Displaying publications 1 - 20 of 160 in total

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  1. Yunnanosticta gen. nov., from Yunnan, a new genus from the Sinostictinae, with the description of two new species (Odonata: Zygoptera: Platystictidae)
    Dow RA, Zhang HM
    Zootaxa, 2018 Jan 25;4375(4):567-577.
    PMID: 29690088 DOI: 10.11646/zootaxa.4375.4.6
    Yunnanosticta gen. nov. in the platystictid subfamily Sinostictinae is described from Yunnan, China. The genotype is Yunnanosticta wilsoni sp. nov., described here (holotype ♂ from Tongbiguan, Yingjiang County, Dehong Dai Jingpo Autonomous Prefecture, Yunnan, China, 23 vi 2015, leg. H.M. Zhang, to be deposited in the Natural History Museum, London). Yunnanosticta cyaneocollaris sp. nov. (holotype ♂ from Tongbiguan, Yingjiang County, Dehong Dai Jingpo Autonomous Prefecture, Yunnan, China, 23 vi 2015, leg. H.M. Zhang, to be deposited in the Natural History Museum, London) is also described.
    Matched MeSH terms: Serogroup
  2. Fulltext Whole-Genome Sequences of Salmonella enterica subsp. enterica Serovar Typhimurium Strains TT6675 and TT9097 Employed in the Isolation and Characterization of a Giant Phage Mutant Collection
    Gan HM, Eng WWH, Barton MK, Adams LE, Samsudin NA, Bartl AJ, et al.
    Genome Announc, 2017 Aug 24;5(34).
    PMID: 28839032 DOI: 10.1128/genomeA.00857-17
    We report here the genome sequences of Salmonella enterica subsp. enterica serovar Typhimurium strains TT6675 and TT9097, which we utilize for genetic analyses of giant bacterial viruses. Our analyses identified several genetic variations between the two strains, most significantly confirming strain TT6675 as a serine suppressor and TT9097 as a nonsuppressor.
    Matched MeSH terms: Serogroup
  3. Whole-Genome Sequence of Salmonella enterica subsp. enterica Serovar Typhimurium Strain UPM 260, Isolated from a Broiler Chicken in Perak, Malaysia
    Roslan NS, Jabeen S, Mat Isa N, Omar AR, Bejo MH, Ideris A
    Genome Announc, 2017 Nov 16;5(46).
    PMID: 29146857 DOI: 10.1128/genomeA.01272-17
    Salmonella enterica subsp. enterica serovar Typhimurium is one of several well-categorized Salmonella serotypes recognized globally. Here, we report the whole-genome sequence of S Typhimurium strain UPM 260, isolated from a broiler chicken.
    Matched MeSH terms: Serogroup
  4. Viability of dengue virus in culture stocks is efficiently preserved by storage in diluted forms
    Suppiah J, Nadaraju S, Hamzah S, Chee HY
    Trop Biomed, 2020 Jun 01;37(2):282-287.
    PMID: 33612798
    Storage of dengue virus (DENV) culture stocks in -80°C is a common laboratory practice to maintain the viability of the virus for long-term usage. However, the efficiency of this method could still be hindered by multiple factors. In our laboratory, we observed a constant and substantial deterioration in the titer of DENV in Vero culture supernatant stored in -80°C. Such incident had badly hampered the laboratory work and prompted an investigation to determine the cause. DENV isolates representing all four serotypes were propagated and the culture supernatants were harvested and stored in aliquots of original stock and 10 fold dilutions (10-1 -10-4). DENV titer in these stocks was determined prior to storage and reassessed on the third and sixth month of storage by focus forming unit assay (FFUA). The result demonstrated a constant preservation of titer ranging from 104 ffu/ml to 105 ffu/ml in the diluted DENV virus culture stocks of 10-1, and 10-2 of DENV1-4, a minor reduction of titer from 103 ffu/ml to 102 ffu/ml at dilution 10-3 for DENV4 only and complete deterioration in undiluted culture stock and lower dilution (10-4) within 6 months of storage in -80°C for all serotypes. It is recommended that propagated DENV in Vero cells are stored in 10 fold dilutions as compared to the original form to preserve the titer for long-term usage.
    Matched MeSH terms: Serogroup
  5. Vector competence of Malaysian Aedes albopictus with and without Wolbachia to four dengue virus serotypes
    Joanne S, Vythilingam I, Teoh BT, Leong CS, Tan KK, Wong ML, et al.
    Trop Med Int Health, 2017 09;22(9):1154-1165.
    PMID: 28653334 DOI: 10.1111/tmi.12918
    OBJECTIVE: To determine the susceptibility status of Aedes albopictus with and without Wolbachia to the four dengue virus serotypes.

