Displaying publications 1 - 20 of 57 in total

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  1. Replication and innate immune responses of two chikungunya virus genotypes in human monocyte-derived macrophages
    Lau JZH, Chua CL, Chan YF, Nadarajan VS, Lee CLL, Sam IC
    J Gen Virol, 2023 Apr;104(4).
    PMID: 37043371 DOI: 10.1099/jgv.0.001842
    Chikungunya virus (CHIKV) is a re-emerging mosquito-borne virus, which causes epidemics of fever, joint pain and rash. There are three genotypes: West African, East/Central/South/Africa (ECSA) and Asian, with the latter two predominant globally. Genotype-specific differences in clinical presentations, virulence and immunopathology have been described. Macrophages are key cells in immune responses against CHIKV. Circulating blood monocytes enter tissue to differentiate into monocyte-derived macrophages (MDMs) in response to CHIKV infection at key replication sites such as lymphoid organs and joints. This study analyses differences in replication and induced immune mediators following infection of MDMs with Asian and ECSA CHIKV genotypes. Primary human MDMs were derived from residual blood donations. Replication of Asian (MY/06/37348) or ECSA (MY/08/065) genotype strains of CHIKV in MDMs was measured by plaque assay. Nineteen immune mediators were measured in infected cell supernatants using multiplexed immunoassay or ELISA. MY/08/065 showed significantly higher viral replication at 24 h post-infection (h p.i.) but induced significantly lower expression of proinflammatory cytokines (CCL-2, CCL-3, CCL-4, RANTES and CXCL-10) and the anti-inflammatory IL-1Ra compared to MY/06/37348. No differences were seen at later time points up to 72 h p.i. During early infection, MY/08/065 induced lower proinflammatory immune responses in MDMs. In vivo, this may lead to poorer initial control of viral infection, facilitating CHIKV replication and dissemination to other sites such as joints. This may explain the consistent past findings that the ECSA genotype is associated with greater viremia and severity of symptoms than the Asian genotype. Knowledge of CHIKV genotype-specific immunopathogenic mechanisms in human MDMs is important in understanding of clinical epidemiology, biomarkers and therapeutics in areas with co-circulation of different genotypes.
    Matched MeSH terms: Chikungunya Fever*
  2. Lactic acid bacteria waste infusion as a source of attraction and oviposition stimulation of gravid female Aedes albopictus mosquitoes
    Suria MM, Yap PC, Lov VL, AbuBakar S, Lee HY
    Trop Biomed, 2022 Dec 01;39(4):499-503.
    PMID: 36602207 DOI: 10.47665/tb.39.4.004
    Aedes albopictus poses a public health risk in tropical countries and temperate countries in recent decades due to its capability to transmit various human arboviruses including dengue, yellow fever, and chikungunya. Vector control is the key for preventing transmission of these pathogenic viruses. Improving the effectiveness of currently utilized collection methods, such as ovitraps, is important for best species abundance monitoring, assessment of the threat of arbovirus transmission, and optimizing control activities. Therefore, this study aimed to assess the potential use of lactic acid bacteria (LAB) waste as an infusion-baited ovitrap for Aedes collection. The performance of overnight tap water, grass hay infusion and LAB waste infusion were compared for their ability in attracting gravid female Ae. albopictus. In this study, the LAB waste infusion was substantially more alluring to Ae. albopictus mosquitoes than the two controls grass hay infusion and tap water.
    Matched MeSH terms: Chikungunya Fever*
  3. Therapeutics and vaccines against chikungunya virus
    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 Fever/drug therapy; Chikungunya Fever/immunology; Chikungunya Fever/prevention & control*
  4. Fulltext Chikungunya virus-associated death in Malaysia
    Sam IC, Kamarulzaman A, Ong GS, Veriah RS, Ponnampalavanar S, Chan YF, et al.
    Trop Biomed, 2010 Aug;27(2):343-7.
