Brill-Zinsser disease

 Brill-Zinsser disease is  the recrudescence of epidemic typhus in persons who  earlier suffered from the disease. It is characterised by fever, transient rash and fall in blood pressure. It is caused by reactivation of Rickettsia prowazeki present in the spinal marrow when the immunity is decreased. It is also called Recrudescent Typhus. 

It is named after physician Nathan Bill and bacteriologist Hans Zinsser.

Weil Felix reaction is negative or slightly positive in Brill Zinsser disease.