review article antiviral perspectives for chikungunya...

Review ArticleAntiviral Perspectives for Chikungunya Virus

Deepti Parashar and Sarah Cherian

National Institute of Virology 20-A Dr Ambedkar Road Pune 411001 India

Correspondence should be addressed to Deepti Parashar deeptiparasharstergmailcom

Received 29 January 2014 Revised 22 April 2014 Accepted 30 April 2014 Published 15 May 2014

Academic Editor Fumio Imazeki

Copyright copy 2014 D Parashar and S Cherian This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Chikungunya virus (CHIKV) is a mosquito-borne pathogen that has a major health impact in humans and causes acute febrileillness in humans accompanied by joint pains and inmany cases persistent arthralgia lasting for weeks to years CHIKV reemergedin 2005-2006 in several parts of the Indian Ocean islands and India after a gap of 32 years causing millions of cases The re-emergence of CHIKV has also resulted in numerous outbreaks in several countries in the eastern hemisphere with a threat tofurther expand in the near future However there is no vaccine against CHIKV infection licensed for human use and therapy forCHIKV infection is still mainly limited to supportive care as antiviral agents are yet in different stages of testing or developmentIn this review we explore the different perspectives for chikungunya treatment and the effectiveness of these treatment regimensand discuss the scope for future directions

1 Introduction

The reemergence of chikungunya virus (CHIKV) in manyparts of the world is a significant public health concern Sincethe 2005-2006 chikungunya fever epidemic in the IndianOcean island of La Reunion [1 2] millions of people inmore than 40 countries including India Malaysia IndonesiaThailand Singapore the United States and some Europeancountries have been infected [3ndash5]

The CHIKV was first isolated from febrile individualsin Tanzania in 1952 [6 7] Initially researchers classifiedit among viruses such as Sindbis and Semliki Forest virusLater studies characterized it as an alpha virus that belongsto the family Togaviridae CHIKV is an enveloped viruswith a genome approximately 118 kb in size It consists of asingle stranded positive sense RNA genome with two openreading frames (ORFs) [8] The one at the 51015840 end encodesfour nonstructural proteins (nsP1ndashnsP4) and the secondORFat the 31015840 end encodes the structural proteins the capsid (C)envelope glycoproteins E1 and E2 and two small cleavageproducts (E3 6K)

CHIKV is transmitted to humans by several species ofmosquitoes with Aedes aegypti and A albopictus being thetwo main vectors The symptoms generally start 4ndash7 daysafter the bite Acute infection lasts for 1ndash10 days and is

characterized by abrupt onset of fever headache fatigue nau-sea vomiting rash myalgia and severe arthralgia Painfulpolyarthralgia is the typical symptom and may persist in sim10 of cases for several months causing serious economicand social impacts on both the individual and the affectedcommunities in some instances [9]

Thus far due to the lack of licensed vaccines or effectiveantivirals against CHIKV most of the treatment regimensare symptomatic and based on the clinical manifestationsNonsalicylate analgesics and nonsteroidal anti-inflammatorydrugs are most commonly used for symptomatic relief [10]Immune-based control strategies have also been tested andhave shown effectiveness The elaboration of mouse [11 12]and nonhuman primate models [13 14] together with antivi-rals currently undergoing clinical trials and new approachesinvolving screening of libraries of small molecules and syn-thetic compounds with antiviral potential as well as naturalproducts of plants [15] is further providing the stimulus forimproving the development of antiviral candidates

Recently Rashad et al [16] have presented a detailedreview of the currentmedicinal chemistry aspects supportingthe development of chemotherapeutics targeting the CHIKVthrough drug discovery and design On the other hand thisreview is an attempt to compile and explore the variousstrategies that have been tried for the management and

Hindawi Publishing CorporationBioMed Research InternationalVolume 2014 Article ID 631642 11 pageshttpdxdoiorg1011552014631642

2 BioMed Research International

treatment of CHIKV from a virological perspective andfurther discuss possible directions for the future

2 Chemical Compounds

We describe here some of the commonly used nonsteroidalanti-inflammatory drugs (NSAIDs) and nonsalicylate anal-gesics that have played a major role in symptomatic treat-ment of the chikungunya disease along with some newercompounds that have been recently tested against the CHIKVinfection(A) Symptomatic Treatment Strategies

Nonsteroidal Anti-Inflammatory Drugs Current treatmentsfor viral arthropathies rely mainly on NSAIDs though theseoften provide only partial relief [17] A number of patientswho experienced chronic rheumatic symptoms followinginfection with CHIKV during the 2005-2006 La Reunionoutbreak were successfully treated with methotrexate (MTX)[18] MTX which was originally developed as a chemother-apeutic forms the basis of most rheumatoid arthritis (RA)treatment regimens due to its anti-inflammatory effects atlow doses [19] Despite this details of its anti-inflammatorymechanism and its effect on acute viral induced arthritisremain unclear Some rare chronic patients did benefit fromMTX but seem to be in a different diagnostic class ldquopost-chikungunya rheumatismrdquo [20] However treatment efficacyis hard to evaluate when multiple diseases are present Ina study of post-CHIKV chronic arthritis in Maharashtra asouth-western state of India antirheumatic drugs includingSulfasalazine and MTX were needed for effective treatment[21] In a recent study aimed at understanding the anti-inflammatorymechanismofMTX and its effect on acute viralinduced arthritis amousemodel of Ross River virus-inducedinflammatory disease demonstrated that MTX treatmentcaused early onset of disease through increased monocyteproduction [22]Thefindings ofMTX effectiveness thus seemto be contradictive

Further although adverse effects of NSAIDs occur inonly a small proportion of users the widespread use of thesedrugs has resulted in serious gastrointestinal complicationsin a substantial overall number of affected persons SelectiveCOX-II inhibitors such as rofecoxib celecoxib and pare-coxib have shown consistently comparable efficacy to that ofconventional NSAIDs in patients with rheumatoid arthritiswith a significantly reduced propensity to cause gastrointesti-nal toxicity The safety benefits of COX-II inhibitors givenalone appear similar to combined therapy with conventionalNSAIDs and gastroprotective agents justifying the consid-eration of such inhibitors as first-line therapy in patientsrequiring long-term pain control [23]Nonsalicylate Analgesics (Paracetamol Acetaminophen Mor-phine and Traditional Herbal Medicine) Most data availableregarding the use of nonsalicylate analgesics against theCHIKV is from the follow-up of La Reunion patients Basedon clinical manifestations the analgesic drug Paracetamolwas the most used (in 954 of treatments) and often wascombined with NSAIDs The wide use of paracetamol led

to the emergence of severe liver afflictions diagnosed duringthe epidemic particularly when doses gt3 gday were taken[24] The hepatotoxicity of paracetamol in combinationwith interferon and vinblastine has also been reported [25]Further studies have shown that acetaminophen (APAP)another analgesic which is commonly used for the relief offever and flu-like symptoms modulates the transcriptionalresponse to recombinant interferon-beta [26] This also sug-gests that the use of this class of drugs might need some cau-tion Morphine was seldom used in the La Reunion althoughit was reported to be effective during early treatments in aperiod when the CHIKV was first discovered [27] Plantsare an integral part of the Reunion Island pharmacopeia andtherefore were mainly used during the outbreaks to treatfever pain and inflammation Some plant species such asFernelia spp are also known for their antiviral propertiesHowever the efficacy of these plants or association of plantshas not been studied particularly for the hepatotoxic risk thatmight be present when taken with paracetamol [24]

SteroidsCorticoids were prescribed to treat arthralgia (277of cases) particularly invalidating forms during the chikun-gunya disease in the Reunion Island hospital staff [24]A study carried out in South India during the chikun-gunya epidemic in 2007 with the objective of evolving auniform treatment protocol demonstrated that addition ofprednisolone to aceclofenac reduced pain and improved thequality of life in patients with acute chikungunya arthritiscompared to aceclofenac given alone in the management ofearly chikungunya fever Their studies thus recommendedcoadministration of low-dose systemic corticosteroids withNSAIDs as the best regimen in treating acute chikungunyacases with arthralgia [28] In another report regarding a caseof post chikungunya reversible demyelinating encephalitisthat was presented with vertigo dysarthria and ataxia therewas complete clinical as well as radiological improvementwith steroids [29] However corticosteroid use during acuteviral arthritis is considered to be contraindicated as a result ofthe risk of immunosuppression causing enhanced infectionand disease exacerbation [30]

