The assessment of risk factors for the Central/East African Genotype of chikungunya virus infections in the state of Kelantan: a case control study in Malaysia

BACKGROUND: The aims of the study were to assess the risk factors in relation to cross border activities, exposure to mosquito bite and preventive measures taken. An outbreak of chikungunya virus (CHIKV) infection in Malaysia has been reported in Klang, Selangor (1998) and Bagan Panchor, Perak (2006). In 2009, CHIKV infection re-emerged in some states in Malaysia. It raises the possibilities that re-emergence is part of the epidemics in neighbouring countries or the disease is endemic in Malaysia. For this reason, A community-based case control study was carried out in the state of Kelantan. METHODS: Prospective case finding was performed from June to December 2009. Those who presented with signs and symptoms of CHIKV infection were investigated. We designed a case control study to assess the risk factors. Assessment consisted of answering questions, undergoing a medical examination, and being tested for the presence of IgM antibodies to CHIKV. Descriptive epidemiological studies were conducted by reviewing both the national surveillance and laboratory data. Multivariable logistic regression analysis was performed to determine risk factors contributing to the illness. Cases were determined by positive to RT-PCR or serological for antibodies by IgM. CHIKV specificity was confirmed by DNA sequencing. RESULTS: There were 129 suspected cases and 176 controls. Among suspected cases, 54.4% were diagnosed to have CHIKV infection. Among the controls, 30.1% were found to be positive to serology for antibodies [IgM, 14.2% and IgG, 15.9%]. For analytic study and based on laboratory case definition, 95 were considered as cases and 123 as controls. Those who were positive to IgG were excluded. CHIKV infection affected all ages and mostly between 50–59 years old. Staying together in the same house with infected patients and working as rubber tappers were at a higher risk of infection. The usage of Mosquito coil insecticide had shown to be a significant protective factor. Most cases were treated as outpatient, only 7.5% needed hospitalization. The CHIKV infection was attributable to central/east African genotype CHIKV. CONCLUSIONS: In this study, cross border activity was not a significant risk factor although Thailand and Malaysia shared the same CHIKV genotype during the episode of infections

A Virological Study of Enterovirus Infections in Peninsular Malaysia

Background: Hand, foot, and mouth disease (HFMD) is a common illness in infants and children. It can be caused by many different human enteroviruses. Of these human enteroviruses, human enterovirus 71 (EV71) infection is more frequently associated with serious neurological complications and fatalities. The emergence of this virus emphasized the need for surveillance study and identification of EV71 to provide early warning of potential EV71 encephalitis outbreaks and assist in directing public health interventions as well as inform clinical decisions. This surveillance study was aimed to examine the prevalence of enteroviruses and EV71 in suspected clinical specimens. Methods: Samples preparation: Specimens with the clinical and epidemiological data were received from various hospitals in West Malaysia from January to December 2007. The samples were analyzed immediately upon arrival in our laboratory otherwise stored at −80 ◦C. RNA extraction: The RNA from the specimens were extracted using High Pure Viral Nucleic Acid Kit. PCR analysis and primer sequences: One step RT-PCR was employed with primers EVPCR1 (5�-ACA-CGG-ACA-CCCAAA-GTA-GTC-GGT-TCC-3�) and EVPCR2 (5�-TCC-GGC-CCCTGA-ATG-CGG-CTA-ATC-C-3�) for enteroviruses and MAS01S (5�-ATA-ATA-GCA-YTR-GCG-GCA-GCC-CA-3�) and MAS02A (5�-AGA-GGG-AGR-TCT-ATC-TCY-CC-3�) for EV71. Results: A total number of 2,381 clinical specimens were analyzed for the presence of enteroviruses and EV71 by RTPCR analysis. Out of all of the specimens analyzed, 531 (22.3%) were positive for enteroviruses and 21 (0.04%) of these were positive for EV71. These results showed that EV71 is less prevalent than other enteroviruses in the clinical specimens analyzed. Conclusion: The outcomes of the present surveillance study suggested that the EV71 which is more frequently associated with serious neurological and complications and fatalities is less prevalent than other enteroviruses. The results obtained also confirmed the usefulness of the PCR as a simple and rapid method for the detection of enteroviruses and discrimination of EV71 from other enteroviruses in clinical specimens

Draft genome sequence of the prazosin-degrading bacillus sp. Strain pr5, isolated from a river receiving hospital and urban wastewater in Malaysia

We report the complete genome sequence of Bacillus sp. strain PR5, isolated from a river receiving hospital and urban wastewater in Malaysia, which demonstrated a high capability for degrading prazosin. This genome sequence of 4,525,264 bp exhibited 41.5% GC content, 4,402 coding sequences, and 32 RNAs

Sentinel surveillance for human enterovirus 71 in Sarawak, Malaysia: lessons from the first 7 years

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

Genomic Approach to Understanding Epidemic Potentials and Tissue Tropism of Enterovirus A71 (EV-A 71) Strains

