Murine typhus as a common cause of fever of intermediate duration - A 17-year study in the south of Spain

Background: Fever of intermediate duration (FID), characterized by a febril e syndrome lasting from 7 to 28 days, is a frequent condition in clinical p ractice, but its epidemiological and etiologic features are not well descri bed. Murine typhus (MT) is a worldwide illness; nevertheless, to our knowle dge, no studies describing its epidemiological and clinical characteristics have been performed in the south of Spain. Also, its significance as a cau se of FID is unknown. Objective: To determine the epidemiological features, clinical characterist ics, and prognosis of MT and, prospectively, its incidence as a cause of FI D. Design: Prospective study of cases of MT over 17 years (1979-1995) and of a ll cases of FID treated in a tertiary teaching hospital in Seville, Spain. Results: One hundred and four cases of MT were included, and MT was the cau se in 6.7% of 926 cases of FID. Insect bites were reported in only 3.8% of the cases of MT previous to the onset of illness. Most cases (62.5%) occurr ed in the summer and fall. A high frequency of rash (62.5%) was noted. Arth romyalgia (77%), headache (71%), and respiratory (25%) and gastrointestinal (23%) symptoms were also frequent. Laboratory findings were unspecific. Or gan complications were uncommon (8.6%), but they were severe in 4 cases. Th e mean duration of fever was 12.5 days. Cure was achieved in all cases, alt hough only 44 patients received specific treatment. Conclusions: Murine typhus is prevalent in the south of Spain and is a sign ificant cause of FID. Clinical signs are benign, but some patients may deve lop severe complications. A high degree of clinical suspicion is required f or diagnosis.