Recurrent tick-borne typhus: causes, symptoms, diagnosis, treatment
Last reviewed: 23.04.2024
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Return typhus tick-borne (endemic recurrent typhus, tick-borne spirochetosis, tick-borne relapsing fever), zoonosis, acute natural focal disease of warm and hot climate zones, transmitted to humans by mites, characterized by multiple attacks of fever, divided by periods of apyrexia.
ICD-10 code
A68.1. Endemic recurrent typhus.
Epidemiology of recurrent tick-borne typhus
Recurrent tick-borne typhus is a classic natural-focal disease. The source of the infection is various animals, including rodents, predators, insectivores, reptiles, etc. The main reservoir and specific carrier of the causative agent are Argus mite of the genus Alectorobius. They are found in deserts and semi-deserts, foothills and mountains, as well as in settlements (farm buildings, cattlemen, mud houses). Infection occurs during the suction of an infected tick. Human susceptibility to recurrent tick-borne typhus is high. People permanently living in endemic foci usually develop immunity. Mostly newcomers from other regions are sick (tourists, travelers stopping at rest in ruins, abandoned dwellings, caves, servicemen).
Foci of tick-borne recurrent typhus are scattered everywhere except in Australia, in zones with a hot and subtropical climate. Recurrent tick-borne typhus is widespread in many countries of Asia (including in the former Central Asian republics of the Soviet Union, as well as in Israel, Jordan, Iran), Africa and Latin America; in Europe it is registered in Spain, Portugal, in the south of Ukraine, the North Caucasus and in Transcaucasia.
The incidence increases in spring and summer, which is associated with the greatest activity of tick-carriers; In countries with a tropical climate, infection can occur throughout the year.
What causes recurrent tick-borne typhus?
Endemic recurrent typhus is caused by spirochaetes of the genus Borrelia (more than 20 species), which are morphologically identical to the Obermeyer spirochete, which differ from it by antigenic structure and pathogenicity. Most often, recurrent tick-borne typhus is caused by African B. Duttoni, Asian B. Persica, and B. Hermsii and B. Nereensis.
In the external environment Borrelia are not very stable.
Pathogenesis of recurrent tick-borne typhus
Pathogenesis, pathomorphology, and immunity are identical with those in vernal recurrent typhus.
Symptoms of recurrent tick-borne typhoid
Recurrent tick-borne typhus has an incubation period that lasts from 4 to 20, more often 11-12 days.
At the site of the tick bite, a pink spot appears a few minutes later, then a nodule (papule) with a diameter of about 5 mm with a hemorrhagic rim. This is a primary affect, which can persist until 2-3 weeks.
The first febrile attack usually occurs suddenly, less often after the prodrome, the following symptoms of recurrent tick-borne typhus occur : high body temperature, chills, severe headache and other symptoms of intoxication, as in typhus, but instead of adynamia and apathy, excitement, delirium, hallucinations . The attack lasts 2-4 days (less often - several hours), then the body temperature drops sharply, the patients sweat profusely, after which the state of health normalizes. The duration of the apyrexia period is from 4 to 20 days. The number of seizures can be 10-12 or more. Each subsequent attack is shorter, and the period of apyrexia is longer than the previous one. Perhaps a disorderly alternation of fever and non-fever intervals. The total duration of the disease is several months, but with the early appointment of antibiotic therapy, the clinical picture is stunted, one wave of fever is observed.
During seizures, note flushing of the face, subcyteric sclera. Cardiac tones are muffled, blood pressure lowering, relative bradycardia, abdominal pain, loose stools are possible; from the 3rd day, the liver and spleen increase moderately.
In East Africa and in some US states there are cases of severe flow of recurrent tick-borne typhus, in other regions it occurs usually in a mild or moderate form, which may be due to the biological features of local strains of Borrelia,
Complications of recurrent tick-borne typhus
Recurrent tick-borne typhus is complicated by other diseases less often than with typhoid return typhus. These include acute psychosis, encephalitis, uveitis, iridocyclitis, keratitis.
Mortality and causes of death
Lethal cases are extremely rare, but are possible with "African" inverted recurrent typhus caused by B, duttoni.
Diagnosis of recurrent tick-borne typhus
Essential role played by epidemiological history (stay in the habitat of tick-carriers), detection of primary affect, alternation of febrile seizures with periods of apyrexia.
Finally, the diagnosis is established when Borrelia are detected in the patient's blood (a thick drop, colored according to Romanovsky-Giemsa, is being examined). Borrelia in the peripheral blood may be small, so blood is taken several times a day, preferably during a febrile attack. Diagnosis of recurrent tick-borne typhoid with the indirect reaction of immunofluorescence: specific antibodies in the serum are tested from the 5th-7th day of the disease. Currently, PCR is successfully used for diagnosis.
In clinical blood analysis, a small leukocytosis, lymphocytosis, monocytosis, eosinopenia, increased ESR; after several attacks there is a moderate hypochromic anemia.
[7], [8], [9], [10], [11], [12],
Differential diagnosis of recurrent tick-borne typhus
Differential diagnostics of recurrent tick-borne typhus is carried out with vesicular recurrent typhus, malaria, sepsis, influenza and other diseases accompanied by high fever. In contrast to voxal recurrent tick-borne typhus is characterized by less fever, short-term and numerous attacks, rapid improvement in the patient's well-being after the attack, lack of sore spleen and moderate increase, excitation (not adynamia) of the patient, characteristic type of temperature curve, lack of regularity in duration both the seizures themselves, and the periods of apyrexia, the presence of primary affect, a lighter course. The similarity of tick-borne recurrent typhoid and malaria can be so great that only the result of a study of a smear smeared with Romanov-Giemsa and a thick drop of blood allows us to establish the final diagnosis.
What do need to examine?
What tests are needed?
Treatment of recurrent tick-borne typhus
Treatment of recurrent tick-borne typhoid is carried out in the hospital with the same antibiotics and at the same doses as in case of typhoid return typhus, until 5-7th day of a persistently normal temperature. If necessary, prescribe detoxification treatment for recurrent tick-borne typhus.
How to prevent relapsing tick-borne typhus?
Specific prevention is not developed.
Nonspecific prophylaxis of recurrent tick-borne typhus consists in the destruction of ornithodic mites and rodents in the outbreaks, wearing protective clothing in the habitat of ticks, and using repellents.
What is the prognosis of recurrent tick-borne typhus?
Recurrent tick-borne typhus has a favorable prognosis.