adj. without, or not showing any signs of, a fever.
Louse-borne relapsing fever is an EPIDEMIC disease, usually associated with wars and famines, which has occurred in practically every country in the world. For long confused with TYPHUS FEVER and typhoid fever (see ENTERIC FEVER), it was not until the 1870s that the causal organism was described by Obermeier. It is now known as the Borrelia recurrentis, a motile spiral organism 10–20 micrometres in length. The organism is transmitted from person to person by the louse, Pediculus humanus.
Symptoms The incubation period is up to 12 days (but usually seven). The onset is sudden, with high temperature, generalised aches and pains, and nose-bleeding. In about half of cases, a rash appears at an early stage, beginning in the neck and spreading down over the trunk and arms. JAUNDICE may occur; and both the LIVER and the SPLEEN are enlarged. The temperature subsides after ?ve or six days, to rise again in about a week. There may be up to four such relapses (see the introductory paragraph above).
Treatment Preventive measures are the same as those for typhus. Rest in bed is essential, as are good nursing and a light, nourishing diet. There is usually a quick response to PENICILLIN; the TETRACYCLINES and CHLORAMPHENICOL are also e?ective. Following such treatment the incidence of relapse is about 15 per cent. The mortality rate is low, except in a starved population.
Tick-borne relapsing fever is an ENDEMIC disease which occurs in most tropical and sub-tropical countries. The causative organism is Borrelia duttoni, which is transmitted by a tick, Ornithodorus moubata. David Livingstone suggested that it was a tick-borne disease, but it was not until 1905 that Dutton and Todd produced the de?nitive evidence.
Symptoms The main di?erences from the louse-borne disease are: (a) the incubation period is usually shorter, 3–6 days (but may be as short as two days or as long as 12); (b) the febrile period is usually shorter, and the afebrile periods are more variable in duration, sometimes only lasting for a day or two; (c) relapses are much more numerous.
Treatment Preventive measures are more di?cult to carry out than in the case of the louse-borne infection. Protective clothing should always be worn in ‘tick country’, and old, heavily infected houses should be destroyed. Curative treatment is the same as for the louse-borne infection.... relapsing fever
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