The indirect fluorescence antibody technique has been employed to study the prevalence of toxoplasma antibodies in Singapore. 42.5% of clinically suspected cases of toxoplasmosis showed antibody titres. Of these, 17.5% had titres greater than or equal to 1.64. Malays and Indians have higher positive rates compared to the main ethnic group, the Chinese. Antibody titres are found in both males and females and span through the various age groups. The possible mode of transmission is discussed and the importance of congenital toxoplasmosis is indicated.
Epidemiological studies of human leptospirosis have generally been limited to countries with specialized laboratories employing the microscopic-agglutination (MA) test. The sensitized-erythrocyte-lysis (SEL) test is much simpler for routine hospital laboratories to carry out and it has been found valuable in the diagnosis of human leptospirosis. This paper reports the results of studies of the SEL test as an epidemiological tool in serological surveys.The results showed that the significant SEL titre was 1:80 and that the sensitivity of the test depended possibly on the antigen preparation and the amount of complement used. Most of the SEL antibodies were found to persist at significant titres for about 1 year after active infection, but less than half persisted longer than that. The SEL test is therefore useful for detecting recent infections and for indicating that stability of leptospirosis in an area.The endemicity of leptospirosis in West Malaysia was confirmed by the SEL test, based on the employment of 1:80 as the significant titre.
Serum specimens were collected from 6 species of animals living in 9 states of Malaysia including Sabah, North Borneo in 1993. Antibodies against Japanese encephalitis (JE) virus in these sera were detected by means of hemagglutination-inhibition (HI) and neutralization (NT) tests. By HI test, 702 of 2,152 (32.6%) sera showed positive results. Higher positive rates were obtained by the NT test, in which 1,787 of 1,927 (92.7%) sera had antibodies against JE virus. All serum specimens with positive HI were confirmed as positive by the NT. Swine sera showed especially higher rates of antibody positive and higher antibody titers compared with other animals. These results suggest that JE infections are widely distributed among many animals of Malaysia, and pig is the most susceptible amplifier host for JE virus.