Displaying publications 181 - 200 of 864 in total

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  1. Tajima S, Nakayama E, Kotaki A, Moi ML, Ikeda M, Yagasaki K, et al.
    Jpn J Infect Dis, 2017 Jan 24;70(1):45-49.
    PMID: 27169954 DOI: 10.7883/yoken.JJID.2016.086
    Cases of autochthonous infections of dengue virus type 1 (DENV-1) were detected in Japan after a 70-year period devoid of dengue outbreaks. We previously showed that E gene sequences are identical in 11 of the 12 DENV-1 strains autochthonous to Japan. However, the E sequence represents only 14% of the DENV-1 genome. In the present study, we have sequenced the entire genome of 6 autochthonous DENV-1 strains that were isolated from patients during the 2014 outbreak. Sequencing of 5 Yoyogi group strains with identical E sequences and 1 Shizuoka strain with a different E sequence revealed that the first Yoyogi group strain differed from the Shizuoka strain by 18 amino acid residues. Furthermore, 2 Yoyogi group strains had different genomic sequences while the other 3 had identical genomes. Phylogenetic analyses indicated that the Hyogo strain, a Yoyogi group strain, was the first to diverge from the other 4 Yoyogi group strains. The E gene sequence of the Yoyogi group strains exhibits the highest homology to those of the strains isolated in Malaysia and Singapore between 2013 and 2014. The patient infected with the Hyogo strain visited Malaysia before the onset of dengue fever, suggesting that this was a case of dengue infection imported from Malaysia.
    Matched MeSH terms: Dengue/epidemiology*; Dengue/virology*; Dengue Virus/classification*; Dengue Virus/genetics*; Dengue Virus/isolation & purification
  2. Ooi CP, Rohani A, Zamree I, Lee HL
    Trop Biomed, 2005 Jun;22(1):73-6.
    PMID: 16880757
    The rapid detection of dengue infection in mosquito vectors is important for early warning to forestall an outbreak. Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) provides a rapid method for dengue detection in man and mosquitoes. An RT-PCR kit developed by the Medical Entomology Unit, Institute for Medical Research to detect dengue infection in mosquitoes, was tested for its shelf life at 3 storage temperatures: room temperature, refrigerator and freezer. Test kits were tested once every 3 days for kits stored at room temperature, and once every week for those stored at refrigerator and freezer temperatures. The results showed that the test kit could only be stored above its recommended storage temperature of -20 degrees C for not more than 3 days. DNA 100 bp markers in the kits appeared to be stable at the tested temperatures and were usable up to the 20th day when stored at 2 degrees C and below.
    Matched MeSH terms: Dengue/diagnosis*; Dengue/prevention & control; Dengue/virology; Dengue Virus/genetics; Dengue Virus/isolation & purification*
  3. Li G, Pan P, He Q, Kong X, Wu K, Zhang W, et al.
    Virol Sin, 2017 Feb;32(1):63-72.
    PMID: 28120220 DOI: 10.1007/s12250-016-3872-8
    The dengue virus (DENV) is a vital global public health issue. The 2014 dengue epidemic in Guangzhou, China, caused approximately 40,000 cases of infection and five deaths. We carried out a comprehensive investigation aimed at identifying the transmission sources in this dengue epidemic. To analyze the phylogenetics of the 2014 dengue strains, the envelope (E) gene sequences from 17 viral strains isolated from 168 dengue patient serum samples were sequenced and a phylogenetic tree was reconstructed. All 17 strains were serotype I strains, including 8 genotype I and 9 genotype V strains. Additionally, 6 genotype I strains that were probably introduced to China from Thailand before 2009 were widely transmitted in the 2013 and 2014 epidemics, and they continued to circulate until 2015, with one affinis strain being found in Singapore. The other 2 genotype I strains were introduced from the Malaya Peninsula in 2014. The transmission source of the 9 genotype V strains was from Malaysia in 2014. DENVs of different serotypes and genotypes co-circulated in the 2014 dengue outbreak in Guangzhou. Moreover, not only had DENV been imported to Guangzhou, but it had also been gradually exported, as the viruses exhibited an enzootic transmission cycle in Guangzhou.
    Matched MeSH terms: Dengue/epidemiology*; Dengue/virology*; Dengue Virus/classification*; Dengue Virus/genetics*; Dengue Virus/isolation & purification
  4. Lin F, Yang H, Zhang L, Fang SH, Zhan XF, Yang LY
    Arch Virol, 2019 Aug;164(8):2131-2135.
    PMID: 31102050 DOI: 10.1007/s00705-019-04266-1
    A large-scale dengue fever (DF) outbreak occurred in Chaozhou, Guangdong province, China 2015. In our study, 528 dengue-positive patient samples were collected for clinical and laboratory data analysis. 491 cases (93.0%) were primary dengue fever (PDF), 22 cases (4.2%) were dengue hemorrhagic fever (DHF) and 15 cases (2.8%) were diagnosed with severe dengue fever (SDF). All cases were infected by dengue virus serotype 2 (DENV-2), and the isolated strains belonged to cosmopolitan genotype, which were grouped closely with Malaysia strains from 2010 to 2014. Moreover, the study showed that laboratory indices have significantly difference in PDF, DHF and SDF patients. A comprehensive analysis of these data could assist and guide the clinical diagnosis for DF, which has an important significance for the control of dengue virus infection.
