Displaying publications 61 - 80 of 90 in total

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  1. [Chikungunya, La Réunion and Mayotte, 2005-2006: an epidemic without a story?]
    Flahault A, Aumont G, Boisson V, de Lamballerile X, Favier F, Fontenille D, et al.
    Sante Publique, 2007 May-Jun;19 Suppl 3:S165-95.
    PMID: 17929405
    Many triggering factors for onset of emerging infectious diseases are now recognised, such as: globalisation, demographic increase, population movements, international trade, urbanisation, forest destruction, climate changes, loss in biodiversity, and extreme life conditions such as poverty, famine and war. Epidemic burden is often leading to disasters, in terms of human losses, as well as economic, political or social consequences. These outbreaks may jeopardize within a few weeks or months, industry, trade, or tourism. While dengue and its most severe forms (hemorrhagic and shock syndrome) is spreading all over the tropical world, another arbovirosis, chikungunya disease dramatically spread in Indian Ocean islands where 30 to 75% of population were infected in 2005 and 2006, and then extended its progression towards India, Sri Lanka, Indonesia, Malaysia, Maldives islands with more than a million people infected with the East-African strain, replacing the former Asian strain which was known to prevail more than 30 years ago in India. Patients experience sequelae with disability, work loss, and rarely severe outcome recently identified in La Réunion and Mayotte (French overseas territories). No country, no part of the world may consider itself as protected against such events. However, consequences of emerging or re-emerging diseases are more and more unacceptable when they impact the poorest countries of the world. Viruses, bacteria, as well as wild animals, birds, or arthropods are not stopped by borders. It is time now to promote barriers against infectious diseases, including prevention, anticipation, disease surveillance and research. This is not only for humanitarian reasons, but also for contributing to a sustainable development with equity for worldwide population. This report presents comprehensive actions taken in 2006 for tracing the epidemic and mobilise research, as requested to the task force set up by the Prime Minister by March 20, 2006.
    Matched MeSH terms: Chikungunya virus
  2. Combined detection and genotyping of Chikungunya virus by a specific reverse transcription-polymerase chain reaction
    Hasebe F, Parquet MC, Pandey BD, Mathenge EG, Morita K, Balasubramaniam V, et al.
    J Med Virol, 2002 Jul;67(3):370-4.
    PMID: 12116030
    A reverse transcription-polymerase chain reaction (RT-PCR) was developed for the detection of Chikungunya virus infection. Based on the nonstructural protein 1 (nsP1) and glycoprotein E1 (E1) genes of Chikungunya, two primer sets were designed. Total RNA were extracted from the cell culture fluid of Aedes albopictus C6/36 cells inoculated with the S27 prototype virus, isolated in Tanzania in 1953, and the Malaysian strains (MALh0198, MALh0298, and MALh0398), isolated in Malaysia in 1998. For both sets of RNA samples, the expected 354- and 294-base pair (bp) cDNA fragments were amplified effectively from the nsP1 and E1 genes, respectively. Phylogenetic analysis was conducted for the Malaysian strain and other virus strains isolated from different regions in the world endemic for Chikungunya, using partial E1 gene sequence data. The Malaysian strains isolated during the epidemics of 1998 fell into a cluster with other members of the Asian genotype.
    Matched MeSH terms: Chikungunya virus/classification*; Chikungunya virus/genetics; Chikungunya virus/isolation & purification*
  3. Fulltext Clinical Symptoms of Arboviruses in Mexico
    Ananth S, Shrestha N, Treviño C JA, Nguyen US, Haque U, Angulo-Molina A, et al.
    Pathogens, 2020 Nov 19;9(11).
    PMID: 33228120 DOI: 10.3390/pathogens9110964
    Arboviruses such as Chikungunya (CHIKV), Dengue (DENV), and Zika virus (ZIKV) have emerged as a significant public health concern in Mexico. The existing literature lacks evidence regarding the dispersion of arboviruses, thereby limiting public health policy's ability to integrate the diagnosis, management, and prevention. This study seeks to reveal the clinical symptoms of CHIK, DENV, and ZIKV by age group, region, sex, and time across Mexico. The confirmed cases of CHIKV, DENV, and ZIKV were compiled from January 2012 to March 2020. Demographic characteristics analyzed significant clinical symptoms of confirmed cases. Multinomial logistic regression was used to assess the association between clinical symptoms and geographical regions. Females and individuals aged 15 and older had higher rates of reported significant symptoms across all three arboviruses. DENV showed a temporal variation of symptoms by regions 3 and 5, whereas ZIKV presented temporal variables in regions 2 and 4. This study revealed unique and overlapping symptoms between CHIKV, DENV, and ZIKV. However, the differentiation of CHIKV, DENV, and ZIKV is difficult, and diagnostic facilities are not available in rural areas. There is a need for adequately trained healthcare staff alongside well-equipped lab facilities, including hematological tests and imaging facilities.