(B) Specific Chemical Compounds Tested against CHIKV

21 Chloroquine Chloroquine was first reported to inhibitSindbis virus (SINV) and Semliki Forest Virus (SFV) infectiv-ity in vitromore than 35 years ago [31ndash35] but studies inmicesuggested that the drug might enhance viral replication andaggravate the disease [36] However chloroquine was foundto be effective in treating chronic CHIKV-induced arthralgiawith the possiblemechanism attributedmost likely to its anti-inflammatory properties that are adapted for the treatment ofsome autoimmune illnesses [37] Recent research on the effi-cacy of chloroquine has focused on the dosage used to treatacute CHIKV infections [38 39] To advance the studies withchloroquine and CHIKV a double blind placebo-controlledrandomized trial [38 40] was conducted in the ReunionIsland No statistical difference was observed between thechloroquine and placebo groups either in mean duration offebrile arthralgia or rate of decrease of viraemia However

BioMed Research International 3

the number of patients included in the study was too smallto draw definitive conclusions regarding the efficacy of thechloroquine treatment In another in vitro study [41] sincechloroquine exerted its antiviral effects in all the three modesof treatment (pretreatment concurrent and posttreatment)it was suggested that it has prophylactic and therapeuticpotentials However in a recent controlled evaluation ofchloroquine in treating patients with early persistent mus-culoskeletal pain and arthritis following CHIKV infectionselected cytokine assays that were carried out to study theinflammatory nature and the response of the symptoms to itdo not support a meaningful therapeutic role of oral chloro-quine in the management of the symptoms studied [42]Further the studies carried out by Padmakumar et al [28]also suggested that coadministration of hydroxychloroquinewith NSAIDs in acute stages of the disease does not offer anyadditional benefits

22 Ribavirin and 6-Azauridine Ribavirin has shown widein vitro inhibitory activity against RNA viruses with differentmodes of action depending on the virus [40] Some of thesuggested mechanisms of action are through the inhibitionof IMP dehydrogenase error catastrophe mechanism bycausing mutations and by interaction with viral polymerase[43] Ravichandran and Manian [44] determined whetherantiviral treatment would make any difference in thosepatients who continue to have arthritis even after two weeksafter the febrile episode Preliminary observations showedthat ribavirin may have a direct antiviral activity againstchikungunya Compared to ribavirin 6-azauridine a broad-spectrum antimetabolite was more effective against CHIKVand showed a similar antiviral activity against SFV [4546] Further interferon-alpha and ribavirin in combinationalso showed a synergistic effect on the in vitro inhibitionof CHIKV [46] Human infection with CHIKV appearsto induce immunological dysfunction Though interferonusually boosts the immune response caution in its usageis recommended until more extensive nonhuman primatemodels have been studied Polyethylene glycol-conjugated(pegylated PEG) alpha interferon appears to be an effec-tive treatment against infection with Venezuelan equineencephalitis virus (VEEV) and has profound effects on thehost immune response to infection [47] Treatment of VEEV-infected BALBc mice with PEG IFN-120572 resulted in a greatlyenhanced survival from either a subcutaneous or an aerosolinfection Treatment results in a number of changes to theimmune response characteristics normally associated withVEEV infection including increased macrophage activationabsence of splenic CD4 CD8 and B cells by day 2 postinfection normally associated with VEEV infection andreduction in the high tumor necrosis factor alpha productionby macrophages

In an animal model study for CHIKV Couderc et al[11] have demonstrated that adult mice with a partially ortotally abrogated type-I IFN pathway develop a mild orsevere infection thus it might be justified to test pegy-lated alpha interferon on CHIKV and other pathogenicalphaviruses

23 Arbidol The antiviral drug arbidol (ARB) was originallydeveloped at theRussianResearchChemical andPharmaceu-tical Institute about 20 years ago This drug has been usedin Russia for prophylaxis and treatment of acute respiratoryinfection including influenza from 1990 It has been shownthat ARB exhibits a wide range of activities against a numberof RNAandDNAenvelopednonenveloped viruses In celluloantiviral ARB activity against CHIKV has been investigated[48] This compound was found to present potent inhibitoryactivity against the virus propagated onto immortalizedprimary human fibroblast and vero cells Their study alsodemonstrated the growth of anARB resistant CHIKVmutantpossessing a single amino acid substitution (G407R) localizedin the E2 envelope protein Though this study helps explainthemechanismof action of arbidol it also brings out the pointthat ARB usage may be impaired as in vivo there could beselection of a resistant virus that is able to be disseminated

24 Harringtonine In a recent study harringtonine acephalotaxine alkaloid displayed potent inhibition ofCHIKV infection with minimal cytotoxicity Treatment ofharringtonine against SINV a related alphavirus suggestedthat harringtonine could inhibit other alphaviruses as well[49] It was indicated that harringtonine inhibited an earlystage of the CHIKV replication cycle which occurred afterviral entry into cells Interestingly harringtonine displayedgreater potency with a CHIKV strain carrying the E1 A226Vmutation as compared with a strain carrying the wild typeE1

Table 1 presents a summary of the assays used thehypothesized target and the pros and cons of the compoundsdescribed above

3 Inhibitors Based onRNA-Mediated Interference

RNA interference (RNAi) is a posttranscriptional processtriggered by the introduction of double-stranded RNA(dsRNA) which leads to gene silencing in a sequence-specificmanner The method is based on targeting specific viralproteins which consequently leads to the shutdown of theprotein expression process thereby stopping viral replicationRNAi mediated inhibition of viral replication has emergedas a promising antiviral strategy The small interfering RNA(siRNA) and small hairpin RNA (shRNA) molecules arecentral to RNA interference

Small interfering RNAs (siRNAs) are formed by cleavingthe dsRNAs by the RNase III family member Dicer into 19ndash23 nucleotide (nt) fragmentswith 51015840 phosphorylated ends and2-nt unpaired and unphosphorylated 31015840 endsThe processingof the target RNA is achieved by endonuclease argonaute2 (Ago 2) which is further incorporated into the RNAispecificity complex (RISC) On the other hand plasmid-expressed short hairpin RNA (shRNA) requires the activityof endogenous exportin 5 and Ago2 (Argonaute 2) thatforms a dimer with Dicer which then receives the shRNAThe shRNA is cleaved in one step by Dicer generating a19ndash23 nt duplex siRNA with 2 nt 31015840 overhangs The siRNAsguide RISC to the target mRNA RISC delivers the mRNA to


Table 1 Major tested anti-CHIKV chemical compounds

Products Assay type Hypothesized target Pros Cons References

Chloroquine In vitro (vero cells)

Disruptedendosome-mediatedCHIKV internalizationpossibly through theprevention of endosomalacidification

In vitro study proved thatit blocks the production ofproinflammatorycytokines and theproliferation ofmonocytes macrophagesand lymphocytes

In vivo study required

Delogu anddeLamballerie2011 [50]Khan et al2010 [41]

Ribavirin HumanCan interact with theintracellular viral RNAproduction

Faster resolution of jointand soft tissuemanifestations

Involvement of a smallnumber of patients andlack of planning asrandomly distributedpatients were notcompared with a placebogroup

Ravichandranand Manian2008 [44]

6-Azauridine In vitro (vero cells)

Inhibition of orotidinemonophosphatedecarboxylase an enzymeinvolved in the de novobiosynthesis of pyrimidinecytidine and thymidine

Showed a significantinhibition of CHIKV at alow concentration

The antiviral activity hasbeen difficult to replicatein vivo

Briolant et al2004 [46]

ArbidolIn vitro (vero andprimary humanfibroblast cells)

Inhibition of virusmediated fusion andblocking of the viral entryinto the target cells throughinhibition of glycoproteinconformational changesthat are essential for thefusion process

Well-tolerated withminimal side effects

Not tested in in vivosystem

Delogu et al2011 [48]

Harringtonine In vitro (BHK21cells)

Affects CHIKV RNAproduction inside theinfected cell as well as viralprotein expression such asthe nsP3 and the E2proteins