    Matched MeSH terms: Dengue/epidemiology*; Dengue/virology; Dengue Virus/genetics; Severe Dengue/epidemiology
  5. Wong RR, Abd-Aziz N, Affendi S, Poh CL
    J Biomed Sci, 2020 Jan 03;27(1):4.
    PMID: 31898495 DOI: 10.1186/s12929-019-0614-x
    Dengue virus (DENV) is the etiological agent of dengue fever. Severe dengue could be fatal and there is currently no effective antiviral agent or vaccine. The only licensed vaccine, Dengvaxia, has low efficacy against serotypes 1 and 2. Cellular miRNAs are post-transcriptional regulators that could play a role in direct regulation of viral genes. Host miRNA expressions could either promote or repress viral replications. Induction of some cellular miRNAs could help the virus to evade the host immune response by suppressing the IFN-α/β signaling pathway while others could upregulate IFN-α/β production and inhibit the viral infection. Understanding miRNA expressions and functions during dengue infections would provide insights into the development of miRNA-based therapeutics which could be strategized to act either as miRNA antagonists or miRNA mimics. The known mechanisms of how miRNAs impact DENV replication are diverse. They could suppress DENV multiplication by directly binding to the viral genome, resulting in translational repression. Other miRNA actions include modulation of host factors. In addition, miRNAs that could modulate immunopathogenesis are discussed. Major hurdles lie in the development of chemical modifications and delivery systems for in vivo delivery. Nevertheless, advancement in miRNA formulations and delivery systems hold great promise for the therapeutic potential of miRNA-based therapy, as supported by Miravirsen for treatment of Hepatitis C infection which has successfully completed phase II clinical trial.
    Matched MeSH terms: Dengue/drug therapy*; Dengue/genetics; Dengue/virology; Dengue Virus/genetics; Dengue Virus/pathogenicity
  6. Murphy A, Rajahram GS, Jilip J, Maluda M, William T, Hu W, et al.
    PLoS Negl Trop Dis, 2020 05;14(5):e0007504.
    PMID: 32392222 DOI: 10.1371/journal.pntd.0007504
    In South East Asia, dengue epidemics have increased in size and geographical distribution in recent years. We examined the spatiotemporal distribution and epidemiological characteristics of reported dengue cases in the predominantly rural state of Sabah, in Malaysian Borneo-an area where sylvatic and urban circulation of pathogens are known to intersect. Using a public health data set of routinely notified dengue cases in Sabah between 2010 and 2016, we described demographic and entomological risk factors, both before and after a 2014 change in the clinical case definition for the disease. Annual dengue incidence rates were spatially variable over the 7-year study period from 2010-2016 (state-wide mean annual incidence of 21 cases/100,000 people; range 5-42/100,000), but were highest in rural localities in the western districts of the state (Kuala Penyu, Nabawan, Tenom and Kota Marudu). Eastern districts exhibited lower overall dengue rates, although a high proportion of severe (haemorrhagic) dengue cases (44%) were focused in Sandakan and Tawau. Dengue incidence was highest for those aged between 10 and 29 years (24/100,000), and was slightly higher for males compared to females. Available vector surveillance data indicated that during large outbreaks in 2015 and 2016 the mosquito Aedes albopictus was more prevalent in both urban and rural households (House Index of 64%) than Ae. aegypti (15%). Demographic patterns remained unchanged both before and after the dengue case definition was changed; however, in the years following the change, reported case numbers increased substantially. Overall, these findings suggest that dengue outbreaks in Sabah are increasing in both urban and rural settings. Future studies to better understand the drivers of risk in specific age groups, genders and geographic locations, and to test the potential role of Ae. albopictus in transmission, may help target dengue prevention and control efforts.
    Matched MeSH terms: Dengue/mortality; Dengue/epidemiology*; Dengue/transmission; Dengue/virology; Dengue Virus/physiology
  7. Guad RM, Carandang RR, Solidum JN, W Taylor-Robinson A, Wu YS, Aung YN, et al.
    PLoS One, 2021;16(12):e0261412.
    PMID: 34929011 DOI: 10.1371/journal.pone.0261412
    BACKGROUND: Dengue is the most rapidly spreading mosquito-borne viral disease of humans worldwide, including southeast Asia region. This review provides a comprehensive overview of questionnaire-related dengue studies conducted in the Philippines and evaluates their reliability and validity in these surveys.

