Reversible typhoid fever

Relapsing fever is a group of acute infectious transmissible diseases of humans caused by Borrelia. It is characterized by attacks of fever, alternating with periods of apyrexia. It is transmitted by lice or ticks.

Louse-borne relapsing fever (epidemic relapsing fever, relapsing fever, epidemic relapsing spirochetosis, louse-borne relapsing fever) is an acute infectious disease caused by several types of spirochetes, transmitted by lice or ticks and characterized by recurring attacks of fever lasting 3-5 days, which alternate with periods of apparent health. Clinical diagnosis of louse-borne relapsing fever is confirmed by staining a smear of peripheral blood. Treatment of louse-borne relapsing fever is carried out with tetracycline and erythromycin.

ICD-10 code

A68.0. Lice-associated relapsing fever.

What causes louse-borne relapsing fever?

The carriers are Ornithodoros ticks or body lice, depending on the geographic region. Louse-borne relapsing fever is rare in the United States and endemic in some areas of Africa and South America, tick-borne - in America, Africa, Asia, Europe. In the United States, louse-borne relapsing fever occurs mainly in the western states from May to September.

Lice become infected with spirochetes from sick people by biting them during a fever. They are transmitted to humans not directly by biting, but with the material of crushed lice through skin damage, scratching, friction of clothing, etc. Uncrushed lice do not transmit the disease. Ticks become infected from rodents, which are a natural reservoir of infection, and transmit pathogens to humans with saliva or excreta that get into the wound during a bite. Congenital borreliosis has also been reported.

Mortality is usually low (up to 5%), but can be significantly higher in children, the elderly, pregnant women, with inadequate nutrition, weakened conditions, and during epidemics.

What are the symptoms of louse-borne relapsing fever?

Since ticks feed irregularly and painlessly, mostly at night, most patients do not remember the bites, but can say that they spent the night in tents, caves, village houses. In these cases, the probability of a bite is very high.

Louse-borne relapsing fever has an incubation period that lasts from 3 to 11 days (6 days on average). Louse-borne relapsing fever has an acute onset: chills, high temperature, tachycardia, severe headache, vomiting, muscle and joint pain, often delirium. At an early stage, there are erythematous spots or hemorrhagic rashes on the trunk and limbs, hemorrhages under the skin, mucous membranes, and in the conjunctiva are possible. The temperature remains high for 3-5 days, after which a crisis occurs and it drops sharply. Louse-borne relapsing fever lasts from 1 to 54 days (18 days on average).

Later in the course of the fever, the liver and spleen enlarge, jaundice, signs of myocarditis, and heart failure occur, especially when the infection is carried by lice. Complications include spontaneous abortion, ophthalmitis, exacerbations of asthma and erythema multiforme. Iritis and iridocyclitis are possible, meningeal symptoms are rare.

Patients are usually asymptomatic for several days to a week between the initial episodes and the first attack of fever. Relapse occurs in accordance with the life cycle of the pathogen and is manifested by a sudden resumption of fever, arthralgia, and other symptoms described above. Jaundice is more common during relapses. For several days or weeks after the crisis, the patient usually has no symptoms of louse-borne relapsing fever. There may be 2-10 such febrile periods, with an interval of 1-2 weeks between them. The severity of relapses weakens each time, and as immunity is acquired, complete recovery is achieved.

How is louse-borne relapsing fever diagnosed?

Diagnosis of louse-borne relapsing fever is based on the recurring nature of the fever and is confirmed by the detection of spirochetes in the blood during the period of elevated temperature. Spirochetes are visible in blood smears by dark-field microscopy and by Wright or Giemsa staining. (Acridine orange staining of blood or tissue samples is more informative.) Serologic tests are uninformative. Leukocytosis (with a predominance of polymorphic nuclear cells) occurs.

Differential diagnosis of louse-borne relapsing fever is carried out with arthritis in Lyme disease, malaria, dengue fever, yellow fever, leptospirosis, typhus and typhoid fever, influenza and enteric fever.

How is louse-borne relapsing fever treated?

For tick fever, tetracycline or erythromycin is taken orally at 500 mg every 6 hours for 5-10 days. For louse fever, a single dose of 500 mg of one of these drugs is sufficient. Doxycycline is also effective orally at 100 mg 2 times a day for 5-10 days.

Children under 8 years of age are prescribed erythromycin estolate 40 mg/kg/day. If oral administration of medications is impossible due to vomiting or the patient's severe condition, tetracycline is administered intravenously (500 mg in 100 or 500 ml of saline) 1-2 times a day (for children 25-50 mg/kg/day).

Children under 8 years of age are given penicillin G 25 thousand units/kg intravenously every six hours.

Treatment of louse-borne relapsing fever should begin as early as possible in the febrile or afebrile stage, but not before the crisis itself, because of the danger of developing the Jarisch-Herxheimer reaction, which can be fatal. In tick fever, the Jarisch-Herxheimer reaction can be reduced by acetaminophen orally 650 mg 2 hours before and 2 hours after the first dose of tetracycline or erythromycin.

Dehydration and electrolyte imbalance are corrected by parenteral administration of fluids.

Headache is relieved by acetaminophen with codeine. For nausea and vomiting, prochlorperazine is prescribed orally or intramuscularly at 5-10 mg 1-4 times a day. In case of heart failure, appropriate therapy is indicated.

What is the prognosis for louse-borne relapsing fever?

Louse-borne relapsing fever has a favorable prognosis if specific treatment is administered early. Unfavorable prognostic signs include intense jaundice, massive bleeding, and cardiac arrhythmia.