Using cultured mouse fibroblast L929 cells, this study demonstrated the hemolytic and cytotoxic activities and induction of apoptosis in cells infected with Orientia tsutsugamushi. Low levels of hemolytic activity were detected using heavily infected cells. No hemolysin or cytotoxin were detected in the infected culture fluid regardless of the pathogenicity of the O. tsutsugamushi strains in mice. Using propidium iodide uptake assay, acridine orange/ethidium bromide staining and terminal deoxynucleotide transferase-mediated dUTP-digoxigenin nick-end labeling assay, apoptosis was observed in L929 cells infected with Karp and Gilliam strains.
The seroprevalence of Orientia tsutsugamushi (OT), Rickettsia typhi (RT) and TT118 spotted fever group rickettsiae (SFGR) among blood donors and febrile Malaysian patients in the urban areas was determined. Of the 240 blood donors, 5.4%, 9.2% and 1.7% had either present or previous exposure to OT, RT and SFG rickettsiae, respectively. Patients admitted to an urban hospital had high seroprevalences of OT (43.5%) and RT (22.9%), as compared to SFGR (11.6%). Antibody levels suggestive of recent infections of scrub typhus, murine typhus and tick typhus were detected in 16.8%, 12.7% and 8.2% of patients respectively. No significant difference was noted in the distribution of rickettsial antibodies among urban patients from 2 geographical locations. However, the serologic patterns of rickettsial infection in the urban areas were different form those of rural areas.
The pathogenicity of Malaysian isolates of Orientia tsutsugamushi was investigated by a mouse virulence assay. The isolates could be differentiated as low (4 isolates), moderately (3 isolates) and highly virulent (2 isolates) based on the different responses in infected mice. No direct correlation between severity of human scrub typhus infections and virulence of the O. tsutsugamushi in mice was observed. Mice infected with virulent strains of O. tsutsugamushi showed splenomegaly, ascitis accumulation and enlargement of kidneys and livers whereas avirulent O. tsutsugamushi strains were asymptomatic and exhibited ruffled fur for a short period after infection. There was low antibody response in mice infected with isolates of low pathogenicity as compared with those of highly virulent isolates. Upon dissection of the infected mice, enlargement of mouse organs such as spleen, kidney and liver was noted. Presence of rickettsemia in mice was confirmed by the growth of O. tsutsugamushi in the L929 cells when inoculated with blood from infected mice. O. tsutsugamushi was also cultured from the peritoneal exudates of the infected mice. However, DNA of O. tsutsugamushi was only detected in the peritoneal exudates (by PCR) and blood (by cell culture) and not from other tissue samples.
We performed a case control study to examine protective and risk factors for acute respiratory infections (ARI) in hospitalized children in Kuala Lumpur. Consecutive children between the ages of one month and five years hospitalized for pneumonia (n = 143), acute bronchiolitis (n = 92), acute laryngotracheobronchitis (n = 32) and empyema (n = 4) were included as cases and were compared with 322 children hospitalized during the same 24 hour period for non-respiratory causes. Potential risk and protective factors were initially analysed by univariate analysis. Logistic regression analysis confirmed that several home environmental factors were significantly associated with ARI. The presence of a coughing sibling (OR = 3.76, 95%CI 2.09, 6.77), a household with more than five members (OR = 1.52, 95%CI 1.03, 2.19) and sleeping with three other persons (OR = 1.45, 95%CI 1.00, 2.08) were independent risk factors. Significant host factors were history of allergy (OR = 2.50, 95%CI 1.74, 3.61) and ethnicity (Malay race) (OR = 2.07 95%CI, 1.27, 3.37). Breast feeding for at least one month was confirmed as an independent protective factor (OR = 0.58, 95%CI 0.38, 0.86). However, the study was not able to demonstrate that domestic air pollution had an adverse effect. This study provides further evidence that home environmental factors, particularly those associated with crowding, may predispose to ARI and that breast feeding is an important protective factor.
This study was carried out to determine if Japanese encephalitis virus is an important causative agent of viral encephalitis among pediatric admissions in Penang, Malaysia. 195 children with CNS symptoms and 482 children with non-specific febrile illness admitted into the Pediatric Ward of Penang Hospital during a 16 month period were entered into the study. The presence in serum of cerebrospinal fluid (csf) of Japanese encephalitis virus (JEV) specific IgM was determined by an IgM capture ELISA and cytomegalovirus (CMV) specific IgM was determined using a commercially available kit (Behringwerke AG). It was determined that 5 of 13 children with a discharge diagnosis of viral encephalitis had JEV specific IgM in csf, indicating that 38.5% of the viral encephalitis cases was due to JEV. One of the non-JEV cases was found to have mumps virus specific IgM in csf, while no etiology was determined for the other cases. It was also determined that 4 of the 195 (2.1%) cases with CNS symptoms had IgM to CMV, suggesting CMV may be an agent of encephalopathy in children in Penang. Other viruses found to be associated with CNS symptoms in children admitted into our study were measles and herpes simplex virus. A viral etiology was confirmed for 13 or the 195 cases (6.7%). We also screened 482 non-specific febrile cases for IgM to JEV and to dengue viruses and found that 2 (0.4%) had IgM specific for JEV and 9 (1.9%) had IgM specific for dengue virus.
