Background and purpose: Taiwan is an endemic area for scrub typhus. Recent increases have been noted in two other infectious diseases caused by obligate intracellular organisms, Q fever and murine typhus. These diseases usually present as an acute febrile illness with non-specific symptoms and are difficult to distinguish. This study describes the clinical manifestations and complications of cases of rickettsial infections treated at a medical center in southern Taiwan.
Methods: Serum samples from patients with acute febrile illness with or without shock, but without a clinical diagnosis of localized bacterial infection after a preliminary work-up, were collected for serologic study. Medical records of cases with serologic evidence of infection were reviewed and their clinical manifestations were analyzed.
Results: From October 1992 to July 2000, 51 serologically diagnosed cases of rickettsiosis were studied. Q fever predominated (28 cases). All cases of acute Q fever presented with hepatitis during the course of the illness and more than half (54%) reported an animal contact history. Most patients with Q fever (96%) and murine typhus (86%) were male, Serious complications, especially pneumonitis, occurred more frequently with scrub typhus than with acute Q fever. Spontaneous remission frequently occurred with acute Q fever. Administration of tetracycline or its analogues usually resulted in defervescence by the third day of treatment of scrub typhus.
Conclusions: In our study, serious complications including pneumonitis, meningitis/meningoencephalitis, shock, acute renal failure, and disseminated intravascular coagulation were not uncommon in patients with scrub typhus. Physicians should include scrub typhus in the differential diagnosis of suspected cases of community-acquired febrile illness with multiple organ dysfunction in this endemic area. As Q fever is an emerging infectious disease in southern Taiwan, further large-scale epidemiologic surveillance and clinical data are needed.