MyMedR

Displaying publications 1 - 20 of 33 in total

Abstract:

Sort:

Vector competence of Malaysian Aedes aegypti to Zika virus and impact of sequential arbovirus infections

Ong NH, Chua CL, Liew JWK, Wan Sulaiman WY, Chan YF, Sam IC, et al.

Acta Trop, 2020 Aug;208:105472.
PMID: 32389451 DOI: 10.1016/j.actatropica.2020.105472

Zika virus (ZIKV) is a mosquito-borne flavivirus with global impact since 2015. Although ZIKV was first isolated from Aedes aegypti in Malaysia in 1965, not much is known about the competency of Malaysian Ae. aegypti to ZIKV. To date only 9 cases of ZIKV have been reported in Malaysia despite the abundance of mosquito vectors. This study aimed to determine the susceptibility of Ae. aegypti to ZIKV, and the impact of sequential infections in Ae. aegypti mosquitoes with DENV serotype 2 (DENV-2) followed by ZIKV. Field-caught urban Ae. aegypti were orally challenged with a Martinique strain of ZIKV, and midgut, head/thorax and saliva were collected at 3, 7 and 14 days post-infection (dpi). At 14 dpi, ZIKV-exposed mosquitoes had infection and dissemination rates of 59% (n=10/17) and 90% (n=9/10), respectively. Average titres of 3.9 and 4.4 log pfu infectious ZIKV were recovered in midgut and head/thorax, respectively. In sequential infection, prior exposure of Ae. aegypti to DENV did not affect the subsequent ZIKV infection in head/thorax albeit with a low sample size. In conclusion, Malaysian urban Ae. aegypti is susceptible to the contemporary Asian lineage of ZIKV. The established and continuous DENV circulation in Ae. aegypti did not suppress ZIKV emergence in Malaysia. Other factors contributing to low level of ZIKV circulation in Malaysia remain to be explored.

Matched MeSH terms: Flavivirus
Polysulfonate suramin inhibits Zika virus infection

Tan CW, Sam IC, Chong WL, Lee VS, Chan YF

Antiviral Res, 2017 07;143:186-194.
PMID: 28457855 DOI: 10.1016/j.antiviral.2017.04.017

Zika virus (ZIKV) is an arthropod-borne flavivirus that causes newborn microcephaly and Guillian-Barré syndrome in adults. No therapeutics are available to treat ZIKV infection or other flaviviruses. In this study, we explored the inhibitory effect of glycosaminoglycans and analogues against ZIKV infection. Highly sulfated heparin, dextran sulfate and suramin significantly inhibited ZIKV infection in Vero cells. De-sulfated heparin analogues lose inhibitory effect, implying that sulfonate groups are critical for viral inhibition. Suramin, an FDA-approved anti-parasitic drug, inhibits ZIKV infection with 3-5 log10 PFU viral reduction with IC50value of ∼2.5-5 μg/ml (1.93 μM-3.85 μM). A time-of-drug-addition study revealed that suramin remains potent even when administrated at 1-24 hpi. Suramin inhibits ZIKV infection by preventing viral adsorption, entry and replication. Molecular dynamics simulation revealed stronger interaction of suramin with ZIKV NS3 helicase than with the envelope protein. Suramin warrants further investigation as a potential antiviral candidate for ZIKV infection. Heparan sulfate (HS) is a cellular attachment receptor for multiple flaviviruses. However, no direct ZIKV-heparin interaction was observed in heparin-binding analysis, and downregulate or removal of cellular HS with sodium chlorate or heparinase I/III did not inhibit ZIKV infection. This indicates that cell surface HS is not utilized by ZIKV as an attachment receptor.

Matched MeSH terms: Flavivirus/drug effects
Fulltext Electrochemical biosensor detection on respiratory and flaviviruses

Ang PC, Perumal V, Ibrahim MNM, Adnan R, Mohd Azman DK, Gopinath SCB, et al.

