relapsing fever

relapsing fever,

infectious disease caused by a spirochete bacteria of the genus Borrelia and characterized by a high fever that breaks and then recurs a one to two weeks later. Relapsing fever may be transmitted by body lice or soft ticks. Louse-borne relapsing fever (LBRF) is caused by B. recurrentis, and tick-borne relapsing fever (TBRF) is caused by more than a dozen Borrelia species and transmitted by several soft ticks of the genus Ornithodoros; hard ticks of the genus Ixodes can transmit B. miyamotoi, which causes infection in humans with similar symptoms but usually without a true relapsing fever. Symptoms of relapsing fever include fever and chills, severe headache, muscle and joint aches, and nausea and vomiting. The fever typically breaks after a crisis in which it spikes and is accompanied by rapid breathing and heart rate; the fever then drops precipitously, accompanied by profuse sweating. Recurring, generally less severe episodes of fever and other symptoms are much more numerous in TBRF, but untreated LBRF is more likely to lead to liver and spleen complications, myocarditis, and heart failure with a death rate that can reach 30–70%. Neurological complications may occur with both forms. Both forms of relapsing fever and B. miyamotoi infection may be treated with antibiotics. LBRF is now endemic only in the Horn of Africa, but outbreaks often occur in the overcrowded situations associated with war, famine, and refugee camps. TBRF is found on all continents except Australia; in the United States it occurs in the western half of the country, where patients are most typically infected when sleeping in rural cabins frequented by rodents.

Relapsing Fever

an acute infectious disease caused by spirochetes transmitted through bloodsucking insects (lice, ticks) and characterized by periodic paroxysms of fever alternating with periods of no fever. Epidemic, or louse-borne, and endemic, or tick-borne, relapsing fever are distinguished.

Only man suffers from epidemic relapsing fever. The causative agent is a spirochete discovered in 1868 by the German scientist O. Obermeier. It reproduces in the body cavity (coelomic fluid) of the body louse infected by Obermeier’s spirochetes. Epidemic relapsing fever was widespread during wars and famines, being aided by the migration of people and their infestation with lice. Relapsing fever was one of the commonest diseases in prerevolutionary Russia. In the USSR, the disease has been eradicated. It occurs mainly in countries with poor cultural and economic development. A louse can infect a human only after four days from the time it sucked the blood of someone with relapsing fever. A louse bite is not infectious in itself. Spirochetes enter the blood of a healthy person through small wounds and scratches in the skin after crushing the lice. After penetrating the skin and then passing through the lymphatic vessels into the general bloodstream, the spirochetes enter the spleen, liver, bone marrow, and central nervous system. The periodic entry of spirochetes from these organs into the bloodstream causes recurrences of febrile attacks. Most of the spirochetes are killed at the end of each attack by antibodies (spirochetolysins) and phagocytosis. The incubation period (time from the moment of infection to the appearance of the first symptoms of the disease) varies from two to 14 days. The onset of the disease is sudden, with chills and rapidly rising temperature, which climbs to 40°-41° C within a few hours. General weakness and severe muscle pain, especially in the region of the gastrocnemius, occur. Many patients suffer repeated nose bleeds. The skin is dry, hot to the touch, and slightly jaundiced. The pulse is rapid. The spleen and liver enlarge, the latter to a lesser extent. The first febrile attack lasts five to eight days, after which the temperature drops abruptly to normal while the patient sweats profusely. This is followed by a period of normal temperature—apyrexia—which continues six to eight days. Suddenly, after a chill, the temperature again rises to a high level and the second attack occurs, lasting three to five days. Again apyrexia develops and it continues eight to twelve days. Sometimes there is a third and shorter (one to three days) febrile period. In rare cases there may be as many as four or five recurrences.

Analysis of the blood taken during an attack reveals the presence of spirochetes. Relapsing fever may be complicated by inflammatory changes in the eyes (iridocyclitis), infarcts, and ruptures of the greatly enlarged spleen. Treatment is administered only in a hospital. Patients are discharged 15 days after the temperature drops. Prevention includes early detection and hospitalization of infected individuals and control of louse infestation (pediculosis).

