Exposure to tick-infested habitats or a history of
tick bite(s) is reported for nearly 60% of all human
cases.3,13,14 People who live near wooded lots or have
frequent exposure to dogs may also be at some
increased risk of R rickettsii infection, compared with
urban or nondog-owning populations. Approximately
10% of humans with RMSF report only a known exposure
to dogs or a dog’s ticks. Common exposure to the
same population of ticks (in surrounding environment)
is the likely source of these human infections.2,3
Although RMSF is primarily a rural and suburban disease,
microecologic niches have also been found in
large metropolitan areas.15