What Is Causing Active Trachoma? The Role of Nonchlamydial Bacterial Pathogens in a Low Prevalence Setting

Burton, Matthew J.; Hu, Victor; Massae, Patrick; Burr, Sarah E.; Chevallier, Caroline; Afwamba, Isaac A.; Courtright, Paul; Weiss, Helen A.; Mabey, David; Bailey, Robin L.

doi:10.1167/iovs.11-7326

Cited by 64 publications

(87 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The study procedures have been previously described (9). Briefly, participants were examined by an ophthalmologist and clinical signs graded using the 1981 WHO Trachoma Grading System (follicles, papillae, and conjunctival scarring [FPC]) (15).…”

Section: Methodsmentioning

confidence: 99%

“…We have previously reported the clinical and microbiological characteristics of this group, which had a community prevalence of follicular trachoma (TF) of 14% (9). Although C. trachomatis was detected in 5% of individuals, this was not associated with the presence of TF.…”

mentioning

confidence: 95%

“…Although C. trachomatis was detected in 5% of individuals, this was not associated with the presence of TF. In contrast, nonchlamydial bacterial pathogens were frequently associated with TF (9). This raises the possibility that in low-prevalence areas, at least, nonchlamydial bacterial pathogens may contribute to the inflammatory process.…”

mentioning

confidence: 96%

“…The principal driver for this inflammatory scarring process in communities where trachoma is endemic is thought to be infection with Chlamydia trachomatis, although direct evidence is limited (59). The signs of inflammation and the detection of chlamydial infection may show only a relatively weak correlation, particularly in low-prevalence settings (8,9,60). This relationship weakens after the introduction of antibiotic treatment (28).…”

mentioning

confidence: 99%

“…This relationship weakens after the introduction of antibiotic treatment (28). Nonchlamydial bacterial pathogens have been associated with signs of active trachoma in a low-prevalence setting and in adults with established scarring (9,10,25). These observations raise the possibility that the chronic inflammatory reaction characterizing trachoma, which is the hypothesized basis for the development of scarring, may not always require an ongoing replicating chlamydial infection.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Active Trachoma Is Associated with Increased Conjunctival Expression ofIL17Aand Profibrotic Cytokines

et al. 2011

Self Cite

View full text Add to dashboard Cite

The immunological basis of scarring trachoma is not well understood. It is unclear whether it is driven primarily through cell-mediated adaptive or epithelial-cell-derived innate responses. The purpose of this study was to investigate the expression of the inflammatory and fibrogenic mediators which may be involved. We conducted a cross-sectional survey of children living in an untreated trachoma-endemic community in Tanzania. The children were examined for signs of trachoma, and swabs were collected for bacteriological culture and RNA and DNA isolation. Chlamydia trachomatis was detected by the Amplicor PCR test. The expression of the following genes was measured by quantitative reverse transcription-PCR (RT-PCR): S100A7, IL1B, IL17A, IL23A, CXCL5, CCL18, TLR2, NLRP3, KLRD1, CTGF, and MMP9. Four hundred seventy children under the age of 10 years were included. Follicular trachoma (TF) was detected in 65 children (14%), C. trachomatis was detected in 25 (5%), and bacterial pathogens were cultured in 161 (34%). TF was associated with significantly increased expression of S100A7, IL17A, CCL18, CXCL5, and CTGF. Expression was increased further in the presence of papillary inflammation. Nonchlamydial bacterial infection was associated with increased expression of IL17A, CXCL5, CCL18, and KLRD1. IL17A expression was associated with increased expression of S100A7, CXCL5, CCL18, KLRD1, and CTGF. These data are consistent with a role for IL-17A in orchestrating the proinflammatory response in trachoma. Its activity may be promoted either as part of the cell-mediated response or through innate pathways. It may drive a range of proinflammatory factors leading to excessive tissue damage and repair involving fibrosis.

show abstract

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 95%

mentioning

confidence: 96%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Active Trachoma Is Associated with Increased Conjunctival Expression ofIL17Aand Profibrotic Cytokines

et al. 2011

Self Cite

View full text Add to dashboard Cite

show abstract

Lateral flow-based antibody testing for Chlamydia trachomatis

Gwyn

Mitchell

Dean

et al. 2016

Journal of Immunological Methods

View full text Add to dashboard Cite

We describe here a lateral flow-based assay (LFA) for the detection of antibodies against immunodominant antigen Pgp3 from Chlamydia trachomatis, the causative agent of urogenital chlamydia infection and ocular trachoma. Optimal signal detection was achieved when the gold-conjugate and test line contained Pgp3, creating a dual sandwich capture assay. The LFA yielded positive signals with serum and whole blood but not with eluted dried blood spots. For serum, the agreement of the LFA with the non-reference multiplex assay was 96%, the specificity using nonendemic pediatric sera was 100%, and the inter-rater agreement was κ=0.961. For whole blood, the agreement of LFA with multiplex was 81.5%, the specificity was 100%, and the inter-rater agreement was κ=0.940. The LFA was tested in a field environment and yielded similar results to those from laboratory-based testing. These data show the successful development of a lateral flow assay for detection of antibodies against Pgp3 with reliable use in field settings, which would make antibody-based testing for trachoma surveillance highly practical, especially after cessation of trachoma elimination programs.

show abstract

Ocular Chlamydia trachomatis infection, anti-Pgp3 antibodies and conjunctival scarring in Vanuatu and Tarawa, Kiribati before antibiotic treatment for trachoma

Butcher

Handley

Garae

et al. 2020

Journal of Infection

View full text Add to dashboard Cite

Introduction: In the peri-elimination setting, the positive predictive value of trachomatous inflammationfollicular (TF), the primary marker used to determine need for antibiotics for trachoma, is suboptimal. Here, three non-TF measures are used to compare two regions where TF prevalence exceeds the threshold for intervention, but where the Chlamydia trachomatis (Ct) prevalence is different. Methods: Population prevalence of trachoma was measured in Vanuatu (n = 3470) and Kiribati (n = 2922). Dried blood spots (DBS) and conjunctival photographs were collected from every survey participant, and conjunctival swabs were collected from those aged 1-9 years. Individuals were tested for blood anti-Pgp3 antibodies, Ct DNA at the conjunctiva and severity of conjunctival scarring. Results: The prevalence of TF in 1-9-year-olds was 16.5% in Vanuatu and 38.2% in Tarawa. 7% of people aged ≥1 year in Vanuatu had conjunctival scarring compared to 27% in Tarawa. The prevalence of ocular Ct infection in 1-9-year-olds was 1.5% in Vanuatu and 27.4% in Tarawa. The seroconversion rate amongst 1-9-year-old children in Vanuatu and Tarawa was 0.018 and 0.197 events per child per year, respectively. Conclusions: Comparing Vanuatu to Tarawa demonstrates several markers that could be used to differentiate the trachoma status of populations in these (and other) locations.

show abstract

What Is Causing Active Trachoma? The Role of Nonchlamydial Bacterial Pathogens in a Low Prevalence Setting

Cited by 64 publications

References 22 publications

Active Trachoma Is Associated with Increased Conjunctival Expression ofIL17Aand Profibrotic Cytokines

Active Trachoma Is Associated with Increased Conjunctival Expression ofIL17Aand Profibrotic Cytokines

Lateral flow-based antibody testing for Chlamydia trachomatis

Ocular Chlamydia trachomatis infection, anti-Pgp3 antibodies and conjunctival scarring in Vanuatu and Tarawa, Kiribati before antibiotic treatment for trachoma

Contact Info

Product

Resources

About