The rhinoceros beetle, Oryctes rhinoceros, has emerged as a serious pest of oil palm since the prohibition of burning as a method for maintaining estate hygiene in the 1990s. The abundance of beetles is surprising given that the Malay peninsula was the site of first discovery of the Oryctes virus, which has been used to effect good as a biological control agent in other regions. A survey of adult beetles was carried out throughout Malaysia using pheromone traps. Captured beetles were examined for presence of virus using both visual/microscopic examination and PCR detection methods. The survey indicated that Oryctes virus was common in Malaysia among the adult beetles. Viral DNA analysis was carried out after restriction with HindIII enzyme and indicated at least three distinct viral genotypes. Bioassays were used to compare the viral strains and demonstrate that one strain (type B) is the most virulent against both larvae and adults of the beetle. Virus type B has been cultured and released into healthy populations where another strain (type A) forms the natural background. Capture and examination of beetles from the release site and surrounding area has shown that the spread and persistence of the applied virus strain is accompanied by a reduction in palm frond damage.
A Hepatitis A outbreak occurred in Mukim Hulu Langat, Hulu Langat district from April 2002 to October 2002. Of the 51 cases notified, most were among students and the ethnic groups involved were Malays and the Orang Asli (local indigenous community). Epidemiological investigations revealed that the cases were localized along rivers used for recreational activities in this area. River water analysis indicated human faecal contamination and it was believed that the contamination was due to the Orang Asli community living upstream. This occurred due to lack of toilet facilities, water at point of use and the existing traditional practices of the Orang Asli community. Control measures instituted were intense health education to the Orang Asli to avoid using the rivers for defecation, multi agency efforts to provide sanitary toilets and adequate water to the villages affected. Future measures include conducting a sero- prevalence survey to determine the feasibility of Hepatitis A immunization to the susceptible population in this area. The outbreak that began in April 2002 was controlled by October 2002.
Understanding the mechanisms involved in cellular immune responses against control of human immunodeficiency virus (HIV) infection is key to development of effective immunotherapeutic strategies against viral proliferation. Clear insights into the regulation of cytotoxic CD8+ T cells is crucial to development of effective immunotherapeutic strategies due to their unique ability to eliminate virus-infected cells during the course of infection. Here, we reviewed the roles of transcription factors, co-inhibitory molecules and regulatory cytokines following HIV infection and their potential significance in regulating the cytotoxic potentials of CD8+ T cells.
Human immunodeficiency virus (HIV)-1 epidemics in Asian countries are driven by varying exposures. The epidemiology of the regional pandemic has been changing with the spread of HIV-1 to lower-risk populations through sexual transmission. Common HIV-1 genotypes include subtype B and circulating recombinant form (CRF) 01_AE. Our objective was to use HIV-1 genotypic data to better quantify local epidemics. TASER-M is a multicenter prospective cohort of HIV-infected patients. Associations between HIV exposure, patient sex, country of sample origin and HIV-1 genotype were evaluated by multivariate logistic regression. Phylogenetic methods were used on genotypic data to investigate transmission relationships. A total of 1086 patients from Thailand, Hong Kong, Malaysia and the Philippines were included in analyses. Proportions of male patients within countries varied (Thailand: 55.6%, Hong Kong: 86.1%, Malaysia: 81.4%, Philippines: 93.8%; p
Indonesia is one of the biggest dengue endemic countries, and, thus, is an important place to investigate the evolution of dengue virus (DENV). We have continuously isolated DENV in Surabaya, the second biggest city in Indonesia, since 2008. We previously reported sequential changes in the predominant serotype from DENV type 2 (DENV-2) to DENV type 1 (DENV-1) in November 2008 and from DENV-1 to DENV-2 in July 2013. The predominance of DENV-2 continued in 2014, but not in 2015. We herein phylogenetically investigated DENV-2 transitions in Surabaya between 2008 and 2014 to analyze the divergence and evolution of DENV-2 concomitant with serotype shifts. All DENV-2 isolated in Surabaya were classified into the Cosmopolitan genotype, and further divided into 6 clusters. Clusters 1-3, dominated by Surabaya strains, were defined as the "Surabaya lineage". Clusters 4-6, dominated by strains from Singapore, Malaysia, and many parts of Indonesia, were the "South East Asian lineage". The most recent common ancestor of these strains existed in 1988, coinciding with the time that an Indonesian dengue outbreak took place. Cluster 1 appeared to be unique because no other DENV-2 isolate was included in this cluster. The predominance of DENV-2 in 2008 and 2013-14 were caused by cluster 1, whereas clusters 2 and 3 sporadically emerged in 2011 and 2012. The characteristic amino acids of cluster 1, E-170V and E-282Y, may be responsible for its prevalence in Surabaya. No amino acid difference was observed in the envelope region between strains in 2008 and 2013-14, suggesting that the re-emergence of DENV-2 in Surabaya was due to the loss or decrease of herd immunity in the 5-year period when DENV-2 subsided. The South East Asian lineage primarily emerged in Surabaya in 2014, probably imported from other parts of Indonesia or foreign countries.