Appl Microbiol Biotechnol, 2023 Mar;107(5-6):1503-1513.
PMID: 36719432 DOI: 10.1007/s00253-023-12400-y

Viruses have spread throughout the world and cause acute illness or death among millions of people. There is a growing concern about methods to control and combat early-stage viral infections to prevent the significant public health problem. However, conventional detection methods like polymerase chain reaction (PCR) requires sample purification and are time-consuming for further clinical diagnosis. Hence, establishing a portable device for rapid detection with enhanced sensitivity and selectivity for the specific virus to prevent further spread becomes an urgent need. Many research groups are focusing on the potential of the electrochemical sensor to become a key for developing point-of-care (POC) technologies for clinical analysis because it can solve most of the limitations of conventional diagnostic methods. Herein, this review discusses the current development of electrochemical sensors for the detection of respiratory virus infections and flaviviruses over the past 10 years. Trends in future perspectives in rapid clinical detection sensors on viruses are also discussed. KEY POINTS: • Respiratory related viruses and Flavivirus are being concerned for past decades. • Important to differentiate the cross-reactivity between the virus in same family. • Electrochemical biosensor as a suitable device to detect viruses with high performance.

Matched MeSH terms: Flavivirus*
Tembusu-like flavivirus (Perak virus) as the cause of neurological disease outbreaks in young Pekin ducks

Homonnay ZG, Kovács EW, Bányai K, Albert M, Fehér E, Mató T, et al.

Avian Pathol, 2014;43(6):552-60.
PMID: 25299764 DOI: 10.1080/03079457.2014.973832

A neurological disease of young Pekin ducks characterized by ataxia, lameness, and paralysis was observed at several duck farms in Malaysia in 2012. Gross pathological lesions were absent or inconsistent in most of the cases, but severe and consistent microscopic lesions were found in the brain and spinal cord, characterized by non-purulent panencephalomyelitis. Several virus isolates were obtained in embryonated duck eggs and in cell cultures (Vero and DF-1) inoculated with the brain homogenates of affected ducks. After exclusion of other viruses, the isolates were identified as a flavivirus by flavivirus-specific reverse transcription-polymerase chain reaction (RT-PCR) assays. Inoculation of 2-week-old Pekin ducks with a flavivirus isolate by the subcutaneous or intramuscular route resulted in typical clinical signs and histological lesions in the brain and spinal cord. The inoculated virus was detected by RT-PCR from organ samples of ducks with clinical signs and histological lesions. With a few days delay, the disease was also observed among co-mingled contact control birds. Phylogenetic analysis of NS5 and E gene sequences proved that the isolates were representatives of a novel phylogenetic group within clade XI (Ntaya virus group) of the Flavivirus genus. This Malaysian Duck Tembusu Virus (DTMUV), named Perak virus, has moderate genomic RNA sequence similarity to a related DTMUV identified in China. In our experiment the Malaysian strain of DTMUV could be transmitted in the absence of mosquito vectors. These findings may have implications for the control and prevention of this emerging group of flaviviruses.

Matched MeSH terms: Flavivirus/genetics; Flavivirus/isolation & purification*; Flavivirus Infections/epidemiology; Flavivirus Infections/pathology; Flavivirus Infections/veterinary*; Flavivirus Infections/virology
Fulltext Zika virus infection in Malaysia: an epidemiological, clinical and virological analysis

Woon YL, Lim MF, Tg Abd Rashid TR, Thayan R, Chidambaram SK, Syed Abdul Rahim SS, et al.

BMC Infect Dis, 2019 Feb 13;19(1):152.
PMID: 30760239 DOI: 10.1186/s12879-019-3786-9

BACKGROUND: A major outbreak of the Zika virus (ZIKV) has been reported in Brazil in 2015. Since then, it spread further to other countries in the Americas and resulted in declaration of the Public Health Emergency of International Concern (PHEIC) by World Health Organization. In 2016, Singapore reported its first minor ZIKV epidemic. Malaysia shares similar ecological environment as Brazil and Singapore which may also favor ZIKV transmission. However, no ZIKV outbreak has been reported in Malaysia to date. This study aimed to discuss all confirmed ZIKV cases captured under Malaysia ZIKV surveillance system after declaration of the PHEIC; and explore why Malaysia did not suffer a similar ZIKV outbreak as the other two countries.
METHODS: This was an observational study reviewing all confirmed ZIKV cases detected in Malaysia through the ZIKV clinical surveillance and Flavivirus laboratory surveillance between June 2015 and December 2017. All basic demographic characteristics, co-morbidities, clinical, laboratory and outcome data of the confirmed ZIKV cases were collected from the source documents.
RESULTS: Only eight out of 4043 cases tested positive for ZIKV infection during that period. The median age of infected patients was 48.6 years and majority was Chinese. Two of the subjects were pregnant. The median interval between the onset of disease and the first detection of ZIKV Ribonucleic Acid (RNA) in body fluid was 3 days. Six cases had ZIKV RNA detected in both serum and urine samples. Phylogenetic analysis suggests that isolates from the 7 cases of ZIKV infection came from two clusters, both of which were local circulating strains.
CONCLUSION: Despite similar ecological background characteristics, Malaysia was not as affected by the recent ZIKV outbreak compared to Brazil and Singapore. This could be related to pre-existing immunity against ZIKV in this population, which developed after the first introduction of the ZIKV in Malaysia decades ago. A serosurvey to determine the seroprevalence of ZIKV in Malaysia was carried out in 2017. The differences in circulating ZIKV strains could be another reason as to why Malaysia seemed to be protected from an outbreak.

