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Relapsing fever refers to two similar illnesses, both of which cause high fevers. The fevers resolve, only to recur again within about a week.
Relapsing fever is caused by spiral-shaped bacteria of the genus Borrelia. This bacterium lives in rodents and in insects, specifically ticks and body lice. The form of relapsing fever acquired from ticks is slightly different from that acquired from body lice.
In tick-borne relapsing fever (TBRF), rodents (rats, mice, chipmunks, and squirrels) which carry Borrelia are fed upon by ticks. The ticks then acquire the bacteria, and are able to pass it on to humans. TBRF is most common in sub-Saharan Africa, parts of the Mediterranean, areas in the Middle East, India, China, and the south of Russia. Also, Borrelia causing TBRF exist in the western regions of the United States, particularly in mountainous areas. The disease is said to be endemic to these areas, meaning that the causative agents occur naturally and consistently within these locations.
In louse-borne relapsing fever (LBRF), lice acquire Borrelia from humans who are already infected. These lice can then go on to infect other humans. LBRF is said to be epidemic, as opposed to endemic, meaning that it can occur suddenly in large numbers in specific communities of people. LBRF occurs in places where poverty and overcrowding predispose to human infestation with lice. LBRF has flared during wars, when conditions are crowded and good hygiene is next to impossible. At this time, LBRF is found in areas of east and central Africa, China, and in the Andes Mountains of Peru.
Causes and symptoms
In TBRF, humans contract Borrelia when they are fed upon by ticks. Ticks often feed on humans at night, so many people who have been bitten are unaware that they have been. The bacteria is passed on to humans through the infected body fluids of the tick.
In LBRF, a louse must be crushed or smashed in order for Borrelia to be released. The bacteria then enter the human body through areas where the person may have scratched him or herself.
Both types of relapsing fever occur some days after having acquired the bacteria. About a week after becoming infected, symptoms begin. The patient spikes a very high fever, with chills, sweating, terrible headache, nausea, vomiting, severe pain in the muscles and joints, and extreme weakness. The patient may become dizzy and confused. The eyes may be bloodshot and very sensitive to light. A cough may develop. The heart rate is greatly increased, and the liver and spleen may be swollen. Because the substances responsible for blood clotting may be disturbed during the illness, tiny purple marks may appear on the skin, which are evidence of minor bleeding occurring under the skin. The patient may suffer from a nosebleed, or may cough up bloody sputum. All of these symptoms last for about three days in TBRF, and about five days in LBRF.
With or without treatment, a crisis may occur as the bacteria are cleared from the blood. This crisis, called a Jarisch-Herxheimer reaction, results in a new spike in fever, chills, and an initial rise in blood pressure. The blood pressure then falls drastically, which may deprive tissues and organs of appropriate blood flow (shock). This reaction usually lasts for about a day.
Recurrent episodes of fever with less severe symptoms occur after about a week. In untreated infections, fevers recur about three times in TBRF, and only once or twice in LBRF.
Diagnosis of relapsing fever is relatively easy, because the causative bacteria can be found by examining a sample of blood under the microscope. The characteristically spiral-shaped bacteria are easily identifiable. The blood is best drawn during the period of high fever, because the bacteria are present in the blood in great numbers at that time.
Either tetracycline or erythromycin is effective against both forms of relapsing fever. The medications are given for about a week for cases of TBRF; LBRF requires only a single dose. Children and pregnant women should receive either erythromycin or penicillin. Because of the risk of the Jarish-Herxheimer reaction, patients must be very carefully monitored during the initial administration of antibiotic medications. Solutions containing salts must be given through a needle in the vein (intravenously) to keep the blood pressure from dropping too drastically. Patients with extreme reactions may need medications to improve blood circulation until the reaction resolves.
In epidemics of LBRF, death rates among untreated victims have run as high as 30%. With treatment, and careful monitoring for the development of the Jarish-Herxheimer reaction, prognosis is good for both LBRF and TBRF.
Prevention of TBRF requires rodent control, especially in and near homes. Careful use of insecticides on skin and clothing is important for people who may be enjoying outdoor recreation in areas known to harbor the disease-carrying ticks.