    METHODS: A review protocol constructed by a panel of experienced academic reviewers was used to formulate the methodology, research design, search strategy and selection criteria. An extensive literature search was conducted between March-June 2020 in various major electronic biomedical databases including PubMed, EMBASE, MEDLINE and ScienceDirect. A systematic review and meta-analysis (PRISMA) were selected as the preferred item reporting method.

    RESULTS: Out of a total of 34 peer-reviewed dengue-related KAP studies that were identified, 15 published from 2000 to April 2020 met the inclusion criteria. Based on the meta-analysis, a poor mean score was obtained for each of knowledge (68.89), attitude (49.86) and preventive practice (64.69). Most respondents were equipped with a good knowledge of the major clinical signs of dengue. Worryingly, 95% of respondents showed several negative attitudes towards dengue prevention, claiming that this was not possible and that enacting preventive practices was not their responsibility. Interestingly, television or radio was claimed as the main source of gaining dengue information (range 50-95%). Lastly, only five articles (33.3%) piloted or pretested their questionnaire before surveying, of which three reported Cronbach's alpha coefficient (range 0.70 to 0.90).

    CONCLUSION: This review indicates that to combat the growing public health threat of dengue to the Philippines, we need the active participation of resident communities, full engagement of healthcare personnel, promotion of awareness campaigns, and access to safe complementary and alternative medicines. Importantly, the psychometric properties of each questionnaire should be assessed rigorously.