    Matched MeSH terms: Chikungunya virus
  4. Fulltext New Paradigms for Virus Detection, Surveillance and Control of Zika Virus Vectors in the Settings of Southeast Asia
    Vythilingam I, Sam JI, Chan YF, Khaw LT, Sulaiman WY
    Front Microbiol, 2016;7:1452.
    PMID: 27679623 DOI: 10.3389/fmicb.2016.01452
    Zika virus (ZIKV) has now become a global public health concern. The vectors for ZIKV are Aedes aegypti and A. albopictus. Both these mosquitoes are predominant in Southeast Asia and are also responsible for the spread of other arboviral diseases like dengue virus and chikungunya virus. The incidence of dengue has been increasing over the years and this is of concern to public health workers. Simple laboratory tools for the detection of ZIKV is also lacking. In the absence of drugs and vaccine for these arboviral diseases, vector control is the main option for surveillance and control. Aedes larval surveys have been the hallmark of dengue control along with larviciding and fogging when cases are reported. However, we need new paradigms and options for control of these vectors. The current situation in Southeast Asia clearly proves that effective strategies for vector control need to be proactive and not reactive. This will be the way forward to control epidemics of these diseases inclusive of ZIKV until a vaccine becomes available.
    Matched MeSH terms: Chikungunya virus
  5. Fulltext Expression of recombinant E1 Glycoprotein of Chikungunya virus in Baculovirus expression system
    Sum, Magdline Sia Henry, Andrew, Anna, Maling, Milda Aren
    Journal of Biochemistry, Microbiology and Biotechnology, 2015;3(1):26-29.
    MyJurnal
    Chikungunya is an acute febrile illness caused by chikungunya virus (CHIKV). In this study, the envelope E1 gene of CHIKV was cloned and expressed in a baculovirus system. The recombinant E1 protein with N-term 6-His residues protein was successfully expressed and purified as confirmed by SDS-PAGE and western blot analysis. The seroreactivity of the recombinant protein was evaluated in immunoassay for anti-CHIKV IgM and IgG antibodies. The recombinant antigen showed 69% sensitivity and 100% specificity for anti-CHIKV IgG by dot blot assay. Detection of anti-CHIKV IgM by dot assay showed 79% sensitivity and 100% specificity. No cross reactivity of the antigen was observed with anti-dengue virus serum samples. The results strongly support that the recombinant E1 protein has potential to be used as diagnostic antigen. The used of the antigen in a dot blot assay gives an advantage for laboratory detection without the need of any specialised equipment.
    Matched MeSH terms: Chikungunya virus
  6. Countries at risk of importation of chikungunya virus cases from Southern Thailand: A modeling study
    Tuite AR, Watts AG, Khan K, Bogoch II
    Infect Dis Model, 2019;4:251-256.
    PMID: 31667444 DOI: 10.1016/j.idm.2019.09.001
    Southern Thailand has been experiencing a large chikungunya virus (CHIKV) outbreak since October 2018. Given the magnitude and duration of the outbreak and its location in a popular tourist destination, we sought to determine international case exportation risk and identify countries at greatest risk of receiving travel-associated imported CHIKV cases. We used a probabilistic model to estimate the expected number of exported cases from Southern Thailand between October 2018 and April 2019. The model incorporated data on CHIKV natural history, infection rates in Southern Thailand, average length of stay for tourists, and international outbound air passenger numbers from the outbreak area. For countries highly connected to Southern Thailand by air travel, we ran 1000 simulations to estimate the expected number of imported cases. We also identified destination countries with conditions suitable for autochthonous CHIKV transmission. Over the outbreak period, we estimated that an average of 125 (95% credible interval (CrI): 102-149) cases would be exported from Southern Thailand to international destinations via air travel. China was projected to receive the most cases (43, 95% CrI: 30-56), followed by Singapore (7, 95% CrI: 2-12) and Malaysia (5, 95% CrI: 1-10). Twenty-three countries were projected to receive at least one imported case, and 64% of these countries had one or more regions that could potentially support autochthonous CHIKV transmission. The overall risk of international exportation of CHIKV cases associated with the outbreak is Southern Thailand is high. Our model projections are consistent with recent reports of CHIKV in travelers returning from the region. Countries should be alert to the possibility of CHIKV infection in returning travelers, particularly in regions where autochthonous transmission is possible.
