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Disease Profile

Bacterial

Trachoma

沙眼

Trachoma is an eye infection concept caused by repeated conjunctival infection with Chlamydia trachomatis and is described as the leading infectious cause of blindness worldwide [1][2]. It is a neglected tropical disease targeted by WHO for elimination by 2030, and recent reports note progress in elimination in some countries while persistent transmission remains a concern in others [1]. The available evidence base here emphasizes a childhood-onset infection linked to recurrent conjunctivitis and later scarring complications [1][2].

Definition

Trachoma is a bacterial eye disease associated with repeated conjunctival infection by Chlamydia trachomatis [1][2]. In the provided sources, it is framed as the etiologic agent of trachoma and as a strict intracellular human pathogen [3]. The condition is also described in surveillance and public-health literature as a neglected tropical disease under elimination efforts [1].

Clinical features

The clinical course described in the sources begins in childhood with repeated episodes of conjunctival infection and recurrent conjunctivitis, referred to as active trachoma [1]. With ongoing or untreated disease, the conjunctiva may become scarred, a stage termed cicatricial trachoma [1]. Later complications can include in-turned eyelashes, described as trachomatous trichiasis or entropion, which may be blinding [1][2]. The sources characterize these as the key sight-threatening sequelae, but more granular symptom timing or grading details are not yet available from the provided material [1][2].

Epidemiology

Trachoma is reported as the leading or most common infectious cause of blindness in the cited sources [1][2]. It mainly affects the poorest and most rural communities, particularly where access to water and hygiene facilities is limited [1]. Another source describes occurrence in resource-poor areas with inadequate hygiene, aligning the disease with social and environmental deprivation [2]. By December 2024, 21 countries had eliminated trachoma as a public-health problem, while some populations still had persistent or recrudescent active trachoma that could complicate elimination targets [1].

Transmission

The provided sources indicate transmission in settings where children with unclean faces share infected ocular secretions [2]. Repeated conjunctival infection in childhood is the central exposure pattern described, but the snippets do not give a more detailed mechanism beyond ocular secretions and hygiene-related contact [1][2]. Source-backed detail on persistence outside the host or specific environmental transmission routes is not yet available [1][2].

Risk groups

The sources identify the poorest and most rural communities as the main affected populations, especially where water access and hygiene facilities are limited [1]. Children are central to transmission and early infection, while women are noted as more likely to experience blinding complications in some settings because they often serve as caregivers for infected children from a young age [1]. Beyond these groups, source-backed detail on additional risk categories is not yet available [1][2].

Prevention

The sources describe the WHO-supported SAFE strategy as the main public-health control package: surgery for trachomatous trichiasis, antibiotic mass drug administration, facial cleanliness, and environmental improvement [1][2]. These measures are presented as elimination-oriented interventions that have already produced substantial success in several countries [1][2]. No vaccine is reported in the provided material [3].

Surveillance note

In surveillance terms, trachoma should be read as a childhood-acquired, transmission-associated eye infection with late blinding sequelae, rather than only as a present-day symptomatic conjunctivitis [1][2]. Monitoring should distinguish active trachoma from cicatricial disease and trichiasis, because the sources emphasize progression from repeated infection to scarring and later blindness risk [1][2]. The public-health context is elimination-oriented, so persistence or recrudescence in specific populations is notable for program performance and target assessment [1].

References
  1. 1 Habtamu E et al. Trachoma. Lancet. 2025 May 24. PMID: 40412861. doi: 10.1016/S0140-6736(25)00551-3. PubMed: https://pubmed.ncbi.nlm.nih.gov/40412861/
  2. 2 Taylor HR et al. Trachoma. Lancet. 2014 Dec 13. PMID: 25043452. doi: 10.1016/S0140-6736(13)62182-0. PubMed: https://pubmed.ncbi.nlm.nih.gov/25043452/
  3. 3 Jury B et al. Molecular pathogenesis of Chlamydia trachomatis. Front Cell Infect Microbiol. 2023. PMID: 37920447. doi: 10.3389/fcimb.2023.1281823. PubMed: https://pubmed.ncbi.nlm.nih.gov/37920447/
  4. 4 Chlamydia trachomatis Infection. Infectious Diseases. 2017. doi: 10.1016/b978-0-7020-6285-8.00066-6. DOI: https://doi.org/10.1016/b978-0-7020-6285-8.00066-6
  5. 5 Chlamydia Trachomatis Infection. Sexually Transmitted Diseases. 1989. doi: 10.1007/978-1-4612-3528-6_20. DOI: https://doi.org/10.1007/978-1-4612-3528-6_20
  6. 6 Trachoma. Control of Communicable Diseases. 2019. doi: 10.2105/ccdml.2868.132. DOI: https://doi.org/10.2105/ccdml.2868.132
Coding Register
ICD-10
A71
ICD-11
Key Statistics
Total cases
140K
Peak month
2014-08
Coverage
1 reporting countries · 2009-01-01 → 2026-05-01

Figure 1 | Full historical trajectories across all reporting countries.

Figure 2 | Year-over-year monthly comparison for seasonality and structural shifts.

Dataset Archive

Supplementary Data | Multi-country disease dataset

Machine-readable multi-country disease dataset (JSON/CSV) with source metadata.

Rows
158
Data Version
2026-06-20
Coverage
Included metadata
Source links, scope, cadence

Source Register

Official sources and update cadences used to construct the downloadable dataset.

BR
Brazil DATASUS SINANmonthlyftp_dbc

Brazil

Brazil Ministry of Health DATASUS/SINAN public DBC microdata aggregated to national monthly notification counts.

Official source
Suggested presentation pattern: cite the data version and coverage window when exporting charts or tables for publication.