Matched MeSH terms: Flavivirus
Antibodies against prM protein distinguish between previous infection with dengue and Japanese encephalitis viruses

Cardosa MJ, Wang SM, Sum MS, Tio PH

BMC Microbiol, 2002 May 5;2:9.
PMID: 12019028

In Southeast Asia, dengue viruses often co-circulate with other flaviviruses such as Japanese encephalitis virus, and due to the presence of shared antigenic epitopes it is often difficult to use serological methods to distinguish between previous infections by these flaviviruses.

Matched MeSH terms: Flavivirus Infections/blood; Flavivirus Infections/diagnosis*
Fulltext Interaction between Flavivirus and Cytoskeleton during Virus Replication

Foo KY, Chee HY

Biomed Res Int, 2015;2015:427814.
PMID: 26347881 DOI: 10.1155/2015/427814

Flaviviruses are potentially human pathogens that cause major epidemics worldwide. Flavivirus interacts with host cell factors to form a favourable virus replication site. Cell cytoskeletons have been observed to have close contact with flaviviruses, which expands the understanding of cytoskeleton functions during virus replication, although many detailed mechanisms are still unclear. The interactions between the virus and host cytoskeletons such as actin filaments, microtubules, and intermediate filaments have provided insight into molecular alterations during the virus infection, such as viral entry, in-cell transport, scaffold assembly, and egress. This review article focuses on the utilization of cytoskeleton by Flavivirus and the respective functions during virus replication.

Matched MeSH terms: Flavivirus/physiology*; Flavivirus Infections/metabolism*
Fulltext Entomological Surveillance on Resistance of Aedes to Aqua K-Otherine at Taman Sri Rugading, Tuaran, Sabah, Malaysia

Netto, Marcus

Borneo Journal of Medical Sciences, 2018;12(101):39-0.
MyJurnal

Dengue fever and its fatal complications have made a comeback since its control in the 1990â€™s. The Flavivirus has evolved into 4 serotypes DEN 1,2,3,4 which can be passed on by the mosquitoes for 7 generations for each serotype. This communicable disease is predominantly confined to urban areas. Quick control of the spread of the disease will prevent it from becoming an epidemic. The two species mosquitoes involved have different behaviours. The Aedes aegypti is an indoor vector which breeds in clean, clear and calm freshwater. The Aedes albopictus is an outdoor breeding mosquito which breeds in stagnant waters. Surveillance of the areas prone to outbreaks is vital. One of the roles of the entomologist is to monitor the vector for resistance to the insecticides. Localities that have been subjected to recurrent outbreaks will have vector which develop resistance to the insecticides used.

Matched MeSH terms: Flavivirus
Fulltext Epizootology and experimental infection of Yokose virus in bats

Watanabe S, Omatsu T, Miranda ME, Masangkay JS, Ueda N, Endo M, et al.

Comp Immunol Microbiol Infect Dis, 2010 Jan;33(1):25-36.
PMID: 18789527 DOI: 10.1016/j.cimid.2008.07.008

To reveal whether bats serve as an amplifying host for Yokose virus (YOKV), we conducted a serological survey and experimentally infected fruit bats with YOKV isolated from microbats in Japan. YOKV belongs to the Entebbe bat virus group of vector unknown group within the genus Flavivirus and family Flaviviridae. To detect antibodies against YOKV, we developed an enzyme-linked immunosorbent assay (ELISA) using biotinylated anti-bat IgG rabbit sera. Serological surveillance was conducted with samples collected in the Philippines and the sera supplied from Malaysia. One of the 36 samples from the Philippines (2.7%) and 5 of the 26 samples from Malaysia (19%) had detectable ELISA antibodies. In the experimental infections, no clinical signs of disease were observed. Moreover, no significant viral genome amplification was detected. These findings revealed that YOKV replicates poorly in the fruit bat, suggesting that fruit bats do not seem to serve as an amplifying host for YOKV.

