Relapsing fever describes two separate diseases caused by Borrelia bacteria which are either louse-borne or tick-borne. Both diseases result in periods of spiral bacteria in the blood (spirochetemia), and fever alternating with absence of spirochetemia and apyrexia (no fever).

Body lice or soft ticks usually spread relapsing fever. Louse-borne relapsing fever occurs only in parts of Africa and South America. Tick-borne relapsing fever occurs in North and South America, Africa, Asia, and Europe. The United States occurrence is generally confined to the western states, and most frequently occurs between May and September. Body lice become infected when they feed on an infected person. The infection can be passed on to another person when the infected lice change hosts. If the lice are crushed, bacteria are at large and enter skin through a scrape or bite.

Ticks become infectious by feeding on rodents. Rodents harbor the bacteria naturally. The infection is then spread to humans through a tick bite.

Symptoms may not manifest until 3 to 11 days after exposure. Early symptoms include: sudden chills followed by a high fever, rapid heart rate, severe headache, vomiting, muscle and joint pain, and often delirium. In addition, a reddish rash may appear on the trunk, arms, and legs. With progression of the disease, fever, jaundice, an enlarged liver and spleen, heart inflammation, and heart failure may occur, particularly with the louse-borne infection. Fever continues for 3 to 5 days, and then ends suddenly along with other symptoms. After 7 to 10 days, the fever and symptoms reappear suddenly. There may also be pain in the joints, and jaundice often accompanies a relapse. Relapsing fever from the louse-borne infection usually occurs with a single relapse, whereas several relapses are common with the tick-borne disease. The relapses will steadily become less acute, and the person ultimately recovers as immunity develops.

Diagnosis is established when the spirochete bacteria are found in a blood sample taken during a fever episode.

Curing the infection involves antibiotic treatment. If dehydration occurs, it is treated with intravenous (IV) fluids. Pain from severe headache is treated with codeine. Medications for nausea may be necessary.

Starting treatment at the end of a fever may bring about the Jarisch-Herxheimer reaction, which manifests with high fever and a rise and a successive fall in blood pressure. At times, the blood pressure can fall to unsafe levels. This reaction is characteristic, and sometimes causes fatality in individuals who contract the louse-borne disease.

Less than 5% of people with relapsing fever die. However, those who are very young, elderly, underfed, or debilitated are at greater danger. Complications of the disease include eye inflammation, asthma flare-ups, and erythema multiforme all over the body. Other areas that may become inflamed are the brain, spinal cord, and the iris of the eye. Pregnant patients may miscarry.

1. May be entitled to special monthly compensation where the veteran has a single service-connected disability rated as 100% and/or other requirements/qualifications under 38 CFR §3.350 [Special monthly compensation ratings]. Also reference 38 CFR 3.155(d)(2).

As active disease rate as 100%, thereafter rate under the appropriate body system any residual disability of infection, which includes, but is not limited to, liver or spleen damage, iritis, uveitis, or central nervous system involvement.