Surveillance for peri-elimination trachoma recrudescence: exploratory studies in Ghana

Summary

Countries need to implement a suitable surveillance system for trachoma infections, to identify any return to higher transmission levels. The best methodology for doing this is not known.

We first explored the approach used by Ghana in its standard programme, which involved monitoring a limited number of randomly selected communities for evidence of active (inflammatory) trachoma visible in children’s eyes on examination by trained observers. Although this strategy led to identification of at least one community that had probably had recent Chlamydia trachomatis (Ct) transmission, the approach is unlikely to consistently identify places where return to higher levels of transmission is a risk.

We also explored using information on infection (detected in eye swabs) and antibodies to Ct (detected in the blood) to identify communities at risk. We found evidence of both persistent eye-to-eye Ct transmission and areas where infection was transient and has now gone away.

There is added value in monitoring Ct infection and anti-Ct antibodies, using these indicators to interrogate past or present surveillance strategies. This can result in a deeper understanding of transmission dynamics and inform new post-validation surveillance strategies, including informing which areas are most at risk for recrudescence that would benefit from further monitoring. Opportunities should be explored for integrating PCR and serological-based markers into surveys conducted in trachoma elimination settings.