New modelling research from African biostatisticians shows that flies play a far more important role in spreading cholera than previously recognised. While cholera is traditionally associated with contaminated water, the study demonstrates that flies can mechanically transmit the cholera-causing bacterium from contaminated environments to human food, making outbreaks faster and more unpredictable.
The models show that when fly-related transmission factors are high, even small contamination events can trigger explosive outbreaks, likened to sparks igniting dry grass. The findings come as Africa faces its worst cholera outbreak in 25 years, with 300,000 confirmed and suspected cases reported across 20 countries in 2025.
The research also reinforces the importance of vaccination, showing that high coverage can rapidly reduce transmission even before long-term water and sanitation improvements take effect.