    Matched MeSH terms: Dengue/etiology; Dengue/prevention & control*; Dengue/psychology; Dengue/virology; Dengue Virus/isolation & purification*
  8. Wallace HG, Lim TW, Rudnick A, Knudsen AB, Cheong WH, Chew V
    PMID: 6105712
    The first major Malaysian epidemic of dengue hemorrhagic fever with severe manifestations occurred in 1973, with 969 reported cases and 54 deaths. In a detailed study of 138 clinically diagnosed and laboratory confirmed cases at the General Hospital in Kuala Lumpur, hemorrhagic manifestations were observed in 68.7% and shock in 18.1% of the patients. The cases occurred mainly from May to September, largely in urban and suburban areas of the majority of the states in the country. A main focus of infection was Jinjang, a heavily populated outlying district of Kuala Lumpur, where unusually high incidences of morbidity, severe disease and mortality were seen. Severe disease was seen mostly in children under the age of 15 years, although a significant number of adults suffered milder illnesses. The Chinese population was chiefly affected, due to their living in crowded, low-income housing where the vector, Aedes aegypti, occurred in the greatest numbers. All four dengue types were recovered during the epidemic period, although dengue 3 (DEN-3) was incriminated as the major epidemic type. Entomological data revealed high indices of A. aegypti throughout the country and left little doubt that this epidemic was aegypti transmitted. Spraying and fogging operations were carried out in attempts to control vector populations.
    Matched MeSH terms: Dengue/classification; Dengue/immunology; Dengue/epidemiology*; Dengue Virus/immunology; Dengue Virus/isolation & purification
  9. L'Azou M, Moureau A, Sarti E, Nealon J, Zambrano B, Wartel TA, et al.
    N Engl J Med, 2016 Mar 24;374(12):1155-66.
    PMID: 27007959 DOI: 10.1056/NEJMoa1503877
    BACKGROUND: The control groups in two phase 3 trials of dengue vaccine efficacy included two large regional cohorts that were followed up for dengue infection. These cohorts provided a sample for epidemiologic analyses of symptomatic dengue in children across 10 countries in Southeast Asia and Latin America in which dengue is endemic.
    METHODS: We monitored acute febrile illness and virologically confirmed dengue (VCD) in 3424 healthy children, 2 to 16 years of age, in Asia (Indonesia, Malaysia, the Philippines, Thailand, and Vietnam) from June 2011 through December 2013 and in 6939 children, 9 to 18 years of age, in Latin America (Brazil, Colombia, Honduras, Mexico, and Puerto Rico) from June 2011 through April 2014. Acute febrile episodes were determined to be VCD by means of a nonstructural protein 1 antigen immunoassay and reverse-transcriptase-polymerase-chain-reaction assays. Dengue hemorrhagic fever was defined according to 1997 World Health Organization criteria.
    RESULTS: Approximately 10% of the febrile episodes in each cohort were confirmed to be VCD, with 319 VCD episodes (4.6 episodes per 100 person-years) occurring in the Asian cohort and 389 VCD episodes (2.9 episodes per 100 person-years) occurring in the Latin American cohort; no trend according to age group was observed. The incidence of dengue hemorrhagic fever was less than 0.3 episodes per 100 person-years in each cohort. The percentage of VCD episodes requiring hospitalization was 19.1% in the Asian cohort and 11.1% in the Latin American cohort. In comparable age groups (9 to 12 years and 13 to 16 years), the burden of dengue was higher in Asia than in Latin America.
    CONCLUSIONS: The burdens of dengue were substantial in the two regions and in all age groups. Burdens varied widely according to country, but the rates were generally higher and the disease more frequently severe in Asian countries than in Latin American countries. (Funded by Sanofi Pasteur; CYD14 and CYD15 ClinicalTrials.gov numbers, NCT01373281 and NCT01374516.).
    Note: Malaysia is a study site (CYD14 Primary Study Group authors: HIHJMI, Pediatric Institute, Kuala Lumpur Hospital, Kuala Lumpur; RN, Department of Paediatrics, Hospital Pulau Pinang, Pulau Pinang, Malaysia)
    Matched MeSH terms: Dengue/diagnosis; Dengue/epidemiology*; Dengue Virus/genetics; Dengue Virus/immunology; Dengue Virus/isolation & purification*; Dengue Vaccines*
  10. Yong YK, Tan HY, Jen SH, Shankar EM, Natkunam SK, Sathar J, et al.
    J Transl Med, 2017 05 31;15(1):121.
    PMID: 28569153 DOI: 10.1186/s12967-017-1226-4
    BACKGROUND: Currently, several assays can diagnose acute dengue infection. However, none of these assays can predict the severity of the disease. Biomarkers that predicts the likelihood that a dengue patient will develop a severe form of the disease could permit more efficient patient triage and allows better supportive care for the individual in need, especially during dengue outbreaks.

