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Displaying publications 21 - 28 of 28 in total

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Outbreak of fatal childhood viral infection in Sarawak, Malaysia in 1997: inocula of patients' clinical specimens induce apoptosis in vitro

Abubakar S, Shafee N, Chee HY

Malays J Pathol, 1998 Dec;20(2):71-81.
PMID: 10879266

Identification of the aetiologic agent(s) associated with an outbreak of fatal childhood viral infection in Sarawak, Malaysia, in mid 1997 remains elusive. It is reported here that African green monkey kidney (Vero) and human monocytic (U937) cells treated with inocula derived from clinical specimens of some of these fatal cases showed the presence of cellular genomic DNA degradation when the extracted DNA was separated by pulsed field gel electrophoresis (PFGE), oligonucleosomal DNA ladders characteristic of apoptotic cells when the infected cells' DNA was separated by agarose gel electrophoresis, and apoptotic cellular DNA fragmentation when cells were stained using terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL). These results suggest that inocula derived from the patients' clinical specimens contain factors which stimulate apoptotic cellular responses in vitro.

Matched MeSH terms: Enterovirus/isolation & purification*
Molecular epidemiology and evolution of enterovirus 71 strains isolated from 1970 to 1998

Brown BA, Oberste MS, Alexander JP, Kennett ML, Pallansch MA

J Virol, 1999 Dec;73(12):9969-75.
PMID: 10559310

Enterovirus 71 (EV71) (genus Enterovirus, family Picornaviridae), a common cause of hand, foot, and mouth disease (HFMD), may also cause severe neurological diseases, such as encephalitis and poliomyelitis-like paralysis. To examine the genetic diversity and rate of evolution of EV71, we have determined and analyzed complete VP1 sequences (891 nucleotides) for 113 EV71 strains isolated in the United States and five other countries from 1970 to 1998. Nucleotide sequence comparisons demonstrated three distinct EV71 genotypes, designated A, B, and C. The genetic variation within genotypes (12% or fewer nucleotide differences) was less than the variation between genotypes (16.5 to 19.7%). Strains of all three genotypes were at least 94% identical to one another in deduced amino acid sequence. The EV71 prototype strain, BrCr-CA-70, isolated in California in 1970, is the sole member of genotype A. Strains isolated in the United States and Australia during the period from 1972 to 1988, a 1994 Colombian isolate, and isolates from a large HFMD outbreak in Malaysia in 1997 are all members of genotype B. Although strains of genotype B continue to circulate in other parts of the world, none have been isolated in the United States since 1988. Genotype C contains strains isolated in 1985 or later in the United States, Canada, Australia, and the Republic of China. The annual rate of evolution within both the B and C genotypes was estimated to be approximately 1.35 x 10(-2) substitutions per nucleotide and is similar to the rate observed for poliovirus. The results indicate that EV71 is a genetically diverse, rapidly evolving virus. Its worldwide circulation and potential to cause severe disease underscore the need for additional surveillance and improved methods to identify EV71 in human disease.

Matched MeSH terms: Enterovirus/isolation & purification
Sentinel surveillance for human enterovirus 71 in Sarawak, Malaysia: lessons from the first 7 years

Podin Y, Gias EL, Ong F, Leong YW, Yee SF, Yusof MA, et al.

BMC Public Health, 2006 Jul 07;6:180.
PMID: 16827926

BACKGROUND: A major outbreak of human enterovirus 71-associated hand, foot and mouth disease in Sarawak in 1997 marked the beginning of a series of outbreaks in the Asia Pacific region. Some of these outbreaks had unusually high numbers of fatalities and this generated much fear and anxiety in the region.
METHODS: We established a sentinel surveillance programme for hand, foot and mouth disease in Sarawak, Malaysia, in March 1998, and the observations of the first 7 years are described here. Virus isolation, serotyping and genotyping were performed on throat, rectal, vesicle and other swabs.
RESULTS: During this period Sarawak had two outbreaks of human enterovirus 71, in 2000 and 2003. The predominant strains circulating in the outbreaks of 1997, 2000 and 2003 were all from genogroup B, but the strains isolated during each outbreak were genetically distinct from each other. Human enterovirus 71 outbreaks occurred in a cyclical pattern every three years and Coxsackievirus A16 co-circulated with human enterovirus 71. Although vesicles were most likely to yield an isolate, this sample was not generally available from most cases and obtaining throat swabs was thus found to be the most efficient way to obtain virological information.
CONCLUSION: Knowledge of the epidemiology of human enterovirus 71 transmission will allow public health personnel to predict when outbreaks might occur and to plan interventions in an effective manner in order to reduce the burden of disease.