Matched MeSH terms: Flavivirus/immunology*; Flavivirus/isolation & purification; Flavivirus Infections/immunology; Flavivirus Infections/epidemiology*; Flavivirus Infections/virology
Diversity and evolution of the envelope gene of dengue virus type 1 circulating in India in recent times

Dey S, Nandy A, Nandy P, Das S

Int J Bioinform Res Appl, 2015;11(6):469-82.
PMID: 26642358 DOI: 10.1504/ijbra.2015.073235

Dengue viral attacks have been reported in various parts of India in recent years. In this paper we report on our studies of the characterisation and evolutionary aspects of gene sequences of the envelope glycoprotein of the prevalent Indian dengue virus type 1. Comparison with sequences from other countries shows that the envelope genes identified in India are closely related to strains from Malaysia. From the evolutionary point of view the envelope gene sequences of this dengue virus of India for past few years show that a marked mutational shift in the nucleotide sequences of the envelope gene have taken place from around the year 2000. Also, phylogenetic relationship with other three sera of dengue virus reported in India from 2005 shows that the dengue virus 1 is more closely related to dengue viruses 3 and 4 and relatively distantly to dengue virus 2.

Matched MeSH terms: Flavivirus
Serological evidence of DENV, JEV, and ZIKV among the indigenous people (Orang Asli) of Peninsular Malaysia

Khor CS, Mohd-Rahim NF, Hassan H, Tan KK, Zainal N, Teoh BT, et al.

J Med Virol, 2020 08;92(8):956-962.
PMID: 31814135 DOI: 10.1002/jmv.25649

Dengue virus (DENV), Japanese encephalitis virus (JEV), and Zika virus (ZIKV) are mosquito-borne flavivirus of medical importance in tropical countries such as Malaysia. However, much remains unknown regarding their prevalence among the underserved indigenous people (Orang Asli) living in communities in the forest fringe areas of Peninsular Malaysia. Information on the prevalence of diseases is necessary to elevate the effectiveness of disease control and preventive measures. This study aimed to determine the seroprevalence of the three major flaviviruses among the Orang Asli and investigate the association between demographic factors and seropositivities. Sampling activities were conducted in the Orang Asli villages to obtain serum samples and demographic data from consenting volunteers. The presence of DENV, JEV, and ZIKV immunoglobulin G (IgG) antibodies in the sera were examined using commercial enzyme-linked immunosorbent assay kits. A focus reduction neutralization assay was performed to measure virus-specific neutralizing antibodies. A total of 872 serum samples were obtained from the Orang Asli volunteers. Serological assay results revealed that DENV IgG, JEV IgG, and ZIKV IgG seropositivities among the Orang Asli were at 4.9%, 48.4%, and 13.2%, respectively. Neutralizing antibodies (FRNT50 ≥ 1:40) against JEV and ZIKV were found in 86.7% and 100.0%, respectively, out of the samples tested. Positive serology to all three viruses corresponded significantly to the age of the volunteers with increasing seropositivity in older volunteers. Findings from the study suggest that Orang Asli are at significant risk of contracting JEV and ZIKV infections despite the lack of active transmission of the viruses in the country.

Matched MeSH terms: Flavivirus/immunology*
Fulltext The West Nile virus-like flavivirus Koutango is highly virulent in mice due to delayed viral clearance and the induction of a poor neutralizing antibody response

Prow NA, Setoh YX, Biron RM, Sester DP, Kim KS, Hobson-Peters J, et al.

