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.
K. V. BUNIN