Background 

Fever of intermediate duration (FID), characterized by a febrile syndrome lasting from 7 to 28 days, is a frequent condition in clinical practice, but its epidemiological and etiologic features are not well described.

Murine typhus (MT) is a worldwide illness ; nevertheless, to our knowledge, no studies describing its epidemiological and clinical characteristics have been performed in the south of Spain.

Also, its significance as a cause of FID is unknown.

Objective 

To determine the epidemiological features, clinical characteristics, and prognosis of MT and, pro-spectively, its incidence as a cause of FID.

Design 

Prospective study of cases of MT over 17 years (1979-1995) and of all 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 cause 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%) occurred in the summer and fall.

A high frequency of rash (62.5%) was noted.

Arthromyalgia (77%), headache (71%), and respiratory (25%) and gastrointestinal (23%) symptoms were also frequent.

Laboratory findings were unspecific

Organ complications were uncommon (8.6%), but they were severe in 4 cases.

The mean duration of fever was 12.5 days.

Cure was achieved in all cases, although only 44 patients received specific treatment. (...)