    METHODS: Two newly colonised colonies of Ae. albopictus from the wild were used for the study. One colony was naturally infected with Wolbachia while in the other Wolbachia was removed by tetracycline treatment. Both colonies were orally infected with dengue virus-infected fresh blood meal. Dengue virus load was measured using quantitative RT-PCR at four-time intervals in the salivary glands, midguts and ovaries.

    RESULTS: Wolbachia did not significantly affect Malaysian Ae. albopictus dengue infection or the dissemination rate for all four dengue virus serotypes. Malaysian Ae. albopictus had the highest replication kinetics for DENV-1 and the highest salivary gland and midgut infection rate for DENV-4.

    CONCLUSION: Wolbachia, which naturally exists in Malaysian Ae. albopictus, does not significantly affect dengue virus replication. Malaysian Ae. albopictus is susceptible to dengue virus infections and capable of transmitting dengue virus, especially DENV-1 and DENV-4. Removal of Wolbachia from Malaysian Ae. albopictus would not reduce their susceptibility status.

    Matched MeSH terms: Serogroup*
  6. 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: Serogroup
  7. Fulltext Vascular pathology associated with Leptospira icterohaemorrhagiae serovar Lai strain Langkawi infection in guinea pigs (Cavia porcellus)
    Bahaman, A.R., Fuzina, N.H., Tengku-Azmi, T.I., Tyagita, G.H., Jasni, S.
    Jurnal Veterinar Malaysia, 2018;30(1):7-14.
    MyJurnal
    Fifteen (15) guinea pigs were experimentally infected with Leptospira icterohemorrhagiae serovar Lai strain
    Langkawi, a new strain that was isolated from a human leptospirosis patient. Hematoxylin and Eosin ((H&E) staining
    showed haemorrhages, congestion and oedema in all internal organs examined (lungs, liver, spleen and kidneys) with
    inflammatory cell infiltration characterized by neutrophils, lymphocytes and macrophages. Hydropic degeneration and
    cell necrosis were also common in our findings. Leptospires were detected starting Day 2 p.i by silver staining and
    Transmission Electron Microscopy (TEM). Rise in antibody titres started on Day 5 p.i and leptospiral DNA was
    detected beginning Day 3 in the kidneys and Day 5 in the liver by Polymerase Chain Reaction (PCR) assay. The
    findings illustrated the pathogenesis of leptospirosis in guinea pigs which disclosed them as a suitable animal model for
    demonstration of clinical symptoms of leptospirosis and pathological changes after being infected with Leptospira
    icterohaemorrhagiae serovar Lai strain Langkawi, particularly pulmonary haemorrhages, a leading cause of mortality
    in human leptospirosis.
    Matched MeSH terms: Serogroup
  8. Fulltext Triple-Band Reconfigurable Monopole Antenna for Long-Range IoT Applications
    Yahya MS, Soeung S, Singh NSS, Yunusa Z, Chinda FE, Rahim SKA, et al.
    Sensors (Basel), 2023 Jun 06;23(12).
    PMID: 37420526 DOI: 10.3390/s23125359
    In this study, a novel reconfigurable triple-band monopole antenna for LoRa IoT applications is fabricated on an FR-4 substrate. The proposed antenna is designed to function at three distinct LoRa frequency bands: 433 MHz, 868 MHz, and 915 MHz covering the LoRa bands in Europe, America, and Asia. The antenna is reconfigurable by using a PIN diode switching mechanism, which allows for the selection of the desired operating frequency band based on the state of the diodes. The antenna is designed using CST MWS® software 2019 and optimized for maximum gain, good radiation pattern and efficiency. The antenna with a total dimension of 80 mm × 50 mm × 0.6 mm (0.12λ0×0.07λ0 × 0.001λ0 at 433 MHz) has a gain of 2 dBi, 1.9 dBi, and 1.9 dBi at 433 MHz, 868 MHz, and 915 MHz, respectively, with an omnidirectional H-plane radiation pattern and a radiation efficiency above 90% across the three frequency bands. The fabrication and measurement of the antenna have been carried out, and the results of simulation and measurements are compared. The agreement among the simulation and measurement results confirms the design's accuracy and the antenna's suitability for LoRa IoT applications, particularly in providing a compact, flexible, and energy efficient communication solution for different LoRa frequency bands.
    Matched MeSH terms: Serogroup
  9. Trends in the antibiotic resistance patterns of enteric Fever isolates - a three year report from a tertiary care centre
    Gupta V, Singla N, Bansal N, Kaistha N, Chander J
    Malays J Med Sci, 2013 Jul;20(4):71-5.
    PMID: 24043999
    BACKGROUND: The incidence of multidrug resistant enteric fever is increasing alarmingly. This study was planned to determine the rate of isolation of Salmonella spp. and to compare the isolates for their epidemiological parameters and antimicrobial susceptibility patterns at our center.

