Purchase this article with an account.
Andrea Isabela Zambrano, Beatriz E Munoz, Laura Dize, Harran Mkocha, Charlotte Gaydos, Thomas Quinn, Sheila K West; Measuring Severe Inflammatory Trachoma (TI) when prevalence is low provides indirect data on infection with C. trachomatis in endemic communities.. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):4060.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Inflammatory trachoma (TI) is not measured when assessing the impact of trachoma programs because it is felt to indicate non-trachoma disease; only follicular trachoma (TF) is measured. We tested the supposition that TI was not associated with infection when disease prevalence is low, and does not add to understanding the effect of programs.
In each of 52 communities in Kongwa Tanzania, 100 children ages 1-9 years were randomly selected for survey at baseline, 6, and 12 months. In 17 communities, Mass Drug Administration (MDA) was stopped at baseline because infection rates were 1% or less; 35 had MDA. Both eyelids were graded for evidence of TF and TI and a swab for detection of infection was taken. The swabs were tested using Aptima (GenProbe/Hologic) for presence of C. trachomatis. Overall prevalence rate of active trachoma in communities with and without MDA at each time point were compared, and the proportion of active trachoma cases that were TI alone was estimated. Proportion of active trachoma cases that were TI alone were compared among the treated and not treated communities. All comparisons were analyzed using Fisher’s exact test.
Overall prevalence of active trachoma at baseline was 6% (318 cases); 15% were TI alone. The prevalence of infection in TF cases was 36% and 37% in TI alone. At 6 months, the prevalence of active trachoma was 5.5% in communities where MDA was stopped; 18% of the cases were TI alone, for whom the rate of infection was 41.2%. In treated communities, prevalence of active trachoma was 3.9% and 10% of cases were TI alone for whom the rate of infection was 30.8%. At 12 months, prevalence of active trachoma in communities with MDA stopped was 5.8% and 17% of cases were TI alone; 59% had infection with C. trachomatis. In treated communities, prevalence rate was 5.1% with 22% of cases being TI alone for whom the rate of infection was 37.5%. Infection in the TI cases in communities where MDA was stopped was significantly greater than in treated communities (p=0.02).
Despite low prevalence, the clinical sign of TI was better correlated with infection than TF, and particularly so when the survey was a year or more after MDA. TI should be measured as part of impact surveys and particularly at surveys several years after the last MDA.
This PDF is available to Subscribers Only