    PMID: 20962735
    Chikungunya virus (CHIKV) is a mosquito-borne alphavirus which causes fever, rash, and arthralgia. In the past, life-threatening complications were very rarely reported. However, during the recent worldwide outbreaks, there have been several reports of unusually severe complications and deaths. Malaysia is experiencing a nationwide outbreak of CHIKV, with over 10 000 patients affected since April 2008. We report the first case of culture-confirmed CHIKV-associated death in Malaysia, in a patient with fever, rash, acute exacerbation of pre-existing heart failure, rhabdomyolysis, and multiple organ failure. CHIKV infections may cause atypical, severe or fatal presentations.
    Matched MeSH terms: Chikungunya Fever
  5. Fulltext Detection of east/central/south African genotype of chikungunya virus in Myanmar, 2010
    Tun MM, Thant KZ, Inoue S, Nabeshima T, Aoki K, Kyaw AK, et al.
    Emerg Infect Dis, 2014 Aug;20(8):1378-81.
    PMID: 25062511 DOI: 10.3201/eid2008.131431
    In 2010, chikungunya virus of the East Central South African genotype was isolated from 4 children in Myanmyar who had dengue-like symptoms. Phylogenetic analysis of the E1 gene revealed that the isolates were closely related to isolates from China, Thailand, and Malaysia that harbor the A226V mutation in this gene.
    Matched MeSH terms: Chikungunya Fever/history; Chikungunya Fever/epidemiology*; Chikungunya Fever/virology*
  6. Fulltext Chikungunya virus in macaques, Malaysia
    Sam IC, Chua CL, Rovie-Ryan JJ, Fu JY, Tong C, Sitam FT, et al.
    Emerg Infect Dis, 2015 Sep;21(9):1683-5.
    PMID: 26291585 DOI: 10.3201/eid2109.150439
    Matched MeSH terms: Chikungunya Fever/epidemiology*; Chikungunya Fever/prevention & control; Chikungunya Fever/transmission
  7. Neurovirulence comparison of chikungunya virus isolates of the Asian and East/Central/South African genotypes from Malaysia
    Wei Chiam C, Fun Chan Y, Chai Ong K, Thong Wong K, Sam IC
    J Gen Virol, 2015 Nov;96(11):3243-3254.
    PMID: 26276497 DOI: 10.1099/jgv.0.000263
    Chikungunya virus (CHIKV), an alphavirus of the family Togaviridae, causes fever, polyarthritis and rash. There are three genotypes: West African, Asian and East/Central/South African (ECSA). The latter two genotypes have caused global outbreaks in recent years. Recent ECSA CHIKV outbreaks have been associated with severe neurological disease, but it is not known if different CHIKV genotypes are associated with different neurovirulence. In this study, the neurovirulence of Asian (MY/06/37348) and ECSA (MY/08/065) strains of CHIKV isolated in Malaysia were compared. Intracerebral inoculation of either virus into suckling mice was followed by virus titration, histopathology and gene expression analysis of the harvested brains. Both strains of CHIKV replicated similarly, yet mice infected with MY/06/37348 showed higher mortality. Histopathology findings showed that both CHIKV strains spread within the brain (where CHIKV antigen was localized to astrocytes and neurons) and beyond to skeletal muscle. In MY/06/37348-infected mice, apoptosis, which is associated with neurovirulence in alphaviruses, was observed earlier in brains. Comparison of gene expression showed that a pro-apoptotic gene (eIF2αK2) was upregulated at higher levels in MY/06/37348-infected mice, while genes involved in anti-apoptosis (BIRC3), antiviral responses and central nervous system protection (including CD40, IL-10RA, MyD88 and PYCARD) were upregulated more highly in MY/08/065-infected mice. In conclusion, the higher mortality observed following MY/06/37348 infection in mice is due not to higher viral replication in the brain, but to differentially expressed genes involved in host immune responses. These findings may help to identify therapeutic strategies and biomarkers for neurological CHIKV infections.