In 1990 and 1991, six laboratories located in the WHO Western Pacific Region (WPR) and South East Asian Region (SEAR) were selected, based on their experience in the immunofluorescence antibody technique (IFAT), to participate in the evaluation of a WHO monoclonal antibody (Mab) kit to detect respiratory syncytial (RS) virus, influenza A virus, influenza B virus, parainfluenza virus and adenovirus. Despite differences in the initial standardization procedures, the WHO monoclonal antibodies were found to be of high quality, sensitivity and specificity when tested on clinical specimens. The constant supply of affordable high quality reagents from WHO would enable their use in clinical virological laboratories in the developing countries as well as promote the utilization of IFAT as an adjunct to cell culture isolation in the diagnosis of acute respiratory viral infections.
Awareness of the disinfection and sterilization policy among hospital staff and their knowledge in basic principles and methods of disinfection and sterilization were studied before and after intervention using a self-administered questionnaire. Survey results showed that awareness (56.2%) before intervention was unsatisfactory. The nurses were more aware of the policy than other groups of medical personnel. Those unaware of the policy perform duties from memory or verbal instructions. A significant increase in awareness to 73.3% was observed after intervention (p < 0.05). Knowledge on methods of decontamination, disinfection and sterilization of equipment varies widely from 28.8% to 90.1%. 23.1% were unaware of the temperature used for sterilization while 72.4% did not know how containers of disinfectant should be refill. Only 14.7% knew the recommended method for washing containers. With education improvement was observed. The average knowledge improved from 44.4% to 57.3%. Our results indicated that continuous in-service education is needed to improve, supplement and update knowledge in this field after basic training. In addition orientation programs for new staff should also be aimed at creating awareness and providing information on guidelines and policies related to their duties.
Comparative DDT-susceptibility status and glutathion s-transferase (GST) activity of Malaysian Anopheles maculatus, Culex quinquefasciatus and Aedes aegypti was investigated to ascertain the role of this enzyme in DDT resistance. The standardised WHO dose-mortality bioassay tests were used to determine DDT susceptibility in these mosquitos, whilst GST microassay (Brogdon and Barber, 1990) was conducted to measure the activity of this enzyme in mosquito homogenate. It appeared that DDT susceptibility status of Malaysian mosquitos was not correlated with GST activity.
Renal biopsy is essential in the management of renal parenchymal diseases. Thus far there is no publish report on the pattern of glomerulonephritis in Kelantan. We decided to establish the pattern of glomerulonephritis in Kelantan and use this information as our reference in future studies. Records of patients who had proven glomerulonephritis histologically were analysed. Their biological data, clinical presentation, etiology and clinicopathological pattern were studied. Where appropriate mean and standard deviation were calculated. A total of 74 biopsies were performed during the study period (between January 1991 and December 1993), out of which 72 biopsies (97.3%) were considered suitable for analysis. The male to female ratio was 1:1.1. Mean age at presentation was 27.6 +/- 12.2 years. Nephrotic syndrome was the commonest clinical presentation (65.3%). The main underlying cause was systemic lupus erythematosus (50%) followed by primary glomerulonephritis. Histologically, IgA nephropathy and minimal change disease were the main patterns among patients with primary glomerulonephritis while diffuse proliferative glomerulonephritis was the commonest pattern among patients with lupus nephritis. Hence the pattern of glomerulonephritis is similar to other reported series. The procedure is considered safe and has a high success rate.
A total of 2,034 subjects aged 15 years and above from different parts of the State of Kelantan were studied to determine goiter size and urinary iodine excretion. The State was divided into 2 areas - area 1 consisting of localities in the districts near the coast and area 2 consisting of localities in the inland districts. There were 1,050 subjects in area 1 and 984 subjects in areas 2. The mean age (+/- SE) of subjects in areas 1 and 2 were 38.2 + 0.5 and 37.1 +/- 0.5 years, respectively. The prevalence of goiter was 31.4% in area 1 and 45.0% in area 2; the difference was statistically significant (p < 0.05). However, the prevalence of large and visible goiters (grades II and III) was only 2.0% in area 1 and 3.3% in area 2; the difference was not statistically significant. The mean (+/- SD) urinary iodine excretion in areas 1 and 2 was 57.1 +/- 2.1 and 56.8 +/- 2.1 micrograms I/g Cr, respectively. The values were below those recommended by WHO. There was no significant difference in urinary iodine excretion between those with and without goiters in both areas and also between the grades of goiters. There were significantly more females with goiters than males in both areas but there was no significant difference in the urinary iodine excretion between the 2 sexes. Thus based on urinary iodine excretion, the iodine intake of the population in this area, was suboptimal and this was associated with a high prevalence of goiter.
