Identification of TT Cases by Community Treatment Assistants: An Assessment (SIMBA)

To achieve the goal of trachoma control as mandated by the World Health Organization, countries must reduce the backlog of trichiasis surgery cases to less than 1/1,000 of their population. However, these cases reside in rural villages in trachoma endemic districts, and finding them to offer services is a challenge. Community Treatment Assistants (CTAs) are village residents who are trained to offer Mass Drug Administration (MDA) to their communities and hence are in contact with most residents. A training guide and tool for screening for trachomatous trichiasis (TT) will be developed to train CTAs in rural Tanzania to identify cases in their communities and refer them to surgery. Compared to the current process by which CTAs passively screen for TT if cases complaint, investigators hypothesize that the trained CTAs will identify twice the usual number of TT surgery cases during ongoing community antibiotic administrations for trachoma and will also miss fewer cases. If this simple system is effective, it can be implemented widely to screen communities for cases of TT. Residents from thirty-six villages holding MDA, for whom a complete census is available, will be randomized on a 1:1 basis to intervention (where the CTAs receive the enhanced training from the enhanced training team) and usual assessment (where the CTAs receive the usual instructions from the regular MDA team). In both arms, the CTAs will keep records of all cases they have screened as positive for TT amongst the residents. A Master TT grader will grade all screened cases of TT to determine the rate of true positivity in both arms.In addition, he will examine a random sample of residents who are screened as negative to detect potentially missed cases and estimate the total burden of trichiasis cases in both arms as well.The assessments of the Master TT grader will serve as the gold standard for calculations of sensitivity, specificity, and positive and negative predictive values of the enhanced training versus usual assessment methods.

Community treatment assistants (CTA ) will receive usual training, including the basic background of trachoma/trichiasis recognition, drug administration, and azithromycin dosing. In addition to the usual training, these CTA's will also receive an additional modest half day training for TT case recognition which is called the TT training program and TT Screening Card to help them identify TT cases and refer them for surgery.

Community treatment assistants will receive only usual training, including the basic background of trachoma/trichiasis recognition, drug administration, and azithromycin dosing.

The intervention is an additional half day training program on trichiasis recognition (TT Training Program) and a TT Screening card to assist community treatment assistants in recognizing TT cases and referring them to surgery.

All the TT cases detected in control versus intervention arms (adjusted for population size) through screening were verified by graders. Grader re-graded all these cases except for the cases lost to follow-up.

Sensitivity of different TT screening methods compared to "true" assessment of cases and controls using the extrapolated values from the follow-up survey. Formula used: True positives/(true positives +false negative)

Specificity of different TT screening methods compared to "true" assessment of cases and controls using the extrapolated values from the follow-up survey. Formula used: True negatives/(true negatives +false positive)

Positive Predictive Values (PPV) of the different screening methods compared to "true" assessment of cases and controls. It was calculated by using extrapolated values. The formula used: True positives /total participants at initial screening screened as positive by CTA's.

Negative Predictive Values (NPV) of the different screening methods compared to "true" assessment of cases and controls. It was calculated by using extrapolated values. Formula used : True Negatives /total participants at initial screening,screened as negative by CTA's

Inclusion Criteria: All persons in the study and control communities are eligible for the MDA. Adults aged 15 and over will be eligible for the survey and re-assessment. Those who are screened positive in the re-assessment will be eligible for treatment at the surgery camp. Those who are screened positive for TT initially but refuse the definitive re-screening will still be offered surgery but told they may not have TT and will be re-screened by the surgeon. Exclusion Criteria: none