A slow decay to extinction: cold temperatures and reduced microbial complexity prolong the persistence of planktonic Francisella tularensis.

Cold temperatures and reduced microbial diversity extend the persistence of virulent Francisella tularensis in aquatic environments, with type B strains remaining culturable after 1 year.

• Why it matters: Understanding how F. tularensis survives outside hosts is crucial for assessing environmental transmission risks and improving public health responses to tularemia outbreaks.
• What they did: Researchers incubated virulent strains of F. tularensis subspecies tularensis (type A) and holarctica (type B) in water under various conditions, monitoring their viability and disease-causing ability over 1.5 years.
• The result: Both strains persisted in natural pond water, often in inactive states, with type B remaining culturable and infectious longer, highlighting environmental reservoirs' role in disease perpetuation.