Minimal cytotoxicity Not tested in in vivosystem

Kaur et al2013 [49]

cytoplasmic foci named processing bodies (P-bodies or GW-bodies) wherein mRNA decay factors are concentrated Thetarget mRNA is cleaved by Ago2 and degraded

31 Small Interfering RNA (siRNA) Molecules The thera-peutic application of siRNA for the inhibition of CHIKVreplication has been examined in vero cells [51] siRNAsagainst the conserved regions of nsP3 and E1 genes of CHIKVhave been designed and siRNA activity was assessed bydetecting both the infectious virus and its genome The titersof the virus yield in the supernatant were determined at24 and 48 hours postinfection Results showed reductionof virus titre by sim15 log10- sim25 log10 in comparison to thecontrol The study thus showed limited success and furtherneeds the investigation of these siRNA sequences in an invivomodel for their ultimate therapeutic application Studieshave also been conducted at National Institute of VirologyPune India by designing eight siRNAs either targetingthe E2 or the ns1 genes of CHIKV The efficiency of thesesiRNAs to inhibit the CHIKV production was assessed invero cells Two of the siRNAs were able to reduce CHIKVE3 transcripts by sim5log10 and sim25log10 when cells were

transfected after 1 hour post infection 100 pmol of siRNAwas found optimum in perturbing CHIKV production Thecombination of these siRNAs was found to be very effectivein inhibiting the production of CHIKV Importantly thesesiRNAs could inhibit the CHIKV replication in Swiss albinomice when administered 72 hours after viral infection AsiRNA dose of 1mgkg body weight (1700 pmol) was foundoptimal to inhibit the CHIKV replication in Swiss albinomice Our findings suggested that RNAi is capable of silenc-ing sequence-specific genes of CHIKV and might constitutea new therapeutic strategy for CHIKV infection [52]

32 Small Hairpin RNA (shRNA) Molecules The efficacy ofplasmid-based short hairpin RNA (shRNA) against CHIKVreplication in three CHIKV-permissive cell lines namelyHeLa RD and BHK cells has been investigated Cell clonesexpressing shRNAs against CHIKV E1 and nsP1 genes dis-played significant inhibition of infectious CHIKV produc-tion while shRNA capsid demonstrated a modest inhibitoryeffect as compared to scrambled shRNA cell clones andnontransfected cell controls Analysis of CHIKV E2 proteinexpression and visualization of shRNA (E1 and nsP1) cell


clones collectively demonstrated similar inhibitory trendsagainst CHIKV replication shRNA E1 showed non cell-typespecific anti-CHIKV effects and broad-spectrum silencingagainst different geographical strains of CHIKV Further-more shRNA E1 clones did not exert any inhibition againstdengue virus and SINV replication thus indicating the highspecificity of shRNA against CHIKV replication Moreoverno shRNA-resistant CHIKV mutant was generated after 50passages of CHIKV in stable cell clones More importantlystrong and sustained anti-CHIKV protection was conferredin suckling mice pretreated with different concentrations(31 95 and 19 pmol) of shRNA (E1) Results have thussuggested the promising efficacy of anti-CHIKV shRNAs inparticular plasmid-shRNA E1 as a novel antiviral strategyagainst CHIKV infection [53]

4 Cellular Factors

Another approach to inhibiting the CHIKV infection is bytargeting cellular factors such as proteases that are involved inthe processing of the CHIKV particles and cellular receptorsthat may have a role in viral replication or in another way bythe induction of immune-based cellular enzymes that possessantiviral activity

41 Furin Inhibitors Molecules that inhibit alphavirus entryinto susceptible cells by blocking the intracellular cleavage ofviral envelope glycoproteins have been investigated CHIKVinfection of cultured human cells was shown to be inhibitedby impairing the maturation of the CHIKV E2 surfaceglycoprotein using the furin inhibitor peptide decanoyl-RVKR-chloromethyl ketone [54] Another study reportedthe possible inhibition of the replication of VEEV usingpolyclonal antibodies to laminin-binding protein [55]

42 2101584051015840-Oligoadenylate Synthetase (OAS3) CHIKV ishighly sensitive to the antiviral activity of Type-I interferons(IFN-120572120573) Brehin et al [56] investigated the role of IFN-induced 2101584051015840-oligoadenylate synthetase (OAS) family ininnate immunity to CHIKV They have established induciblehuman epithelial HeLa cell lines expressing either the largeform of human OAS and OAS3 or the genetic variantOAS3-R844X which is predicted to lack about 20 ofthe OAS3 protein from the carboxy terminus HeLa cellsrespond to ectopic OAS3 expression by efficiently inhibitingCHIKV growth The characteristic of the antiviral effect wasa blockade in early stages of virus replication Thus OAS3pathway may represent a novel antialphaviral mechanismby which IFN-120572120573 controls CHIKV growth HeLa cellsexpressing the truncated form of OAS3 were less resistant toCHIKV infection raising the question on the involvementof OAS3 genetic polymorphism in human susceptibility toalphavirus infection [56] In another study [57] a CHIKVvariant exhibiting remarkable resistance towards the antiviralactivity of OAS3 through an enhancement of viral RNAreplication was identified It was shown that a single aminoacid change in the E2 glycoprotein allows the rescue of viralgrowth in OAS3 expressing HeLa cells by acting on the early

stages of viral life cycle These observations also providea new insight into the role of E2 into the pathogenicity ofCHIKV in human cells [57]

43 Cellular IMPDH Enzyme Mycophenolic acid (MPA) isa weak organic acid and a well-known immunosuppressiveagent It has been investigated as an effective agent againstgrowth and multiplication of several microbial pathogensincluding viruses [58]MPA inhibits the replication of severalviruses in vitro to varying degrees [59] MPA is a non-competitive inhibitor of inosine monophosphate dehydro-genase (IMPDH) MPA is used clinically in the preventionof rejection of transplanted organs [60] Various studieshave reported that MPA blocked the cytopathic effect andreplications of several viruses [61]

Khan et al [62] have assessed the antiviral potentialof MPA against CHIKV via inhibition of IMPDH enzymein vero cells Inhibition of virus induced apoptosis wasobserved as measured by caspase-3 PARP and Bcl-2 Totalgenome infectivity was determined by analyzing the ratio oftotal infectious viral particles to the genome copy numberNontoxic concentration of MPA (10120583M) reduced ge999CHIKV titre in vero cells MPA via depletion of substrate forpolymerase (GTP) inhibited CHIKV-induced apoptosis

44 Viperin The antiviral role of viperin has been demon-strated inCHIKV infection by studying the longitudinal tran-scriptional profiles of the innate immune response in PBMCsfrom a cohort of 24 CHIKV-infected patients Results showedthat type I IFNs controlled CHIKV infection via RSAD2(which encodes viperin) an enigmatic multifunctional IFN-stimulated gene (ISG) Viperin was highly induced in mono-cytes the major target cell of CHIKV in blood In vivostudy demonstrated the direct role of viperin in controllingCHIKV replication Mice lacking Rsad2 had higher viremiaand severe joint inflammation compared with wild-typemice[63]

45 Human Antibodies Immunotherapy in the form ofhuman polyclonal antibody has been used for treatment ofhuman viral infections and in alphavirus-infected animalmodels passive immunization with convalescent sera fromanimals was protective Sera from patients and monkeyswho have recovered from acute alphavirus-infections havebeen shown to contain neutralizing antibodies in sucklingmouse models Human polyclonal antibodies (CHIKV Ig)have been purified from plasma of convalescent donors andused in mouse models of CHIKV infection [64] Results arepromising with CHIKV Ig showing both prophylactic andtherapeutic potential In both IFN-120572120573R-- and immune-competent mouse neonates a single prophylactic dose ofCHIKV Ig was found to be protective against lethalityassociated with CHIKV with undetectable viral levels in theserum and no dissemination to the central nervous systemThe degree of protection correlated to the dose of antibodiesadministered CHIKV Ig also has a therapeutic effect asit is protective against lethality when given up to 8 hourspostinfection The results also supported the hypothesis that


viremia precedes CNS dissemination and controlling theviremia prevents neurologic complications [64]