J Virol, 2014 Sep 1;88(17):9947-62.
PMID: 24942584 DOI: 10.1128/JVI.01304-14

The mosquito-borne West Nile virus (WNV) is responsible for outbreaks of viral encephalitis in humans, horses, and birds, with particularly virulent strains causing recent outbreaks of disease in eastern Europe, the Middle East, North America, and Australia. Previous studies have phylogenetically separated WNV strains into two main genetic lineages (I and II) containing virulent strains associated with neurological disease. Several WNV-like strains clustering outside these lineages have been identified and form an additional five proposed lineages. However, little is known about whether these strains have the potential to induce disease. In a comparative analysis with the highly virulent lineage I American strain (WNVNY99), the low-pathogenicity lineage II strain (B956), a benign Australian strain, Kunjin (WNVKUN), the African WNV-like Koutango virus (WNVKOU), and a WNV-like isolate from Sarawak, Malaysia (WNVSarawak), were assessed for neuroinvasive properties in a murine model and for their replication kinetics in vitro. While WNVNY99 replicated to the highest levels in vitro, in vivo mouse challenge revealed that WNVKOU was more virulent, with a shorter time to onset of neurological disease and higher morbidity. Histological analysis of WNVKOU- and WNVNY99-infected brain and spinal cords demonstrated more prominent meningoencephalitis and the presence of viral antigen in WNVKOU-infected mice. Enhanced virulence of WNVKOU also was associated with poor viral clearance in the periphery (sera and spleen), a skewed innate immune response, and poor neutralizing antibody development. These data demonstrate, for the first time, potent neuroinvasive and neurovirulent properties of a WNV-like virus outside lineages I and II.

Matched MeSH terms: Flavivirus Infections/immunology; Flavivirus Infections/pathology*; Flavivirus Infections/virology
Fulltext Binding of Duck Tembusu Virus Nonstructural Protein 2A to Duck STING Disrupts Induction of Its Signal Transduction Cascade To Inhibit Beta Interferon Induction

Zhang W, Jiang B, Zeng M, Duan Y, Wu Z, Wu Y, et al.

J Virol, 2020 04 16;94(9).
PMID: 32075929 DOI: 10.1128/JVI.01850-19

Duck Tembusu virus (DTMUV), which is similar to other mosquito-borne flaviviruses that replicate well in most mammalian cells, is an emerging pathogenic flavivirus that has caused epidemics in egg-laying and breeding waterfowl. Immune organ defects and neurological dysfunction are the main clinical symptoms of DTMUV infection. Preinfection with DTMUV makes the virus impervious to later interferon (IFN) treatment, revealing that DTMUV has evolved some strategies to defend against host IFN-dependent antiviral responses. Immune inhibition was further confirmed by screening for DTMUV-encoded proteins, which suggested that NS2A significantly inhibited IFN-β and IFN-stimulated response element (ISRE) promoter activity in a dose-dependent manner and facilitated reinfection with duck plague virus (DPV). DTMUV NS2A was able to inhibit duck retinoic acid-inducible gene-I (RIG-I)-, and melanoma differentiation-associated gene 5 (MDA5)-, mitochondrial-localized adaptor molecules (MAVS)-, stimulator of interferon genes (STING)-, and TANK-binding kinase 1 (TBK1)-induced IFN-β transcription, but not duck TBK1- and interferon regulatory factor 7 (IRF7)-mediated effective phases of IFN response. Furthermore, we found that NS2A competed with duTBK1 in binding to duck STING (duSTING), impaired duSTING-duSTING binding, and reduced duTBK1 phosphorylation, leading to the subsequent inhibition of IFN production. Importantly, we first identified that the W164A, Y167A, and S361A mutations in duSTING significantly impaired the NS2A-duSTING interaction, which is important for NS2A-induced IFN-β inhibition. Hence, our data demonstrated that DTMUV NS2A disrupts duSTING-dependent antiviral cellular defenses by binding with duSTING, which provides a novel mechanism by which DTMUV subverts host innate immune responses. The potential interaction sites between NS2A and duSTING may be the targets of future novel antiviral therapies and vaccine development.IMPORTANCE Flavivirus infections are transmitted through mosquitos or ticks and lead to significant morbidity and mortality worldwide with a spectrum of manifestations. Infection with an emerging flavivirus, DTMUV, manifests with clinical symptoms that include lesions of the immune organs and neurological dysfunction, leading to heavy egg drop and causing serious harm to the duck industry in China, Thailand, Malaysia, and other Southeast Asian countries. Mosquito cells, bird cells, and mammalian cell lines are all susceptible to DTMUV infection. An in vivo study revealed that BALB/c mice and Kunming mice were susceptible to DTMUV after intracerebral inoculation. Moreover, there are no reports about DTMUV-related human disease, but antibodies against DTMUV and viral RNA were detected in serum samples of duck industry workers. This information implies that DTMUV has expanded its host range and may pose a threat to mammalian health. However, the pathogenesis of DTMUV is largely unclear. Our results show that NS2A strongly blocks the STING-induced signal transduction cascade by binding with STING, which subsequently blocks STING-STING binding and TBK1 phosphorylation. More importantly, the W164, Y167, or S361 residues in duSTING were identified as important interaction sites between STING and NS2A that are vital for NS2A-induced IFN production and effective phases of IFN response. Uncovering the mechanism by which DTMUV NS2A inhibits IFN in the cells of its natural hosts, ducks, will help us understand the role of NS2A in DTMUV pathogenicity.