    Matched MeSH terms: Chikungunya Fever/epidemiology; Chikungunya Fever/pathology; Chikungunya Fever/virology*
  8. Kajian ekologi nyamuk aedes di senawang Negeri Sembilan, Malaysia
    Mazrura Sahani, Hidayatulfathi Othman, Nadia Atiqah Mohd Nor, Rozita Hod, Zainudin Mohd Ali, Mohamad Naim Mohmad Rasidi, et al.
    Sains Malaysiana, 2012;41:261-269.
    Kajian ekologi nyamuk merupakan kajian yang penting dalam merangka sesuatu aktiviti kawalan penyakit bawaan nyamuk. Satu kajian ekologi nyamuk Aedes telah dijalankan di Senawang, Negeri Sembilan dari Julai 2009 hingga Febuari 2010. Senawang terletak di pinggir bandaraya Seremban yang merupakan kawasan perindustrian kecil dan sederhana dengan jumlah penduduk yang padat. Kajian ekologi vektor ini bertujuan menentukan komposisi nyamuk secara keseluruhan terutamanya kepadatan populasi Aedes, masa kemuncak gigitan nyamuk, mengenal pasti kehadiran tempat pembiakan nyamuk dan menentukan hubung kait antara nyamuk Aedes dengan faktor persekitarannya seperti suhu, kelembapan relatif, halaju angin dan curahan hujan. Pensampelan nyamuk Aedes menggunakan empat kaedah iaitu perangkap cahaya (CDC), tangkapan nyamuk berumpan kaki (BLC), ovitrap dan kajian Aedes. Terdapat dua spesies nyamuk di lokasi kajian yang didominasi oleh Ae. albopictus (93.29%) dan Ae. aegypti (0.11%). Terdapat dua masa kemuncak gigitan nyamuk Ae. albopictus iaitu awal pagi (0700-0900 pagi) dan lewat petang (jam 1700-1900). Suhu persekitaran, kelembapan relatif dan kelajuan angin didapati mempunyai kaitan dengan gigitan nyamuk Aedes pada perumah (p < 0.05). Taburan hujan didapati tidak mempunyai hubungan dengan kepadatan nyamuk Aedes (r = -0.137, n =6 , p > 0.05). Kepadatan nyamuk Ae. albopictus adalah tinggi di lokasi kajian dengan Indeks Ovitrap 100% bagi kesemua stesen. Kajian Aedes mendapati daripada 30 bekas yang positif larva, 93.33% daripadanya didominasi oleh Ae. albopictus. Kajian ini menunjukkan kepadatan Ae. albopictus adalah tinggi dan berpotensi membawa penyakit demam denggi dan chikungunya di lokasi kajian. Penjagaan persekitaran perlu ditekankan kepada masyarakat setempat untuk mengawal penyebaran penyakit-penyakit tersebut.
    Matched MeSH terms: Chikungunya Fever
  9. Leptospirosis: Molecular trial path and immunopathogenesis correlated with dengue, malaria and mimetic hemorrhagic infections
    Priya SP, Sakinah S, Sharmilah K, Hamat RA, Sekawi Z, Higuchi A, et al.
    Acta Trop, 2017 Dec;176:206-223.