    METHODS: The study was conducted over a span of three years with a total of 8142, 8134, and 8114 blood culture samples processed for the years 2008, 2009, and 2010 respectively. The minimum inhibitory concentration (MIC) for ciprofloxacin and chloramphenicol was determined using an agar dilution method. The MIC for ciprofloxacin was also confirmed by Epsilon-test (E -test) strips.

    RESULTS: Of the total 302 Salmonella spp. isolated, 257 were Salmonella enterica serotype Typhi (85.1%) and 45 (14.9%) were S. enterica serotype Paratyphi A. The majority of the isolates recovered were from the pediatric age group (54.6%) and males (60.6%). Complete susceptibility was observed to chloramphenicol, cefotaxime, ceftriaxone, and azithromycin over the last two years (2009 and 2010), with an increase in resistance to nalidixic acid (100%) and ciprofloxacin (13.6%).

    CONCLUSION: In our study, we found augmentation of resistance to nalidixic acid and fluoroquinolones and complete sensitivity to ceftriaxone along with reemergence of chloramphenicol sensitivity for Salmonella isolates. This report emphasises the necessity of continuous surveillance of antibiograms of enteric fever isolates in an area.

    Matched MeSH terms: Serogroup
  10. Transcription start site mapping and small RNA profiling of Leptospira biflexa serovar Patoc
    Cheah HL, Ahmed SA, Tang TH
    World J Microbiol Biotechnol, 2023 Feb 21;39(4):104.
    PMID: 36808011 DOI: 10.1007/s11274-023-03540-4
    Leptospirosis is an emerging zoonotic disease caused by bacterial species of the genus Leptospira. However, the regulatory mechanisms and pathways underlying the adaptation of pathogenic and non-pathogenic Leptospira spp. in different environmental conditions remain elusive. Leptospira biflexa is a non-pathogenic species of Leptospira that lives exclusively in a natural environment. It is an ideal model not only for exploring molecular mechanisms underlying the environmental survival of Leptospira species but also for identifying virulence factors unique to Leptospira's pathogenic species. In this study, we aim to establish the transcription start site (TSS) landscape and the small RNA (sRNA) profile of L. biflexa serovar Patoc grown to exponential and stationary phases via differential RNA-seq (dRNA-seq) and small RNA-seq (sRNA-seq) analyses, respectively. Our dRNA-seq analysis uncovered a total of 2726 TSSs, which are also used to identify other elements, e.g., promoter and untranslated regions (UTRs). Besides, our sRNA-seq analysis revealed a total of 603 sRNA candidates, comprising 16 promoter-associated sRNAs, 184 5'UTR-derived sRNAs, 230 true intergenic sRNAs, 136 5'UTR-antisense sRNAs, and 130 open reading frame (ORF)-antisense sRNAs. In summary, these findings reflect the transcriptional complexity of L. biflexa serovar Patoc under different growth conditions and help to facilitate our understanding of regulatory networks in L. biflexa. To the best of our knowledge, this is the first study reporting the TSS landscape of L. biflexa. The TSS and sRNA landscapes of L. biflexa can also be compared with its pathogenic counterparts, e.g., L. borgpetersenii and L. interrogans, to identify features contributing to their environmental survival and virulence.
    Matched MeSH terms: Serogroup
  11. Fulltext The upper respiratory tract microbiome of indigenous Orang Asli in north-eastern Peninsular Malaysia
    Cleary DW, Morris DE, Anderson RA, Jones J, Alattraqchi AG, A Rahman NI, et al.
    NPJ Biofilms Microbiomes, 2021 01 05;7(1):1.
    PMID: 33402693 DOI: 10.1038/s41522-020-00173-5
    Much microbiome research has focused on populations that are predominantly of European descent, and from narrow demographics that do not capture the socio-economic and lifestyle differences which impact human health. Here we examined the airway microbiomes of the Orang Asli, the indigenous peoples of Malaysia. A total of 130 participants were recruited from two sites in the north-eastern state of Terengganu in Peninsular Malaysia. Using 16S rRNA sequencing, the nasal microbiome was significantly more diverse in those aged 5-17 years compared to 50+ years (p = 0.023) and clustered by age (PERMANOVA analysis of the Bray-Curtis distance, p = 0.001). Hierarchical clustering of Bray-Curtis dissimilarity scores revealed six microbiome clusters. The largest cluster (n = 28; 35.4%) had a marked abundance of Corynebacterium. In the oral microbiomes Streptococcus, Neisseria and Haemophilus were dominant. Using conventional microbiology, high levels of Staphylococcus aureus carriage were observed, particularly in the 18-65 age group (n = 17/36; 47.2% 95% CI: 30.9-63.5). The highest carriage of pneumococci was in the <5 and 5 to 17 year olds, with 57.1% (4/7) and 49.2% (30/61), respectively. Sixteen pneumococcal serotypes were identified, the most common being the nonvaccine-type 23A (14.6%) and the vaccine-type 6B (9.8%). The prevalence of pneumococcal serotypes covered by pneumococcal conjugate vaccines support introduction into a Malaysian national immunisation schedule. In addition, the dominance of Corynebacterium in the airway microbiomes is intriguing given their role as a potentially protective commensal with respect to acute infection and respiratory health.
    Matched MeSH terms: Serogroup
  12. Fulltext The role of interspecies recombination in the evolution of antibiotic-resistant pneumococci