Endemic relapsing fever is one of the natural endemic infections responsible for similar diseases in animals and man. It is caused by spirochetes transmitted by ticks. Natural seats are found in Africa, Asia (Iran, Iraq, Afghanistan, China, and other countries), North and South America, and Europe (Spain, the Balkans). In the USSR, it occurs in Kazakhstan, the Middle Asian republics, Transcaucasia, and southern Ukraine. Under natural conditions rodents (for example, mice, rats, hamsters, and jerboas) suffer from relapsing fever. The disease develops in human beings bitten by infected ticks. Once these insects are infected they remain capable of transmitting the disease to healthy persons throughout their lives. The disease occurs more often in the spring and summer in persons newly arrived in the locality of a natural seat of relapsing fever (expeditions, military units, and the like). The infection produces stable immunity. The course of endemic relapsing fever is similar to that of the epidemic form but is milder and characterized by numerous and irregular attacks. Treatment must be administered in a hospital. Prevention includes eradication of ticks in their habitats (disinsectization) and protection against their bites.

REFERENCES

Gromashevskii, L. V., and G. M. Vaindrakh. Vozvratnyi tif. Moscow, 1946.
Favorova, L. A., and E. A. Gal’perin. “Vozvratnyi tif epidemicheskii.” In Mnogotomnoe rukovodstvo po mikrobiologii, klinike i epidemiologii infektsionnykh boleznei, vol. 7. Moscow, 1966. (Bibliography.)
Pavlovskii, E. N. “Kleshchevoi vozvratnyi tif.” In ibid. (Bibliography.)

K. V. BUNIN

relapsing fever

[ri′laps·iŋ ‚fē·vər] (medicine) An acute infectious disease caused by various species of the spirochete Borrelia, characterized by episodes of fever which subside spontaneously and recur over a period of weeks.

relapsing fever

Relapsing Fever

Definition

Relapsing fever refers to two similar illnesses, both of which cause high fevers. The fevers resolve, only to recur again within about a week.

Description

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

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.

Treatment

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.

Prognosis

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

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.

Key terms

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.

Resources

Organizations

Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. (800) 311-3435, (404) 639-3311. http://www.cdc.gov.

relapsing fever

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.

re·lap·sing fe·ver

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. Synonym(s): bilious typhoid of Griesinger, recurrent fever, spirillum fever, typhinia

relapsing fever

(rĭ-lăp′sĭng)n. Any of several infectious diseases characterized by chills and fever and caused by spirochetes transmitted by lice and ticks. Also called recurrent fever.

relapsing fever

A 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.

relapsing fever

An infection with organisms from the Borrelia genus of SPIROCHAETES transmitted by the bite of a louse or an Ornithodorus tick. Epidemics are common in times of war, famine or civil disorder. The infection causes a sharp rise of fever with shivering, headache, muscle aches, vomiting and PHOTOPHOBIA. The fever and symptoms continue for 3–6 days and may end fatally, but usually settle down completely only to recur 7–10 days later. Each recurrence tends to be shorter and milder than the previous. Treatment is with antibiotics but these must be given cautiously as death of the spirochaetes causes a severe and sometimes fatal reaction.

relapsing fever

re·laps·ing fever

relapsing fever

relaps′ing fe′ver

relapsing fever

relapsing fever,

Relapsing Fever

REFERENCES

relapsing fever

relapsing fever

Relapsing Fever

Definition

Description

Causes and symptoms

Diagnosis

Treatment

Prognosis

Prevention

Key terms

Resources

Organizations

relapsing fever

re·lap·sing fe·ver

relapsing fever

relapsing fever

re·lap·sing fe·ver

relapsing fever

relapsing fever

Synonyms for relapsing fever

noun marked by recurring high fever and transmitted by the bite of infected lice or ticks

Synonyms

Related Words