Zoonotic Chlamydiaceae Species Associated with Trachoma, Nepal

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Abstract

Trachoma is the leading cause of preventable blindness. Commercial assays do not discriminate among all Chlamydiaceae species that might be involved in trachoma. We investigated whether a commercial Micro-ArrayTube could discriminate Chlamydiaceae species in DNA extracted directly from conjunctival samples from 101 trachoma patients in Nepal. To evaluate organism viability, we extracted RNA, reverse transcribed it, and subjected it to quantitative real-time PCR. We found that 71 (70.3%) villagers were infected. ArrayTube sensitivity was 91.7% and specificity was 100% compared with that of real-time PCR. Concordance between genotypes detected by microarray and ompA genotyping was 100%. Species distribution included 54 (76%) single infections with Chlamydia trachomatis, C. psittaci, C. suis, or C. pecorum, and 17 (24%) mixed infections that includied C. pneumoniae. Ocular infections were caused by 5 Chlamydiaceae species. Additional studies of trachoma pathogenesis involving Chlamydiaceae species other than C. trachomatis and their zoonotic origins are needed.

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Effect of a single mass antibiotic distribution on the prevalence of infectious trachoma.

Zhaoxia Zhou, Kathryn Maxey, Jenafir House … (2006)

The World Health Organization recommends mass antibiotic distributions in its strategy to eliminate blinding trachoma as a public health concern. Some hypothesize that a single distribution is sufficient to control the ocular strains of chlamydia that cause trachoma. Others believe infection will inevitably return and periodic treatments or other measures are essential. To determine whether ocular chlamydial infection returns to the community up to 24 months after a single mass antibiotic distribution in a hyperendemic region of Ethiopia. Longitudinal cohort study conducted March 2003 to March 2005 in the Gurage Zone of Ethiopia. Eight randomly selected villages were assessed for ocular chlamydial infection. Fifteen untreated villages were randomly chosen at 12 months to allow assessment of a secular trend. A single dose of oral azithromycin was offered to all residents of the 8 selected villages who were aged 1 year or older. Prevalence of ocular chlamydial infection in all children aged 1 to 5 years from each intervention village prior to treatment and 2, 6, 12, 18, and 24 months after mass antibiotic treatment, and also in untreated villages enrolled at 12 months. Five hundred fifteen children were examined for ocular chlamydial infection at baseline. For the follow-up examinations, the mean participation rate was 83%. The mean prevalence of infection in children aged 1 to 5 years decreased from 43.5% (95% confidence interval [CI], 35.0%-52.0%) to 5.1% (95% CI, 1.1%-9.2%) after treatment. On average, infection returned gradually over 24 months to 11.3% (95% CI, 4.5%-18.1%; P = .001). In 7 of 8 villages, infection was higher at 24 months than at 2 months. In the remaining village, no infection could be identified at any point after treatment. Villages enrolled at 12 months had significantly fewer infections than those enrolled 12 months earlier, suggesting a secular trend (P<.001). Ocular chlamydial infection was not eliminated in children aged 1 to 5 years after a single mass azithromycin distribution; it slowly returned over 24 months, although not to baseline levels. Repeated treatments or other effective measures will be necessary for elimination.

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Detection of all Chlamydophila and Chlamydia spp. of veterinary interest using species-specific real-time PCR assays.

Alexandra Pantchev, Reinhard Sting, Rolf Bauerfeind … (2010)

The aim of the present study was to analyse the occurrence of chlamydiae in several mammalian host species. Clinical samples that previously tested positive in a Chlamydiaceae-specific real-time PCR were retested using six species-specific real-time PCR assays to identify the chlamydial species involved. Chlamydophila (Cp.) abortus was the agent most frequently found in cattle, sheep, horses, goats, and pigs. Detection in cattle of Cp. psittaci (11% of samples) and Chlamydia (C.) suis (9%), as well as Cp. psittaci in a goat sample was somewhat unexpected. DNA of two different chlamydiae was identified in 56 (12.7%) of 440 samples tested. Cp. felis was the predominant species found in cats, while in guinea pigs and rabbits only Cp. caviae was detected. Interestingly, the latter two pathogens were also identified in samples from dogs. The data show that mixed chlamydial infections are not rare and suggest an extended host range of individual species. Copyright © 2009 Elsevier Ltd. All rights reserved.

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Recent developments in the laboratory diagnosis of chlamydial infections.

Konrad Sachse, Evangelia Vretou, Morag Livingstone … (2009)

There are two main approaches to diagnosing infections by Chlamydia and Chlamydophila spp. in mammals and birds. The first involves the direct detection of the agent in tissue or swab samples, while the second involves the serological screening of blood samples for the presence of anti-chlamydial antibodies. Ultimately, the test that is used is dependent on the types of samples that are submitted to the diagnostic laboratory for analysis. The present paper gives an overview on methodologies and technologies used currently in diagnosis of chlamydial infections with emphasis on recently developed tests. The performance characteristics of individual methods, such as the detection of antigen in smears and in pathological samples, the isolation of the pathogen, various antibody detection tests and DNA-based methods utilising conventional and real-time PCR, as well as DNA microarray technology are assessed, and specific advantages and drawbacks are discussed. Further, a combination of a specific real-time PCR assay and a microarray test for chlamydiae is proposed as an alternative reference standard to isolation by cell culture.

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Author and article information

Journal

Journal ID (nlm-ta): Emerg Infect Dis

Journal ID (iso-abbrev): Emerging Infect. Dis

Journal ID (publisher-id): EID

Title: Emerging Infectious Diseases

Publisher: Centers for Disease Control and Prevention

ISSN (Print): 1080-6040

ISSN (Electronic): 1080-6059

Publication date (Print): December 2013

Volume: 19

Issue: 12

Pages: 1948-1955

Affiliations

[1]Children's Hospital Oakland Research Institute, Oakland, California, USA (D. Dean, J. Rothschild);

[2]University of California, San Francisco, California, USA (D. Dean);

[3]University of California, Berkeley, California, USA (D. Dean);

[4]Friedrich-Loeffler-Institut, Jena, Germany (A. Ruettger, K. Sachse);

[5]Lumini Eye Hospital, Bhairahawa, Nepal (R.P. Kandel)

Author notes

Address for correspondence: Deborah Dean, Children’s Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609, USA; email: ddean@ 123456chori.org

Article

Publisher ID: 13-0656

DOI: 10.3201/eid1912.130656

PMC ID: 3840858

PubMed ID: 24274654

SO-VID: 8f2ddab9-99b6-423b-ab77-50fb9b68e763

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Zoonotic Chlamydiaceae Species Associated with Trachoma, Nepal

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Most cited references 38

Effect of a single mass antibiotic distribution on the prevalence of infectious trachoma.

Detection of all Chlamydophila and Chlamydia spp. of veterinary interest using species-specific real-time PCR assays.

Recent developments in the laboratory diagnosis of chlamydial infections.

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