Matched MeSH terms: Enterovirus/isolation & purification*
Fulltext Genetic diversity of Coxsackievirus A21 associated with sporadic cases of acute respiratory infections in Malaysia

Supian NI, Ng KT, Chook JB, Takebe Y, Chan KG, Tee KK

BMC Infect Dis, 2021 May 17;21(1):446.
PMID: 34001016 DOI: 10.1186/s12879-021-06148-x

BACKGROUND: Coxsackievirus A21 (CVA21), a member of Enterovirus C from the Picornaviridae family, has been associated with respiratory illnesses in humans.
METHODS: A molecular epidemiological investigation of CVA21 was conducted among patients presenting with acute upper respiratory illnesses in the ambulatory settings between 2012 and 2014 in Kuala Lumpur, Malaysia.
RESULTS: Epidemiological surveillance of acute respiratory infections (n = 3935) showed low-level detection of CVA21 (0.08%, 1.4 cases/year) in Kuala Lumpur, with no clear seasonal distribution. Phylogenetic analysis of the new complete genomes showed close relationship with CVA21 strains from China and the United States. Spatio-temporal mapping of the VP1 gene determined 2 major clusters circulating worldwide, with inter-country lineage migration and strain replacement occurring over time.
CONCLUSIONS: The study highlights the emerging role of CVA21 in causing sporadic acute respiratory outbreaks.

Matched MeSH terms: Enterovirus/isolation & purification
Fulltext Detection and characterization of viruses causing hand, foot and mouth disease from children in Seri Kembangan, Malaysia

Ling BP, Jalilian FA, Harmal NS, Yubbu P, Sekawi Z

Trop Biomed, 2014 Dec;31(4):654-62.
PMID: 25776590 MyJurnal

Hand, foot and mouth disease (HFMD) is a common viral infection among infants and children. The major causative agents of HFMD are enterovirus 71 (EV71) and coxsackievirus A16 (CVA16). Recently, coxsackievirus A6 (CVA6) infections were reported in neighboring countries. Infected infants and children may present with fever, mouth/throat ulcers, rashes and vesicles on hands and feet. Moreover, EV71 infections might cause fatal neurological complications. Since 1997, EV71 caused fatalities in Sarawak and Peninsula Malaysia. The purpose of this study was to identify and classify the viruses which detected from the patients who presenting clinical signs and symptoms of HFMD in Seri Kembangan, Malaysia. From December 2012 until July 2013, a total of 28 specimens were collected from patients with clinical case definitions of HFMD. The HFMD viruses were detected by using semi-nested reverse transcription polymerase chain reaction (snRT-PCR). The positive snRT-PCR products were sequenced and phylogenetic analyses of the viruses were performed. 12 of 28 specimens (42.9%) were positive in snRT-PCR, seven are CVA6 (58.3%), two CVA16 (16.7%) and three EV71 (25%). Based on phylogenetic analysis studies, EV71 strains were identified as sub-genotype B5; CVA16 strains classified into sub-genotype B2b and B2c; CVA6 strains closely related to strains in Taiwan and Japan. In this study, HFMD in Seri Kembangan were caused by different types of Enterovirus, which were EV71, CVA6 and CVA16.

Matched MeSH terms: Enterovirus/isolation & purification*
Evaluation of different clinical sample types in diagnosis of human enterovirus 71-associated hand-foot-and-mouth disease

Ooi MH, Solomon T, Podin Y, Mohan A, Akin W, Yusuf MA, et al.

