Retrospective study of human leptospirosis in Malaysia based on microscopic
agglutination test (MAT) showed 13% overall prevalence of infection for the period
1983-1998. Results indicated that the prevalence was decreasing in the last five years
(1994-1998). The prevalence was highest among Indians (16.67%) followed by
Malays (11.48%) and the least among Chinese (5.88%). The 20-29 year-old group
showed the highest prevalence of infection (17.13%). Less than 10 year-old group
showed the least prevalence of infection (5.66%). Generally, many of the cases
occurred between the ages of 20-50 years. Serological survey based on enzymelinked
immunosorbent assay (ELISA) showed a high overall prevalence (12.56%) of
leptospiral infection. Kuala Lumpur showed the highest prevalence (19%) whilst
Penang recorded the lowest prevalence (6.67%). No significant differences in the
prevalence between the other states was noted A comparative study of three serological tests, namely enzyme-linked
immunosorbent assay (ELISA), microscopic agglutination test (MAT) and indirect
hemagglutination (IHA), test was carried out to evaluate these tests in the diagnosis
of human leptospirosis. A total of 3000 serum samples from three groups of people
were examined. In Group I, IgM and IgG-ELISA were able to detect a number of
cases in the first sampling before MAT titres were detectable. In the second
sampling, all samples positive for MAT were also positive for IgM-ELISA. IHA test
gave positive reactions with only 38% of the samples while all samples were positive
for ELISA. In Group II, ELISA detected IgM and IgG to leptospires in the samples
which were negative to MAT. These were samples from patients with clinical signs
of leptospirosis.
The polymerase chain reaction (peR) was evaluated as a tool for diagnosis of
leptospirosis and differentiation of leptospiral strains. Urine samples with as little as
10 serovar hardjo cells per ml of urine were positive on peR indicating high
sensitivity of the test. Detection of small number of leptospiral cells in urine by peR
was an advantage over culture. Random amplification polymorphic DNA (RAPD)
fingerprinting was applied to differentiate leptospiral strains. Two primers were
tested for their abilities to generate individual RAPD fingerprints. The DNA profiles
obtained with each primer were distinct and reproducible. The fingerprint obtained
could be useful for distinguishing the serovars up to the strain level. Profiles
obtained revealed genetic heterogeneity between serovars belong to one serogroup.Analysis of leptospiral DNA with restriction enzymes, Hind III, BamH I and
EeoR I revealed a high heterogeneity between the serovars examined. This high
heterogeneity may be due to the large genome of the genus Leptospira. No
relationship was found between the restriction patterns and the species from which
the isolate was isolated. Similarities were observed among isolates of the same
serovar. The 1 0 leptospiral field isolates were assayed for presence of plasmid DNA.
Only two isolates were found to harbour plasmid DNA. The plasmid profiling
obtained is of limited epidemiological value for differentiation of leptospiral isolates.
It appears that human leptospirosis is an endemic infection in Malaysia. The
findings showed that ELISA was a suitable serological test for diagnosis of
leptospirosis compared to MAT and IRA tests. On the other hand, the application of
peR and REA in the diagnosis of leptospirosis would be useful