    D'Aeth JC, van der Linden MP, McGee L, de Lencastre H, Turner P, Song JH, et al.
    Elife, 2021 Jul 14;10.
    PMID: 34259624 DOI: 10.7554/eLife.67113
    Multidrug-resistant Streptococcus pneumoniae emerge through the modification of core genome loci by interspecies homologous recombinations, and acquisition of gene cassettes. Both occurred in the otherwise contrasting histories of the antibiotic-resistant S. pneumoniae lineages PMEN3 and PMEN9. A single PMEN3 clade spread globally, evading vaccine-induced immunity through frequent serotype switching, whereas locally circulating PMEN9 clades independently gained resistance. Both lineages repeatedly integrated Tn916-type and Tn1207.1-type elements, conferring tetracycline and macrolide resistance, respectively, through homologous recombination importing sequences originating in other species. A species-wide dataset found over 100 instances of such interspecific acquisitions of resistance cassettes and flanking homologous arms. Phylodynamic analysis of the most commonly sampled Tn1207.1-type insertion in PMEN9, originating from a commensal and disrupting a competence gene, suggested its expansion across Germany was driven by a high ratio of macrolide-to-β-lactam consumption. Hence, selection from antibiotic consumption was sufficient for these atypically large recombinations to overcome species boundaries across the pneumococcal chromosome.
    Matched MeSH terms: Serogroup
  13. The identification of active compounds in Ganoderma lucidum var. antler extract inhibiting dengue virus serine protease and its computational studies
    Lim WZ, Cheng PG, Abdulrahman AY, Teoh TC
    J Biomol Struct Dyn, 2020 Sep;38(14):4273-4288.
    PMID: 31595837 DOI: 10.1080/07391102.2019.1678523
    The number of global dengue incidences is alarmingly high in recent years. The global distribution of four dengue serotypes has also added economic burden in the dengue-endemic countries. To discover the potent dengue virus inhibitors in the antler form of Ganoderma lucidum (Lingzhi or Reishi), the water extraction of normal G. lucidum and its antler form were conducted and the chemical compounds were identified by LC-MS. Six distinct chemical compounds identified in high abundance were hesperetin, thymidine, lucidenic acid, 11-aminoundecanoic acid, 5-carboxyvanillic acid and ganocin B. The water extracts of G. lucidum in its antler form inhibited the DENV2 NS2B-NS3 protease activity at 84.6 ± 0.7%, higher than the normal G. lucidum. Then, molecular docking was performed on the homology model built from an in-house sequence. Docking simulation results showed that hesperetin and ganocin B were the best leads to bind at the catalytic triad of DENV2 NS2B-NS3pro via hydrogen bonding, van der Waals and pi-pi interactions. Extensive overlapping of HOMO-LUMO orbitals at the ringed regions of hesperetin helped to facilitate the entry of ligand to the catalytic triad cleft. LC-MS, molecular docking and density functional theory analyses confirmed that hesperetin was the strongest inhibitor against NS2B-NS3 protease. Communicated by Ramaswamy H. Sarma.
    Matched MeSH terms: Serogroup
  14. Fulltext The effect of pH on the survival of leptospires in water
    Smith CE, Turner LH
    Bull World Health Organ, 1961;24(1):35-43.
    PMID: 20604084
    One of the factors on which the incidence of leptospirosis is dependent is the survival time of shed leptospires in surface water or soil water, and this time is in turn affected by the acidity or alkalinity of the water. The authors have therefore studied the survival of four leptospiral serotypes in buffered distilled water at pH's ranging from 5.3 to 8.0. All survived longer in alkaline than in acid water, and significant differences between the serotypes were found in response to pH. Survival at pH's under 7.0 ranged from 10 to 117 days and at pH's over 7.0 from 21 to 152 days. Survival was also studied in aqueous extracts of soil samples from different areas in Malaya; no correlation was found between pH and survival time.It was also noted that in a group of Malayan ricefields a low incidence of leptospirosis in man was accompanied by a high infection rate among rodents, and when it was found that this phenomenon could not be explained by pH or salinity, attention was turned to the soil. Bentonite clay, similar to the montmorrillonite clay of the ricefields, was found to adsorb about half the leptospires in suspension. The authors recommend that field study of this laboratory observation be undertaken.
    Matched MeSH terms: Serogroup
  15. Fulltext The east coast districts are the possible epicenter of severe dengue in Sabah
    Kaur N, Rahim SSSA, Jaimin JJ, Dony JJF, Khoon KT, Ahmed K
    J Physiol Anthropol, 2020 Aug 14;39(1):19.
    PMID: 32795350 DOI: 10.1186/s40101-020-00230-0
    BACKGROUND: Malaysia recorded the highest number of dengue cases between 2014 and 2017. There are 13 states and three federal territories in Malaysia, and each area varies in their prevalence of dengue. Sabah is one of the states situated in Borneo, Malaysia. Although dengue has been increasing for the last several years, no study was being done to understand the burden and serotype distribution of the dengue virus (DENV) in Sabah. Therefore, the present study was carried out to understand the epidemiology of the dengue infection and the factors responsible for severe dengue in Sabah.

