Cross-reactivity of Malaysian rat cytomegalovirus strains with its human counterpart.

This study probes into the prospect of cross-reactivity of HCMV with RCMV which has not been acknowledged to date. We describe the uncovering of a protein with an estimated size of between 61-68 kDa from local RCMV strains which reacted with HCMV positive sera. Our findings are a first disclosure of a plausible immunological cross-reactivity between RCMV with its human counterpart which grounds substantial interest implying existence of conserved determinants between rat and human CMV polypeptides. The cross-reactive protein most likely represents an enveloped glycoprotein, though the precise identification and its degree of similarity needs to be evidently defined and further elucidated in forthcoming experiments.

Cross-reactivity of Malaysian rat cytomegalovirus strains with its human counterpart

This study probes into the prospect of cross-reactivity of HCMV with RCMV which has not been acknowledged to date. We describe the uncovering of a protein with an estimated size of between 61-68 kDa from local RCMV strains which reacted with HCMV positive sera. Our findings are a first disclosure of a plausible immunological cross-reactivity between RCMV with its human counterpart which grounds substantial interest implying existence of conserved determinants between rat and human CMV polypeptides. The cross-reactive protein most likely represents an enveloped glycoprotein, though the precise identification and its degree of similarity needs to be evidently defined and further elucidated in forthcoming experiments.

Circulating human group A rotavirus genotypes in Malaysia.

This study examined the temporal distribution of rotavirus genotypes in Malaysia. Rotaviruses from children with diarrhea admitted to hospitals in 1996 (n = 93) and 2007 (n = 12) in two different regions of Peninsular (West) Malaysia were analyzed for their G and P genotypes using a hemi-nested RT-PCR assay. In the 2007 samples, the dominant strain was G9P[8]. It was identified in 42% of the samples. Different strains all possessing the G1 genotype were identified in the rest of the samples. In contrast, 81% of the samples collected in 1996 were the G1P[8] strain. No strains with G9 genotype were detected in samples collected in 1996.

Molecular characterization and epidemiology of rotavirus isolates obtained from children with diarrhoea in Malaysia.

This retrospective study examined the G/P type of rotavirus in RNA samples that have previously been e-typed by RNA-PAGE in 1996. The results were then compared to 2007 samples to ascertain the extent of changes that may have occurred in this 11-years time interval. The G and P genotypes were determined by hemi-nested PCR and further analysed by phylogenetic study. In 1996, the G/P combination G1P[8], G(UT)P[8] and G1P(UT) prevalence rate were 81%, 9% and 7%, respectively. As expected, the G9 genotype which has already emerged worldwide was identified in 42% of the 2007 samples with the remaining 33% G1P[8] and 25% G1P(UT) Analysis of the RNA pattern showed that majority of the isolates were long e-type in both series, nevertheless minor differences within electropherotypes were observed. Genetic diversity in some strains of the human group A rotaviruses was analysed by phylogenetic methods. These findings will help in the decision to introduce rotavirus vaccines within the next decade.

A comparative study on the performance of two commercial anti-dengue IgM assay kits.

The performance of a commercial rapid immunochromatographic dengue IgG/IgM assay device was evaluated against an in-place dengue IgM-capture ELISA in the National Public Health laboratory. Of the 239 serum samples from patients with clinical diagnosis of acute dengue illness, 140 and 99 samples were tested positive and negative respectively for anti-dengue IgM by the in-placed ELISA. Comparatively, 72 and 76 samples were tested positive and negative respectively, and 91 samples gave equivocal results by the rapid dengue test device. The rapid immunochromatographic assay device gave a relative sensitivity of 49.3% and a relative specificity of 62.6%. Though the rapid immunochromatographic assay device has the advantages of rapid testing which simultaneously detects both IgG and IgM and can also be performed with whole blood, serum or plasma, the user has to exercise extreme caution with the interpretation of the test result.

Isolation of monoclonal antibodies-escape variant of dengue virus serotype 1.