There are few small animals models for filariasis, even more so for onchocerciasis. Therefore it is difficult to test under drug screening conditions large numbers of potentially macrofilaricidal compounds. One way around this difficulty is to use mice infected with Trichinella spiralis which by reason of anatomical location in the host would show some correlation in antinematode activity between the test and target organisms. This study investigated the activity of 16 compounds against the immature larval stage of T. spiralis. All the nine benzimidazole compounds (albendazole, flubendazole, mebendazole, oxfendazole, oxibendazole 780118, 780120, 790163, and 790392) were active, the most potent being oxfendazole. The benzothiazoles (CGP21306, CGP20376, CGP21833 and CGP24588A) also indicated some anti-nematode activity together with 35vr, an imidazopyridine, but not as marked as the benzimidazole group. However, the organic arsenical compounds (Mel Ga and Mel Ni) showed little activity and this was at a rather highly toxic level. The prospects of using the Trichinella-mouse model as a primary screen to test for potential macrofilaricides are discussed.
The prevalence of hepatitis A virus (HAV) in a country largely reflects its standards of hygiene and socioeconomic conditions. Countries which undergo socioeconomic development show major change in HAV prevalence from high to low endemicity, and this is largely reflected in patterns of age-related seroprevalence. This paper presents age-related HAV seroprevalence patterns of SE Asian countries, and highlights how these patterns have changed over recent decades. Singapore, Thailand and Malaysia have experienced a decline in childhood and adolescent HAV seroprevalence, typical of countries which undergo socioeconomic development. By contrast, India has remained a country of high endemicity, with almost universal seroconversion in childhood. The Philippines and Vietnam show age-related seroprevalence patterns typical of high to moderate endemicity, while Indonesia shows significant regional variation in HAV seroprevalence. Populations within countries which exhibit major improvements in endemicity and age related HAV seroprevalence patterns are at risk of HAV epidemics, and a paradoxical increase in incidence tends to occur as seroconversion shifts from children to adults. The residents of these countries, a significant number of whom are at-risk, would benefit from a program of vaccination, as would non-infected individuals visiting high-risk areas.
A cohort of one hundred 8-9 year old school children in Northeastern Peninsular Malaysia underwent stool examination, weight and height measurements. Seventy-three children were infected with Ascaris lumbricoides and/or Trichuris trichiura. All infected children were treated with albendazole at baseline, 6 months and 9 months. Measurements were repeated on all but 2 children at 1 year. Repeat stool examination (n = 94) at 1 year revealed a marked reduction in the level of Ascaris infection and a modest reduction in Trichuris infection. There was no difference in net growth between treated children and uninfected controls. Post-hoc analysis by gender however revealed that infected girls (n = 33) experienced significantly higher increments in weight, height and weight for age. Furthermore, children found to be infected at baseline level but worm free at follow-up, were observed to have experienced greater increments in height and height for age. The evidence suggests that periodic antihelminthic treatment may have a positive effect on the growth of subsets of pre-adolescent children but it is emphasised that further work is required to validate these findings.
A total of 402 Escherichia coli isolates were obtained from a variety of food samples and screened for enteropathogenic E. coli (EPEC). Screening was carried out using 15 specific monovalent antisera from Murex Diagnostic Limited. A total of 19 E. coli isolates were serotyped as EPEC. The EPEC strains were shown to belong to 8 serotypes. Eight out of 19 EPEC strains belonged to serotype 018C:K77 (B21). Seventeen out of 19 of the EPEC strains were isolated from cooked food. The presence of E. coli in cooked food is an indicator of fecal contamination and a sign of unhygienic food handling. The presence of EPEC in food could be a potential source of food-borne outbreak. Hygiene training for every food-handler is a necessity.
Soil-transmitted helminthiasis is a common problem in communities with poor socio-environmental conditions. This study was undertaken to identify important socio-environmental predictors of soil-transmitted helminthiasis in Bachok, a rural community in Kelantan for the development and implementation of an effective prevention and control program. Of 363 children randomly sampled, 38.8% were infected with soil-transmitted helminthiasis. Risk predictors of soil-transmitted helminthiasis found to be significant after adjustment included poor household hygiene score and large household size. The probability of being infected was 0.58 amongst children with both of these risk factors.
Records of 183 patients with renal stones managed at Hospital Universiti Sains Malaysia between 1985 and 1995 were retrospectively evaluated. The commonest symptom was lumbar pain which may be associated with either frequency, blood stained urine or dysuria. One hundred and sixty-one patients (88%) had upper tract stones while the remainder had lower tract stones. Positive urine cultures were seen in 33 patients. The commonest organism isolated was Escherichia coli followed by Klebsiella aeruginosa and Staphylococcus aureus. Almost all of our patients had renal impairment at presentation and 70% of them progressed to chronic renal failure. In contrast to previous findings, the pattern of renal stone in this region is similar to that described in Western society. Its effect on renal function is serious and hence warrant special attention.