Clinical and laboratory characteristics, epidemiology, and outcomes of murine typhus: A systematic review

- A characteristic clinical, laboratory and epidemiological profile of murine typhus is described.
- The classic triad was reported in 35% of patients overall.
- Important differences are noted in children.
- Mortality was extremely low, but untreated patients had longer fever duration.

Murine or endemic typhus, a febrile disease caused by Rickettsia typhi, is often misdiagnosed due to its non-specific presentation. We sought to evaluate all available evidence in the literature regarding the clinical and laboratory manifestations, epidemiological characteristics, and outcomes of murine typhus. Pubmed was searched for all articles providing available data. In an effort to incorporate contemporary data, only studies from 1980 were included. Thirty-three case series including 2074 patients were included in final analysis. Available evidence suggests that the classic triad of fever, headache and rash is encountered in only one-third of patients. Other frequent symptoms were chills, malaise, myalgia, and anorexia. A tetrad of reported laboratory abnormalities consisting of elevated liver enzymes, lactate dehydrogenase, erythrocyte sedimentation rate and hypoalbuminemia was detected. Complications were observed in one-fourth of patients, reported mortality was extremely low, but untreated patients had notably longer duration of fever. Among epidemiological characteristics, a seasonal distribution with most cases reported during warmer months, was the most prominent finding. Murine typhus in children exhibits several different characteristics, with abdominal pain, diarrhea, and sore throat reported more commonly, higher frequency of anemia, lower frequency of hypoalbuminemia, hematuria and proteinuria and a much lower rate of complications. This systematic review of published evidence provides a thorough description of the clinical and laboratory features of murine typhus and highlights important differences in children.