Purification of virus-like particles (VLPs) in bind-and-elute mode has reached a bottleneck. Negative chromatography has emerged as the alternative solution; however, benchmark of negative chromatography media and their respective optimized conditions are absent. Hence, this study was carried out to compare the performance of different negative chromatography media for the purification of hepatitis B VLPs (HB-VLPs) from clarified Escherichia coli feedstock. The modified anion exchange media, core-shell adsorbents (InertShell and InertLayer 1000) and polymer grafted adsorbents (SQ) were compared. The results of chromatography from packed bed column of core-shell adsorbents showed that there is a trade-off between the purity and recovery of HB-VLPs in the flowthrough fraction due to the shell thickness. Atomic force microscopic analysis revealed funnel-shaped pore channels in the shell layer which may contribute to the entrapment of HB-VLPs. A longer residence time at a lower feed flow rate (0.5ml/min) improved slightly the HB-VLPs purity in all modified adsorbents, but the recovery in InertShell reduced substantially. The preheat-treatment is not recommended for the negative chromatography as the thermal-induced co-aggregation of HCPs and HB-VLPs would flow along with HB-VLPs and thus reduced the HB-VLPs purity in the flowthrough. Further reduction in the feedstock concentration enhanced the purity of HB-VLPs especially in InertLayer 1000 but reduced substantially the recovery of HB-VLPs. In general, the polymer grafted adsorbent, SQ, performed better than the core-shell adsorbents in handling a higher feedstock concentration.
Enterovirus A71 (EV-A71) is an important emerging pathogen causing large epidemics of hand, foot and mouth disease (HFMD) in children. In Malaysia, since the first EV-A71 epidemic in 1997, recurrent cyclical epidemics have occurred every 2-3 years for reasons that remain unclear. We hypothesize that this cyclical pattern is due to changes in population immunity in children (measured as seroprevalence). Neutralizing antibody titers against EV-A71 were measured in 2,141 residual serum samples collected from children ≤12 years old between 1995 and 2012 to determine the seroprevalence of EV-A71. Reported national HFMD incidence was highest in children <2 years, and decreased with age; in support of this, EV-A71 seroprevalence was significantly associated with age, indicating greater susceptibility in younger children. EV-A71 epidemics are also characterized by peaks of increased genetic diversity, often with genotype changes. Cross-sectional time series analysis was used to model the association between EV-A71 epidemic periods and EV-A71 seroprevalence adjusting for age and climatic variables (temperature, rainfall, rain days and ultraviolet radiance). A 10% increase in absolute monthly EV-A71 seroprevalence was associated with a 45% higher odds of an epidemic (adjusted odds ratio, aOR1.45; 95% CI 1.24-1.69; P<0.001). Every 10% decrease in seroprevalence between preceding and current months was associated with a 16% higher odds of an epidemic (aOR = 1.16; CI 1.01-1.34 P<0.034). In summary, the 2-3 year cyclical pattern of EV-A71 epidemics in Malaysia is mainly due to the fall of population immunity accompanying the accumulation of susceptible children between epidemics. This study will impact the future planning, timing and target populations for vaccine programs.
Matched MeSH terms: Hand, Foot and Mouth Disease/virology*
Nipah virus (NiV) is a highly pathogenic, recently emerged paramyxovirus that has been responsible for sporadic outbreaks of respiratory and encephalitic disease in Southeast Asia. High case fatality rates have also been associated with recent outbreaks in Malaysia and Bangladesh. Although over two billion people currently live in regions in which NiV is endemic or in which the Pteropus fruit bat reservoir is commonly found, there is no approved vaccine to protect against NiV disease. This report examines the feasibility and current efforts to develop a NiV vaccine including potential hurdles for technical and regulatory assessment of candidate vaccines and the likelihood for financing.