Matched MeSH terms: Flavivirus/metabolism*; Flavivirus/pathogenicity; Flavivirus Infections/virology
Fulltext Islamic perspective on elective abortion of Zika virus infected pregnant women

Syazwani Hamdan, Mohd Rahman Omar, Mohammad Naqib Hamdan, Ummu Aiman Faisal

Malaysian Journal of Medicine and Health Sciences, 2019;15(106):60-60.
MyJurnal

Introduction: Zika virus infection is caused by flavivirus virus and spread by Aedes mosquitoes. Since first report-ed in 1947, it spread to various countries especially in the equatorial region including Malaysia. The infection is non-fatal to an adult. However, the major risk of its infection is towards unborn baby when the mother is infected. The vertical transmission to the foetus possess various risks include the teratogenic effect that may lead to elective abortion. Thus, the objectives of this review are to discover about Zika virus and its effect on pregnant women and to evaluate Islamic perspective about elective abortion of Zika virus-infected women. Methods: This review was done through reviewing evidence from the journals, books and reports. The data were reviewed thematically according to the objectives. Results: Studies shown that Zika virus may cause miscarriage, preterm birth, microcephaly and other malformation known as Congenital Zika syndrome. This leads to a demand for elective abortion which raised Islamic ethical issue if it is permissible. In Islam, abortion is extremely prohibited once the foetus reached 120-day of con-ception unless it causes harm to the mother’s life. But, if the foetus age is less than 120-day, abortion is permissible when the pregnancy affects the mother’s health. Abortion due to foetal microcephaly and congenital malformation is prohibited. Conclusion: Effort must be taken to prevent the spread of Zika virus to reduce the need for an elective abortion through an education Muslim community regarding elective abortion.

Matched MeSH terms: Flavivirus
Fulltext A systematic review: public health policies on Zika infection surveillance for Malaysia

Chin Mun Wong, Rozita Hod, Mohd Rohaizat Hassan, Sazaly Abu Bakar

Malaysian Journal of Medicine and Health Sciences, 2019;15(106):3-3.
MyJurnal

Introduction: Zika infection was declared as Public Health Emergency of International Concern since year 2015. Despite of no new reported case via National Surveillance System for flavivirus, an underestimated seroprevalence might occur as the country contributes to the Asian lineage of the virus. Methods: Systematic literature search using PICO framework and PRISMA checklist across four databases for articles published from year 2013-2018 yielded 189 results, 37 articles accepted by titles following criteria were subjected to abstract screening, leaving 8 articles with clear risk proceed to full text analysis using Cochrane checklist and GRADE assessment. Results: There were four high quality articles and four low quality articles based on biases in studies. Blood product management and vac-cination are strategies strongly recommended to be implemented as Zika response while vector control and family planning are public health measures to be proposed as policy if feasible. Successful factors to improve Zika surveil-lance and management includes developing algorithm for blood product management, anti-Zika vaccine research, algorithm for new-born screening, participation of policy makers, healthcare capacity building, raising healthcare and public awareness on the infection, international funding, utilization of technology in data management and bio-logical control of vector. Conclusion: Implementation of Zika response as policy is timely, should be evidence-based and follow guidelines from WHO / CDC / FDA US after cost-effectiveness evaluation for Malaysia setting.

Matched MeSH terms: Flavivirus
Fulltext Evidence of West Nile virus infection in migratory and resident wild birds in west coast of peninsular Malaysia

Ain-Najwa MY, Yasmin AR, Omar AR, Arshad SS, Abu J, Mohammed HO, et al.

