Relapsing fever

Definition:

A bacterial disease causing repeated multiple episodes of fever interspersed with apparently disease free periods.

Causes, incidence, and risk factors:

Relapsing fever is a tick-born disease and is seen primarily in the western United States. The organisms which cause relapsing fever belong to the Borrelia family and are carried by the Ornithodorus tick. Epidemic relapsing fever is caused by the same organism, but carried by body lice.

Following infection by a tick bite, symptoms begin with a high fever (103 to 104 degrees Fahrenheit) of sudden onset, headache, vomiting, and muscle, joint aches and chest pain. Nosebleeds, blood in the urine, and blood in the vomit are not uncommon. The fever may also be accompanied by a rash.

The fever may last more than a week and its passing produces dramatic symptoms of sweating (diaphoresis), weakness, low blood pressure and low body temperature. Within a week, the cycle repeats itself. With each cycle, the fevers are generally lower and the symptoms less severe.

Some children after several cycles of fever may develop dramatic central nervous system signs such as seizures, stupor and neuritis. The Borrelia organism may also invade heart and liver tissues causing inflammation of the heart muscle (myocarditis) and inflammation of the liver (hepatitis). Myocarditis may be fatal.