Antibodies to Chlamydia species in patients attending a genitourinary clinic and the impact of antibodies to C. pneumoniae and C. psittaci on the sensitivity and the specificity of C. trachomatis serology tests.

In a retrospective study, the prevalence of antibodies to Chlamydia trachomatis serovars D to K, C. pneumoniae, and C. psittaci in cases attending a genitourinary clinic was examined. Blood samples were collected from 7,002 cases attending the clinic in Doncaster, England between May 1983 and May 1990. Sera from these samples were tested by a modified microimmunofluorescence test using panels of microdots of egg-grown, purified elementary bodies representing a pool of C. trachomatis D to K, a single C. pneumoniae agent, a single C. psittaci agent, and a negative control. Serum specimens were tested for the presence of IgG and IgM at starting dilutions of 1/16 and 1/8, respectively. Chlamydial IgG at a level of 1/16 or higher and IgM at a level of 1/8 or higher was present in 66.6% and 2.6% of samples, respectively. Species-specific or cross-reactive IgG against C. trachomatis D to K, C. pneumoniae, and C. psittaci was present in 32.6%, 25.1%, and 0.1% of the samples, respectively. In 8.7% of samples, the level of IgG was similar against two or all three species (group-specific). IgM against C. trachomatis D to K, C. pneumoniae, or C. psittaci was present in 2.5%, 0.03%, and 0.04% of the samples, respectively. The results of the study show that antibodies to C. pneumoniae and C. psittaci account for up to half of all chlamydia IgG positive cases attending genitourinary clinics.(ABSTRACT TRUNCATED AT 250 WORDS)

Chlamydial genital infection in Ibadan, Nigeria. A seroepidemiological survey.

Sera from patients attending a sexually transmitted diseases (STD) clinic, a family planning clinic, and an antenatal clinic in Ibadan, Nigeria, as well as from male blood donors from the same area were tested for the presence of type specific antichlamydial antibodies using a modified micro-immunofluorescence test. Among men and women attending the STD clinic the exposure rates to Chlamydia trachomatis serotypes D to K (genital pathogens) were 18.7% and 26.7% respectively. Antibody titres suggesting active disease in these men and women were found in 11.8% and 22.7% respectively. The highest rate of exposure (35%) was among women attending the family planning clinic; of these women 25% had antibody suggesting active disease. Titres of IgG antibody in this study were similar to those found among men and women with chlamydial genital infections in the United Kingdom. Antibodies to serotypes D to K were also detected in 10.3% of women attending an antenatal clinic and in 9.9% of male blood donors. The prevalence of antibodies to C trachomatis serotypes A to C and lymphogranuloma venereum serotypes was low. These results suggest that the prevalence of chlamydial genital infections in Ibadan, both among STD patients and especially among those individuals not seeking treatment (family planning and antenatal clinic patients), is high. Since serious sequelae can follow chlamydial genital infections it is imperative to carry out further investigations in this area.

Chlamydial genital infection in Addis Ababa, Ethiopia. A seroepidemiological survey.

A seroepidemiological survey was undertaken in Addis Ababa to assess the prevalence of chlamydial genital infections among patients attending a sexually transmitted diseases (STD) clinic and patients with no overt genital symptoms. In the STD clinic patients antibodies to Chlamydia trachomatis serotypes D to K (genital types) were detected in 68 of 210 (32.4%) men and in 72 of 159 (45.3%) women, a rate of exposure as high or higher than that found in Europe. Serological evidence of active chlamydial infection was present in 26.7% of men and 28.9% of women. Women were at risk of contracting STD, including chlamydial infections, at the age of 14 years or earlier. The titres of antichlamydial IgG were extremely high in some patients attending the STD clinic, with titres of between 1/512 and 1/8192 in 9.5% of men and 13.2% of women. This suggests that some patients had severe or disseminated chlamydial disease. The prevalence of exposure to chlamydial genital infections among 148 patients with no overt genital disease was 14.2%, which is significantly higher than that found in the United Kingdom. Among the total of 517 patients tested the prevalence of exposure to trachoma, lymphogranuloma venereum, and Chlamydia psittaci agents was very low.

Rapid serological test for diagnosis of chlamydial ocular infections.

A rapid serodiagnostic test for the diagnosis of paratrachoma (TRIC ophthalmia neonatorum, inclusion conjunctivitis, TRIC punctate keratoconjunctivitis, and trachoma of sexually transmitted origin) has been developed. The technique is based on using a modified micro-immunofluorescence test for detecting antichlamydial IgG and IgM in the blood and IgG and IgA in tears. The blood samples are collected on cellulose sponges after a finger prick, and tears are collected by introducing small sponges into the lower conjunctival fornix of the eye. The blood and tear samples collected in this way could be sent to the diagnostic laboratory by post without special arrangements for cold storage. In general the presence of antichlamydial IgG at a level of greater than or equal to 1/32 or IgM at a level of greater than or equal to 1/8 in blood and antichlamydial IgG or IgA at a level of greater than or equal to 1/8 in tears was closely associated with ocular paratrachoma. The combined results of the micro-IF test of blood and tears has yielded the highest rate of positivity (90%). In patients with acute untreated paratrachoma the sensitivity of this test was similar to that of irradiated McCoy cells. In patients with a milder infection receiving antibiotics the sensitivity of the serodiagnostic test was superior to that of the cultural test. The high sensitivity and specificity of this rapid, simple and inexpensive serodiagnostic test for the diagnosis of chlamydial ocular infections, coupled with simple and practical methods of collection and transport of blood and tear specimens, offer advantages over cultural tests for routine diagnosis and study of chlamydial ocular infections.