    Matched MeSH terms: Chikungunya virus
  7. Chikungunya virus of Asian and Central/East African genotypes in Malaysia
    Sam IC, Chan YF, Chan SY, Loong SK, Chin HK, Hooi PS, et al.
    J Clin Virol, 2009 Oct;46(2):180-3.
    PMID: 19683467 DOI: 10.1016/j.jcv.2009.07.016
    BACKGROUND: Chikungunya virus (CHIKV) of the Central/East African genotype has caused large outbreaks worldwide in recent years. In Malaysia, limited CHIKV outbreaks of the endemic Asian and imported Central/East African genotypes were reported in 1998 and 2006. Since April 2008, an unprecedented nationwide outbreak has affected Malaysia.
    OBJECTIVE: To study the molecular epidemiology of the current Malaysian CHIKV outbreak, and to evaluate cross-neutralisation activity of serum from infected patients against isolates of Asian and Central/East African genotypes.
    STUDY DESIGN: Serum samples were collected from 83 patients presenting in 2008, and tested with PCR for the E1 gene, virus isolation, and for IgM. Phylogenetic analysis was performed on partial E1 gene sequences of 837bp length. Convalescent serum from the current outbreak and Bagan Panchor outbreak (Asian genotype, 2006) were tested for cross-neutralising activity against representative strains from each outbreak.
    RESULTS: CHIKV was confirmed in 34 patients (41.0%). The current outbreak strain has the A226V mutation in the E1 structural protein, and grouped with Central/East African isolates from recent global outbreaks. Serum cross-neutralisation activity against both Central/East African and Asian genotypes was observed at titres from 40 to 1280.
    CONCLUSIONS: The CHIKV strain causing the largest Malaysian outbreak is of the Central/East African genotype. The presence of the A226V mutation, which enhances transmissibility of CHIKV by Aedes albopictus, may explain the extensive spread especially in rural areas. Serum cross-neutralisation of different genotypes may aid potential vaccines and limit the effect of future outbreaks.
    Matched MeSH terms: Chikungunya virus/genetics*
  8. Chikungunya infection in Malaysia: comparison with dengue infection in adults and predictors of persistent arthralgia
    Mohd Zim MA, Sam IC, Omar SF, Chan YF, AbuBakar S, Kamarulzaman A
    J Clin Virol, 2013 Feb;56(2):141-5.
    PMID: 23201456 DOI: 10.1016/j.jcv.2012.10.019
    Chikungunya virus (CHIKV) and dengue virus (DENV) co-circulate in areas endemic with the Aedes mosquito vectors. Both viruses cause similar illnesses which may be difficult to distinguish clinically. CHIKV is also associated with persistent arthralgia.
    Matched MeSH terms: Chikungunya virus/isolation & purification*
  9. Fulltext Emergence of chikungunya seropositivity in healthy Malaysian adults residing in outbreak-free locations: chikungunya seroprevalence results from the Malaysian Cohort
    Azami NA, Salleh SA, Shah SA, Neoh HM, Othman Z, Zakaria SZ, et al.
    BMC Infect Dis, 2013;13:67.
    PMID: 23379541 DOI: 10.1186/1471-2334-13-67
    In 1998, Malaysia experienced its first chikungunya virus (CHIKV) outbreak in the suburban areas followed by another two in 2006 (rural areas) and 2008 (urban areas), respectively. Nevertheless, there is still a lack of documented data regarding the magnitude of CHIKV exposure in the Malaysian population. The aim of this study was to determine the extent of chikungunya virus infection in healthy Malaysian adults residing in outbreak-free locations.