Nipah virus (NiV) is an emerging paramyxovirus that can cause lethal respiratory illness in humans. No vaccine/therapeutic is currently licensed for humans. Human-to-human transmission was previously reported during outbreaks and NiV could be isolated from respiratory secretions, but the proportion of cases in Malaysia exhibiting respiratory symptoms was significantly lower than that in Bangladesh. Previously, we showed that primary human basal respiratory epithelial cells are susceptible to both NiV-Malaysia (M) and -Bangladesh (B) strains causing robust pro-inflammatory responses. However, the cells of the human respiratory epithelium that NiV targets are unknown and their role in NiV transmission and NiV-related lung pathogenesis is still poorly understood. Here, we characterized NiV infection of the human respiratory epithelium using a model of the human tracheal/bronchial (B-ALI) and small airway (S-ALI) epithelium cultured at an air-liquid interface. We show that NiV-M and NiV-B infect ciliated and secretory cells in B/S-ALI, and that infection of S-ALI, but not B-ALI, results in disruption of the epithelium integrity and host responses recruiting human immune cells. Interestingly, NiV-B replicated more efficiently in B-ALI than did NiV-M. These results suggest that the human tracheal/bronchial epithelium is favourable to NiV replication and shedding, while inducing a limited host response. Our data suggest that the small airways epithelium is prone to inflammation and lesions as well as constituting a point of virus entry into the pulmonary vasculature. The use of relevant models of the human respiratory tract, such as B/S-ALI, is critical for understanding NiV-related lung pathogenesis and identifying the underlying mechanisms allowing human-to-human transmission.
Cervical cancer is a common malignancy which poses a significant health burden among women, especially those living in the developing countries. Although human papillomavirus (HPV) infection has been unequivocally implicated in the etiopathogenesis of the cancer, it alone is not adequate to contribute to the malignant transformation of cervical cells. Most HPV infections regress spontaneously, and only a small proportion of women have persistent infections which eventually lead to malignancy. This suggests that interplays between HPV infection and other cofactors certainly exist during the process of cervical carcinogenesis, which synergistically contribute to the differential susceptibility of an individual to the malignancy. Undoubtedly, host genetic factors represent a major element involved in such a synergistic interaction, and accumulating evidence suggests that polymorphisms in apoptosis-related genes play an important role in the genetic susceptibility to cervical cancer. This review consolidates the recent literatures on the role of common polymorphisms in apoptosis-related genes in genetic susceptibility to cervical cancer.
In many parts of Southeast Asia, the HIV-1 epidemic has been driven by the sharing of needles and equipment among intravenous drug users (IDUs). Over the last few decades, many studies have proven time and again that the diversity of HIV-1 epidemics can often be linked to the route of infection transmission. That said, the diversity and complexity of HIV-1 molecular epidemics in the region have been increasing at an alarming rate, due in part to the high tendency of the viral RNA to recombine. This scenario was exemplified by the discovery of numerous circulating recombinant forms (CRFs), especially in Thailand and Malaysia. In this study, we characterized a novel CRF designated CRF74_01B, which was identified in six epidemiologically unlinked IDUs in Kuala Lumpur, Malaysia. The near-full length genomes were composed of CRF01_AE and subtype B', with eight breakpoints dispersed in the gag-pol and nef regions. Remarkably, this CRF shared four and two recombination hotspots with the previously described CRF33_01B and the less prevalent CRF53_01B, respectively. Genealogy-based Bayesian phylogenetic analysis of CRF74_01B genomic regions showed that it is closely related to both CRF33_01B and CRF53_01B. This observation suggests that CRF74_01B was probably a direct descendent from specific lineages of CRF33_01B, CRF53_01B and subtype B' that could have emerged in the mid-1990s. Additionally, it illustrated the active recombination processes between prevalent HIV-1 subtypes and recombinants in Malaysia. In summary, we report a novel HIV-1 genotype designated CRF74_01B among IDUs in Kuala Lumpur, Malaysia. The characterization of the novel CRF74_01B is of considerable significance towards the understanding of the genetic diversity and population dynamics of HIV-1 circulating in the region.
The majority of hepatitis C virus (HCV) infection results in chronic infection, which can lead to liver cirrhosis and hepatocellular carcinoma. Global burden of hepatitis C virus (HCV) is estimated at 150 million individuals, or 3% of the world's population. The distribution of the seven major genotypes of HCV varies with geographical regions. Since Asia has a high incidence of HCV, we assessed the distribution of HCV genotypes in Thailand and Southeast Asia. From 588 HCV-positive samples obtained throughout Thailand, we characterized the HCV 5' untranslated region, Core, and NS5B regions by nested PCR. Nucleotide sequences obtained from both the Core and NS5B of these isolates were subjected to phylogenetic analysis, and genotypes were assigned using published reference genotypes. Results were compared to the epidemiological data of HCV genotypes identified within Southeast Asian. Among the HCV subtypes characterized in the Thai samples, subtype 3a was the most predominant (36.4%), followed by 1a (19.9%), 1b (12.6%), 3b (9.7%) and 2a (0.5%). While genotype 1 was prevalent throughout Thailand (27-36%), genotype 3 was more common in the south. Genotype 6 (20.9%) constituted subtype 6f (7.8%), 6n (7.7%), 6i (3.4%), 6j and 6m (0.7% each), 6c (0.3%), 6v and 6xa (0.2% each) and its prevalence was significantly lower in southern Thailand compared to the north and northeast (p = 0.027 and p = 0.030, respectively). Within Southeast Asia, high prevalence of genotype 6 occurred in northern countries such as Myanmar, Laos, and Vietnam, while genotype 3 was prevalent in Thailand and Malaysia. Island nations of Singapore, Indonesia and Philippines demonstrated prevalence of genotype 1. This study further provides regional HCV genotype information that may be useful in fostering sound public health policy and tracking future patterns of HCV spread.