INTRODUCTION: During an outbreak from December 2004 to March 2005, 138 isolates of dengue virus were prospectively obtained from acute-phase serum samples of 1,067 patients with the provisional clinical diagnosis of acute dengue illness admitted to the adult wards of Hospital Tengku Ampuan Rahimah, Klang, Malaysia. Of the 138 dengue virus isolates, 87, 11, 24 and 3 were typed as dengue serotypes 1, 2, 3 and 4, respectively, by a commercial dengue virus typing kit using monoclonal antibodies (Mab). 13 dengue virus isolates could not be assigned to any specific serotype by serotyping Mab and molecular typing using dengue-type specific molecular typing primer pairs. We report the associated clinical features and limited molecular genetics of this Mab-escape dengue virus variant. METHODS: Limited molecular characterisation of the Mab-escape dengue virus variants with respect to a few concurrently isolated dengue serotype 1 virus was performed by reverse transcriptase polymerase chain reaction (RT-PCR), followed by nucleic acid sequencing of the 500-bp dengue virus partial genomic capsid-PreM fragment. RESULTS: The aligned nucleic acid sequence of RT-PCR products showed that these Mab-escape variants were of identical nucleic acid sequence, and shared the highest sequence homology (99 percent) with dengue virus serotype 1 (GeneBank accession No. AB178040) isolated from a Japanese patient in 2004. Though these Mab-escape dengue virus variants were noted to replicate to a 2-log higher titre than the current circulating dengue virus serotype 1, there was no significant difference between these variants and the currently circulating dengue virus serotype 1 with respect to disease severity (dengue fever versus dengue haemorrhagic fever) and clinical features. CONCLUSION: There was no significant difference in the proportion of patients developing dengue haemorrhagic fever following acute infection by Mab-escape dengue virus 1 variant in comparison with infection by the conventional dengue virus 1. Similarly, there was no significant difference in the pattern of clinical presentations following acute infection by the two different strains of virus.

Re-emergence of Chikungunya virus in Malaysia.

An outbreak of Chikugunya (CHIK) fever occurred among the fishing community in Bagan Pancor, Perak. The outbreak was laboratory confirmed within 48 hours after the receipt of the specimens. Fifty-three patients' serum samples were submitted for laboratory investigation and 47 (88.7%) were confirmed to be positive for CHIK infection by RT-PCR, and/or virus isolation, and/or in-house immunoflourescent test. RT-PCR and virus isolation were the tests of choice for patients with illness of four days or less and detection of CHIK specific IgM for those with more than four days of fever. The nucleic acid sequence based on the 354- and 294-bp of the nsP1 and E1 genes of the CHIK virus detected from pools of adults Aedes aegypti mosquitoes were identical to those CHIKV virus isolated from humans in the same locality. Phylogenetic analysis of the CHIK virus based on the 257 nts partial E1 gene indicates that Bagan Panchor's strain was closely related to the first CHIK virus isolated during the outbreak in Klang in 1998.

Congenital rubella syndrome with positive serology and virus isolation.

An effective live attenuated rubella vaccine was available since 1969 and congenital rubella syndrome can be prevented with appropriate vaccination. We report a baby with congenital rubella syndrome born in Klang valley to indicate that the Universal Rubella Vaccination Programme adopted by the Ministry of Health Malaysia since 2002 has yet to achieve its effect of eliminating transmission of rubella and preventing congenital rubella infection in the community. To our knowledge, the virus isolate represents the first successful isolation of rubella virus in this country and will serve as the reference strain for future comparison in molecular epidemiological tracking of rubella virus activity this country.

Rubella outbreak amongst residential students in a military vocational school of Malaysia.

An outbreak of rubella occurred amongst 303 newly recruited residential Form IV students in a military vocational training school in Malaysia. Of the 303 Form IV students, 77 gave a history of acute illness. Rubella specific IgM was detected in the sera of 46.5% (141/303) whereas rubella specific IgG was detected in 100% of all Form IV students. Sixty five students with no clinical history of acute illness during the outbreak period had detectable rubella IgM in their sera and rubella specific IgM was detected in the sera of all symptomatic students except one. Maculopapular rash was the commonest presenting clinical feature among students with acute rubella infection in this outbreak (97.4%) followed by fever (88.2%). The duration of rash ranged from one to nine days with a mean of 4.6 days. Of the 65 students that had both fever and rash, 56 (85.2%) students had maculopapular skin eruption on the same day as the date of onset of fever, six (9.2%) developed the rash a day after the onset of fever and three (4.6%) had the rash after two days of fever. The duration of fever ranged from one to eight days with a mean of 3.5 days. The duration of conjunctivitis ranged from one to four days with a mean of 2.3 days, and all those who developed conjunctivitis had mild eye-discharge without photophobia. The duration of arthralgia ranged from one to three days with a mean of 2.1 days. The commonest type of joints affected was knee joints (66.7%, 12/18), followed by elbow and shoulder joints (27.8%, 5/18) and wrist joints (5.6%, 1/18). A good clinical history of the temporal relationship between the occurrence of rash and fever during the outbreak could easily differentiate rubella illness from that of measles.

Rotavirus RNA electropherotype in different states in Malaysia for the year 2000 and 2001.