Prevention of LBRF is possible, but probably more difficult. Good hygiene and decent living conditions would prevent the spread of LBRF, but these may be difficult for those people most at risk for the disease.
Endemic — Refers to a particular organism which consistently exists in a particular location under normal conditions.
Epidemic — Refers to a condition suddenly acquired by a large number of people within a specific community, and which spreads rapidly throughout that community.
Shock — A state in which the blood pressure is so low that organs and tissues are not receiving an appropriate flow of blood.
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any of a group of similar infectious diseases transmitted to humans by the bites of lice and ticks, and marked by alternating periods of normal temperature and periods of fever relapse. The diseases in the group are caused by several different species of spirochetes belonging to the genus Borrelia. Called also recurrent fever.
Symptoms and Diagnosis. Generally, relapsing fever starts with a sudden high fever of 40° to 40.5°C (104° to 105°F), accompanied by chills, headache, muscle aches, nausea, and vomiting. There may also be jaundice and a rash. The attack lasts 2 or 3 days, after which the symptoms disappear by crisis, with profuse sweating accompanying the rapid drop in temperature. In elderly people this may be accompanied by collapse, in which the heart and respiratory system function poorly. After 3 or 4 days there is a relapse and the symptoms return in their former severity. The cycle continues through four or more attacks before the disease has run its course. Relapsing fevers are rarely fatal, but they can be serious.
Treatment and Prevention. Treatment is with antibiotics. Sponge baths and aspirin help to control the fever and comfort the patient. Although tickborne relapsing fever still occurs in the western United States as well as in other parts of the world, louse-borne fever is now largely confined to underdeveloped parts of Asia, Africa, and Latin America. Improved public sanitation and louse and tick control account for the decline in the incidence of the disease.
an acute infectious disease caused by any one of a number of strains of Borrelia, marked by a number of febrile attacks lasting about 6 days and separated from each other by apyretic intervals of about the same length; the microorganism is found in the blood during the febrile periods but not during the intervals, the disappearance being associated with specific antibodies and previously evoked antibodies. There are two epidemiologic varieties: the louse-borne variety, occurring chiefly in Europe, northern Africa, and India, and caused by strains of B. recurrentis; and the tick-borne variety, occurring in Africa, Asia, and North and South America, caused by various species, each of which is transmitted by a different species of the soft tick, Ornithodoros.
Any of several infectious diseases characterized by chills and fever and caused by spirochetes transmitted by lice and ticks. Also called recurrent fever.
relapsing feverA tick-born bacterial infection seen primarily in the western US, characterized by multiple episodes of fever interspersed with disease free intervals Epidemic borreliosis.B recurrentis–louse-borne–Pediculus humanis and transmitted person-to-person Clinical History of recent outdoor camping, fevers with 'negative' blood cultures, Jarisch-Herxheimer-like hypotensive 'crises' after therapy with antibiotics, thrombocytopenia Endemic borreliosis B recurrentis, B hemisi, B turicatae, B parkeri and others–transmitted by ticks–Ornithodoros spp, which inject borrelia during a blood meal Clinical Abrupt onset of high fever, rash, headache, photophobia, N&V, myalgias, arthralgias, abdominal and chest pain, hematuria, hematemesis, epistaxis, productive cough and minimal respiratory distress; after febrile wave passes, diaphoresis, weakness, hypotension, hypothermia; ±1 wk later, the cycle repeats itself; each successive cycle is less severe than previous one; late relapses typically involve the CNS–meningismus, peripheral neuritis, cranial nerve paralysis, seizures, coma; late disease may cause hepatitis, potentially fatal myocarditis Treatment Tetracycline, erythromycin, chloramphenicol
re·lap·sing fe·ver(rē-lap'sing fē'vĕr)
An acute infectious disease caused by any one of a number of strains of Borrelia, marked by febrile attacks lasting about 6 days and separated from each other by apyretic intervals of about the same length; the microorganism is found in the blood during the febrile periods but not during the intervals. There are two epidemiologic varieties: 1) the louse-borne variety, occurring chiefly in Europe, northern Africa, and India, and caused by strains of B. recurrentis; 2) the tick-borne variety, occurring in Africa, Asia, and North and South America, caused by various species of Borrelia, each of which is transmitted by a different species of Ornithodoros, a soft tick.