Free-swimming cholera bacteria are much less infectious than bacteria in biofilms, aggregates of bacterial cells embedded in a sticky matrix that form on surfaces. This accounts for the surprising effectiveness of filtering water through cloth, such as a folded sari, which can reduce infections dramatically in places where the disease is endemic, despite the fact that individual cholera bacteria easily pass through such a filter.
Click here for original story, Cholera studies reveal mechanisms of biofilm formation and hyperinfectivity
Source: Phys.org