    METHODS: Data on dengue infection were extracted from the dengue database of the state of Sabah from 2013 through 2018. DENV NS-1-positive serum samples from multiple sites throughout Sabah were sent to the state public health laboratory, Kota Kinabalu Public Health Laboratory, for serotype determination. The analysis of factors associated with severe dengue was determined from the data of 2018 only.

    RESULTS: In 2013, there were 724 dengue cases; however, from 2014, dengue cases increased exponentially and resulted in 3423 cases in 2018. Increasing dengue cases also led to increased dengue mortality. The number of dengue deaths in 2013 was only five which then gradually increased, and in 2018, 29 patients died. This is an increase of 580% from 2013 to 2018. Deaths were considerably more in the districts of the east coast of Sabah compared with districts in the west coast. During the study period, all DENV serotypes could be identified as serotypes circulating in Sabah. In 2018, the predominant serotype was DENV-3. The monthly peak of dengue infection varied in different years. In the logistic regression analysis, it was identified that children were 6.5 times, patients infected with mixed serotype of DENV were 13 times, and cases from the districts of the east coast were 5.2 times more likely to develop severe dengue.

    CONCLUSIONS: An increasing trend of dengue infection has been observed in Sabah. The burden of dengue, severe dengue, and mortality was noted especially in the districts of the east coast of Sabah. Severe dengue was most likely developed in children, cases from the east coast, and patients infected with mixed serotype of DENV.

