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Severe disease in children with trachoma is associated with persistent Chlamydia trachomatis infection
1Pediatric and Adult Infectious Diseases, Dana Center for Investigative Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
Insights
Host variation in clearing Chlamydia trachomatis influences trachoma severity in children. Persistent infections and higher bacterial loads correlate with more severe disease, suggesting genetic factors impact infection duration and outcome.
Area of Science:
- Ophthalmology
- Infectious Diseases
- Immunogenetics
Background:
- Trachoma, a leading cause of preventable blindness, exhibits variable disease severity.
- The role of host genetic factors in Chlamydia trachomatis infection clearance and disease progression is not fully understood.
Purpose of the Study:
- To investigate if host variation in clearing Chlamydia trachomatis contributes to differing trachoma severity in children.
- To identify sibling cohorts with variant infection phenotypes for future immunogenetic research.
Main Methods:
- A 3-month weekly survey in a trachoma-endemic village.
- Detection of Chlamydia trachomatis DNA and grading of trachoma severity.
- Analysis of infection duration and bacterial load in children and their siblings.
Main Results:
- 62% of children experienced at least one Chlamydia trachomatis infection episode.
- Persistently infected children (64%) had higher bacterial loads and more severe trachoma than sporadically infected children.
- Sibling infection duration varied in 60% of families, indicating potential host-related differences.
Conclusions:
- Chlamydial load and infection duration are key determinants of severe, chronic trachoma.
- Host variation in the efficiency of clearing Chlamydia trachomatis, observed even between siblings, plays a role in disease severity.
Abstract:
The immediate study objective was to determine if variable disease severity in children with trachoma could be attributable in part to host variation in the ability to clear Chlamydia trachomatis infection. Identification of sibling cohorts with these variant phenotypes would be useful for immunogenetic studies. A weekly survey for 3 months in a trachoma-hyperendemic village using detection of chlamydial DNA and grading of disease severity indicated that 62% (33/53) of children had at least one infection episode. Of those, 64% (21/33) who were persistently infected had both significantly higher mean chlamydial DNA loads and more severe trachoma than did sporadically infected children. Of importance, duration of infection differed between siblings in 60% (6/10) of families. The results suggest that chlamydial load and duration of infection determine the chronic nature of severe disease in trachoma and that host variable efficiency for chlamydial clearance between siblings is in part determined by host variation.