J Clin Microbiol, 2007 Jun;45(6):1858-66.
PMID: 17446325

Human enterovirus 71 and coxsackievirus A16 are important causes of hand-foot-and-mouth disease (HFMD). Like other enteroviruses, they can be isolated from a range of sterile and nonsterile sites, but which clinical sample, or combination of samples, is the most useful for laboratory diagnosis of HFMD is not clear. We attempted virus culture for 2,916 samples from 628 of 725 children with HFMD studied over a 3 1/2-year period, which included two large outbreaks. Overall, throat swabs were the single most useful specimen, being positive for any enterovirus for 288 (49%) of 592 patients with a full set of samples. Vesicle swabs were positive for 169 (48%) of 333 patients with vesicles, the yield being greater if two or more vesicles were swabbed. The combination of throat plus vesicle swabs enabled the identification of virus for 224 (67%) of the 333 patients with vesicles; for this patient group, just 27 (8%) extra patients were diagnosed when rectal and ulcer swabs were added. Of 259 patients without vesicles, use of the combination of throat plus rectal swab identified virus for 138 (53%). For 60 patients, virus was isolated from both vesicle and rectal swabs, but for 12 (20%) of these, the isolates differed. Such discordance occurred for just 11 (10%) of 112 patients with virus isolated from vesicle and throat swabs. During large HFMD outbreaks, we suggest collecting swabs from the throat plus one other site: vesicles, if these are present (at least two should be swabbed), or the rectum if there are no vesicles. Vesicle swabs give a high diagnostic yield, with the added advantage of being from a sterile site.

Matched MeSH terms: Enterovirus/isolation & purification*
RT-PCR, nucleotide, amino acid and phylogenetic analyses of enterovirus type 71 strains from Asia

Singh S, Chow VT, Chan KP, Ling AE, Poh CL

J Virol Methods, 2000 Aug;88(2):193-204.
PMID: 10960707

A specific and sensitive method based on RT-PCR was developed to detect enterovirus 71 (EV71) from patients with hand, foot and mouth disease, myocarditis, aseptic meningitis and acute flaccid paralysis. RT-PCR primers from conserved parts of the VP1 capsid gene were designed on the basis of good correlation with sequences of EV71 strains. These primers successfully amplified 44 strains of EV71 including 34 strains isolated from Singapore in 1997 and 1998, eight strains from Malaysia isolated in 1997 and 1998, one Japanese strain and the neurovirulent strain EV71/7423/MS/87. RT-PCR of 30 strains of other enteroviruses including coxsackievirus A and B, and echoviruses failed to give any positive amplicons. Hence, RT-PCR with these primers showed 100% correlation with serotyping. Direct sequencing of the RT-PCR products of 20 EV71 strains revealed a distinct cluster with two major subgroups, thus enabling genetic typing of the viruses. The genetic heterogeneity of these strains culminated in amino acid substitutions within the VP1, VP2 and VP3 regions. The sequencing of a 2.9 kb fragment comprising the capsid region and the major part of 5' UTR of two Singapore strains revealed that they belonged to a group distinct from the prototype EV71/BrCr strain and the EV71/7423/MS/87 strain. The dendrogram generated from 341 bp fragments within the VP1 region revealed that the strains of Singapore, Malaysia and Taiwan belong to two entirely different EV71 genogroups, distinct from the three genogroups identified in another recent study.

Matched MeSH terms: Enterovirus/isolation & purification*
Emerging and re-emerging epidemic encephalitis: a tale of two viruses

Wong KT

Neuropathol. Appl. Neurobiol., 2000 Aug;26(4):313-8.
PMID: 10931364

Two major epidemics of viral encephalitis occurred in Asia in 1997 and 1998. The first was a re-emergence of neurovirulent strains of enterovirus 71, which caused severe encephalomyelitis in children in Malaysia, Taiwan and Japan, on a background of hand, foot and mouth disease. Necropsy studies of patients who died of enterovirus 71 infection showed severe perivascular cuffing, parenchymal inflammation and neuronophagia in the spinal cord, brainstem and diencephalon, and in focal areas in the cerebellum and cerebrum. Although no viral inclusions were detected, immunohistochemistry showed viral antigen in the neuronal cytoplasm. Inflammation was often more extensive than neuronal infection, suggesting that other factors, in addition to direct viral cytolysis, may be involved in tissue damage. The second epidemic of viral encephalitis was the result of a novel paramyxovirus called Nipah, which mainly involved pig handlers in Malaysia and Singapore. Pathological evidence suggested that the endothelium of small blood vessels in the central nervous system was particularly susceptible to infection. This led to disseminated endothelial damage and syncytium formation, vasculitis, thrombosis, ischaemia and microinfarction. However, there was also evidence of neuronal infection by the virus and this may also have contributed to the neurological dysfunction in Nipah encephalitis. Some patients who seemed to recover from the acute symptoms have been re-admitted with clinical findings suggestive of relapsing encephalitis. As these two epidemics indicate, the emergence and re-emergence of viral encephalitides continue to pose considerable challenges to the neuropathologist, in establishing the diagnosis and unravelling the pathogenesis of the neurological disease.

Matched MeSH terms: Enterovirus/isolation & purification