    Matched MeSH terms: Chikungunya virus/immunology*
  10. Fulltext Early clearance of Chikungunya virus in children is associated with a strong innate immune response
    Simarmata D, Ng DC, Kam YW, Lee B, Sum MS, Her Z, et al.
    Sci Rep, 2016 05 16;6:26097.
    PMID: 27180811 DOI: 10.1038/srep26097
    Chikungunya fever (CHIKF) is a global infectious disease which can affect a wide range of age groups. The pathological and immunological response upon Chikungunya virus (CHIKV) infection have been reported over the last few years. However, the clinical profile and immune response upon CHIKV infection in children remain largely unknown. In this study, we analyzed the clinical and immunological response, focusing on the cytokine/chemokine profile in a CHIKV-infected pediatric cohort from Sarawak, Malaysia. Unique immune mediators triggered upon CHIKV infection were identified through meta-analysis of the immune signatures between this pediatric group and cohorts from previous outbreaks. The data generated from this study revealed that a broad spectrum of cytokines/chemokines is up-regulated in a sub-group of virus-infected children stratified according to their viremic status during hospitalization. Furthermore, different immune mediator profiles (the levels of pro-inflammatory cytokines, chemokines and growth and other factors) were observed between children and adults. This study gives an important insight to understand the immune response of CHIKV infection in children and would aid in the development of better prognostics and clinical management for children.
    Matched MeSH terms: Chikungunya virus/physiology*
  11. Alphaviruses in Peninsular Malaysia: II. Serological evidence of human infection
    Marchette NJ, Rudnick A, Garcia R
    Southeast Asian J. Trop. Med. Public Health, 1980 Mar;11(1):14-23.
    PMID: 7403943
    A serum survey of several characteristic groups of humans in urban, rural, and forested areas of Peninsular Malaysia for evidence of infection with three alphaviruses (Sindbis, getah, and chikungunya) was made on 4384 specimens collected between 1965 and 1969. Analysis of the serological results indicated that 1) persons residing in predominantly rural and forested areas have higher frequencies of specific alphavirus antibody of all three viruses than persons residing in urban areas, 2) human infection with chikungunya virus appears to be at a low level of activity but is widespread, although more common and recent in the northern part of the country, and 3) Sindbis and getah viruses probably do not represent a threat to the public health, but chikungunya virus remains a potential menance and may be responsible for future epidemics transmitted by A. aegypti and A. albopictus mosquitoes.
    Matched MeSH terms: Chikungunya virus/immunology*
  12. The distribution and prevalence of group A arbovirus neutralizing antibodies among human populations in Southeast Asia and the Pacific islands
    Tesh RB, Gajdusek DC, Garruto RM, Cross JH, Rosen L
    Am J Trop Med Hyg, 1975 Jul;24(4):664-75.
    PMID: 1155702
    Plaque reduction neutralization tests, using five group A arboviruses (chikungunya, Ross River, Getah, Bebaru and Sindbis), were done on sera from human populations in 44 Southeast Asia and Pacific island localities. Specificity of the plaque neutralization test was determined by examining convalescent sera from patients with known alphavirus infections. Chikungunya-specific neutralizing antibodies were demonstrated in sera of persons living in South Vietnam, Northern Malaysia, Indonesia (Kalimantan and Sulawesi), as well as Luzon, Marinduque, Cebu and Mindanao islands in the Philippines. Evidence of Ross River virus infection was found among populations living in West New Guinea and Papua New Guinea mainland, the Bismark Archipelago, Rossel Island and the Solomon Islands. There appeared to be no geographic overlap in the distribution of chikungunya and Ross River viruses, with the separation in their distribution corresponding with Weber's line in the Pacific. Sindbis neutralizing antibodies were found in 7 of 21 populations sampled, but in general the prevalence of infection was low. Four sera, from Vietnam, Malaysia and Mindanao gave monospecific reactions with Getah virus. No evidence of specific Bebaru virus infection was detected. The epidemiology of these five alphaviruses in Southeast Asia and the Pacific islands is discussed.
    Matched MeSH terms: Chikungunya virus/immunology
  13. Clinical and radiological features of imported chikungunya fever in Japan: a study of six cases at the National Center for Global Health and Medicine
    Mizuno Y, Kato Y, Takeshita N, Ujiie M, Kobayashi T, Kanagawa S, et al.