One Health, 2020 Dec;10:100134.
PMID: 32405525 DOI: 10.1016/j.onehlt.2020.100134

West Nile virus (WNV) is a zoonotic mosquito-borne flavivirus that is harbored and amplified by wild birds via the enzootic transmission cycle. Wide range of hosts are found to be susceptible to WNV infection including mammals, amphibians and reptiles across the world. Several studies have demonstrated that WNV was present in the Malaysian Orang Asli and captive birds. However, no data are available on the WNV prevalence in wild birds found in Malaysia. Therefore this study was conducted to determine the serological and molecular prevalence of WNV in wild birds in selected areas in the West Coast of Peninsular Malaysia. Two types of wild birds were screened, namely migratory and resident birds in order to explore any possibility of WNV transmission from the migratory birds to the resident birds. Thus, a cross-sectional study was conducted at the migratory birds sanctuary located in Kuala Gula, Perak and Kapar, Selangor by catching 163 migratory birds, and 97 resident birds from Kuala Gula and Parit Buntar, Perak at different time between 2016 and 2017 (Total, n = 260). Blood and oropharyngeal swabs were collected for serological and molecular analysis, respectively. Serum were screened for WNV antibodies using a commercial competitive ELISA (c-ELISA) (ID Screen® West Nile Competition Multi-species ELISA, ID VET, Montpellier, France) and cross-reactivity towards Japanese Encephalitis virus (JEV) was also carried out using the JEV-double antigen sandwich (DAS) ELISA. Oropharyngeal swabs were subjected to one-step RT-PCR to detect WNV RNA, in which positive reactions were subsequently sequenced. WNV seropositive rate of 18.71% (29/155) at 95% CI (0.131 to 0.260) and molecular prevalence of 15.2% (16/105) at 95% CI (0.092 to 0.239) were demonstrated in migratory and resident wild birds found in West Coast Malaysia. Phylogenetic analyses of the 16 WNV isolates found in this study revealed that the local strains have 99% similarity to the strains from South Africa and were clustered under lineage 2. Evidence of WNV infection in resident and migratory birds were demonstrated in this study. As a summary, intervention between migratory birds, resident birds and mosquitoes might cause the introduction and maintenance of WNV in Malaysia, however the assumption could be further proven by studying the infection dynamics in the mosquitoes present in the studied areas.

Matched MeSH terms: Flavivirus
Fulltext A novel goose-origin Tembusu virus exhibits pathogenicity in day-old chicks with evidence of direct contact transmission

Liu M, Chen YY, Twu NC, Wu MC, Fang ZS, Dubruel A, et al.

Poult Sci, 2024 Feb;103(2):103332.
PMID: 38128459 DOI: 10.1016/j.psj.2023.103332

In late 2020, an outbreak of Tembusu virus (TMUV)-associated disease occurred in a 45-day-old white Roman geese flock in Taiwan. Here, we present the identification and isolation of a novel goose-origin TMUV strain designated as NTU/C225/2020. The virus was successfully isolated using minimal-pathogen-free duck embryos. Phylogenetic analysis of the polyprotein gene showed that NTU/C225/2020 clustered together with the earliest isolates from Malaysia and was most closely related to the first Taiwanese TMUV strain, TP1906. Genomic analysis revealed significant amino acid variations among TMUV isolates in NS1 and NS2A protein regions. In the present study, we characterized the NTU/C225/2020 culture in duck embryos, chicken embryos, primary duck embryonated fibroblasts, and DF-1 cells. All host systems were susceptible to NTU/C225/2020 infection, with observable lesions. In addition, animal experiments showed that the intramuscular inoculation of NTU/C225/2020 resulted in growth retardation and hyperthermia in day-old chicks. Gross lesions in the infected chicks included hepatomegaly, hyperemic thymus, and splenomegaly. Viral loads and histopathological damage were displayed in various tissues of both inoculated and naïve co-housed chicks, confirming the direct chick-to-chick contact transmission of TMUV. This is the first in vivo study of a local TMUV strain in Taiwan. Our findings provide essential information for TMUV propagation and suggest a potential risk of disease outbreak in chicken populations.

Matched MeSH terms: Flavivirus*
Fulltext Co-infections and transmission networks of HCV, HIV-1 and HPgV among people who inject drugs

Ng KT, Takebe Y, Chook JB, Chow WZ, Chan KG, Abed Al-Darraji HA, et al.

