A study of human respiratory tract chlamydial infections in Cambridgeshire 1986-88

Chlamydia psittaci detected at a live poultry wholesale market in central China

BACKGROUND

We investigated the presence of Chlamydia psittaci in poultry and the environment in live poultry wholesale markets in Changsha during 2021-2022 and conducted a phylogenetic analysis to understand its distribution in this market.

METHODS

In total, 483 samples were analyzed using real-time polymerase chain reaction and 17 C. psittaci-positive samples using high-throughput sequencing, BLAST similarity, and phylogenetic analysis.

RESULTS

Twenty-two out of 483 poultry and environmental samples were positive for C. psittaci (overall positivity rate: 4.55%) with no difference in positivity rates over 12 months. Chlamydia psittaci was detected at 11 sampling points (overall positivity rate: 27.5%), including chicken, duck, and pigeon/chicken/duck/goose shops, with pigeon shops having the highest positivity rate (46.67%). The highest positivity rates were found in sewage (12.5%), poultry fecal (7.43%), cage swab (6.59%), avian pharyngeal/cloacal swab (3.33%), and air (2.29%) samples. The ompA sequences were identified in two strains of C. psittaci, which were determined to bear genotype B using phylogenetic analysis. Thus, during monitoring, C. psittaci genotype B was detected in the poultry and environmental samples from the poultry wholesale market in Changsha.

CONCLUSIONS

To address the potential zoonotic threat, C. psittaci monitoring programs in live poultry markets should be enhanced.

Ocular adnexal non-Hodgkin's lymphoma: a review of epidemiology and risk factors

Ocular adnexal non-Hodgkin's lymphoma (NHL), the most common form of ophthalmic NHL, has a unique incidence pattern showing a steady and rapid increase in the past few decades, nearly equal rates among both genders, and predominance among Asians/Pacific Islanders. No major cause for ocular adnexal NHL has been identified, although infectious agents, immune disorders and genetic/epigenetic factors have all been implicated in its etiology. Identifying putative risk factors and biologic mechanisms leading to carcinogenesis in ocular adnexal NHL may enable implementation of effective preventive and/or therapeutic approaches for this malignancy. This article summarizes current knowledge on epidemiology of ocular adnexal NHL and the role of various potential risk factors in its etiology.

Evaluation of two serological tests for the diagnosis of chlamydial respiratory disease

Serological tests for chlamydial infection are one of the most frequently used methods in the diagnosis of atypical respiratory infections. Use of serological tests has implicated chlamydial infections in asthma, arthritis and coronary heart disease, but the specificity of chlamydial serology tests has been questioned. The immunofluorescence test is the most sensitive and specific serological test available for detection of chlamydial antibodies. This study compares two commercially available immunofluorescent antibody tests. The SeroFIA test using purified elementary bodies of Chlamydia pneumoniae, C. psittaci and C. trachomatis, detected 24 cases of acute C. pneumoniae infection, whereas the Spot IF test using whole cell antigen of C. psittaci and C. trachomatis, misdiagnosed 20 of these as psittacosis and missed four cases.

Utility of complement fixation and microimmunofluorescence assays for detecting serologic responses in patients with clinically diagnosed psittacosis

The serodiagnosis of human psittacosis was considerably improved by a microimmunofluorescence (MIF) assay that uses selected strains of Chlamydia psittaci, C. pneumoniae, and C. trachomatis as antigens. The 78 patients examined in the study were clinically diagnosed as having psittacosis on the basis of compatible clinical symptoms following exposure to sick birds. The conventional complement fixation (CF) test identified 36 patients, or 46% (36 of 78) of the total, as positive. Antibody responses to C. psittaci were demonstrated by the MIF test in all 36 CF-positive patients. The MIF test also detected antibody responses to C. psittaci in 12 patients (15% of the total) whose sera were negative or anticomplementary in the CF test. Seven patients, or 9% (7 of 78) of the total, were identified by the MIF test as having C. pneumoniae infections. About 30% of the study patients (23 of 78) showed no serologic evidence of either C. psittaci or C. pneumoniae infection by both the CF and the MIF tests. Four distinctive serologic reaction patterns were observed in the study patients. Recognition of these reaction patterns and judicious corroboration of serologic responses to the chlamydial species by the MIF test with epidemiologic and clinical information will increase the efficiency and accuracy of serodiagnosis for human psittacosis.

A seroepidemiologic study of Chlamydia pneumoniae in Rhode Island. Evidence of serologic cross-reactivity

OBJECTIVE

Although Chlamydia pneumoniae is considered a common cause of pneumonia worldwide, the evidence is mainly serologic. Therefore, we examined whether the currently used chlamydial microimmunofluorescence (MIF) antibody test is specific for C pneumoniae infection.

DESIGN AND SETTING

Secondary analysis of data from a cohort study of sarcoidosis among the graduates of ten consecutive apprenticeship classes of firefighters and police officers.

PARTICIPANTS

One hundred forty-seven young adult men.

MEASUREMENTS

Immunoglobulin G and M antibodies to C pneumoniae, 15 serovars of C trachomatis, and 2 strains of C psittaci as measured by MIF.

RESULTS

Evidence of previous C pneumoniae and C trachomatis infection (IgG > or = 1:16 yet < 1:512) was present in 108 (73 percent) and 59 (40 percent) subjects, respectively. Serologic evidence of recent C pneumoniae and C trachomatis infection (IgM > or = 1:16 or IgG > or = 1:512) was present in 19 (13 percent) and 14 (10 percent) subjects, respectively. Chlamydia pneumoniae and C trachomatis IgM titers were highly correlated (r = 0.80; 95 percent CI, 0.73 to 0.85) while C pneumoniae and C trachomatis IgG titers were fairly correlated (r = 0.44; 95 percent CI, 0.30 to 0.56).

CONCLUSIONS

The C pneumoniae seroprevalence of 86 percent is the highest yet reported. The correlations between C pneumoniae and C trachomatis antibody titers suggest that chlamydial MIF may be less specific than is generally appreciated. Moreover, the observed 13 percent seroprevalence of recent C pneumoniae infection in a healthy working population challenges the serologically based belief that this agent accounts for 6 to 10 percent of community-acquired pneumonia. A more objective, more specific test is needed in the serodiagnosis of C pneumoniae infection.