Characteristic regression fever

Regression fever is an acute infectious disease caused by the worm-borne transmission of Treponema pallidum. It is clinically characterized by periodic high fever with systemic pain, hepatosplenomegaly, and bleeding tendency, and jaundice in severe cases. According to the different media, it can be divided into two types: lice-borne return fever (epidemic return fever) and tick-borne return fever (endemic return fever).