Rethinking Fasciola hepatica control under changing transmission risk: lessons from Australia and New Zealand.

In many endemic livestock systems, Fasciola hepatica control is built around locally predictable transmission patterns that guide treatment timing. However, both climate change and invasive lymnaeid snails threaten the historical climate-snail-parasite relationships on which such strategies depend. Australia's seasonal treatment approach and New Zealand's experience with invasive Pseudosuccinea columella illustrate how established control can become misaligned when transmission ecology changes. Forecasting can identify emerging risk, but prediction alone is insufficient to justify revised treatment calendars. Contemporary livestock infection and snail data are needed to validate changes in transmission and translate them into locally adapted, integrated parasite management. Local lessons have global implications: historical control strategies should persist only where current evidence shows that their underlying transmission assumptions still hold.