The effect of multiple rounds of mass drug administration on the association between ocular Chlamydia trachomatis infection and follicular trachoma in preschool-aged children.
OBJECTIVE
To examine the relationship between ocular Chlamydia trachomatis infection and follicular trachoma (TF) in children prior to and following multiple rounds of annual mass drug administration (MDA) with azithromycin.


RESULTS
Thirty-two communities with endemic trachoma in Kongwa District, Tanzania, were offered annual MDA as part of a district-wide trachoma control program. Presence of ocular C. trachomatis infection and TF were assessed in 3,200 randomly sampled children aged five years and younger, who were examined prior to each MDA. Infection was detected using the Amplicor CT/NG assay and TF was identified by clinical examination using the World Health Organization (WHO) simplified grading system. The association between chlamydial infection and TF in children was evaluated at baseline prior to any treatment, and 12 months after each of three annual rounds of mass treatment. Factors associated with infection were examined using generalized estimating equation models. At baseline, the overall prevalence of chlamydial infection and TF was 22% and 31%, respectively. Among children with clinical signs of TF, the proportion of those with infection was 49% prior to treatment and declined to 30% after three MDAs. The odds of infection positivity among children with clinical signs of TF decreased by 26% (OR 0.74, 95% CI 0.65 to 0.84, p = <0.01) with each MDA, after adjusting for age. For children aged under one year, who did not receive treatment, the relationship was unchanged.


CONCLUSIONS
The association between ocular C. trachomatis infection and TF weakened in children with each MDA, as both infection and clinical disease prevalence declined. However, there was still a significant proportion of TF cases with infection after three rounds of MDA. New strategies are needed to assess this residual infection for optimal treatment distribution.
Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America.
Jennifer S
JS
Lee
Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America.
Beatriz E
BE
Muñoz
Kongwa Trachoma Project, Kongwa, Tanzania.
Harran
H
Mkocha
Division of Infectious Diseases, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America.
Charlotte A
CA
Gaydos
Division of Infectious Diseases, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America; Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
Thomas C
TC
Quinn
Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America.
Sheila K
SK
West
D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D019072:Antibiotic Prophylaxis / Q000379:methods*; D017963:Azithromycin / Q000627:therapeutic use; D002675:Child, Preschool; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D005123:Eye / Q000382:microbiology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015995:Prevalence; D013636:Tanzania; D014141:Trachoma / Q000188:drug therapy / Q000453:epidemiology* / Q000517:prevention & control*
D000900:Anti-Bacterial Agents; D017963:Azithromycin