Pathogenic leptospiras (1,424) isolated from natural waters and wet soils in Malaysia comprised 29 different serovars (synonym serotypes). All except two of the serovars had been found previously in Malaysia. The exceptional serovars were werrasingha, an Autumnalis serogroup member originally isolated in Ceylon, and a new serovar designated evansi. Serovar evansi had serological affinities with serovar ranarum which was isolated from the kidney of a frog in Iowa. The large variety of serovars found in jungle areas was consistent with similar previous findings of diverse serovar infections in troops who had operated in Malaysian jungles.
Titres of melioidosis haemagglutinating antibodies of 1/40 or more were found in 18 of 905 British, Australian, and New Zealand soldiers serving in West Malaysia. Previous mild unsuspected melioidosis seemed to be responsible for these positive titres, which were more common in men exposed to surface water at work and during recreation. This accords with the current view that soil and surface water is the normal habitat of Pseudomonas pseudomallei, the causal organism. Pyrexia of unknown origin after arriving in Malaysia was significantly more common in men with titres of 1/40 or more than in the remainder. It is suggested that mild melioidosis may present as pyrexia of unknown origin. Pyrexias of unknown origin should be investigated vigorously in patients who are in or who have visited endemic areas.
The decade of the 1980s is declared as a time to solve global domestic water supply problems. By 1990 international goals include the provision of adequate quantities of clean water to every person on earth. Such goals are justified on the basis of human health, economic well being, political development and equity and public safety. Drawing upon observations from Ethiopia, Malaysia and Liberia, cases where attempts to provide domestic water to villagers and rural town dwellers are presented. In all cited cases attempts to provide safe water have failed or are in jeopardy. Conclusions drawn from these cases include acknowledgement that global goals will best be achieved by approaching local problems one-by-one and recognizing the technical, environmental and human constraints upon safe water provision interact differently from one site to another. To properly plan, implement and maintain safe water systems the current technical solutions must be combined with the contributions of social and environmental scientists on a case-by-case basis.
This paper reviews the literature on leptospirosis in Malaysia from its first description in 1928 until the present day. Most of the early reports were on investigations of leptospirosis in wildlife and man and up-to-date, thirty-seven leptospiral serovars from thirteen serogroups have been bacteriologically identified. The thirteen serogroups are: Australis, Autumnalis Bataviae, Canicola, Celledoni, Grippotyphosa, Hebdomadis, Icterohaemorrhagiae, Javanica, Pomona, Pyrogenes, Sejroe and Tarassovi. Rats have been ascribed as the principal maintenance host of leptospires in Malaysia. However, serovars from the Pomona, Pyrogenes and Sejroe serogroups have yet to be isolated from rats. It is considered that the majority of leptospirosis cases in man were due to association of man with an environment where rats were plentiful. Recent investigations on domestic animals disclosed a high prevalence of infection in cattle and pigs and they were suspected as being the maintenance host for serovar hardjo and pomona respectively. There is ample scope for research in leptospirosis, particularly in the epidemiology and control of the disease in domestic animals. The strategy to control the infection in domestic animals and man in Malaysia is bound to be different from that of the temperate countries, basically due to the presence of a large number of leptospiral serovars in wildlife, further confounded by geographical and financial constraints.
A rapid method of assay, using a monoclonal antibody linked to alkaline phosphatase, was used for the detection of the Pontiac subgroup of Legionella pneumophila serogroup 1. It was tested for its specificity against 53 strains of Legionella recently isolated from the environment in Singapore and Malaysia. The specificity and sensitivity of this method of assay was confirmed, though there is some concern that the specificity was too narrow, and there are reservations about the criteria suggested for interpreting the results.
The membrane-filter assay, GM1-ELISA, and DNA-DNA hybridization assay, were used to detect enterotoxigenic Escherichia coli (ETEC) in samples of water, weaning food, food preparation surface swabs, fingerprints of mothers, and the fingerprints and stools of children under 5 years of age, in 20 households in a Malaysian village. Weaning food and environmental samples were frequently contaminated by faecal coliforms, including ETEC. The membrane-filter assay detected and enumerated faecal coliforms and LT-ETEC in all types of water and weaning food samples. Highest concentrations of faecal coliforms and LT-ETEC were found in weaning food, followed by well-water, stored water and stored drinking water. The GM1-ELISA detected LT-ETEC in weaning food, food preparation surfaces, fingerprints and stool samples. The DNA-DNA hybridization assay detected a larger proportion of STa2-ETEC than the other toxotypes, either singly or in combination. All the assays in combination detected the presence of ETEC in all types of samples on at least one occasion in each household. It was not possible to classify households as consistently more or less contaminated with ETEC. On individual occasions it was possible to show a significant association of the presence of LT-ETEC between the fingerprints of children and their stools, fingerprints of mothers and children, and weaning food and the stools of the child consuming the food.
