Displaying publications 1 - 20 of 90 in total

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  1. 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
  2. Ahola T, Couderc T, Courderc T, Ng LF, Hallengärd D, Powers A, et al.
    Vector Borne Zoonotic Dis, 2015 Apr;15(4):250-7.
    PMID: 25897811 DOI: 10.1089/vbz.2014.1681
    Currently, there are no licensed vaccines or therapies available against chikungunya virus (CHIKV), and these were subjects discussed during a CHIKV meeting recently organized in Langkawi, Malaysia. In this review, we chart the approaches taken in both areas. Because of a sharp increase in new data in these fields, the present paper is complementary to previous reviews by Weaver et al. in 2012 and Kaur and Chu in 2013 . The most promising antivirals so far discovered are reviewed, with a special focus on the virus-encoded replication proteins as potential targets. Within the vaccines in development, our review emphasizes the various strategies in parallel development that are unique in the vaccine field against a single disease.
    Matched MeSH terms: Chikungunya virus/immunology*
  3. Sam IC, Kümmerer BM, Chan YF, Roques P, Drosten C, AbuBakar S
    Vector Borne Zoonotic Dis, 2015 Apr;15(4):223-30.
    PMID: 25897809 DOI: 10.1089/vbz.2014.1680
    Chikungunya virus (CHIKV) is an Aedes-borne alphavirus, historically found in Africa and Asia, where it caused sporadic outbreaks. In 2004, CHIKV reemerged in East Africa and spread globally to cause epidemics, including, for the first time, autochthonous transmission in Europe, the Middle East, and Oceania. The epidemic strains were of the East/Central/South African genotype. Strains of the Asian genotype of CHIKV continued to cause outbreaks in Asia and spread to Oceania and, in 2013, to the Americas. Acute disease, mainly comprising fever, rash, and arthralgia, was previously regarded as self-limiting; however, there is growing evidence of severe but rare manifestations, such as neurological disease. Furthermore, CHIKV appears to cause a significant burden of long-term morbidity due to persistent arthralgia. Diagnostic assays have advanced greatly in recent years, although there remains a need for simple, accurate, and affordable tests for the developing countries where CHIKV is most prevalent. This review focuses on recent important work on the epidemiology, clinical disease and diagnostics of CHIKV.
    Matched MeSH terms: Chikungunya virus/genetics; Chikungunya virus/immunology; Chikungunya virus/isolation & purification*
  4. Ummul Haninah A, Vasan SS, Ravindran T, Chandru A, Lee HL, Shamala Devi S
    Trop Biomed, 2010 Dec;27(3):611-23.
    PMID: 21399603 MyJurnal
    This paper reports the development of a one-step SYBR-Green I-based realtime RT-PCR assay for the detection and quantification of Chikungunya virus (CHIKV) in human, monkey and mosquito samples by targeting the E1 structural gene. A preliminary evaluation of this assay has been successfully completed using 71 samples, consisting of a panel of negative control sera, sera from healthy individuals, sera from patients with acute disease from which CHIKV had been isolated, as well as monkey sera and adult mosquito samples obtained during the chikungunya fever outbreak in Malaysia in 2008. The assay was found to be 100-fold more sensitive than the conventional RT-PCR with a detection limit of 4.12x10(0) RNA copies/μl. The specificity of the assay was tested against other related viruses such as Dengue (serotypes 1-4), Japanese encephalitis, Herpes Simplex, Parainfluenza, Sindbis, Ross River, Yellow fever and West Nile viruses. The sensitivity, specificity and efficiency of this assay were 100%, 100% and 96.8% respectively. This study on early diagnostics is of importance to all endemic countries, especially Malaysia, which has been facing increasingly frequent and bigger outbreaks due to this virus since 1999.
    Matched MeSH terms: Chikungunya virus/isolation & purification*
  5. Pongsiri P, Auksornkitti V, Theamboonlers A, Luplertlop N, Rianthavorn P, Poovorawan Y
    Trop Biomed, 2010 Aug;27(2):167-76.