    METHODS: We measured 20 plasma markers i.e. IFN-γ, IL-10, granzyme-B, CX3CL1, IP-10, RANTES, CXCL8, CXCL6, VCAM, ICAM, VEGF, HGF, sCD25, IL-18, LBP, sCD14, sCD163, MIF, MCP-1 and MIP-1β in 141 dengue patients in over 230 specimens and correlate the levels of these plasma markers with the development of dengue without warning signs (DWS-), dengue with warning signs (DWS+) and severe dengue (SD).

    RESULTS: Our results show that the elevation of plasma levels of IL-18 at both febrile and defervescence phase was significantly associated with DWS+ and SD; whilst increase of sCD14 and LBP at febrile phase were associated with severity of dengue disease. By using receiver operating characteristic (ROC) analysis, the IL-18, LBP and sCD14 were significantly predicted the development of more severe form of dengue disease (DWS+/SD) (AUC = 0.768, P 

    Matched MeSH terms: Dengue/blood*; Dengue/diagnosis; Dengue/immunology*; Dengue Virus; Severe Dengue/blood*; Severe Dengue/diagnosis; Severe Dengue/immunology*
  11. Chen RE, Smith BK, Errico JM, Gordon DN, Winkler ES, VanBlargan LA, et al.
    Cell Host Microbe, 2021 Nov 10;29(11):1634-1648.e5.
    PMID: 34610295 DOI: 10.1016/j.chom.2021.09.006
    Although divergent dengue viruses (DENVs) have been isolated in insects, nonhuman primates, and humans, their relationships to the four canonical serotypes (DENV 1-4) are poorly understood. One virus isolated from a dengue patient, DKE-121, falls between genotype and serotype levels of sequence divergence to DENV-4. To examine its antigenic relationship to DENV-4, we assessed serum neutralizing and protective activity. Whereas DENV-4-immune mouse sera neutralize DKE-121 infection, DKE-121-immune sera inhibit DENV-4 less efficiently. Passive transfer of DENV-4 or DKE-121-immune sera protects mice against homologous, but not heterologous, DENV-4 or DKE-121 challenge. Antigenic cartography suggests that DENV-4 and DKE-121 are related but antigenically distinct. However, DENV-4 vaccination confers protection against DKE-121 in nonhuman primates, and serum from humans immunized with a tetravalent vaccine neutralize DENV-4 and DKE-121 infection equivalently. As divergent DENV strains, such as DKE-121, may meet criteria for serotype distinction, monitoring their capacity to impact dengue disease and vaccine efficacy appears warranted.
    Matched MeSH terms: Dengue/immunology*; Dengue/prevention & control; Dengue/virology; Dengue Virus/genetics*; Dengue Virus/immunology*; Dengue Vaccines/immunology*
  12. Thayan R, Huat TL, See LL, Khairullah NS, Yusof R, Devi S
    PMID: 19323035
    We determined the differential expression levels of proteins in peripheral blood mononuclear cells of patients with dengue fever (DF) and dengue hemorrhagic fever (DHF). Proteins were subjected to two-dimensional electrophoresis, mass spectrometry and Western blot analysis. We identified 8 proteins that were 2-fold or more up-regulated in patients compared to healthy control, three of which, aldolase, thioredoxin peroxidase and alpha tubulin, were related to dengue infection. Both thioredoxin peroxidase and alpha tubulin were over-expressed 4.9 and 3.3 times respectively in DHF compared to DF patients while aldolase was up-regulated 2.2 times in DF compared to DHF patients. Alpha tubulin and thioredoxin peroxidase have the potential to be utilized as biomarkers for DHF.
    Matched MeSH terms: Dengue/blood; Dengue/enzymology*; Dengue Virus/enzymology*; Severe Dengue/blood; Severe Dengue/diagnosis; Severe Dengue/enzymology*
  13. Mohd-Zaki AH, Brett J, Ismail E, L'Azou M
    PLoS Negl Trop Dis, 2014;8(11):e3159.
    PMID: 25375211 DOI: 10.1371/journal.pntd.0003159
    A literature survey and analysis was conducted to describe the epidemiology of dengue disease in Malaysia between 2000 and 2012. Published literature was searched for epidemiological studies of dengue disease, using specific search strategies for each electronic database; 237 relevant data sources were identified, 28 of which fulfilled the inclusion criteria. The epidemiology of dengue disease in Malaysia was characterized by a non-linear increase in the number of reported cases from 7,103 in 2000 to 46,171 in 2010, and a shift in the age range predominance from children toward adults. The overall increase in dengue disease was accompanied by a rise in the number, but not the proportion, of severe cases. The dominant circulating dengue virus serotypes changed continually over the decade and differed between states. Several gaps in epidemiological knowledge were identified; in particular, studies of regional differences, age-stratified seroprevalence, and hospital admissions.

