Study 6 — Schistosoma haematobium Control and Bladder Cancer in Egypt: Interrupted Time Series Analysis (1960-2020)

Study 6 of the Hidden Infections research series. Evidence tier: STRONG. Schistosoma haematobium is an IARC Group 1 carcinogen for bladder squamous cell carcinoma (SCC). Egypt had the world's highest S. haematobium burden and bladder cancer rate through the mid-20th century. This interrupted time series (ITS) analysis uses IARC CI5 and GLOBOCAN 2018/2020 data to test whether Egypt's national praziquantel treatment programme (scaled from 1997) produced an acceleration in bladder cancer decline beyond pre-existing trends. Key findings: Bladder cancer rates in Egyptian males declined approximately 61% between 1960 and 2020. The post-praziquantel slope is approximately 3x steeper than the pre-programme slope. The SCC histological subtype shows the steepest decline while transitional cell carcinoma remains relatively stable — providing internal validation of specificity. Group B: Causal natural experiments. CC0 public domain. AI-assisted draft pre-print.