    J Infect Chemother, 2011 Jun;17(3):419-23.
    PMID: 20862507 DOI: 10.1007/s10156-010-0124-y
    Chikungunya fever (CHIKF) is currently distributed in Africa and in South and Southeast Asia; outbreaks have occurred periodically in the region over the past 50 years. After a large outbreak had occurred in countries in the western Indian Ocean region in 2005, several countries reported cases of CHIKF from travelers who had visited affected areas. In Japan, there have been only 15 cases of CHIKF patients so far, according to the National Institute of Infectious Diseases. Therefore, to evaluate the clinical and radiological features associated with the disease, we describe 6 imported cases of CHIKF. All of the patients had had prolonged arthralgia on admission to our hospital, and diagnosis was confirmed with specific antibodies by using an IgM-capture enzyme-linked immunoassay and a plaque reduction neutralizing antibody assay. Magnetic resonance imaging (MRI) of one patient revealed erosive arthritis and tenosynovitis during the convalescence stage. Clinicians should be aware of the late consequences of infection by the chikungunya virus (CHIKV) and recognize the possible association of subacute and chronic arthritis features. In addition, competent vectors of CHIKV, Aedes aegypti, can now be found in many temperate areas of the eastern and western hemispheres, including Japan. This fact raises concern that the virus could be introduced and become established in these areas. This necessitates an increased awareness of the disease, because imported cases are likely to contribute to the spread of CHIKV infection wherever the competent mosquito vectors are distributed.
    Matched MeSH terms: Chikungunya virus/isolation & purification*
  14. Fulltext Immunological surveys of arbovirus infections in South-East Asia, with special reference to dengue, chikungunya, and Kyasanur Forest disease
    Rao TR
    Bull World Health Organ, 1971;44(5):585-91.
    PMID: 4400821
    Serological surveys have been widely used in South-East Asia to determine the presence and activity of arboviruses. The haemagglutination-inhibition test has been most frequently employed but complement-fixation and neutralization tests have also been used in some investigations.Although virus isolations provide the most conclusive evidence, they can be carried out in a few specialized centres only, and serological surveys are very important for studying the distribution of arboviruses.The surveys have shown that group B arboviruses (principally all four types of dengue, Japanese encephalitis, and West Nile) are widely prevalent. Dengue and Japanese encephalitis viruses are more widespread than West Nile virus, which was not known previously to extend east of India although recent survyes have shown that its range extends to Burma. Japanese encephalitis is frequent in most of South-East Asia but in India is found mainly in eastern and south-eastern parts of the country. Kyasanur Forest disease (KFD) and Langat viruses are the only tick-borne group B arboviruses definitely known to occur in the region, the former in India, the latter in Malaysia. KFD virus has been isolated only from a small focus in Mysore, although human and animal sera containing neutralizing antibodies to this virus have been found sporadically in widely scattered areas. Among the group A arboviruses, chikungunya and Sindbis have been detected in serological surveys, but the former has not yet been found in Malaysia.
    Matched MeSH terms: Chikungunya virus/immunology*
  15. Alphaviruses in Peninusular Malaysia: I. Virus isolations and animal serology
    Marchette NJ, Rudnick A, Garcia R, MacVean DW
    Southeast Asian J. Trop. Med. Public Health, 1978 Sep;9(3):317-29.
    PMID: 34888
    A survey of the activity of three alphaviruses (Sindbis, getah and chikungunya) in Peninsular Malaysia was conducted between 1962 and 1970. Serum samples were examined from 3,917 vertebrates representing a wide variety of wild and domestic animals throughout the peninsula for hemagglutination-inhibiting and neutralizing antibodies. A total of 548,939 mosquitoes were collected from different habitats, including jungle, rural, suburban and urban areas, and the majority of the females taken were examined for the presence of virus. Two strains of Sindbis virus and one strain of getah virus were isolated from pools of Culex mosquitoes collected in and around domestic animal shelters. Analysis of the serological results indicated that, 1) getah virus is associated principally with large domestic animals, particularly swine, 2) Sindbis virus is associated with large domestic animals and birds, especially domestic ducks, and 3) chikungunya virus, which has not yet been isolated in Malaysia, appeared to be present at a very low level of activity, probably with wild monkeys as the vertebrate hosts.