Breast cancer is the malignant tumour that developed from cells of the breast and is the first leading cause of cancer death among women worldwide. Surgery, radiotherapy, and chemotherapy are the available treatments for breast cancer, but these were reported to have side effects. Newcastle disease virus (NDV) known as Avian paramyxovirus type-1 (APMV1) belongs to the genus Avulavirus in a family Paramyxoviridae. NDV is shown to be a promising anticancer agent, killing tumour cells while sparing normal cells unharmed. In this study, the oncolytic and cytotoxic activities of NDV AF2240 strain were evaluated on MDA-MB-231, human mammary carcinoma cell line, using MTT assay, and its inhibitory effects were further studied using proliferation and migration assays. Morphological and apoptotic-inducing effects of NDV on MD-MB-231 cells were observed using phase contrast and fluorescence microscopes. Detection of DNA fragmentation was done following terminal deoxyribonucleotide transferase-mediated Br-dUTP nick end labeling staining (TUNEL) assay, which confirmed that the mode of death was through apoptosis and was quantified by flow cytometry. Furthermore, analysis of cellular DNA content demonstrated that the virus caused an increase in the sub-G1 phase (apoptotic peak) of the cell cycle. It appears that NDV AF2240 strain is a potent anticancer agent that induced apoptosis in time-dependent manner.
Evaluation of binding between analytes and its relevant ligands on surface plasmon resonance (SPR) biosensor is of considerable importance for accurate determination and screening of an interference in immunosensors. Dengue virus serotype 2 was used as a case study in this investigation. This research work compares and interprets the results obtained from analytical analysis with the experimental ones. Both the theoretical calculations and experimental results are verified with one sample from each category of dengue serotypes 2 (low, mid, and high positive), which have been examined in the database of established laboratorial diagnosis. In order to perform this investigation, the SPR angle variations are calculated, analyzed, and then validated via experimental SPR angle variations. Accordingly, the error ratios of 5.35, 6.54, and 3.72% were obtained for the low-, mid-, and high-positive-specific immune globulins of patient serums, respectively. In addition, the magnetic fields of the biosensor are numerically simulated to show the effect of different binding mediums.
Enterovirus 71 (EV71) was first recognized in 1974. Since then it has been implicated in 13 small and large outbreaks world-wide. Large outbreaks of hand, foot and mouth disease (HFMD), mostly benign, occurred in Japan in 1973 and 1978. Four outbreaks with brain stem encephalitis and significant numbers of deaths occurred in Bulgaria and Hungary in the late 1970's and in Malaysia and Taiwan in 1997 and 1998 respectively. During the latter two epidemics, pulmonary edema and hemorrhage often leading to quick deaths in children aged from 0.5 to 3 years old was first recognized. In Taiwan 78 deaths and over 100,000 cases of HFMD occurred. Coxsackie A16 cocirculated with EV 71, without however, causing any severe illnesses. The transmission of EV 71 was related to number of siblings in a household, rural residence and contact with cases of HFMD. Genotype analyses show that genotypes have changed with time in the United States and Japan. Recent isolates from Japan are similar to the isolates from Malaysia and Taiwan in 1997 and 1998, respectively. Even though genotype analysis has not identified specific sequences responsible for neurovirulence, the strains causing brain stem encephalitis and pulmonary edema in the Far East are similar and have arisen since 1997. Seroepidemiological studies in Taiwan suggest that children aged from 0.5 to 4 years old are most susceptible while the rest of the population are over 50% immune. Theoretically there is a pool of such susceptible subjects every few years. In prevention for another major outbreak, a simple, inactivated Salk type vaccine should be immediately prepared and made available.
The nucleocapsid protein (NP) of Newcastle disease virus expressed in E. coli assembled as ring- and herringbone-like particles. In order to identify the contiguous NP sequence essential for assembly of these particles, 11 N- or C-terminally deleted NP mutants were constructed and their ability to self-assemble was tested. The results indicate that a large part of the NP N-terminal end, encompassing amino acids 1 to 375, is required for proper folding to form a herringbone-like structure. In contrast, the C-terminal end covering amino acids 376 to 489 was dispensable for the formation of herringbone-like particles. A region located between amino acids 375 to 439 may play a role in regulating the length of the herringbone-like particles. Mutants with amino acid deletions further from the C-terminal end (84, 98, 109 and 114 amino acids) tended to form longer particles compared to mutants with shorter deletions (25 and 49 amino acids).