    Matched MeSH terms: Serogroup
  16. Fulltext The association between climatic factors and dengue fever: a study in Subang Jaya and Sepang, Selangor
    Nik Syaza Lina Nik Ruzman, Haliza Abdul Rahman
    Malaysian Journal of Public Health Medicine, 2017;17(101):0-0.
    MyJurnal
    Dengue fever is one of the most dangerous vector-borne diseases. According to the World Health Organization (WHO), dengue fever is a mosquito-borne infection caused by virus serotype DEN-1, DEN-2, DEN-3 and DEN-4. In Malaysia, dengue fever cases are on the rise from 6,000 cases in 1995 to over 40,000 in 2010, and this number is still rising. In 2014, the increase of dengue fever cases was alarming. It was reported that up to the end of the year 2014, there were 108,698 notified cases, indicating an increment of 151% compared to the same period of time in 2013 with only 43,346 reported cases. Selangor was the highest contributor of dengue fever cases in 2014. The objective of this paper is to study the relationship between climatic factors namely temperature, rainfall and humidity to the prevalence of dengue fever in Subang Jaya and Sepang district, Selangor. Data on monthly average temperature, precipitation, relative humidity and dengue fever cases for each month in 2014 and 2013 were collected. Data collection was dealt with a few institutions such as Malaysian Meteorological Department, Subang Jaya and Sepang Municipal Council and health district offices. Data were analysed using SPSS (Statistical Package for the Social Sciences) Version 20. General linear model analysis was used to investigate the relationship between the climatic variables and dengue prevalence. Results and Discussion: Based on the general linear model, rainfall and humidity were found to have significant relationships to monthly dengue fever cases (p=
    Matched MeSH terms: Serogroup
  17. Fulltext The association between climatic factors and dengue fever: a study in Subang Jaya and Sepang, Selangor
    Nik Syaza Lina Nik Ruzman, Haliza Abdul Rahman
    Malaysian Journal of Public Health Medicine, 2017;17 Special(1):140-150.
    Dengue fever is one of the most dangerous vector-borne diseases. According to the World Health Organization (WHO), dengue fever is a mosquito-borne infection caused by virus serotype DEN-1, DEN-2, DEN-3 and DEN-4. In Malaysia, dengue fever cases are on the rise from 6,000 cases in 1995 to over 40,000 in 2010, and this number is still rising. In 2014, the increase of dengue fever cases was alarming. It was reported that up to the end of the year 2014, there were 108,698 notified cases, indicating an increment of 151% compared to the same period of time in 2013 with only 43,346 reported cases. Selangor was the highest contributor of dengue fever cases in 2014. The objective of this paper is to study the relationship between climatic factors namely temperature, rainfall and humidity to the prevalence of dengue fever in Subang Jaya and Sepang district, Selangor. Data on monthly average temperature, precipitation, relative humidity and dengue fever cases for each month in 2014 and 2013 were collected. Data collection was dealt with a few institutions such as Malaysian Meteorological Department, Subang Jaya and Sepang Municipal Council and health district offices. Data were analysed using SPSS (Statistical Package for the Social Sciences) Version 20. General linear model analysis was used to investigate the relationship between the climatic variables and dengue prevalence. Results and Discussion: Based on the general linear model, rainfall and humidity were found to have significant relationships to monthly dengue fever cases (p= <0.001, p= 0.002). Rainfall was identified as the most significant predictor because rainfall can provide more breeding places for Aedes mosquitoes. As for humidity, higher relative humidity had been associated with increased Aedes aegypti feeding activity, survival and egg development. Temperature was not significantly related to monthly dengue fever cases (p= 0.561) in this study. However, this could be due to the short period of study. Conclusion: Climatic factors play an important role in the prevalence of dengue fever. However, there are many other factors of dengue fever that should be considered such as urbanisation as well as community knowledge, attitude and practice.
    Matched MeSH terms: Serogroup
  18. Fulltext The analysis of clinical and laboratory data: a large outbreak of dengue fever in Chaozhou, Guangdong province, China
    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: Serogroup
  19. Fulltext The Role of Serotype Interactions and Seasonality in Dengue Model Selection and Control: Insights from a Pattern Matching Approach
