Clusters of Mediterranean spotted fever in Israel.

Mediterranean spotted fever (MSF) usually occurs as sporadic cases. We report five clusters of MSF in Israel. Each cluster consisted of two to three patients. In two clusters, one patient died while the other recovered. In the other three clusters the patients presented with a benign course of the disease. The diagnosis of MSF in the fatal cases was confirmed by nested-polymerase chain reaction (PCR) tests performed on samples obtained from internal organs. Rickettsial DNA was also found in a tick obtained from a dog owned by one of the patients. MSF was diagnosed in the recovered patients by serology. The diagnosis of MSF fever in one family member should raise the awareness to the possibility of other cases in the vicinity.