    PMID: 20962712 MyJurnal
    The resurgence of Chikungunya virus (CHIKV) in the southern, northeastern and northern parts of Thailand, inflicting approximately 46,000 reported cases since October 2008 until December 2009, has raised public health concerns. In the present study, we characterized nearly complete genome sequences of four CHIKV isolates obtained from 2008 to 2009 outbreaks in Thailand. Phylogenetic analysis was performed to determine the relationships of the study viruses with previously reported isolates. Results showed that 2008-2009 Thailand isolates belonged to the East, Central and South African genotype and were most closely related to isolates detected in Malaysia and Singapore in 2008. This was in contrast to isolates from all previous outbreaks in Thailand which were caused by an Asian genotype. We describe several novel mutations in Thailand isolates that warrants further investigation on characterization of CHIKV from different parts of the country to better understand the molecular epidemiology of Chikungunya fever outbreaks in Thailand.
    Matched MeSH terms: Chikungunya virus/genetics*
  6. Rohani A, Yulfi H, Zamree I, Lee HL
    Trop Biomed, 2005 Dec;22(2):149-54.
    PMID: 16883281 MyJurnal
    A study of chikungunya virus was carried out to establish Reverse Transcriptase- Polymerase Chain Reaction (RT-PCR) as a rapid detection technique of the virus. The susceptibility of lab-colonized Aedes aegypti to chikungunya virus was also determined. Artificial membrane feeding technique was used to orally feed the mosquitoes with a human isolate of chikungunya virus. A total of 100 fully engorged female Ae. aegypti were obtained and maintained for 7 days. Seventy of them survived and then pooled at 10 individuals per pool. Total RNA was extracted from the samples and RT-PCR amplifications were carried out. Five out of 7 pools showed positive PCR band at 350-bp, indicating Ae. aegypti is a potential vector of chikungunya virus. The minimum infection rate (MIR) was 71% within these laboratory colonies. RT-PCR is a sensitive technique that is useful in detecting infected mosquitoes in epidemic areas. This technique can de used as a rapid detection method and provide an early virologic surveillance systems of chikungunya virus infected mosquitoes.
    Matched MeSH terms: Chikungunya virus/genetics; Chikungunya virus/isolation & purification*
  7. Fazal F, Anwar T, Waheed Y, Parvaiz F
    Trop Biomed, 2020 Sep 01;37(3):566-577.
    PMID: 33612772 DOI: 10.47665/tb.37.3.566
    This study is focused towards developing a global consensus sequence of nonstructural protein 2 (NSP2), a protease of Chikungunya Virus (CHIKV) and predict immunogenic promiscuous T-cell epitopes based on various bioinformatics tools. To date, no epitope data is available for the Chikungunya virus in the IEDB database. In this study, 100 available nucleotide sequences of NSP2-CHIKV belonging to different strains were downloaded from the National Centre for Biotechnology Information (NCBI) database. The nucleotide sequences were subjected to translated sequencing using the EXPASY tool followed by protein alignment using the CLC workbench and a global consensus sequence for the respective protein was developed. IEDB tool was used to predict HLA-I and HLA-II binding promiscuous epitopes from the consensus sequence of NSP2-CHIKV. Thirty-four B-cell based epitopes are predicted and the promiscuous epitope is VVDTTGSTKPDPGD at position 341-354. Twenty-six MHC-I short peptide epitopes are predicted to bind with HLA-A. The promiscuous epitopes predicted to bind with HLA-A*01:01 are VTAIVSSLHY, SLSESATMVY, FSKPLVYY, QPTDHVVGEY at positions 317-326, 84-93, 535-544 and 15-24 with percentile ranks 0.17, 0.39, 0.51 and 0.81, respectively. Twenty-four MHC-II short peptide epitopes are predicted for HLA-DRB. The promiscuous epitope predicted to bind with HLA-DRB*01:01 is VVGEYLVLSPQTVLRS from 20-35 with a lowest percentile rank of 0.01. These predicted epitopes can be effective targets towards development of vaccine against CHIKV. Epitopes predicted in this study displayed good binding affinity, antigenicity and promiscuity for the HLA classes. These predicted epitopes can prove to be translationally important towards the development of CHIKV.