From another point of view the therapeutic utilityof monoclonalpolyclonal antibodies might be limited aspatients with a serodiagnosis of an alphaviral disease clearlyalready have antibodies and administration of antibodiesbefore endogenous antibody production is likely to beimpractical Nevertheless such antibodies might find utilityin preventing mother-to-child infections Conceivably neu-tralizing antibodies could be used prophylactically duringan epidemic However parenterally administered antibodies(such as tocilizumab and infliximab) have serum half-lives ofonly 8ndash14 days so repeated dosing would be envisaged in anextended epidemic [65]

A summary of the assays used the hypothesized targetand the pros and cons of the cellular inhibitors describedherein is presented in Table 2

5 High Throughput Screening and StructureBased Drug Discovery Approaches

Recently cell-based high throughput assays have been devel-oped to identify potential CHIKV inhibitors One studyreported a focus screen of 356 natural compounds andclinically approved drugs using a CHIKV replicon and aconcomitant screen with SFV surrogate infection model[66] while another study screened 3040 small moleculesfor inhibitors of CHIKV nsP2 using a novel target-basedphenotypic assay approach [67] Cruz et al [68] used acell-based high throughput screening assay using resazurinagainst a kinase inhibitor library combined with the image-based high content assay approach to identify compoundsagainst CHIKV having novel antiviral activity

In addition the availability of the crystal structures ofseveral proteins of the CHIKV RNA genome and otherrelated alphaviruses is encouraging the drug discovery pro-cess through target structure-based pharmacophore model-ing virtual library screening and drug docking approachesWhen used prior to experimental screening it can be consid-ered as a powerful computational filter for reducing the sizeof a chemical library that can be further experimentally tested[69] Upon the identification of compound hits through suchscreening structural models are further used to develop astructure activity relationship to optimize the compoundrsquosactivity [70] Rashad and Keller [71] used in silico techniquesof virtual screening and docking studies for structure baseddesign towards the identification of novel binding sitesand inhibitors for the chikungunya virus envelope proteinsBased on multiple enzymatic activities and functional rolesof the nsP2 [72 73] recent studies have considered it asa potential target for CHIKV inhibitors [48 56] Bassettoet al [74] used a bioinformatics approach considering ahomology-based model of CHIKV virus based on the crystalstructure of nsP2 of the alphavirus VEE as a template Thestudy identified a few compounds that selectively inhibitedCHIKV in a virus-cell based CPE reduction assay thoughfurther experimental studies are ongoing to prove that thecompounds are indeed nsP2 inhibitors Lucas-Hourani et al[67] on the other hand used a phenotypic assay to identify

one natural compound that partially blocks nsP2 activityand inhibits CHIKV replication in vitro A recent work [75]showed that the nsP4 protein of CHIKV is involved in themechanism of action of T-705 (favipiravir) that was seen toinhibit CHIKV replication in vitro and in vivo Thus it isimperative to target other viral proteins also for structure-based drug design

6 Antiviral Vaccine Approaches

An alternative approach to virus disease control involvesthe use of vaccines There is still no effective vaccine toprevent the disease In 1967 formalin-inactivated CHIKVvaccines were prepared in chick embryo and suckling mousebrain in 1967 and 1972 and in green monkey kidney celltissue culture [76 77] In 1970 CHIKV vaccine was preparedby tween ether extraction [78] In 1973 Nakao and Hotta[79] indicated that the UV-inactivated virus was superiorto the formalinized virus in regard to its immunogenicityin monkeys In 2000 Edelman et al [80] published aphase II assay with an attenuated vaccine (strain obtainedfrom an infected patient during the 1962 outbreak in Thai-land)

A number of preclinical CHIKV vaccines have beendescribed including inactivated virus formulations [81ndash83]live-attenuated virus vaccines [84ndash86] chimeric virus vac-cines [87] DNA vaccines [88 89] T cell based peptidevaccine [90] a recombinant adenovirus vaccine [91] subunitprotein vaccines [92ndash94] and a virus-like particle (VLP)formulation [95 96]

The immunogenic potential of recombinant CHIKVenvelope proteins has been evaluated in mice Recombinantprotein elicited a strong humoral response and a balancedTh1Th2 response Recombinant CHIKV antigens can beproposed as potent subunit vaccine candidates [97]

Live CHIKV vaccine (CHIKVIRES) that is highly atten-uated yet immunogenic in mouse models and is incapable ofreplicating in mosquito cells has been developed [98] Thedevelopment and evaluation of CHIKV vaccine candidatesthat were attenuated by deleting a large part of the geneencoding nsP3 or the entire gene encoding 6K have beendescribed This stable and efficient attenuated CHIKV vac-cine candidate can be administered either as viral particles oras infectious genomes launched by DNA [99] Recently twolive-attenuated vaccine candidates based on the insertion ofa picornavirus internal ribosome entry site (IRES) sequenceinto the genome of CHIKV have been generated TheseCHIKVIRES vaccine candidates appear to be safe and effi-cacious supporting their strong potential as a human vaccineto protect against CHIKV infection and reduce transmissionand further spread [100] The immunogenicity profile andthe efficacy of a novel CHIKV vaccine candidate basedon the highly attenuated poxvirus vector modified vacciniavirus Ankara (MVA) expressing the CHIKV structural genesC E3 E2 6K and E1 (termed MVA-CHIKV) have beengenerated and characterized [101] MVA-CHIKV was foundto be an effective vaccine against CHIKV infection andit induced strong broad highly polyfunctional and long-lasting CHIKV-specific CD8+ T cell responses together with


Table 2 Some of the major cellular inhibitors against chikungunya virus

Cellular factors Assays Targeteffectors Pros Cons References

Furin inhibitorsIn vitro

(myoblastcells)

Intracellularfurin-mediated cleavage ofviral envelopeglycoproteins the E2E3 orp62 precursor

Able to induce astronger inhibition ofviral infection

Not tested in invivo system Ozden et al2008 [54]

2101584051015840-Oligoadenylatesynthetase (OAS3)

HumanepithelialHeLa celllines

Affects CHIKV replicationthrough a RNaseL-dependent pathway

Ability of OAS3 toinhibit alphavirusgrowth may beimportant for thedevelopment ofantiviral moleculesagainst CHIKV

Cannot rule out thepossibility thatOAS3-mediated inhibitionof CHIKV was also due to ablock early in virus lifecycle for example viralentry and uncoating ofvirus particles

Brehin et al2009 [56]

Cellular IMPDH enzyme In vitro (verocells)

Depletion of intracellularguanosine pool

CHIKV utilizes IMPDHactivity for its growthand multiplicationwhich is a potential andeffective target toprevent its infection

It would be useful toexplore similar findings bytargeting IMPDH in case ofother alphaviruses whichare more lethal thanchikungunya like Sindbisvirus Semliki forest virusand so forth

Khan et al2011 [62]

Viperin In vivo(monocytes) Endoplasmic reticulum

Critical antiviral hostprotein that controlsCHIKV infection andprovides a preclinicalbasis for the design ofeffective controlstrategies againstCHIKV

Large gaps in ourunderstanding of theprecise mechanisms at playfor viperin to exert such awide variety of roles withinthe cell

Teng et al2012 [63]

neutralizing antibodies against CHIKV A recent paper [102]has reviewed several vaccine approaches for CHIKV

7 Conclusions

The explosive chikungunya fever epidemic of 2005 in LaReunion and its rapid dissemination to several countries inthe Indian Ocean stressed the need for appropriate CHIKVantivirals In the sections above we have tried to explorethe different perspectives for chikungunya management andtreatment and the effectiveness of these regimens Thoughadvances in molecular and bioinformatics tools have expe-dited in identifying novel drug and vaccine candidates themajor thrust that is now required is to explore the efficacyof these for CHIKV treatment As shown in Tables 1 and2 evaluation studies in in vivo systems and further clinicaltesting of lead compounds are essential for establishing theeffectiveness of the potential compounds

In the management of CHIKV arthralgia the differentialdiagnosis of CHIKV against presence of other conditionssuch as chronic rheumatic diseases would be important totreat patients suffering from arthropathy Among the chemi-cal compounds that have been attempted for CHIKV some ofthe well-known broad-spectrum antivirals like chloroquineribavirin and interferon which have displayed some efficacyin humans may prove to be promising Though there isno evidence supporting the clinical efficacy of ribavirin on