    Ten Bosch QA, Singh BK, Hassan MR, Chadee DD, Michael E
    PLoS Negl Trop Dis, 2016 05;10(5):e0004680.
    PMID: 27159023 DOI: 10.1371/journal.pntd.0004680
    The epidemiology of dengue fever is characterized by highly seasonal, multi-annual fluctuations, and the irregular circulation of its four serotypes. It is believed that this behaviour arises from the interplay between environmental drivers and serotype interactions. The exact mechanism, however, is uncertain. Constraining mathematical models to patterns characteristic to dengue epidemiology offers a means for detecting such mechanisms. Here, we used a pattern-oriented modelling (POM) strategy to fit and assess a range of dengue models, driven by combinations of temporary cross protective-immunity, cross-enhancement, and seasonal forcing, on their ability to capture the main characteristics of dengue dynamics. We show that all proposed models reproduce the observed dengue patterns across some part of the parameter space. Which model best supports the dengue dynamics is determined by the level of seasonal forcing. Further, when tertiary and quaternary infections are allowed, the inclusion of temporary cross-immunity alone is strongly supported, but the addition of cross-enhancement markedly reduces the parameter range at which dengue dynamics are produced, irrespective of the strength of seasonal forcing. The implication of these structural uncertainties on predicted vulnerability to control is also discussed. With ever expanding spread of dengue, greater understanding of dengue dynamics and control efforts (e.g. a near-future vaccine introduction) has become critically important. This study highlights the capacity of multi-level pattern-matching modelling approaches to offer an analytic tool for deeper insights into dengue epidemiology and control.
    Matched MeSH terms: Serogroup
  20. The ABA392/pET30a protein of Pasteurella multocida provoked mucosal immunity against HS disease in a rat model
    Kang TL, Velappan RD, Kabir N, Mohamad J, Rashid NN, Ismail S
    Microb Pathog, 2019 Mar;128:90-96.
    PMID: 30584901 DOI: 10.1016/j.micpath.2018.12.042
    Haemorrhagic septicaemia (HS) is a well-known high fatality septicaemic disease happening among bovines. The disease is caused by the Pasteurella multocida serotype B:2 bacteria. P. multocida B:2 has high mortality and morbidity rates and is spread through the intranasal and oral routes in bovines. In this study, our aim was to investigate the efficacy of the recombinant protein vaccine, ABA392/pET30a via intranasal inoculation by targeting the mucosal immunity. The constructed recombinant protein vaccine ABA392/pET30a was subjected to an animal study using Sprague Dawley rats. The study was divided into two parts: active and passive immunization studies. Both studies were carried out through the determination of immunogenicity (using Total White Blood Cell (TWBC) Count with Indirect ELISA) and histopathogenicity, analyzing (Bronchus Associated Lymphoid Tissue (BALT) formation) in lungs. As a result, the IgA and IgG development of both tested groups: group 1 (50μg/mL protein vaccine) and group 2 (100μg/mL protein vaccine) showed equivalent with the positive control group 4 (formalin-killed P. multocida B:2). However, there was a significant difference when compared with the negative control group 3 (normal saline). These results demonstrate that both the protein vaccine at the concentration 50μg/mL and 100μg/mL have the same efficacy as the commercially available positive control vaccine. From the studies, higher concentration of protein vaccine at 100μg/mL showed higher development of both IgA and IgG compared to 50μg/mL protein vaccine. Higher and rapid development of IgA compared to IgG showed that mucosal immunity has been induced through the intranasal administration of the protein vaccine. In addition, leucocytosis was observed at each dose of vaccination showed that the protein vaccine is capable to induce the immune responses of the host. Histopathogenicity studies of the vaccinated groups showed more BALT formation and no severe lesions after challenge compared to the negative control group. Besides, no inflammatory onsite or anaphylactic responses were observed after the intranasal inoculation which proved to be safer and provided longer lasting immunity. Therefore, recombinant protein vaccine ABA392/pET30a could be a potential candidate for intranasal administration which can provoke mucosal immunity against HS disease.
    Matched MeSH terms: Serogroup
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