    PMID: 28823908 DOI: 10.1016/j.actatropica.2017.08.007
    Immuno-pathogenesis of leptospirosis can be recounted well by following its trail path from entry to exit, while inducing disastrous damages in various tissues of the host. Dysregulated, inappropriate and excessive immune responses are unanimously blamed in fatal leptospirosis. The inherent abilities of the pathogen and inabilities of the host were debated targeting the severity of the disease. Hemorrhagic manifestation through various mechanisms leading to a fatal end is observed when this disease is unattended. The similar vascular destructions and hemorrhage manifestations are noted in infections with different microbes in endemic areas. The simultaneous infection in a host with more than one pathogen or parasite is referred as the coinfection. Notably, common endemic infections such as leptospirosis, dengue, chikungunya, and malaria, harbor favorable environments to flourish in similar climates, which is aggregated with stagnated water and aggravated with the poor personal and environmental hygiene of the inhabitants. These factors aid the spread of pathogens and parasites to humans and potential vectors, eventually leading to outbreaks of public health relevance. Malaria, dengue and chikungunya need mosquitoes as vectors, in contrast with leptospirosis, which directly invades human, although the environmental bacterial load is maintained through other mammals, such as rodents. The more complicating issue is that infections by different pathogens exhibiting similar symptoms but require different treatment management. The current review explores different pathogens expressing specific surface proteins and their ability to bind with array of host proteins with or without immune response to enter into the host tissues and their ability to evade the host immune responses to invade and their affinity to certain tissues leading to the common squeal of hemorrhage. Furthermore, at the host level, the increased susceptibility and inability of the host to arrest the pathogens' and parasites' spread in different tissues, various cytokines accumulated to eradicate the microorganisms and their cellular interactions, the antibody dependent defense and the susceptibility of individual organs bringing the manifestation of the diseases were explored. Lastly, we provided a discussion on the immune trail path of pathogenesis from entry to exit to narrate the similarities and dissimilarities among various hemorrhagic fevers mentioned above, in order to outline future possibilities of prevention, diagnosis, and treatment of coinfections, with special reference to endemic areas.
    Matched MeSH terms: Chikungunya Fever/immunology; Chikungunya Fever/epidemiology*; Chikungunya Fever/transmission
  10. Fulltext First chikungunya outbreak in Pakistan: a trail of viral attacks
    Mallhi TH, Khan YH, Khan AH, Tanveer N, Qadir MI
    New Microbes New Infect, 2017 Sep;19:13-14.
    PMID: 28663798 DOI: 10.1016/j.nmni.2017.05.008
    Despite explicit warning from the National Institute of Health, Pakistan experienced its first chikungunya outbreak in the metropolis of Karachi. We underscore the attention of health authorities and healthcare professionals towards contributing factors associated with this outbreak and the measures required to combat this viral disease.
    Matched MeSH terms: Chikungunya Fever
  11. Fulltext Assessing the threat of chikungunya virus emergence in Australia
    Viennet E, Knope K, Faddy HM, Williams CR, Harley D
    Commun Dis Intell Q Rep, 2013 Jun;37(2):E136-43.
    PMID: 24168087
    Chikungunya virus (CHIKV) is a major threat to Australia given the distribution of competent vectors, and the large number of travellers returning from endemic regions. We describe current knowledge of CHIKV importations into Australia, and quantify reported viraemic cases, with the aim of facilitating the formulation of public health policy and ensuring maintenance of blood safety.
    Matched MeSH terms: Chikungunya Fever/epidemiology*; Chikungunya Fever/virology
  12. Fulltext The neutralizing role of IgM during early Chikungunya virus infection
    Chua CL, Sam IC, Chiam CW, Chan YF
    PLoS One, 2017;12(2):e0171989.
    PMID: 28182795 DOI: 10.1371/journal.pone.0171989
    The antibody isotype IgM appears earlier than IgG, within days of onset of symptoms, and is important during the early stages of the adaptive immune response. Little is known about the functional role of IgM during infection with chikungunya virus (CHIKV), a recently reemerging arbovirus that has caused large global outbreaks. In this study, we studied antibody responses in 102 serum samples collected during CHIKV outbreaks in Malaysia. We described the neutralizing role of IgM at different times post-infection and examined the independent contributions of IgM and IgG towards the neutralizing capacity of human immune sera during the early phase of infection, including the differences in targets of neutralizing epitopes. Neutralizing IgM starts to appear as early as day 4 of symptoms, and their appearance from day 6 is associated with a reduction in viremia. IgM acts in a complementary manner with the early IgG, but plays the main neutralizing role up to a point between days 4 and 10 which varies between individuals. After this point, total neutralizing capacity is attributable almost entirely to the robust neutralizing IgG response. IgM preferentially binds and targets epitopes on the CHIKV surface E1-E2 glycoproteins, rather than individual E1 or E2. These findings provide insight into the early antibody responses to CHIKV, and have implications for design of diagnostic serological assays.