CHIKV the combination with interferon could be subjectedto clinical trials for the treatment of CHIKV infectionsFurther the in vitro use of siRNA or plasmid based shRNAshas shown promising results in the cell based infectionmodelof CHIKV In spite of this further studies are warrantedto rationalize the therapeutic significance of these siRNAsin primates The data obtained from the studies related tocellular factors could form the basis for future developmentof novel immune-based control strategies The chemicalstructure of the furin inhibiting peptide could be used asa starting point for development of more novel and activepeptidomimetics that target the intracellular furin cleavagestep Compounds that have emerged from virtual libraryscreening and structure-based drug discovery would beexpected to display lower toxicity and side effects owingto their selectivity to specific viral targets Some of theissues related to vaccine development are the requirementof further in vivo evaluation the need for clinical trials andcost and scalability issues Though the MVA-CHIKV may beconsidered as a potential vaccine candidate against CHIKVconsidering the essential role for B cells and antibodiesin controlling CHIKV infection eliciting strong humoralresponse through the use of suitable adjuvants would be vitalfor improvement of the vaccine efficacy

Nevertheless fighting CHIKV is not only a matter ofdrugs and vaccines Preventive measures should also beapplied to avoid mosquito bites responsible for disease


transmission These simple measures include the use ofinsect repellents the minimization of skin surface exposedto mosquito bites the elimination of standing water wheremosquitoes can lay eggs and the installation of window anddoor screens Precise measures need to be implemented bythe government in the form of surveillance and awarenessprograms among people and medical practitioners for bettermanagement of the disease and for the prevention of newoutbreaks

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] I Schuffenecker I Iteman A Michault et al ldquoGenomemicroevolution of Chikungunya viruses causing the IndianOcean outbreakrdquo PLoS Medicine vol 3 no 7 pp 1058ndash10702006

[2] M Sourisseau C Schilte N Casartelli et al ldquoCharacterizationof reemerging Chikungunya virusrdquo PLoS Pathogens vol 3article e89 2007

[3] H C Hapuarachchi K B A T Bandara S D M Sumanadasaet al ldquoRe-emergence of Chikungunya virus in South-east Asiavirological evidence from Sri Lanka and Singaporerdquo Journal ofGeneral Virology vol 91 no 4 pp 1067ndash1076 2010

[4] V A Arankalle S Shrivastava S Cherian et al ldquoGeneticdivergence of Chikungunya viruses in India (1963ndash2006) withspecial reference to the 2005-2006 explosive epidemicrdquo Journalof General Virology vol 88 no 7 pp 1967ndash1976 2007

[5] S S Cherian A M Walimbe S M Jadhav et al ldquoEvolution-ary rates and timescale comparison of Chikungunya virusesinferred from the whole genomeE1 gene with special referenceto the 2005ndash07 outbreak in the Indian subcontinentrdquo InfectionGenetics and Evolution vol 9 no 1 pp 16ndash23 2009

[6] EG S J Strauss Ed Structure andReplication of theAlphavirusGenome Plenum Press New York NY USA 1986

[7] C Peters and J Dalrymple ldquoAlphavirusesrdquo in Fields Virology BN Fields and D M Knipe Eds pp 713ndash761 Raven Press NewYork NY USA 2nd edition 1990

[8] S K Singh and S K Unni ldquoChikungunya virus host pathogeninteractionrdquo Reviews in Medical Virology vol 21 no 2 pp 78ndash88 2011

[9] P G Jupp and B M McIntosh ldquoChikungunya virus diseaserdquo inThe Arboviruses Epidemiology and Ecology T P Monath Edpp 137ndash157 CRC Press Boca Raton Fla USA 1988

[10] G Pialoux B A Gauzere S Jaureguiberry and M StrobelldquoChikungunya an epidemic arbovirosisrdquo The Lancet InfectiousDisease vol 7 no 5 pp 319ndash327 2007

[11] T Couderc F Chretien C Schilte et al ldquoA mouse modelfor Chikungunya young age and inefficient type-I interferonsignaling are risk factors for severe diseaserdquoPLoSPathogens vol4 no 2 2008

[12] S A Ziegler L Lu A P A Travassos Da Rosa S-Y Xiao andR B Tesh ldquoAn animal model for studying the pathogenesis ofChikungunya virus infectionrdquoTheAmerican Journal of TropicalMedicine and Hygiene vol 79 no 1 pp 133ndash139 2008

[13] P Roques C Joubert and B Malleret ldquoChikungunya et autresarboviroses emergentes enmilieu tropicalrdquo Reunion Islandhttpwwwinvssantefragendacolloquechikungunya 2007

[14] K Labadie T Larcher C Joubert et al ldquoChikungunya diseasein nonhuman primates involves long-term viral persistence inmacrophagesrdquo Journal of Clinical Investigation vol 120 no 3pp 894ndash906 2010

[15] Y Li L Wang S Li et al ldquoSeco-pregnane steroids target thesubgenomic RNA of alphavirus-like RNA virusesrdquo Proceedingsof the National Academy of Sciences of the United States ofAmerica vol 104 no 19 pp 8083ndash8088 2007

[16] A A Rashad S Mahalingam and P A Keller ldquoChikungunyavirus Emerging targets and new opportunities for medicalchemistryrdquo Journal of Medicinal Chemistry vol 57 no 4 pp1147ndash1166 2014

[17] A Suhrbier and M L Linn ldquoClinical and pathologic aspectsof arthritis due to Ross River virus and other alphavirusesrdquoCurrent Opinion in Rheumatology vol 16 no 4 pp 374ndash3792004

[18] J-J Hoarau M-C J Bandjee P K Trotot et al ldquoPersistentchronic inflammation and infection by Chikungunya arthrito-genic alphavirus in spite of a robust host immune responserdquoJournal of Immunology vol 184 no 10 pp 5914ndash5927 2010

[19] M EWeinblatt BNWeissmanD EHoldsworth et al ldquoLong-term prospective study of methotrexate in the treatment ofrheumatoid arthritis 84-Month updaterdquoArthritis and Rheuma-tism vol 35 no 2 pp 129ndash137 1992

[20] F Simon and E Javelle ldquoAdministrative issues linked to healthinsurance coverage of chronic post-Chikungunya rheumatismrdquoMedecine Tropicale vol 72 pp 99ndash102 2012

[21] M A Ganu and A S Ganu ldquoPost-Chikungunya chronicarthritismdashour experience with dmards over two year follow uprdquoJournal of Association of Physicians of India vol 59 no 2 pp83ndash86 2011

[22] A Taylor K C Sheng and L J Herrero ldquoMethotrexatetreatment causes early onset of disease in amousemodel of rossriver virus-induced inflammatory disease through increasedmonocyte productionrdquo PLoS ONE vol 8 no 8 article e71146Article ID 007114 2013

[23] M Lazzaroni and G Bianchi Porro ldquoGastrointestinal side-effects of traditional non-steroidal anti-inflammatory drugs andnew formulationsrdquoAlimentary Pharmacology andTherapeuticsvol 20 no 2 pp 48ndash58 2004

[24] F Staikowsky K Le Roux I Schuffenecker et al ldquoRetrospectivesurvey ofChikungunya disease inReunion Island hospital staffrdquoEpidemiology and Infection vol 136 no 2 pp 196ndash206 2008

[25] P Kellokumpu-Lehtinen E Iisalo and E Nordman ldquoHepa-totoxicity of paracetamol in combination with interferon andvinblastinerdquoThe Lancet vol 1 no 8647 p 1143 1989

[26] A Farnsworth A S Flaman S S Prasad et al ldquoAcetaminophenmodulates the transcriptional response to recombinantinterferon-betardquo PLoS ONE vol 5 no 6 Article ID e110312010

[27] M C Robinson ldquoAn epidemic of virus disease in SouthernProvince Tanganyika territory in 1952-1953rdquoTransactions of theRoyal Society of Tropical Medicine andHygiene vol 49 no 1 pp28ndash32 1955

[28] B Padmakumar J B Jayan R M R Menon B KrishnankuttyR Payippallil and R S Nisha ldquoComparative evaluation of fourtherapeutic regimes in Chikungunya arthritis a prospectiverandomized parallel-group studyrdquo Indian Journal of Rheuma-tology vol 4 no 3 pp 94ndash101 2009