A total of 157 stool samples were examined for Group A rotaviruses in diarrheic children admitted to 8 different major hospitals in Malaysia. The overall incidence rate in this study was 19.7% (31 of 157) with a variation of 9.5% to 39.1% in different locations. Majority of the infections detected were in those under 2 years of age and there were fewer admissions in the older age group. The stool samples were initially screened for rotavirus Group A by latex agglutination method and followed by RNA electrophoresis. The size and the characteristics wheel-shaped morphology of the viral preparations when examined by electron-microscopy further confirmed the presence of rotaviruses in the positive stool samples. Analysis of the RNA pattern showed that majority of the isolates, 51.6% (16 of 31) were Type IIC ('long' with comigration of RNA segments 7 and 8), 35.5% (11 of 31) with Type IIG ('long' with comigration of segments 7, 8, 9), 9.7% (3 of 31) with Type IG ('short' with comigration of RNA segments 7, 8, 9) and 3.2% (1 of 31) of mixed or atypical pattern. It appeared that over a 12 year interval, only one new or unusual rotavirus electropherotype was found. This is the first comprehensive report on the electropherotypes of rotaviruses covering eight different geographical locations in Malaysia and the data obtained is useful for understanding the geographic distribution and types of rotaviruses transmitting in Malaysia.

Molecular fingerprinting of fusidic acid- and rifampicin-resistant strains of methicillin-resistant Staphylococcus aureus (MRSA) from Malaysian hospitals.

The emergence and spread of multiresistant methicillin-resistant Staphylococcus aureus (MRSA) strains, especially those resistant to fusidic acid and rifampicin, in Malaysian hospitals is of concern. In this study DNA fingerprinting by PFGE was performed on fusidic acid- and rifampicin-resistant isolates from Malaysian hospitals to determine the genetic relatedness of these isolates and their relationship with the endemic MRSA strains. In all, 32 of 640 MRSA isolates from 9 Malaysian hospitals were resistant to fusidic acid and rifampicin. Seven PFGE types (A, ZC, ZI, ZJ, ZK, ZL and ZM) were observed. The commonest type was type ZC, seen in 72% of isolates followed by type A, seen in 13%. Each of the other types (ZI, ZJ, ZK, ZL and ZM) was observed in a single isolate. Each type, even the commonest, was found in only one hospital. This suggests that the resistant strains had arisen from individual MRSA strains in each hospital and not as a result of the transmission of a common clone.

Hepatitis delta virus in intravenous drug users in Kuala Lumpur.

The hepatitis delta virus (HDV) is an RNA containing virus that requires hepatitis B virus (HBV) to supply the envelope proteins. HDV only infect man in the presence of HBV, either as a coinfection or as superinfection in HBV carriers. In the presence of hepatitis B infection, the HDV may cause more severe liver damage than that caused by the hepatitis B virus alone. HDV infection was studied in 44 HBsAg positive serum samples collected from male intravenous drug users sent for screening to the Blood Services Centre (BSC), Hospital Kuala Lumpur (HKL) between 1990 and 1992. The majority (39) were in the 20 to 39 age group. The youngest was 19 years old and the oldest was 61 years old. There were 25 Malays, 13 Chinese, five Indians and one Albanian. Anti hepatitis delta antibody (Anti-HDV) was detected in 15 out of 44 (34%) of the drug addicts. These results shows an increased in delta infection in HBsAg positive intravenous drug addicts compared to the surveillance results in 1985 when no delta antibodies were detected, and the 1986 and 1989 surveillance which showed 17.8% and 20% delta antibody positivity respectively.

Prevalence of hepatitis C virus antibodies in blood donors in Malaysia.

Hepatitis C virus (HCV) is the chief aetiologic agent for the parenterally transmitted Non-A, Non-B (NANB) hepatitis. This preliminary study was done to determine the prevalence of anti-HCV in the blood donor population. Blood from 3,540 donors who donated blood to the Blood Services Centre, Hospital, Kuala Lumpur, from 25th August 1991 to 13th January 1992, was tested for anti-HCV using both the Ortho and Abbott 2nd Generation ELISA test kits. ELISA positive specimens were repeated twice but no confirmatory test was done. There were 53 out of 3,540 (1.49%) blood donors who were repeatedly reactive to anti-HCV by ELISA. We plan to do further tests to confirm the results, using RIBA-2 or Abbott Neutralising test. Twenty eight out of 1,713 (1.63%) Malays, 22 out of 1,373 (1.60%) Chinese and 2 out of 393 (0.50%) Indians had antibodies to HCV. There was no significant difference in prevalence in the different age groups. The majority of donors tested were males (3,511 out of 3,540) of which 53 (1.50%) were anti-HCV positive. Only 29 females were tested and all were negative. To determine infectivity of the anti-HCV positive cases we would like to introduce testing for RNA by polymerate chain reaction (PCR). Screening all donated blood for anti-HCV will decrease, but not totally eliminate, post-transfusion hepatitis.