    Matched MeSH terms: Chikungunya Fever/blood; Chikungunya Fever/immunology*
  13. A summary of the imported cases of Chikungunya fever in Japan from 2006 to June 2016
    Nakayama E, Tajima S, Kotaki A, Shibasaki KI, Itokawa K, Kato K, et al.
    J Travel Med, 2018 01 01;25(1).
    PMID: 29394382 DOI: 10.1093/jtm/tax072
    Background: Due to the huge 2-way human traffic between Japan and Chikungunya (CHIK) fever-endemic regions, 89 imported cases of CHIK fever were confirmed in Japan from January 2006 to June 2016. Fifty-four of 89 cases were confirmed virologically and serologically at the National Institute of Infectious Diseases, Japan and we present the demographic profiles of the patients and the phylogenetic features of 14 CHIK virus (CHIKV) isolates.

    Methods: Patients were diagnosed with CHIK fever by a combination of virus isolation, viral RNA amplification, IgM antibody-, IgG antibody-, and/or neutralizing antibody detection. The whole-genome sequences of the CHIKV isolates were determined by next-generation sequencing.

    Results: Prior to 2014, the source countries of the imported CHIK fever cases were limited to South and Southeast Asian countries. After 2014, when outbreaks occurred in the Pacific and Caribbean Islands and Latin American countries, there was an increase in the number of imported cases from these regions. A phylogenetic analysis of 14 isolates revealed that four isolates recovered from three patients who returned from Sri Lanka, Malaysia and Angola, belonged to the East/Central/South African genotype, while 10 isolates from 10 patients who returned from Indonesia, the Philippines, Tonga, the Commonwealth of Dominica, Colombia and Cuba, belonged to the Asian genotype.

    Conclusion: Through the phylogenetic analysis of the isolates, we could predict the situations of the CHIK fever epidemics in Indonesia, Angola and Cuba. Although Japan has not yet experienced an autochthonous outbreak of CHIK fever, the possibility of the future introduction of CHIKV through an imported case and subsequent local transmission should be considered, especially during the mosquito-active season. The monitoring and reporting of imported cases will be useful to understand the situation of the global epidemic, to increase awareness of and facilitate the diagnosis of CHIK fever, and to identify a future CHIK fever outbreak in Japan.

    Matched MeSH terms: Chikungunya Fever/epidemiology*; Chikungunya Fever/transmission
  14. Evaluation of neutralizing antibodies produced by papaya mosaic virus nanoparticles fused to the E2EP3 peptide epitope of Chikungunya envelope
    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 Fever/immunology; Chikungunya Fever/prevention & control
  15. Molecular Epidemiology of Chikungunya Virus by Sequencing
    Thayan R, Yusof MA, Saat Z, Sekaran SD, Wang SM
    Methods Mol Biol, 2016;1426:11-9.
    PMID: 27233257 DOI: 10.1007/978-1-4939-3618-2_2
    Molecular surveillance of Chikungunya virus (CHIKV) is important as it provides data on the circulating CHIKV genotypes in endemic countries and enabling activation of measures to be taken in the event of a pending outbreak. Molecular surveillance is carried out by first detecting CHIKV in susceptible humans or among field-caught mosquitoes. This is followed by sequencing a selected region of the virus which will provide evidence on the source of the virus and possible association of the virus to increased cases of Chikungunya infections.
    Matched MeSH terms: Chikungunya Fever/diagnosis*; Chikungunya Fever/epidemiology*
  16. Fulltext Independent Emergence of the Cosmopolitan Asian Chikungunya Virus, Philippines 2012
    Tan KK, Sy AK, Tandoc AO, Khoo JJ, Sulaiman S, Chang LY, et al.
    Sci Rep, 2015 Jul 23;5:12279.
