Brill-Zinsser disease

Brill-Zinsser disease (also known as recrudescent typhus or recrudescent epidemic typhus) is a relapse form of epidemic typhus caused by the bacterium Rickettsia prowazekii. It occurs years or even decades after an initial episode of epidemic typhus, when dormant organisms reactivate in a person whose immunity has waned due to aging, stress, malnutrition, or immunosuppression. Unlike the original epidemic typhus, which is transmitted by body lice, Brill-Zinsser disease arises endogenously from persistent rickettsial organisms harbored in the patient's own tissues, though an affected individual can serve as a source of infection to lice and thereby spark new outbreaks of epidemic typhus in susceptible populations. The disease primarily affects the vascular system, as Rickettsia prowazekii targets endothelial cells lining blood vessels, leading to widespread vasculitis. Key clinical features include sudden onset of fever, severe headache, myalgia (muscle pain), and a maculopapular rash that typically begins on the trunk and spreads to the extremities. Neurological symptoms such as confusion and delirium may occur. Compared to primary epidemic typhus, Brill-Zinsser disease tends to be milder and shorter in duration, with lower mortality rates, partly because of residual partial immunity from the initial infection. Diagnosis is based on clinical suspicion, a history of prior epidemic typhus exposure, and serological testing. Notably, the antibody response in Brill-Zinsser disease is predominantly IgG (an anamnestic response), in contrast to the IgM-predominant response seen in primary infection. Treatment consists of antibiotic therapy, with doxycycline being the drug of choice. Chloramphenicol is an alternative. With appropriate antibiotic treatment, prognosis is generally excellent, and most patients recover fully. Without treatment, mortality is estimated at around 1-2%, significantly lower than untreated primary epidemic typhus.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Brill-Zinsser disease