    Matched MeSH terms: Chikungunya virus/immunology
  16. Fulltext External quality assessment of dengue and chikungunya diagnostics in the Asia Pacific region, 2015
    Soh LT, Squires RC, Tan LK, Pok KY, Yang H, Liew C, et al.
    Western Pac Surveill Response J, 2016 04 22;7(2):26-34.
    PMID: 27508088 DOI: 10.5365/WPSAR.2016.7.1.002
    OBJECTIVE: To conduct an external quality assessment (EQA) of dengue and chikungunya diagnostics among national-level public health laboratories in the Asia Pacific region following the first round of EQA for dengue diagnostics in 2013.

    METHODS: Twenty-four national-level public health laboratories performed routine diagnostic assays on a proficiency testing panel consisting of two modules. Module A contained serum samples spiked with cultured dengue virus (DENV) or chikungunya virus (CHIKV) for the detection of nucleic acid and DENV non-structural protein 1 (NS1) antigen. Module B contained human serum samples for the detection of anti-DENV antibodies.

    RESULTS: Among 20 laboratories testing Module A, 17 (85%) correctly detected DENV RNA by reverse transcription polymerase chain reaction (RT-PCR), 18 (90%) correctly determined serotype and 19 (95%) correctly identified CHIKV by RT-PCR. Ten of 15 (66.7%) laboratories performing NS1 antigen assays obtained the correct results. In Module B, 18/23 (78.3%) and 20/20 (100%) of laboratories correctly detected anti-DENV IgM and IgG, respectively. Detection of acute/recent DENV infection by both molecular (RT-PCR) and serological methods (IgM) was available in 19/24 (79.2%) participating laboratories.

    DISCUSSION: Accurate laboratory testing is a critical component of dengue and chikungunya surveillance and control. This second round of EQA reveals good proficiency in molecular and serological diagnostics of these diseases in the Asia Pacific region. Further comprehensive diagnostic testing, including testing for Zika virus, should comprise future iterations of the EQA.

    Matched MeSH terms: Chikungunya virus/pathogenicity
  17. Characterisation of mouse monoclonal antibodies targeting linear epitopes on Chikungunya virus E2 glycoprotein
    Chua CL, Chan YF, Sam IC
    J Virol Methods, 2014 Jan;195:126-33.
    PMID: 24134938 DOI: 10.1016/j.jviromet.2013.10.015
    Chikungunya virus (CHIKV) is a mosquito-borne arbovirus which has recently re-emerged globally and poses a major threat to public health. Infection leads to severe arthralgia, and disease management remains supportive in the absence of vaccines and anti-viral interventions. The high specificities of monoclonal antibodies (mAbs) have been exploited in immunodiagnostics and immunotherapy in recent decades. In this study, eight different clones of mAbs were generated and characterised. These mAbs targeted the linear epitopes on the CHIKV E2 envelope glycoprotein, which is the major target antigen during infection. All the mAbs showed binding activity against the purified CHIKV virion or recombinant E2 when analysed by immunofluorescence, ELISA and Western blot. The epitopes of each mAb were mapped by overlapping synthetic peptide-based ELISA. The epitopes are distributed at different functional domains of E2 glycoprotein, namely at domain A, junctions of β-ribbons with domains A and B, and domain C. Alignment of mAb epitope sequences revealed that some are well-conserved within different genotypes of CHIKV, while some are identical to and likely to cross-react with the closely-related alphavirus O'nyong-nyong virus. These mAbs with their mapped epitopes are useful for the development of diagnostic or research tools, including immunofluorescence, ELISA and Western blot.
    Matched MeSH terms: Chikungunya virus/immunology*
  18. Epidemiology and control of chikungunya fever in Singapore
    Ho K, Ang LW, Tan BH, Tang CS, Ooi PL, James L, et al.
    J Infect, 2011 Apr;62(4):263-70.
    PMID: 21315108 DOI: 10.1016/j.jinf.2011.02.001
    OBJECTIVES: We conducted an epidemiological review of the chikungunya fever situation in Singapore and described the measures taken to prevent the chikungunya virus from becoming entrenched in the tropical city-state.
    METHODS: All laboratory-confirmed cases and outbreak investigation reports maintained by the Communicable Diseases Division, Ministry of Health, and Aedes mosquito surveillance data obtained by the National Environment Agency during the period 2006 and 2009 were reviewed and analysed.