    PMID: 26201250 DOI: 10.1038/srep12279
    Outbreaks involving the Asian genotype Chikungunya virus (CHIKV) caused over one million infections in the Americas recently. The outbreak was preceded by a major nationwide outbreak in the Philippines. We examined the phylogenetic and phylogeographic relationships of representative CHIKV isolates obtained from the 2012 Philippines outbreak with other CHIKV isolates collected globally. Asian CHIKV isolated from the Philippines, China, Micronesia and Caribbean regions were found closely related, herein denoted as Cosmopolitan Asian CHIKV (CACV). Three adaptive amino acid substitutions in nsP3 (D483N), E1 (P397L) and E3 (Q19R) were identified among CACV. Acquisition of the nsP3-483N mutation in Compostela Valley followed by E1-397L/E3-19R in Laguna preceded the nationwide spread in the Philippines. The China isolates possessed two of the amino acid substitutions, nsP3-D483N and E1-P397L whereas the Micronesian and Caribbean CHIKV inherited all the three amino acid substitutions. The unique amino acid substitutions observed among the isolates suggest multiple independent virus dissemination events. The possible biological importance of the specific genetic signatures associated with the rapid global of the virus is not known and warrant future in-depth study and epidemiological follow-up. Molecular evidence, however, supports the Philippines outbreak as the possible origin of the CACV.
    Matched MeSH terms: Chikungunya Fever/epidemiology*; Chikungunya Fever/virology*
  17. Updates on chikungunya epidemiology, clinical disease, and diagnostics
    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 Fever/diagnosis; Chikungunya Fever/epidemiology*
  18. Fulltext Current concerns and perspectives on Zika virus co-infection with arboviruses and HIV
    Rothan HA, Bidokhti MRM, Byrareddy SN
    J Autoimmun, 2018 05;89:11-20.
    PMID: 29352633 DOI: 10.1016/j.jaut.2018.01.002
    Dissemination of vector-borne viruses, such as Zika virus (ZIKV), in tropical and sub-tropical regions has a complicated impact on the immunopathogenesis of other endemic viruses such as dengue virus (DENV), chikungunya virus (CHIKV) and human immunodeficiency virus (HIV). The consequences of the possible co-infections with these viruses have specifically shown significant impact on the treatment and vaccination strategies. ZIKV is a mosquito-borne flavivirus from African and Asian lineages that causes neurological complications in infected humans. Many of DENV and CHIKV endemic regions have been experiencing outbreaks of ZIKV infection. Intriguingly, the mosquitoes, Aedes Aegypti and Aedes Albopictus, can simultaneously transmit all the combinations of ZIKV, DENV, and CHIKV to the humans. The co-circulation of these viruses leads to a complicated immune response due to the pre-existence or co-existence of ZIKV infection with DENV and CHIKV infections. The non-vector transmission of ZIKV, especially, via sexual intercourse and placenta represents an additional burden that may hander the treatment strategies of other sexually transmitted diseases such as HIV. Collectively, ZIKV co-circulation and co-infection with other viruses have inevitable impact on the host immune response, diagnosis techniques, and vaccine development strategies for the control of these co-infections.
    Matched MeSH terms: Chikungunya Fever/immunology; Chikungunya Fever/epidemiology*
  19. 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 Fever/diagnosis*; Chikungunya Fever/epidemiology
  20. Fulltext A respite from chikungunya for now
    Lim KG
    Med J Malaysia, 2010 Dec;65(4):255.
    PMID: 21901939
    In the last four years, Malaysia has had three outbreaks of chikungunya virus infection. The first two occurred in Perak in 2006.The third began in Johor in early 2008. The genome of the viruses suggests that on each occasion a different virus was introduced into the population. The first outbreak in Bagan Panchor was due to an Asian genotype virus. The second in the Kinta district of Perak in late 2006 was due to a Central/East African genotype virus. Contact tracing was even able to discover the patient who was the source of the virus from the Indian subcontinent. The third outbreak in Johor was also of a Central/East African strain of virus, but introduced independently. The epidemiology of that outbreak is described in this issue of the MJM.
    Matched MeSH terms: Chikungunya Fever
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