    PROTOCOL REGISTRATION: PROSPERO #CRD42012002293.

    Matched MeSH terms: Dengue/epidemiology*; Dengue Virus/classification*; Dengue Virus/immunology
  14. Capeding MR, Tran NH, Hadinegoro SR, Ismail HI, Chotpitayasunondh T, Chua MN, et al.
    Lancet, 2014 Oct 11;384(9951):1358-65.
    PMID: 25018116 DOI: 10.1016/S0140-6736(14)61060-6
    An estimated 100 million people have symptomatic dengue infection every year. This is the first report of a phase 3 vaccine efficacy trial of a candidate dengue vaccine. We aimed to assess the efficacy of the CYD dengue vaccine against symptomatic, virologically confirmed dengue in children.
    Matched MeSH terms: Dengue/prevention & control*; Dengue Vaccines/administration & dosage*; Dengue Vaccines/adverse effects
  15. Matlani M, Chakravarti A, Rawal A, Kashyap B, Gurtoo A
    Trop Doct, 2009 Apr;39(2):115-6.
    PMID: 19299303 DOI: 10.1258/td.2008.080257
    As well as dengue fever (DF) and dengue haemorrhagic fever-dengue shock syndrome (DHF/DSS), other atypical manifestations of dengue virus infection have also been reported. The frequency of CNS involvement in dengue remains unknown, although isolated cases with neurological manifestations have been reported in Southeast Asia, Malaysia, Burma, Puerto Rico and India. We present two cases of encephalitis associated with DF and DHF from New Delhi, India.
    Matched MeSH terms: Dengue/complications; Dengue/diagnosis*; Dengue Virus/isolation & purification*
  16. Thiha A, Ibrahim F
    Sensors (Basel), 2015;15(5):11431-41.
    PMID: 25993517 DOI: 10.3390/s150511431
    The enzyme-linked Immunosorbent Assay (ELISA) is the gold standard clinical diagnostic tool for the detection and quantification of protein biomarkers. However, conventional ELISA tests have drawbacks in their requirement of time, expensive equipment and expertise for operation. Hence, for the purpose of rapid, high throughput screening and point-of-care diagnosis, researchers are miniaturizing sandwich ELISA procedures on Lab-on-a-Chip and Lab-on-Compact Disc (LOCD) platforms. This paper presents a novel integrated device to detect and interpret the ELISA test results on a LOCD platform. The system applies absorption spectrophotometry to measure the absorbance (optical density) of the sample using a monochromatic light source and optical sensor. The device performs automated analysis of the results and presents absorbance values and diagnostic test results via a graphical display or via Bluetooth to a smartphone platform which also acts as controller of the device. The efficacy of the device was evaluated by performing dengue antibody IgG ELISA on 64 hospitalized patients suspected of dengue. The results demonstrate high accuracy of the device, with 95% sensitivity and 100% specificity in detection when compared with gold standard commercial ELISA microplate readers. This sensor platform represents a significant step towards establishing ELISA as a rapid, inexpensive and automatic testing method for the purpose of point-of-care-testing (POCT) in resource-limited settings.
    Matched MeSH terms: Dengue/diagnosis*; Dengue/immunology; Dengue Virus/immunology
  17. Fong MY, Koh CL, Samuel S, Pang T, Lam SK
    Nucleic Acids Res, 1990 Mar 25;18(6):1642.
    PMID: 2139210
    Matched MeSH terms: Dengue/microbiology; Dengue Virus/genetics*; Dengue Virus/isolation & purification
  18. Samuel S, Koh CL, Pang T, Lam SK
    Nucleic Acids Res, 1990 Apr 11;18(7):1904.
    PMID: 2336373
    Matched MeSH terms: Dengue/microbiology; Dengue Virus/genetics*; Dengue Virus/isolation & purification
  19. Fong MY, Yusup R, Yusof R, Lam SK
    Trans R Soc Trop Med Hyg, 2004 Jun;98(6):379-81.
    PMID: 15099995
    The amino acid sequences of the envelope (E) protein of four encephalitogenic and five non-encephalitogenic dengue 3 virus strains isolated in Malaysia were determined and compared. Multiple sequence alignment revealed a high degree of similarity in the E protein of the strains suggesting that neurovirulence of these four encephalitogenic strains is not attributed to this protein.
    Matched MeSH terms: Dengue/virology*; Dengue Virus/classification; Dengue Virus/pathogenicity*
  20. Sam IC, Montoya M, Chua CL, Chan YF, Pastor A, Harris E
    Trans R Soc Trop Med Hyg, 2019 11 01;113(11):678-684.
    PMID: 31294807 DOI: 10.1093/trstmh/trz056
    BACKGROUND: Zika virus (ZIKV) is believed to be endemic in Southeast Asia. However, there have been few Zika cases reported to date in Malaysia, which could be due to high pre-existing levels of population immunity.