    Matched MeSH terms: Chikungunya virus
  8. Tongco AMP, Rivera WL
    Trop Biomed, 2023 Jun 01;40(2):129-137.
    PMID: 37650398 DOI: 10.47665/tb.40.2.002
    Chikungunya virus (CHIKV) is a neglected tropical pathogen that causes fever and long-lasting severe arthralgia. Despite its high morbidity, there is still no licensed specific therapeutic option for it. This study proposes a multi-epitope subunit vaccine candidate for CHIKV, designed using computational methods. It was based on the E2 spike glycoprotein in CHIKV, from which T- and B-cell epitopes were predicted and then refined. The pan HLA DR-binding epitope (PADRE) was added to this refined construct, then simulated compared with the native protein, where it was predicted to elicit more than twice the number of antibody titers. Thus, this construct is potentially effective against CHIKV, which further experimentation using live models would be able to verify. This study also demonstrates the feasibility of using rational tools in the future to further optimize vaccine design.
    Matched MeSH terms: Chikungunya virus*
  9. Nor Rashid N, Teoh TC, Al-Harbi SJ, Yusof R, Rothan HA
    Trop Biomed, 2021 Mar 01;38(1):36-41.
    PMID: 33797522 DOI: 10.47665/tb.38.1.007
    Chikungunya virus (CHIKV) infection is the cause of acute symptoms and chronic symmetrical polyarthritis associated with long-term morbidity and mortality. Currently, there is no available licensed vaccine or particularly useful drug for human use against CHIKV infection. This study was conducted to evaluate the efficacy of antibodies produced by papaya mosaic virus (PapMV) nanoparticles fused to E2EP3 peptide of CHIKV envelope as a recombinant CHIKV vaccine. PapMV, PapMV-C- E2EP3, and E2EP3-N-PapMV were produced in E. coli with an approximate size of 27 to 30 kDa. ICR mice (5 to 6 weeks of age) were injected subcutaneously with 25 micrograms of vaccine construct, and ELISA measured the titer of CHIKV specific IgG antibodies. The results showed that both recombinant proteins E2EP3-N-PapMV and PapMVC-E2EP3 were able to induce IgG antibodies production in immunized mice against CHIKV while immunization with recombinant PapMV showed no IgG antibodies induction. The neutralizing activity of the antibodies generated by either E2EP3-N-PapMV or PapMV-C-E2EP3 exhibited similar inhibition to CHIKV replication in Vero cells using the cells based antibody neutralizing assay and analyzed by plaque formation assay. This study showed the effectiveness of nanoparticles vaccine generated by fusing epitope peptide of CHIKV envelope to papaya mosaic virus envelope in inducing a robust immune response in mice against CHIKV. The data showed that levels of neutralizing antibodies correlate with a protective immune response CHIKV replication.
    Matched MeSH terms: Chikungunya virus/immunology*
  10. Dass S, Ngui R, Gill BS, Chan YF, Wan Sulaiman WY, Lim YAL, et al.
    Trans R Soc Trop Med Hyg, 2021 08 02;115(8):922-931.
    PMID: 33783526 DOI: 10.1093/trstmh/trab053
    BACKGROUND: We studied the spatiotemporal spread of a chikungunya virus (CHIKV) outbreak in Sarawak state, Malaysia, during 2009-2010.

    METHODS: The residential addresses of 3054 notified CHIKV cases in 2009-2010 were georeferenced onto a base map of Sarawak with spatial data of rivers and roads using R software. The spatiotemporal spread was determined and clusters were detected using the space-time scan statistic with SaTScan.

    RESULTS: Overall CHIKV incidence was 127 per 100 000 population (range, 0-1125 within districts). The average speed of spread was 70.1 km/wk, with a peak of 228 cases/wk and the basic reproduction number (R0) was 3.1. The highest age-specific incidence rate was 228 per 100 000 in adults aged 50-54 y. Significantly more cases (79.4%) lived in rural areas compared with the general population (46.2%, p<0.0001). Five CHIKV clusters were detected. Likely spread was mostly by road, but a fifth of rural cases were spread by river travel.