Since its first isolation in 1969, human enterovirus A71 (EV-A71) has been associated with large hand, foot and mouth disease (HFMD) outbreaks in several different countries throughout the world. Although other enteroviruses such as CV-A16, are also associated with large HFMD outbreaks and are generally associated with mild clinical presentations, EV-A71 infections can include neurological complications such as meningitis, acute flaccid paralysis, pulmonary oedema that sometimes have fatal outcomes. There have been concerns as to why some EV-A71 strains were associated with uncomplicated HFMD while others were associated with more severe clinical presentations that sometimes resulted in death. To understand this, full genomes sequences of EV-A71 viruses from all subgenogroups, different geographical areas and isolated from either uncomplicated HFMD, severe and fatal cases were characterized. Sequences comparison of 15 isolates of EV-A71 from this study and other sequences retrieved from the GenBank were done. Phylogenetic analysis was separately done for all individual gene regions, the three P1, P2 and P3 regions and the complete genome sequence. Generally, all analysed regions reflected the three (A, B and C) genogroup clustering that had been previously proposed for EV-A71. No interspecific recombination was observed. The trees of VP4 showed concordant phylogenetic profiles with VP1 and may be useful for quick molecular typing of EV-A71 isolates owing to the smaller genome size of the VP4. Comparing the amino acid sequences for all genes, in the P1 region, VP4 showed 100% conserved amino acids sequences across all subgenogroups. In VP2, 4 amino acid substitutions differentiated between genogroup B from C isolates but were not associated uniquely with any particular clinical presentation (mild, severe and fatal) which suggests that they may not be important in virus virulence. In VP3, substitutions amino acid at 413 and 414 with leucine and glutamic acid were associated with isolates iii from severe and fatal cases but not with isolates from mild/uncomplicated case. The strain TW 2272/98 (isolated from a fatal case) from subgenogroup C2, with variation at several amino acid positions, 708 (S for T), 710 (Q for E), 749 (N for T) and consecutive substitutions from 826 to 830 (ECQTP for AWIPR) and 832-833 (IT for MR) could play a role in virulence and clinical presentation of the diseases. In the P2 region, substitutions of asparagine, serine and alanine at amino acid positions 919, 969 and 986 respectively in the 2A gene and substitutions at positions 1059 and 1097 were observed randomly across isolates from all three genogroups. The 2C gene had the most amino acids differences with 17 in genogroup B and 11 between the genogroups B and C. All these substitutions could not be attributed to differences in strains virulence as isolates from uncomplicated HFMD and fatal cases did not show obvious differences. In the P3 region, the 3A gene had different amino acids in the subgenogroups but not between the genogroups A, B and C. In subgenogroup B, isolates from Singapore and Malaysia were different at positions 1503, 1506, whereas in subgenogroup C, the differences were noted at positions 1484, 1486, 1503, and 1505. The 3B, 3C and 3D genes had amino acids with 86% similarity but no clear association with any particular clinical presentation. These results suggest that virulence of EV-A71 strains may be associated with more than one single amino acid substitution sites and also with differences in the 5’UTR region that play a role in the expression of the viral genome

RESEARCH NOTE MONITORING OF THE H275Y MUTATION IN PANDEMIC INFLUENZA A(H1N1) 2009 STRAINS ISOLATED IN MALAYSIA

Abstract. The 2009 pandemic influenza A(H1N1) infection in Malaysia was first reported in May 2009 and oseltamivir was advocated for confirmed cases in postexposure prophylaxis. However, there are cases of oseltamivir-resistance reported among H1N1-positive patients in other countries. Resistance is due to substitution of histidine by tyrosine at residue 275 (H275Y) of neuraminidase (NA). In this study, we have employed Sanger sequencing method to investigate the occurrence of mutations in NA segments of 67 pandemic 2009 A(H1N1) viral isolates from Malaysian patients that could lead to probable oseltamivir resistance. The sequencing analysis did not yield mutation at residue 275 for all 67 isolates indicating that our viral isolates belong to the wild type and do not confer resistance to oseltamivir

Human Adenovirus Type 7 Outbreak in Police Training Center, Malaysia, 2011

In March 2011, an outbreak of acute respiratory disease was reported at the Kuala Lumpur (Malaysia) Police Training Centre. Approximately 100 trainees were hospitalized and 5 were admitted to the intensive care unit. Three of these 5 trainees died. Human adenovirus type 7 was identified as the etiologic agent

Influenza seasonality and vaccination timing in tropical and subtropical areas of southern and south-eastern Asia

Objective To characterize influenza seasonality and identify the best time of the year for vaccination against influenza in tropical and subtropical countries of southern and south-eastern Asia that lie north of the equator. Methods Weekly influenza surveillance data for 2006 to 2011 were obtained from Bangladesh, Cambodia, India, Indonesia, the Lao People's Democratic Republic, Malaysia, the Philippines, Singapore, Thailand and Viet Nam. Weekly rates of influenza activity were based on the percentage of all nasopharyngeal samples collected during the year that tested positive for influenza virus or viral nucleic acid on any given week. Monthly positivity rates were then calculated to define annual peaks of influenza activity in each country and across countries. Findings Influenza activity peaked between June/July and October in seven countries, three of which showed a second peak in December to February. Countries closer to the equator had year-round circulation without discrete peaks. Viral types and subtypes varied from year to year but not across countries in a given year. The cumulative proportion of specimens that tested positive from June to November was > 60% in Bangladesh, Cambodia, India, the Lao People's Democratic Republic, the Philippines, Thailand and Viet Nam. Thus, these tropical and subtropical countries exhibited earlier influenza activity peaks than temperate climate countries north of the equator. Conclusion Most southern and south-eastern Asian countries lying north of the equator should consider vaccinating against influenza from April to June; countries near the equator without a distinct peak in influenza activity can base vaccination timing on local factors