    METHODS: To determine Zika virus (ZIKV) seroprevalence in Kuala Lumpur, Malaysia, 1085 serum samples from 2012, 2014-2015 and 2017 were screened for anti-ZIKV antibodies using a ZIKV NS1 blockade-of-binding assay. Reactive samples were confirmed using neutralization assays against ZIKV and the four dengue virus (DENV) serotypes. A sample was possible ZIKV seropositive with a ZIKV 50% neutralization (NT50) titre ≥20. A sample was probable ZIKV seropositive if, in addition, all DENV NT50 titres were <20 or the ZIKV NT50 titre was >4-fold greater than the highest DENV NT50 titre.

    RESULTS: We found low rates of possible ZIKV seropositivity (3.3% [95% confidence interval {CI} 2.4 to 4.6]) and probable ZIKV seropositivity (0.6% [95% CI 0.3 to 1.4]). Possible ZIKV seropositivity was independently associated with increasing age (odds ratio [OR] 1.04 [95% CI 1.02 to 1.06], p<0.0001) and male gender (OR 3.5 [95% CI 1.5 to 8.6], p=0.005).

    CONCLUSIONS: The low ZIKV seroprevalence rate, a proxy for population immunity, does not explain the low incidence of Zika in dengue-hyperendemic Kuala Lumpur. Other factors, such as the possible protective effects of pre-existing flavivirus antibodies or reduced transmission by local mosquito vectors, should be explored. Kuala Lumpur is at high risk of a large-scale Zika epidemic.

    Matched MeSH terms: Dengue/immunology*; Dengue/epidemiology*; Dengue Virus/immunology*
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