    CONCLUSIONS: CHIKV initially spread quickly in rural areas mainly via roads, with lesser involvement of urban areas. Delayed spread occurred via river networks to more isolated areas in the rural interior. Understanding the patterns and timings of arboviral outbreak spread may allow targeted vector control measures at key transport hubs or in large transport vehicles.

    Matched MeSH terms: Chikungunya virus*
  11. Apandi Y, Lau SK, Izmawati N, Amal NM, Faudzi Y, Mansor W, et al.
    PMID: 21329313
    Malaysia experienced its first outbreak of chikungunya virus (CHIKV) infection in late 1998 in Klang District in Selangor; six years later the virus re-emerged in the state of Perak. All the CHIKV isolates in 1988 and 2006 shared high sequence similarities and belonged to the Asian genotype. In 2007 and 2008 CHIKV infection again reemerged but the genotype was the Central/East African genotype. This strain was found to be similar to the strains causing outbreaks in the India Ocean. In 2009, the strains circulating in Malaysia, including the state of Kelantan, based on the partial E1 gene, also belong to the Central/East African genotype.
    Matched MeSH terms: Chikungunya virus/classification*; Chikungunya virus/isolation & purification*
  12. Rohani A, Potiwat R, Zamree I, Lee HL
    PMID: 19842428
    In this study, artificial membrane feeding technique was used to orally feed Aedes aegypti with dengue and chikungunya viruses. Virus detection was carried out by reverse transcriptase polymerase chain reaction. The study did not detect dual infection of Ae. aegypti with dengue and chikungunya virus from the same pool or from individual mosquitoes. Oral receptivity of Ae. aegypti to chikungunya virus was higher than that of dengue virus.
    Matched MeSH terms: Chikungunya virus/genetics; Chikungunya virus/isolation & purification*
  13. Lam SK, Chua KB, Hooi PS, Rahimah MA, Kumari S, Tharmaratnam M, et al.
    PMID: 11944696
    Many countries neighboring Malaysia have reported human infections by chikungunya virus, a mosquito-borne togavirus belonging to the genus Alphavirus. However, although there is serological evidence of its presence in Malaysia, chikungunya virus has not been known to be associated with clinical illness in the country. An outbreak of chikungunya virus occurred in Klang, Malaysia, between December 1998 and February 1999. The majority of the cases were in adults and the clinical presentation was similar to classical chikungunya infections. Malaysia is heavily dependent on migrant workers from countries where chikungunya is endemic. It is speculated that the virus has been re-introduced into the country through the movement of these workers.
    Matched MeSH terms: Chikungunya virus/immunology
  14. Marchette NJ, Rudnick A, Garcia R
    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*
  15. Marchette NJ, Rudnick A, Garcia R, MacVean DW
    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. Chem YK, Zainah S, Berendam SJ, Rogayah TA, Khairul AH, Chua KB
    Med J Malaysia, 2010 Mar;65(1):31-5.
    PMID: 21265245 MyJurnal
    Malaysia experienced the first outbreak of chikungunya (CHIK) in Klang in late 1998 due to CHIK virus of Asian genotype. The CHIK virus of Asian genotype reemerged causing outbreak in Bangan Panchor, Perak in March 2006. CHIK virus of Central/East African genotype was first detected from a patient who returned from India in August 2006. In December 2006, CHIK virus of Central/East African genotype was re-introduced into Malaysia from India and caused an outbreak in Kinta district, Perak but was successfully controlled following an early detection and institution of intensive vector control measures. In late April 2008, CHIK virus of Central/East African genotype was laboratory confirmed as the cause of CHIK outbreak in Johore which spread to other parts of Malaysia by August 2008. Phylogenetic analysis based on the 254-bp fragment of the virus envelope protein gene as the genetic marker showed that three different strains of CHIK virus of Central/East African genotype were introduced into Malaysia on three separate occasions from 2006 to 2008. The strain that was introduced into Johor state was responsible for its subsequent spread to other parts of Malaysia, inclusive of Sarawak.
