Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Aug 14;13(8):e0007638.
doi: 10.1371/journal.pntd.0007638. eCollection 2019 Aug.

Progression of scarring trachoma in Tanzanian children: A four-year cohort study

Athumani M Ramadhani  1   2 , Tamsyn Derrick  1   2 , David Macleod  1 , Patrick Massae  2 , Elias Mafuru  2 , Aiweda Malisa  2 , Kelvin Mbuya  2 , Chrissy H Roberts  1 , William Makupa  2 , Tara Mtuy  1   2 , Robin L Bailey  1 , David C W Mabey  1 , Martin J Holland  1 , Matthew J Burton  1
Affiliations

Progression of scarring trachoma in Tanzanian children: A four-year cohort study

Athumani M Ramadhani et al. PLoS Negl Trop Dis. .

Abstract

Background: Trachoma is a progressive blinding disease initiated by infection of the conjunctiva with Chlamydia trachomatis. Repeated infections are thought to cause chronic inflammation, which drives scarring, leading to in-turning of the eyelids. The relationship between C. trachomatis, clinical inflammation and scarring development in children is not fully understood due to a paucity of longitudinal studies with infection data at frequent follow-up.

Methods and findings: This longitudinal cohort study took place in northern Tanzania. Children aged 6-10 years at baseline were eligible for inclusion. Participants were visited every three months for four years. Clinical signs and conjunctival swabs for C. trachomatis detection by qPCR were collected at each time-point. Conjunctival photographs from baseline and final time-points were graded and compared side-by-side to determine scarring incidence and progression. Of the 666 children enrolled in the study, outcome data were obtained for 448. Scarring progression was detected in 103/448 (23%) children; 48 (11%) of which had incident scarring and 55 (12%) had progression of existing scarring. Scarring was strongly associated with increasing episodes of trachomatous papillary inflammation (TP). Weaker associations were found between episodes of C. trachomatis infection and follicular trachoma (TF) with scarring progression in unadjusted models, which were absent in multivariable analysis after adjusting for inflammation (multivariable results: C. trachomatis p = 0.44, TF p = 0.25, TP p = <0.0001, age p = 0.13, female sex p = 0.05). Individuals having TP at 30% or more of the time-points they were seen had an odds ratio of 7.5 (95%CI = 2.7-20.8) for scarring progression relative to individuals without any TP detected during the study period.

Conclusions: These data suggest that the effect of infection on scarring progression is mediated through papillary inflammation, and that other factors contributing to the development of inflammation, in addition to C. trachomatis infection, may be important in driving conjunctival scarring progression in children. The addition of TP as a measure in trachoma control programs would provide an indication of the future risk of developing scarring sequelae.

PubMed Disclaimer

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Flow chart for eligible study participants.
The chart shows the number of individuals enrolled, excluded and included in the analysis of scarring progression.
Fig 2
Fig 2. The prevalence of C. trachomatis infection and clinical signs at each time-point.
Data are shown for the 448 individuals with outcome data. There were three-month intervals between time-points. Red vertical lines indicate annual MDA treatment given to all three study villages. The red dashed vertical line indicates treatment given to one village with residual disease.
Fig 3
Fig 3. Distribution of omcB load in scarring progressors and non-progressors, split by age group at time-point.
See this image and copyright information in PMC

References

    1. Ramadhani A.M., et al., Blinding Trachoma: Systematic Review of Rates and Risk Factors for Progressive Disease. PLoS Negl Trop Dis, 2016. 10(8): p. e0004859 10.1371/journal.pntd.0004859 - DOI - PMC - PubMed
    1. WHO, Global elimination of blinding trachoma. Resolution WHA 51.11. Adopted by the World Health Assembly 16 May 1998 1998.
    1. WHO Alliance for the Global Elimination of Trachoma by 2020: progress report on elimination of trachoma, 2014–2016. Wkly Epidemiol Rec, WHO, 2017. 92(26): p. 359–68. - PubMed
    1. WHO, Weekly Epidemiological Record. WHO, 2018. 93(26): p. 12.
    1. Ramadhani A.M., et al., Immunofibrogenic Gene Expression Patterns in Tanzanian Children with Ocular Chlamydia trachomatis Infection, Active Trachoma and Scarring: Baseline Results of a 4-Year Longitudinal Study. Frontiers in Cellular and Infection Microbiology, 2017. 7: p. 406 10.3389/fcimb.2017.00406 - DOI - PMC - PubMed

Publication types