[29] L A Gauri B L Ranwa K Nagar A Vyas andQ Fatima ldquoPostChikungunyabrain stem encephalitisrdquo Journal of Association ofPhysicians of India vol 60 no 4 pp 68ndash69 2012

[30] A D Mylonas D Harley D M Purdie et al ldquoCorticosteroidtherapy in an alphaviral arthritisrdquo Journal of Clinical Rheuma-tology vol 10 no 6 pp 326ndash330 2004

[31] S Cassell J Edwards and D T Brown ldquoEffects of lysoso-motropic weak bases on infection of BHK-21 cells by Sindbisvirusrdquo Journal of Virology vol 52 no 3 pp 857ndash864 1984

[32] K Coombs E Mann J Edwards and D T Brown ldquoEffectsof chloroquine and cytochalasin B on the infection of cells bySindbis virus and vesicular stomatitis virusrdquo Journal of Virologyvol 37 no 3 pp 1060ndash1065 1981

[33] A Helenius M Marsh and J White ldquoInhibition of SemlikiForest virus penetration by lysosomotropic weak basesrdquo Journalof General Virology vol 58 no 1 pp 47ndash61 1982

[34] A D Inglot ldquoComparison of the antiviral activity in vitroof some non-steroidal anti-inflammatory drugsrdquo Journal ofGeneral Virology vol 4 no 2 pp 203ndash214 1969

[35] Y Shimizu S Yamamoto M Homma and N Ishida ldquoEffectof chloroquine on the growth of animal virusesrdquo Archiv fur diegesamte Virusforschung vol 36 no 1-2 pp 93ndash104 1972

[36] R K Maheshwari V Srikantan and D Bhartiya ldquoChloroquineenhances replication of Semliki Forest virus and encephalomy-ocarditis virus in micerdquo Journal of Virology vol 65 no 2 pp992ndash995 1991

[37] S W Brighton ldquoChloroquine phosphate treatment of chronicChikungunya arthritis An open pilot studyrdquo South AfricanMedical Journal vol 66 no 6 pp 217ndash218 1984

[38] X De Lamballerie V Boisson J-C Reynier et al ldquoOn Chikun-gunya acute infection and chloroquine treatmentrdquoVector-Borneand Zoonotic Diseases vol 8 no 6 pp 837ndash839 2008

[39] A Savarino R Cauda and A Cassone ldquoOn the use ofchloroquine for Chikungunyardquo The Lancet Infectious Diseasesvol 7 no 10 p 633 2007

[40] P Leyssen E De Clercq and J Neyts ldquoThe anti-yellow fevervirus activity of ribavirin is independent of error-prone repli-cationrdquo Molecular Pharmacology vol 69 no 4 pp 1461ndash14672006

[41] M Khan S R Santhosh M Tiwari P V Lakshmana Rao andM Parida ldquoAssessment of in vitro prophylactic and therapeuticefficacy of chloroquine against Chikungunya virus in Verocellsrdquo Journal of Medical Virology vol 82 no 5 pp 817ndash8242010

[42] A Chopra M Saluja and A Venugopalan ldquoEffectiveness ofchloroquine and inflammatory cytokine response in patientswith early persistent musculoskeletal pain and arthritis follow-ing Chikungunya virus infectionrdquo Arthritis amp Rheumatologyvol 66 no 2 pp 319ndash326 2014

[43] X de Lamballerie L Ninove and RN Charrel ldquoAntiviral treat-ment of Chikungunya virus infectionrdquo Infectious DisordersmdashDrug Targets vol 9 no 2 pp 101ndash104 2009

[44] R Ravichandran and M Manian ldquoRibavirin therapy forChikungunya arthritisrdquo Journal of Infection inDeveloping Coun-tries vol 2 no 2 pp 140ndash142 2008

[45] B Rada and M Dragun ldquoAntiviral action and selectivity of 6azauridinerdquo Annals of the New York Academy of Sciences vol284 pp 410ndash417 1977

[46] S Briolant D Garin N Scaramozzino A Jouan and J MCrance ldquoin vitro inhibition of Chikungunya and Semliki Forestviruses replication by antiviral compounds synergistic effect of

interferon-120572 and ribavirin combinationrdquoAntiviral Research vol61 no 2 pp 111ndash117 2004

[47] R A Lukaszewski and T J G Brooks ldquoPegylated alphainterferon is an effective treatment for virulent venezuelanequine encephalitis virus and has profound effects on the hostimmune response to infectionrdquo Journal of Virology vol 74 no11 pp 5006ndash5015 2000

[48] I Delogu B Pastorino C Baronti A Nougairede E Bonnetand X de Lamballerie ldquoin vitro antiviral activity of arbidolagainst Chikungunya virus and characteristics of a selectedresistant mutantrdquo Antiviral Research vol 90 no 3 pp 99ndash1072011

[49] P Kaur M Thiruchelvan R C H Lee et al ldquoInhibitionof Chikungunya virus replication by Harringtonine a novelantiviral that suppresses viral protein expressionrdquoAntimicrobialAgents and Chemotherapy vol 57 no 1 p 155 2013

[50] I Delogu and X de Lamballerie ldquoChikungunya disease andchloroquine treatmentrdquo Journal of Medical Virology vol 83 no6 pp 1058ndash1059 2011

[51] P K Dash M Tiwari S R Santhosh M Parida and P VLakshmana Rao ldquoRNA interference mediated inhibition ofChikungunya virus replication in mammalian cellsrdquo Biochem-ical and Biophysical Research Communications vol 376 no 4pp 718ndash722 2008

[52] D Parashar M S Paingankar S Kumar et al ldquoAdministrationof E2 and NS1 siRNAs inhibit Chikungunya virus replication invitro and protects mice infected with the virusrdquo PLoS NeglectedTropical Diseases vol 7 no 9 article e2405 2013

[53] S Lam K C Chen M M Ng et al ldquoExpression of plasmid-based shRNA against the E1 and nsP1 genes effectively silencedChikungunya virus replicationrdquo PLoSONE vol 7 no 10 ArticleID e46396 2012

[54] S OzdenM Lucas-Hourani P-E Ceccaldi et al ldquoInhibition ofChikungunya virus infection in cultured humanmuscle cells byfurin inhibitors impairment of thematuration of the E2 surfaceglycoproteinrdquo Journal of Biological Chemistry vol 283 no 32pp 21899ndash21908 2008

[55] E I Bondarenko E V Protopopova I V Surovtsev A NShvalov and V B Loktev ldquoInhibition of replication of Venezue-lan equine encephalomyelitis with polyclonal antibodies tolaminin-binding proteinrdquoVoprosy Virusologii vol 49 no 5 pp32ndash37 2004

[56] A-C Brehin I Casademont M-P Frenkiel C Julier ASakuntabhai and P Despres ldquoThe large form of human 2101584051015840-Oligoadenylate Synthetase (OAS3) exerts antiviral effect againstChikungunya virusrdquoVirology vol 384 no 1 pp 216ndash222 2009

[57] H Gad S Paulous E Belarbi et al ldquoThe E2-E166K substitutionrestores Chikungunya virus growth in OAS3 expressing cells byacting on viral entryrdquo Virology vol 434 no 1 pp 27ndash37 2012

[58] J E Kitchin M K Pomeranz G Pak K Washenik and JL Shupack ldquoRediscovering mycophenolic acid a review ofits mechanism side effects and potential usesrdquo Journal of theAmerican Academy of Dermatology vol 37 no 3 pp 445ndash4491997

[59] Z J Gong S de Meyer C Clarysse et al ldquoMycophenolic acidan immunosuppressive agent inhibitsHBV replication in vitrordquoJournal of Viral Hepatitis vol 6 no 3 pp 229ndash236 1999

[60] J J Lipsky ldquoMycophenolate mofetilrdquo The Lancet vol 348 no9038 pp 1357ndash1359 1996

[61] R E Lanford D Chavez B Guerra et al ldquoRibavirin induceserror-prone replication of GB virus B in primary tamarin


hepatocytesrdquo Journal of Virology vol 75 no 17 pp 8074ndash80812001

[62] M Khan R Dhanwani I K Patro P V L Rao and MM Parida ldquoCellular IMPDH enzyme activity is a potentialtarget for the inhibition of Chikungunya virus replication andvirus induced apoptosis in culturedmammalian cellsrdquoAntiviralResearch vol 89 no 1 pp 1ndash8 2011