    Matched MeSH terms: Chikungunya virus/genetics*
  17. Chew LP, Chua HH
    Med J Malaysia, 2009 Sep;64(3):220-2.
    PMID: 20527272
    In 2008, an outbreak of chikungunya infection occurred in Johor. We performed a retrospective review of all laboratory confirmed adult chikungunya cases admitted to Hospital Sultanah Aminah, Johor Bahru from April to August 2008, looking into clinical and laboratory features. A total of 18 laboratory confirmed cases of chikungunya were identified with patients presenting with fever, joint pain, rash and vomiting. Haemorrhagic signs were not seen. Lymphopenia, neutropenia, thrombocytopenia, raised liver enzymes and deranged coagulation profile were the prominent laboratory findings. We hope this study can help guide physician making a diagnosis of chikungunya against other arborviruses infection.
    Matched MeSH terms: Chikungunya virus/isolation & purification*
  18. Noridah O, Paranthaman V, Nayar SK, Masliza M, Ranjit K, Norizah I, et al.
    Med J Malaysia, 2007 Oct;62(4):323-8.
    PMID: 18551938 MyJurnal
    Chikungunya is an acute febrile illness caused by an alphavirus which is transmitted by infective Aedes mosquitoes. Two previous outbreaks of chikungunya in Malaysia were due to chikungunya virus of Asian genotype. The present outbreak involved two adjoining areas in the suburb of Ipoh city within the Kinta district of Perak, a state in the northern part of Peninsular Malaysia. Thirty seven residents in the main outbreak area and two patients in the secondary area were laboratory confirmed to be infected with the virus. The index case was a 44-year Indian man who visited Paramakudi, Tamil Naidu, India on 21st November 2006 and returned home on 30th of November 2006, and subsequently developed high fever and joint pain on the 3rd of December 2006. A number of chikungunya virus isolates were isolated from both patients and Aedes albopictus mosquitoes in the affected areas. Molecular study showed that the chikungunya virus causing the Kinta outbreak was of the Central/East African genotype which occurred for the first time in Malaysia.
    Matched MeSH terms: Chikungunya virus/genetics*; Chikungunya virus/isolation & purification
  19. Nayar SK, Noridah O, Paranthaman V, Ranjit K, Norizah I, Chem YK, et al.
    Med J Malaysia, 2007 Oct;62(4):335-6.
    PMID: 18551940 MyJurnal
    During an outbreak of chikungunya in a dengue hyperendemic area within the Kinta district of Perak, two patients with acute febrile illness were laboratory confirmed to have co-infection of both dengue and chikungunya viruses in their blood. The concomitant presence of two types of viruses transmitted by the same vector in a susceptible population contributed to the resultant event. A good understanding of virus vector ecology in association with population dynamics and wider application of improved laboratory techniques by using different cell-lines suited for optimal replication of each type of virus and the correct utilization of powerful molecular techniques will enhance accurate diagnosis of these infectious diseases.
    Matched MeSH terms: Chikungunya virus*
  20. Soon YY, Junaidi I, Kumarasamy V, Chem YK, Juliana R, Chua KB
    Med J Malaysia, 2007 Aug;62(3):214-7.
    PMID: 18246910 MyJurnal
    Since its isolation in Tanzania in 1953, chikungunya virus has caused periodic outbreaks in both tropical Africa and Asia. In the last decade, the virus has shown not only increased activity but has expanded its geographical locations, thus classical delineation of various genotypes of chikungunya virus to specific geographic locales no longer holds true. Rapid mass movement of people and the constant presence of the right vectors in this region could have contributed to the change in virus ecology. This paper documents the first detection of chikungunya virus of Central/East genotype in Malaysia from a patient who was most likely infected with the virus during her visit to India. Without good Aedes vector measures, only time will tell whether this genotype rather than the existing endemic genotype will subsequently cause the next chikungunya outbreak in Malaysia.
    Matched MeSH terms: Chikungunya virus/genetics*; Chikungunya virus/isolation & purification
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