralgia and is phylogenetically related to the Old World alphaviruses. Although MAYV-induced arthritis in humans is well documented, the molecular and cellular factors that contribute to its pathogenesis are completely unknown. In this study, we demonstrated for the first time that macrophages, key players in arthritis development, are target cells for MAYV infection, which leads to cell death through apoptosis. We showed that MAYV replication in macrophage induced the expression of TNF, a cytokine that would contribute to pathogenesis of MAYV fever, since TNF promotes an inflammatory profile characteristic of arthritis. We also found a significant increase in the production of reactive oxygen species (ROS) at early times of infection, which coincides with the peak of virus replication and precedes TNF secretion. Treatment of the cells with antioxidant agents just after infection completely abolished TNF secretion, indicating an involvement of ROS in inflammation induced during MAYV infection.

Emerging souvenirs-clinical presentation of the returning traveller with imported arbovirus infections in Europe

BACKGROUND

Arboviruses are an emerging group of viruses that are causing increasing health concerns globally, including in Europe. Clinical presentation usually consists of a nonspecific febrile illness that may be accompanied by rash, arthralgia and arthritis, with or without neurological or haemorrhagic syndromes. The range of differential diagnoses of other infectious and noninfectious aetiologies is broad, presenting a challenge for physicians. While knowledge of the geographical distribution of pathogens and the current epidemiological situation, incubation periods, exposure risk factors and vaccination history can help guide the diagnostic approach, the nonspecific and variable clinical presentation can delay final diagnosis.

AIMS AND SOURCES

This narrative review aims to summarize the main clinical and laboratory-based findings of the three most common imported arboviruses in Europe. Evidence is extracted from published literature and clinical expertise of European arbovirus experts.

CONTENT

We present three cases that highlight similarities and differences between some of the most common travel-related arboviruses imported to Europe. These include a patient with chikungunya virus infection presenting in Greece, a case of dengue fever in Turkey and a travel-related case of Zika virus infection in Romania.

IMPLICATIONS

Early diagnosis of travel-imported cases is important to reduce the risk of localized outbreaks of tropical arboviruses such as dengue and chikungunya and the risk of local transmission from body fluids or vertical transmission. Given the global relevance of arboviruses and the continuous risk of (re)emerging arbovirus events, clinicians should be aware of the clinical syndromes of arbovirus fevers and the potential pitfalls in diagnosis.

Mayaro Virus in Child with Acute Febrile Illness, Haiti, 2015

Mayaro virus has been associated with small outbreaks in northern South America. We isolated this virus from a child with acute febrile illness in rural Haiti, confirming its role as a cause of mosquitoborne illness in the Caribbean region. The clinical presentation can mimic that of chikungunya, dengue, and Zika virus infections.