Transmission is during the nymphal or adult stages but more commonly the small nymphs because they are smaller and therefore avoid detection. The risk of disease is 1.2-3.2% if one is in an endemic area.
The infected tick needs to be attached for at least 24 hours and the risk of infection increases with the time the tick has been attached
(higher if greater than 36 hours or tick is engorged), however this time cannot be determined with precision by most patients.
