- A prospective 12-month study was conducted throughout 1998 to determine the frequency of selected bacterial zoonoses as causes of fever among hospitalized Bedouins in southern Israel. One or more zoonoses were diagnosed in 30 (27%) of 110 patients admitted with fever. Brucellosis was diagnosed in 9 (8%), rickettsial infections in 20 (18%), and ehrlichiosis in 2 (2%), one of whom had also evidence of rickettsial spotted fever infection. None of the patients was diagnosed with Q fever. Compared with patients without zoonoses, patients with zoonoses were younger (P = 0.01), fewer of them had underlying conditions (P < 0.02), they had a longer febrile period prior to hospitalization (P = 0.04), a significantly higher proportion had arthralgia (P = 0.02), rash (P = 0.03), and splenomegaly (P = 0.04) and a lower proportion had pathological findings on chest auscultation (P < 0.01). Patients with zoonoses were found to have more commonly anaemia (P = 0.03) and leucopenia (P = 0.02) compared to the rest of the study population. Of the 30 patients with zoonoses 60% were misdiagnosed and only 57% received adequate antibiotic treatment. Zoonotic infections are a common cause of fever in adult Bedouins living in southern Israel. Because of the non-specific features of these diseases they are often misdiagnosed. Blood cultures and multiple serological tests should be used in the investigation of fever in such patients and tetracycline should be considered for initial empirical treatment.