Three building complexes in Kuala Lumpur were surveyed for the presence of legionellae in cooling towers. The organisms were grown from 12 out of 46 samples of water collected from 30 towers. L. pneumophila serogroups 1 and 7 were the commonest serogroups isolated. None belonged to the Pontiac subgroup of L. pneumophila serogroup 1.
The H2S water screening test and the membrane filtration faecal coliform count were compared with Escherichia coli counts for water samples collected from household water sources and domestic drinking water in rural Malaysia. Water samples were taken from 151 wells, 44 taps supplying water from the treated municipal supply and 192 domestic stored water supplies. E. coli were detected in 20% of the samples (42% of wells, 7% of tap water and 6% of drinking water). Excellent correlation (Spearman's rank correlation rs = 0.93) was found between the faecal coliform and E. coli counts for all sample types. The H2S method was poorly correlated whether read at 18 or 30 h. False positive rates were highest for well water, and false negative rates were highest for both well and drinking water samples, with low E. coli counts. The faecal coliform test was an excellent predictor of the presence of E. coli in these water samples, while the H2S test was very inadequate.
Collections of anopheline mosquitos were made twice monthly for 13 months from a cow-baited trap in two villages, Kampung Permatang Rawa and Sungai Udang Kecil, on mainland coastal Penang, Malaysia. Each collection period was six hours from sunset. Unquantified larval collections were made regularly in each area. Although the villages were only about 50km apart, and each had extensive, irrigated rice-fields in its vicinity, the species abundance and the seasonal fluctuations differed significantly. In Kampung Permatang Rawa Anopheles sinensis and An. peditaeniatus were dominant in prevalence, whereas in Sungai Udang Kecil An. indefinitus and An. lesteri paraliae were most common and An. peditaeniatus was relatively rare. The rice growing schedules in the two areas differed, but there was a moderate correlation between the abundance of several species and the rice-growing pattern. There was no correlation at either site with rainfall.
Molecular characterization of a total of 54 isolates of Salmonella typhi from Santiago, Chile, was performed by pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with three restriction endonucleases: XbaI (5'-TCTAGA-3'), AvrII (5'-CCTAGG-3'), and SpeI (5'-ACTAGT-3'). Thirteen of the 54 isolates were obtained from environmental sources (sewage and river water), and the rest were isolates from clinical cases of typhoid fever. Considerable genetic diversity was detected among the human isolates obtained in 1994, as evidenced by the presence of 14 to 19 different PFGE patterns among 20 human isolates, with F (coefficient of similarity) values ranging from 0.69 to 1.0 (XbaI), 0.61 to 1.0 (AvrII), and 0.70 to 1.0 (SpeI). A total of eight phage types were detected among these 20 isolates, with 50% possessing the E1 or 46 phage type. There was no correlation between PFGE pattern and phage types. Similar diversity was seen among 21 isolates obtained in 1983, with 17 to 19 PFGE patterns detected and F values of 0.56 to 1.0 (XbaI), 0.55 to 1.0 (AvrII), and 0.67 to 1.0 (SpeI). Comparison of these two groups of human isolates obtained 11 years apart indicated that certain molecular types of S. typhi are shared and are able to persist for considerable periods. A similar degree of genetic diversity was also detected among the environmental isolates of S. typhi, for which 10 to 12 different PFGE patterns were detected among the 13 isolates analyzed, with F values ranging from 0.56 to 1.0 (XbaI), 0.52 to 1.0 (AvrII), and 0.69 to 1.0 (SpeI). Certain molecular types present among the environmental isolates of S. typhi were also found among the human isolates from the same time period, providing evidence for the epidemiological link between environmental reservoirs and human infection.
Live eels and processed fish products from Malaysia are routinely checked for microbial pathogens before export to Japan. The eels and water from the ponds are screened for Vibrio cholerae and Salmonella spp, whereas the processed fish products are tested for microbial contamination (aerobic plate count), coliforms, E. coil and Vibrio cholerae. Results showed that live eels and water samples were negative for Vibrio cholerae but Salmonella spp were isolated occasionally. Various types of processed fish products had counts below 1.0 x 10(5) whilst coliforms, E. coli and Vibrio cholerae were absent. Records available showed that procedures involved in the production and transportation of live eel, preparation and processing of fish products have resulted in relatively safe food products.