Relapsing fever spreads to a new state

An outbreak in Montana was caused by a bacterium never before seen there and carried by a non-native tick species.

By Victoria Stagg Elliott, AMNews staff. Sept. 22/29, 2003.

Last year, a family visited western Montana's Flathead Lake and returned home to Washington state with high fevers, headaches, joint pain, vomiting, diarrhea and rashes. The family was treated and recovered. The diagnosis, according to a paper published in the September Emerging Infectious Diseases: relapsing fever. The disease was caused by a bacterium not found in Montana and carried by a tick that is not native to the state.

"These were new state records," said Tom G. Schwan, PhD, lead investigator and acting chief of one of the labs at Rocky Mountain Laboratories. "Relapsing fever is not new to science, and it's not new to North America. What it is new to is Montana."

Experts warn that this is another of several recent outbreaks, including severe acute respiratory syndrome and monkeypox, in which illnesses are linked to travel and the movement of animals.

"This investigation demonstrates once again the potential for diseases to emerge unpredictably in areas where they have not been recognized previously," said Marshall Bloom, MD, associate director of Rocky Mountain Laboratories.

This case was caught by an astute clinician, as in the monkeypox outbreak. "[It] clearly demonstrates that the medical establishment in today's world needs to recognize that unexpected infectious diseases can pop up anywhere," Dr. Bloom added.