Research Article: Assessment of a Novel Approach to Identify Trichiasis Cases Using Community Treatment Assistants in Tanzania

Date Published: December 11, 2015

Publisher: Public Library of Science

Author(s): Gregory S. Greene, Sheila K. West, Harran Mkocha, Beatriz Munoz, Shannath L. Merbs, Mathieu Picardeau.

Abstract: BackgroundSimple surgical intervention advocated by the World Health Organization can alleviate trachomatous trichiasis (TT) and prevent subsequent blindness. A large backlog of TT cases remain unidentified and untreated. To increase identification and referral of TT cases, a novel approach using standard screening questions, a card, and simple training for Community Treatment Assistants (CTAs) to use during Mass Drug Administration (MDA) was developed and evaluated in Kongwa District, a trachoma-endemic area of central Tanzania.Methodology/Principal FindingsA community randomized trial was conducted in 36 communities during MDA. CTAs in intervention villages received an additional half-day of training and a TT screening card in addition to the training received by CTAs in villages assigned to usual care. All MDA participants 15 years and older were screened for TT, and senior TT graders confirmed case status by evaluating all screened-positive cases. A random sample of those screened negative for TT and those who did not present at MDA were also evaluated by the master graders. Intervention CTAs identified 5.6 times as many cases (n = 50) as those assigned to usual care (n = 9, p < 0.05). While specificity was above 90% for both groups, the sensitivity for the novel screening tool was 31.2% compared to 5.6% for the usual care group (p < 0.05).Conclusions/SignificanceCTAs appear to be viable resources for the identification of TT cases. Additional training and use of a TT screening card significantly increased the ability of CTAs to recognize and refer TT cases during MDA; however, further efforts are needed to improve case detection and reduce the number of false positive cases.

Partial Text: Trachoma, the leading cause of infectious blindness, affects an estimated 84 million individuals worldwide [1]. Although eliminated in Europe and the United States, trachoma persists in much of the developing world, disproportionately affecting the poorest and most vulnerable populations [2]. Chronic trachomatous inflammation typically begins during childhood, with years of repeated infections with Chlamydia trachomatis leading to the development of conjunctival scarring in a portion of individuals [3–5]. As scarring worsens, an inturning of the lid margin, or entropion, brings the lashes into contact with the cornea. This trachomatous trichiasis (TT), as well as the scarred conjunctiva, leads to damage and opacification of the cornea, ultimately resulting in blindness [6].

This study demonstrates that an expanded but simple training program and use of a TT screening card improves the ability of CTAs to identify cases of TT during MDA. Using this approach, CTAs identified over five times more TT cases than did those assigned to usual care. Additionally, training and use of the card required minimal additional resources, making this intervention an easily implementable approach to identify TT cases in MDA communities. Although this was a substantial improvement, sensitivity for CTA screening was still lower than expected. As the goal of TT screening is to find those individuals with TT who are currently in need of treatment, a higher sensitivity is necessary to reliably identify as many true positive cases as possible. While the scripted questions were designed to be specific for TT, many individuals answering yes did not have TT. In another study, 43% of false positive cases found by CTAs in fact had other eye pathology, including corneal disease and cataract [20]. From a primary eye care perspective, a high number of false positives may identify other eye conditions that require intervention. Therefore, having an eye care professional undertake further verification would not only help identify TT cases, but could also direct other patients into the eye care system.



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