    RESULTS: Sporadic cases were imported into Singapore until the first local transmission occurred in an urban area where Aedes aegypti was the predominant vector. Subsequent introduction of a mutant viral strain (A226V) in early 2008 resulted in the rapid spread to suburban and rural areas where Aedes albopictus was the primary vector. 1072 cases including 812 (75.7%) indigenous cases were reported. The main sources of importation were India and Malaysia. Foreign contract workers were identified as high-risk for indigenous infections.
    CONCLUSIONS: The disease was successfully brought under control through aggressive vector control measures directed at A. albopictus. Although the incidence has sharply declined since January 2009, a high degree of vigilance is maintained to prevent a recurrence of epidemic transmission which can occur even with a well-established nationwide mosquito control programme.
    Matched MeSH terms: Chikungunya virus*
  19. Fulltext Differential Analysis of the Secretome of WRL68 Cells Infected with the Chikungunya Virus
    Thio CL, Yusof R, Ashrafzadeh A, Bahari S, Abdul-Rahman PS, Karsani SA
    PLoS One, 2015;10(6):e0129033.
    PMID: 26083627 DOI: 10.1371/journal.pone.0129033
    The Chikungunya virus (CHIKV) is an arthropod borne virus. In the last 50 years, it has been the cause of numerous outbreaks in tropical and temperate regions, worldwide. There is limited understanding regarding the underlying molecular mechanisms involved in CHIKV replication and how the virus interacts with its host. In the present study, comparative proteomics was used to identify secreted host proteins that changed in abundance in response to early CHIKV infection. Two-dimensional gel electrophoresis was used to analyse and compare the secretome profiles of WRL-68 cells infected with CHIKV against mock control WRL-68 cells. The analysis identified 25 regulated proteins in CHIKV infected cells. STRING network analysis was then used to predict biological processes that may be affected by these proteins. The processes predicted to be affected include signal transduction, cellular component and extracellular matrix (ECM) organization, regulation of cytokine stimulus and immune response. These results provide an initial view of CHIKV may affect the secretome of infected cells during early infection. The results presented here will compliment earlier results from the study of late host response. However, functional characterization will be necessary to further enhance our understanding of the roles played by these proteins in the early stages of CHIKV infection in humans.
    Matched MeSH terms: Chikungunya virus/physiology*
  20. Fulltext A combination of doxycycline and ribavirin alleviated chikungunya infection
    Rothan HA, Bahrani H, Mohamed Z, Teoh TC, Shankar EM, Rahman NA, et al.
    PLoS One, 2015;10(5):e0126360.
    PMID: 25970853 DOI: 10.1371/journal.pone.0126360
    Lack of vaccine and effective antiviral drugs against chikungunya virus (CHIKV) outbreaks have led to significant impact on health care in the developing world. Here, we evaluated the antiviral effects of tetracycline (TETRA) derivatives and other common antiviral agents against CHIKV. Our results showed that within the TETRA derivatives group, Doxycycline (DOXY) exhibited the highest inhibitory effect against CHIKV replication in Vero cells. On the other hand, in the antiviral group Ribavirin (RIBA) showed higher inhibitory effects against CHIKV replication compared to Aciclovir (ACIC). Interestingly, RIBA inhibitory effects were also higher than all but DOXY within the TETRA derivatives group. Docking studies of DOXY to viral cysteine protease and E2 envelope protein showed non-competitive interaction with docking energy of -6.6±0.1 and -6.4±0.1 kcal/mol respectively. The 50% effective concentration (EC50) of DOXY and RIBA was determined to be 10.95±2.12 μM and 15.51±1.62 μM respectively, while DOXY+RIBA (1:1 combination) showed an EC50 of 4.52±1.42 μM. When compared, DOXY showed higher inhibition of viral infectivity and entry than RIBA. In contrast however, RIBA showed higher inhibition against viral replication in target cells compared to DOXY. Assays using mice as animal models revealed that DOXY+RIBA effectively inhibited CHIKV replication and attenuated its infectivity in vivo. Further experimental and clinical studies are warranted to investigate their potential application for clinical intervention of CHIKV disease.
    Matched MeSH terms: Chikungunya virus/drug effects*
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