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A non-competitive enzyme immunoassay (EIA) was developed to detect IgG antibody to the recently-described species Chlamydia pneumoniae strain TWAR. Purified elementary bodies of the organism were used as capture antigen. Cross-reacting antibody to Chlamydia trachomatis was detected in the assay by running a parallel EIA for IgG antibody to C. trachomatis. The C. pneumoniae assay was validated by comparing the results on 60 selected sera with those obtained with the microimmunofluorescence test. The comparison indicated that the EIA had a sensitivity of 88%, specificity of 100% and overall correlation with micro-immunofluorescence of 93%. The assay was applied to 352 sera from 3 populations within Australasia in a limited survey to determine the extent of exposure to this organism. Prevalence rates of up to 55% were found, suggesting that a significant amount of respiratory disease in the region may be due to C. pneumoniae strain TWAR.

An antibody class capture (ACC) enzyme-linked immunosorbent assay (ELISA) utilizing an F(ab)2 conjugate was established and its specificity and reproducibility were determined. The test was further validated by comparing its results with those obtained by 2 overseas reference laboratories which used the indirect immunofluorescence antibody test (IIFT) for Toxoplasma-specific IgM. It was found that the F(ab)2ACC-ELISA was not affected by the presence of rheumatoid and antinuclear factor in serum, that it was reproducible (coefficients of variation less than 10.0%), and that it compared well with tests currently used overseas. ELISA was then used to test for the presence of Toxoplasma-specific IgM in cord blood sera. The results obtained to date are consistent with the hypothesis that the prevalence of congenital toxoplasmosis in the population of Adelaide is less than 1/2,000.

Pharyngeal micro-organisms of 131 Australian and Malaysian children and adults were compared by analysis of aerobic culture of throat swab specimens. Enteric Gram-negative bacilli were commonly isolated in small numbers from Malaysian adults whether they had sore throats (28%) or not (36%), but were detected in only 9% of Australian adults without sore throats and in only 12% and 4% of Malaysian children with and without sore throats respectively. In other respects microbiological findings were similar in the different groups of subjects studied. It is concluded that the pharyngeal carriage rate of enteric Gram-negative bacilli may differ substantially between different groups of normal individuals. Our findings also suggest that these micro-organisms do not have a pathogenic role in pharyngitis.

Sera from 1071 patients in nine age categories were screened for Toxoplasma antibody by indirect immunofluorescence. Thirty per cent of the sera contained antibody at a titre greater than or equal to 1/16. The percentage of sera containing antibody rose from 3% in the 6 months--5 years age group to a maximum of about 40% in the 31--40 years age group. It remained constant thereafter. Eleven per cent of the 84 sera with Toxoplasma antibody titres greater than or equal to 1/128 had Toxoplasma IgM titres greater than or equal to 1/32. No significant difference was found in the possession of antibody between the sexes.