Sci Rep, 2015;5:15198.
PMID: 26459957 DOI: 10.1038/srep15198

Co-infections with human immunodeficiency virus type 1 (HIV-1) and human pegivirus (HPgV) are common in hepatitis C virus (HCV)-infected individuals. However, analysis on the evolutionary dynamics and transmission network profiles of these viruses among individuals with multiple infections remains limited. A total of 228 injecting drug users (IDUs), either HCV- and/or HIV-1-infected, were recruited in Kuala Lumpur, Malaysia. HCV, HIV-1 and HPgV genes were sequenced, with epidemic growth rates assessed by the Bayesian coalescent method. Based on the sequence data, mono-, dual- and triple-infection were detected in 38.8%, 40.6% and 20.6% of the subjects, respectively. Fifteen transmission networks involving HCV (subtype 1a, 1b, 3a and 3b), HIV-1 (CRF33_01B) and HPgV (genotype 2) were identified and characterized. Genealogical estimates indicated that the predominant HCV, HIV-1 and HPgV genotypes were introduced into the IDUs population through multiple sub-epidemics that emerged as early as 1950s (HCV), 1980s (HIV-1) and 1990s (HPgV). By determining the difference in divergence times between viral lineages (ΔtMRCA), we also showed that the frequency of viral co-transmission is low among these IDUs. Despite increased access to therapy and other harm reduction interventions, the continuous emergence and coexistence of new transmission networks suggest persistent multiple viral transmissions among IDUs.

Matched MeSH terms: Flavivirus Infections/epidemiology; Flavivirus Infections/transmission*
Fulltext Development of conventional and real-time reverse transcription polymerase chain reaction assays to detect Tembusu virus in Culex tarsalis mosquitoes

Petz LN, Turell MJ, Padilla S, Long LS, Reinbold-Wasson DD, Smith DR, et al.

Am J Trop Med Hyg, 2014 Oct;91(4):666-71.
PMID: 25114013 DOI: 10.4269/ajtmh.13-0218

Tembusu virus (TMUV) is an important emerging arthropod-borne virus that may cause encephalitis in humans and has been isolated in regions of southeast Asia, including Malaysia, Thailand, and China. Currently, detection and identification of TMUV are limited to research laboratories, because quantitative rapid diagnostic assays for the virus do not exist. We describe the development of sensitive and specific conventional and real-time quantitative reverse transcription polymerase chain reaction assays for detecting TMUV RNA in infected cell culture supernatant and Culex tarsalis mosquitoes. We used this assay to document the replication of TMUV in Cx. tarsalis, where titers increased 1,000-fold 5 days after inoculation. These assays resulted in the detection of virus-specific RNA in the presence of copurified mosquito nucleic acids. The use of these rapid diagnostic assays may have future applications for field pathogen surveillance and may assist in early detection, diagnosis, and control of the associated arthropod-borne pathogens.

Matched MeSH terms: Flavivirus/genetics; Flavivirus/isolation & purification*; Flavivirus Infections/diagnosis*; Flavivirus Infections/virology
Encephalitis and retarded growth of chicks caused by Sitiawan virus, a new isolate belonging to the genus Flavivirus

Kono Y, Tsukamoto K, Abd Hamid M, Darus A, Lian TC, Sam LS, et al.

Am J Trop Med Hyg, 2001 5 19;63(1-2):94-101.
PMID: 11358004

A new virus named Sitiawan virus (SV) was isolated from sick broiler chicks in chicken embryos. The virus replicated well with cytopathogenic effect (CPE) in the chicken B-lymphocyte cell line LSCC-BK3. The virus was an enveloped RNA virus of approximately 41 nm in size with hemagglutinating activity (HA) to goose erythrocytes. It was cross-reactive with Japanese encephalitis virus (JEV), a member of flaviviruses by HA inhibition tests but not by cross-virus neutralization tests. The cDNA fragment of NS5 gene was amplified with primers corresponding to NS5 gene of flaviviruses. The nucleotide sequences were 92% homologous to Tembusu virus, a member of the mosquito-borne virus cluster of the genus Flavivirus. In cross-neutralization tests with Tembusu virus, antiserum to SV did not neutralize Tembusu virus, and antiserum to Tembusu virus neutralized more weakly to SV than against homologous virus. These results indicate that SV is a new virus which can be differentiated serologically from Tembusu virus but is otherwise similar with respect to nucleotide sequence. The virus causes encephalitis, growth retardation, and increased blood glucose levels in inoculated chicks.

Matched MeSH terms: Flavivirus/genetics; Flavivirus/isolation & purification*; Flavivirus/pathogenicity*; Flavivirus/ultrastructure; Flavivirus Infections/epidemiology; Flavivirus Infections/veterinary*; Flavivirus Infections/virology

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links