[63] T S Teng S S Foo D Simamarta et al ldquoViperin restrictsChikungunya virus replication and pathologyrdquo The Journal ofClinical Investigation vol 122 no 12 pp 4447ndash4460 2012

[64] T Couderc N Khandoudi M Grandadam et al ldquoProphylaxisand therapy for Chikungunya virus infectionrdquo Journal of Infec-tious Diseases vol 200 no 4 pp 516ndash523 2009

[65] A Suhrbier M C Jaffar-Bandjee and P Gasque ldquoArthritogenicalphavirusesmdashan overviewrdquo Nature Reviews Rheumatologyvol 8 no 7 pp 420ndash429 2012

[66] L Pohjala A Utt M Varjak et al ldquoInhibitors of alphavirusentry and replication identified with a stable Chikungunyareplicon cell line and virus-based assaysrdquo PLoS ONE vol 6 no12 Article ID e28923 2011

[67] M Lucas-Hourani A Lupan P Despres et al ldquoA phenotypicassay to identify Chikungunya virus inhibitors targeting thenonstructural protein nsP2rdquo Journal of Biomolecular Screeningvol 18 no 2 pp 172ndash179 2013

[68] D J M Cruz R M Bonotto R G B Gomes et al ldquoIden-tification of novel compounds inhibiting Chikungunya virus-induced cell death by high throughput screening of a kinaseinhibitor libraryrdquo PLoS Neglected Tropical Diseases vol 7 no10 Article ID e2471 2013

[69] C Bissantz G Folkers and D Rognan ldquoProtein-based virtualscreening of chemical databases 1 Evaluation of different dock-ingscoring combinationsrdquo Journal of Medicinal Chemistry vol43 no 25 pp 4759ndash4767 2000

[70] E Reichert A Clase A Bacetty and J Larsen ldquoAlphavirusantiviral drug development scientific gap analysis and prospec-tive research areasrdquo Biosecurity and Bioterrorism vol 7 no 4pp 413ndash427 2009

[71] A A Rashad and P P Keller ldquoStructure based design towardsthe identification of novel binding sites and inhibitors for theChikungunya virus envelope proteinsrdquo Journal of MolecularGraphics amp Modelling vol 44 pp 241ndash252 2013

[72] J J Fros W J Liu N A Prow et al ldquoChikungunya virusnonstructural protein 2 inhibits type III interferon-stimulatedJAK-STAT signalingrdquo Journal of Virology vol 84 no 20 pp10877ndash10887 2010

[73] L K White T Sali D Alvarado et al ldquoChikungunya virusinduces IPS-1-dependent innate immune activation and proteinkinase R-independent translational shutoffrdquo Journal of Virologyvol 85 no 1 pp 606ndash620 2011

[74] M Bassetto T de Burghgraeve L Delang et al ldquoComputer-aided identification design and synthesis of a novel series ofcompounds with selective antiviral activity against Chikun-gunya virusrdquo Antiviral Research vol 98 no 1 pp 12ndash18 2013

[75] D Jochmans N Segura Guerrero and L Delang ldquoInhibition ofChikungunya virus replication by T-705 (favipiravir) and ident-ification of resistance associated mutations in the RNA-dependent RNApolymeraserdquo httpregakuleuvenbecmtjnpost-er20132013 dj2013CHIKVT705 Poster KeystoneMeetingV8pdf

[76] V R Harrison L N Binn and R Randall ldquoComparativeimmunogenicities of Chikungunya vaccines prepared in avian

and mammalian tissuesrdquo The American Journal of TropicalMedicine and Hygiene vol 16 no 6 pp 786ndash791 1967

[77] A White S Berman and J P Lowenthal ldquoComparativeimmunogenicities of Chikungunya vaccines propagated inmonkey kidney monolayers and chick embryo suspensionculturesrdquo Applied Microbiology vol 23 no 5 pp 951ndash952 1972

[78] K H Eckels V R Harrison and F M Hetrick ldquoChikungunyavirus vaccine prepared by Tween-ether extractionrdquo AppliedMicrobiology vol 19 no 2 pp 321ndash325 1970

[79] ENakao and SHotta ldquoImmunogenicity of purified inactivatedChikungunya virus in monkeysrdquo Bulletin of the World HealthOrganization vol 48 no 5 pp 559ndash562 1973

[80] R Edelman C O Tacket S S Wasserman S A Bodison JG Perry and J A Mangiafico ldquoPhase II safety and immuno-genicity study of live Chikungunya virus vaccine TSI-GSD-218rdquoAmerican Journal of Tropical Medicine and Hygiene vol 62 no6 pp 681ndash685 2000

[81] V R Harrison K H Eckels P J Bartelloni and C HamptonldquoProduction and evaluation of a formalin-killed Chikungunyavaccinerdquo Journal of Immunology vol 107 no 3 pp 643ndash6471971

[82] M Tiwari M Parida S R Santhosh M Khan P K Dashand P V L Rao ldquoAssessment of immunogenic potential of Veroadapted formalin inactivated vaccine derived from novel ECSAgenotype of Chikungunya virusrdquo Vaccine vol 27 no 18 pp2513ndash2522 2009

[83] J Gardner I Anraku T T Le et al ldquoChikungunya virus arthritisin adult wild-type micerdquo Journal of Virology vol 84 no 16 pp8021ndash8032 2010

[84] N H Levitt H H Ramsburg and S E Hasty ldquoDevelopmentof an attenuated strain of Chikungunya virus for use in vaccineproductionrdquo Vaccine vol 4 no 3 pp 157ndash162 1986

[85] C D Partidos J Paykel J Weger et al ldquoCross-protectiveimmunity against orsquonyong-nyong virus afforded by a novelrecombinant Chikungunya vaccinerdquo Vaccine vol 30 no 31 pp4638ndash4643 2012

[86] K Plante E Wang C D Partidos et al ldquoNovel Chikungunyavaccine candidate with an ires-based attenuation and host rangealteration mechanismrdquo PLoS Pathogens vol 7 no 7 Article IDe1002142 2011

[87] E Wang E Volkova A P Adams et al ldquoChimeric alphavirusvaccine candidates for Chikungunyardquo Vaccine vol 26 no 39pp 5030ndash5039 2008

[88] KMuthumani KM Lankaraman D J Laddy et al ldquoImmuno-genicity of novel consensus-based DNA vaccines againstChikungunya virusrdquo Vaccine vol 26 no 40 pp 5128ndash51342008

[89] K Mallilankaraman D J Shedlock H Bao et al ldquoA DNAvaccine against Chikungunya virus is protective in mice andinduces neutralizing antibodies in mice and nonhuman pri-matesrdquo PLoS Neglected Tropical Diseases vol 5 no 1 articlee928 2011

[90] T G Szabo R Palotai P Antal et al ldquoCritical role of glycosyla-tion in determining the length and structure of T cell epitopesrdquoImmunome Research vol 5 no 1 article 4 2009

[91] DWangA Suhrbier A Penn-Nicholson et al ldquoA complex ade-novirus vaccine against Chikungunya virus provides completeprotection against viraemia and arthritisrdquo Vaccine vol 29 no15 pp 2803ndash2809 2011

[92] M Kumar A B Sudeep and V A Arankalle ldquoEvaluationof recombinant E2 protein-based and whole-virus inactivated


candidate vaccines against Chikungunya virusrdquoVaccine vol 30no 43 pp 6142ndash6149 2012

[93] SWMetz andG P Pijlman ldquoArbovirus vaccines opportunitiesfor the baculovirus-insect cell expression systemrdquo Journal ofInvertebrate Pathology vol 107 pp s16ndashs30 2011

[94] S W Metz C Geertsema B E Martina et al ldquoFunctionalprocessing and secretion of Chikungunya virus E1 and E2glycoproteins in insect cellsrdquoVirology Journal vol 8 article 3532011

[95] WAkahata Z-Y Yang H Andersen et al ldquoA virus-like particlevaccine for epidemic Chikungunya virus protects nonhumanprimates against infectionrdquo Nature Medicine vol 16 no 3 pp334ndash338 2010

[96] R M Kramer Y Zeng N Sahni et al ldquoDevelopment of a stablevirus-like particle vaccine formulation against Chikungunyavirus and investigation of the effects of polyanionsrdquo Journal ofPharmaceutical Sciences vol 102 no 12 pp 4305ndash4314 2013

[97] M Khan R Dhanwani P V Rao et al ldquoSubunit vaccineformulations based on recombinant envelope proteins ofChikungunya virus elicit balancedTh1Th2 response and virus-neutralizing antibodies in micerdquo Virus Research vol 167 no 2pp 236ndash246 2012

[98] H Chu S C Das J F Fuchs et al ldquoDeciphering the protectiverole of adaptive immunity to CHIKVIRES a novel candidatevaccine against Chikungunya in the A129 mouse modelrdquoVaccine vol 31 no 33 pp 3353ndash3360 2013

[99] D Hallengard M Kakoulidou A Lulla et al ldquoNovel attenuatedChikungunya vaccine candidates elicit protective immunity inC57BL6micerdquo Journal of Virology vol 88 no 5 pp 2858ndash28662013

[100] C J Roy A P Adams E Wang et al ldquoChikungunya vaccinecandidate is highly attenuated and protects nonhuman primatesagainst telemetrically-monitored disease following a singledoserdquo Journal of Infectious Diseases In press

[101] J Garcıa-Arriaza V Cepeda D Hallengard et al ldquoA novelpoxvirus-based vaccine (MVA-CHIKV) is highly immunogenicand protects mice against Chikungunya infectionrdquo Journal ofVirology vol 88 no 6 pp 3527ndash3547 2014

[102] J Bettadapura L J Herrero A Taylor et al ldquoApproaches tothe treatment of disease induced by Chikungunya virusrdquo IndianJournal of Medical Research vol 138 pp 762ndash765 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of


Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology


Molecular Biology International

GenomicsInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


BioinformaticsAdvances in

Marine BiologyJournal of



Signal TransductionJournal of


BioMed Research International

Evolutionary BiologyInternational Journal of



Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Genetics Research International


Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational



Enzyme Research



Microbiology


treatment of CHIKV from a virological perspective andfurther discuss possible directions for the future

2 Chemical Compounds

We describe here some of the commonly used nonsteroidalanti-inflammatory drugs (NSAIDs) and nonsalicylate anal-gesics that have played a major role in symptomatic treat-ment of the chikungunya disease along with some newercompounds that have been recently tested against the CHIKVinfection(A) Symptomatic Treatment Strategies

Nonsteroidal Anti-Inflammatory Drugs Current treatmentsfor viral arthropathies rely mainly on NSAIDs though theseoften provide only partial relief [17] A number of patientswho experienced chronic rheumatic symptoms followinginfection with CHIKV during the 2005-2006 La Reunionoutbreak were successfully treated with methotrexate (MTX)[18] MTX which was originally developed as a chemother-apeutic forms the basis of most rheumatoid arthritis (RA)treatment regimens due to its anti-inflammatory effects atlow doses [19] Despite this details of its anti-inflammatorymechanism and its effect on acute viral induced arthritisremain unclear Some rare chronic patients did benefit fromMTX but seem to be in a different diagnostic class ldquopost-chikungunya rheumatismrdquo [20] However treatment efficacyis hard to evaluate when multiple diseases are present Ina study of post-CHIKV chronic arthritis in Maharashtra asouth-western state of India antirheumatic drugs includingSulfasalazine and MTX were needed for effective treatment[21] In a recent study aimed at understanding the anti-inflammatorymechanismofMTX and its effect on acute viralinduced arthritis amousemodel of Ross River virus-inducedinflammatory disease demonstrated that MTX treatmentcaused early onset of disease through increased monocyteproduction [22]Thefindings ofMTX effectiveness thus seemto be contradictive

Further although adverse effects of NSAIDs occur inonly a small proportion of users the widespread use of thesedrugs has resulted in serious gastrointestinal complicationsin a substantial overall number of affected persons SelectiveCOX-II inhibitors such as rofecoxib celecoxib and pare-coxib have shown consistently comparable efficacy to that ofconventional NSAIDs in patients with rheumatoid arthritiswith a significantly reduced propensity to cause gastrointesti-nal toxicity The safety benefits of COX-II inhibitors givenalone appear similar to combined therapy with conventionalNSAIDs and gastroprotective agents justifying the consid-eration of such inhibitors as first-line therapy in patientsrequiring long-term pain control [23]Nonsalicylate Analgesics (Paracetamol Acetaminophen Mor-phine and Traditional Herbal Medicine) Most data availableregarding the use of nonsalicylate analgesics against theCHIKV is from the follow-up of La Reunion patients Basedon clinical manifestations the analgesic drug Paracetamolwas the most used (in 954 of treatments) and often wascombined with NSAIDs The wide use of paracetamol led

to the emergence of severe liver afflictions diagnosed duringthe epidemic particularly when doses gt3 gday were taken[24] The hepatotoxicity of paracetamol in combinationwith interferon and vinblastine has also been reported [25]Further studies have shown that acetaminophen (APAP)another analgesic which is commonly used for the relief offever and flu-like symptoms modulates the transcriptionalresponse to recombinant interferon-beta [26] This also sug-gests that the use of this class of drugs might need some cau-tion Morphine was seldom used in the La Reunion althoughit was reported to be effective during early treatments in aperiod when the CHIKV was first discovered [27] Plantsare an integral part of the Reunion Island pharmacopeia andtherefore were mainly used during the outbreaks to treatfever pain and inflammation Some plant species such asFernelia spp are also known for their antiviral propertiesHowever the efficacy of these plants or association of plantshas not been studied particularly for the hepatotoxic risk thatmight be present when taken with paracetamol [24]

SteroidsCorticoids were prescribed to treat arthralgia (277of cases) particularly invalidating forms during the chikun-gunya disease in the Reunion Island hospital staff [24]A study carried out in South India during the chikun-gunya epidemic in 2007 with the objective of evolving auniform treatment protocol demonstrated that addition ofprednisolone to aceclofenac reduced pain and improved thequality of life in patients with acute chikungunya arthritiscompared to aceclofenac given alone in the management ofearly chikungunya fever Their studies thus recommendedcoadministration of low-dose systemic corticosteroids withNSAIDs as the best regimen in treating acute chikungunyacases with arthralgia [28] In another report regarding a caseof post chikungunya reversible demyelinating encephalitisthat was presented with vertigo dysarthria and ataxia therewas complete clinical as well as radiological improvementwith steroids [29] However corticosteroid use during acuteviral arthritis is considered to be contraindicated as a result ofthe risk of immunosuppression causing enhanced infectionand disease exacerbation [30]

(B) Specific Chemical Compounds Tested against CHIKV

21 Chloroquine Chloroquine was first reported to inhibitSindbis virus (SINV) and Semliki Forest Virus (SFV) infectiv-ity in vitromore than 35 years ago [31ndash35] but studies inmicesuggested that the drug might enhance viral replication andaggravate the disease [36] However chloroquine was foundto be effective in treating chronic CHIKV-induced arthralgiawith the possiblemechanism attributedmost likely to its anti-inflammatory properties that are adapted for the treatment ofsome autoimmune illnesses [37] Recent research on the effi-cacy of chloroquine has focused on the dosage used to treatacute CHIKV infections [38 39] To advance the studies withchloroquine and CHIKV a double blind placebo-controlledrandomized trial [38 40] was conducted in the ReunionIsland No statistical difference was observed between thechloroquine and placebo groups either in mean duration offebrile arthralgia or rate of decrease of viraemia However




































Kaur et al2013 [49]







4 Cellular Factors


























(myoblastcells)














Khan et al2011 [62]




Teng et al2012 [63]


7 Conclusions









References





















































































































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology




































Kaur et al2013 [49]







4 Cellular Factors


























(myoblastcells)














Khan et al2011 [62]




Teng et al2012 [63]


7 Conclusions









References





















































































































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology



4 Cellular Factors


























(myoblastcells)














Khan et al2011 [62]




Teng et al2012 [63]


7 Conclusions









References





















































































































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology


















(myoblastcells)














Khan et al2011 [62]




Teng et al2012 [63]


7 Conclusions









References





















































































































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology





References





















































































































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology

























































































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology

review article antiviral perspectives for chikungunya...

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