Marseille fever: causes, symptoms, diagnosis, treatment

Marseilles fever (Marseilles febris, ixodorickettsiosis, Marseilles rickettsiosis, papular fever, Carducci-Olmer disease, tick-borne fever, Mediterranean fever, etc.) is an acute zoonotic rickettsiosis with a transmissible mechanism of transmission of the pathogen, characterized by a benign course, the presence of a primary affect and a widespread maculopapular rash.

ICD-10 code

A77.1 Spotted fever due to Rickettsia conorii.

Epidemiology of Marseilles fever

The main carrier is the dog tick Rhipicephalus sanguineus, in whose body they remain for up to 1.5 years; transovarial transmission of the pathogen is typical. Other ticks can also be carriers (Rhipicephalus simus, Rh. everbsi. Rh. appendiculatus). The reservoir of the pathogen is many species of domestic and wild animals (for example, dogs, jackals, hedgehogs, rodents). The seasonality of Marseille fever (May-October) is also due to the peculiarity of the biology of the dog tick (during this period, their number increases significantly and their activity increases). The pathogen is transmitted to humans when the tick attaches, but infection is possible when crushing and rubbing infected ticks into the skin. The dog tick attacks humans relatively rarely, so the incidence is sporadic. Marseille fever is diagnosed mainly among dog owners. Cases of Marseilles fever are registered in the Mediterranean countries, on the Black Sea coast, in India. Astrakhan rickettsial fever (ARF - a variant of Marseilles fever) is widespread in the Astrakhan region, considered as an independent nosological form according to a number of epidemiological, ecological and clinical criteria. Cases of transmission of the pathogen from person to person have not been identified. Post-infection immunity is stable.

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What causes Marseilles fever?

Marseilles fever is caused by the rod-shaped gram-negative bacterium Rickettsia conorii. It is an obligate intracellular parasite: it reproduces in tissue culture (in the yolk sac of a chicken embryo) and during infection of laboratory animals (in mesothelial cells). It is pathogenic for guinea pigs, monkeys, rabbits, ground squirrels, white mice and white rats. In terms of antigenic properties, it is close to other pathogens of the tick-borne spotted fever group. It can parasitize in the cytoplasm and nuclei of host cells. In patients, the pathogen is detected in the blood during the first days of the febrile period, in the primary affect and in roseola of the skin. It is unstable in the environment.

Pathogenesis of Marseilles fever

Marseilles fever begins in connection with the development of rickettsiaemia and toxinemia. The pathogen penetrates through the skin or mucous membranes of the nose and conjunctiva. At the site of penetration, a primary affect ("black spot") is formed, revealed soon after the tick bite (5-7 days before the symptoms of Marseilles fever appear). Through the lymphatic system, rickettsia first enter the regional lymph nodes (cause lymphadenitis), and then into the blood (affect the endothelium of capillaries and venules). In this case, changes occur similar to those detected in epidemic typhus, but the number of granulomas (nodules) is smaller and necrotic changes are less pronounced.

Symptoms of Marseilles fever

Marseille fever has an incubation period that lasts from 3 to 7 days.

There are four periods of Marseille fever:

• incubation:
• initial (before the rash appears);
• height;
• recovery.

A distinctive feature of Marseilles fever is the presence of a primary affect, which is detected in most patients before the onset of the disease. The primary affect initially appears as a focus of skin inflammation with a dark crusted area of necrosis 2-3 mm in diameter in the center. The size of the primary affect gradually increases to 5-10 mm by the beginning of the febrile period. The crust falls off only on the 5th-7th day after the normal temperature is established. The small ulcer that opens gradually epithelializes (within 8-12 days), after which a pigmented spot remains. The localization of the primary affect is varied (usually on areas of skin covered by clothing); there may be 2-3 foci. Patients do not complain of subjective sensations in the area of the primary affect. About a third of them develop regional lymphadenitis with a slight increase and soreness of the lymph nodes. The onset of the disease is acute, with a rapid increase in temperature to 38-40 ° C. Constant fever (less often remittent) lasts for 3-10 days and is accompanied by chills, severe headache, general weakness, severe myalgia, as well as arthralgia and insomnia. Vomiting is possible. Examination reveals hyperemia and some puffiness of the face, injection of the vessels of the sclera and mucous membranes of the pharynx.

The peak of the disease is characterized by the appearance of exanthema (on the 2nd-4th day of its course), detected in all patients. The rash first appears on the chest and abdomen, then spreads to the neck, face, limbs; in almost all patients it is found on the palms and soles. The rash is abundant (especially on the limbs), consists of spots and papules, some elements undergo hemorrhagic transformation. In many patients, vesicles appear at the site of papules. The rash is most abundant on the legs; its elements are brighter and larger than on other areas of the skin. The rash disappears after 8-10 days, leaving behind skin pigmentation, which sometimes persists for up to 2-3 months.

Bradycardia and a slight decrease in blood pressure are detected. No significant pathology of the respiratory organs develops. The abdomen is soft or (in some patients, moderately distended), painless upon palpation. In 50% of patients, stool retention and very rarely loose stool are detected during the febrile period. Some patients have an enlarged liver and, less often, spleen. Daily diuresis decreases and proteinuria occurs (especially in the first week). During the convalescence period, the general condition improves and all symptoms subside.

Complications of Marseilles fever

The blood picture is not very characteristic. Complications of Marseilles fever are rare. Pneumonia and thrombophlebitis may develop (usually in elderly people).

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Diagnosis of Marseilles fever

The diagnosis of Marseille fever must take into account epidemiological prerequisites (stay in an endemic area, season, contact with dogs, tick bites, etc.). In the clinical picture, the triad of symptoms is of greatest importance:

• primary affect ("black spot");
• regional lymphadenitis;
• early appearance of a profuse polymorphic rash over the entire body, including the palms and soles.

They take into account the moderate severity of general intoxication and the absence of typhoid status.

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Specific and non-specific laboratory diagnostics of Marseilles fever

Laboratory confirmation of the diagnosis is based on serological reactions: complement fixation reaction with a specific antigen (the reaction with other rickettsial antigens is also carried out in parallel), RIGA. Preference is given to the WHO-recommended RNIF (minimum reliable titer - serum dilution 1:40-1:64). High titers of specific antibodies in RNIF are detected on the 4th-9th day of the disease and at the diagnostic level - at least 45 days.

Differential diagnosis of Marseilles fever

Differential diagnostics of Marseille fever is carried out with infectious diseases that are similar in clinical manifestations: rat-borne, typhus, typhoid, paratyphoid, secondary syphilis, toxic-allergic drug dermatitis, as well as other exanthematic infectious pathologies.

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Indications for hospitalization

Indications for hospitalization are fever, severe intoxication, tick bite, rash.

Treatment of Marseilles fever

Regime and diet

Bed rest. Diet - table No. 13.

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Drug treatment of Marseilles fever

As with other rickettsioses, tetracycline is most effective (0.3-0.4 g orally four times a day for 4-5 days). Doxycycline is also used (0.2 g on the first day and 0.1 g on the following days - up to 3 days after temperature stabilization). In case of intolerance to tetracycline antibiotics, chloramphenicol is prescribed (0.5-0.75 g four times a day for 4-5 days).

Pathogenetic treatment of Marseilles fever is aimed at eliminating intoxication and hemorrhagic manifestations. Depending on the severity of the disease, detoxification is carried out using drugs for oral administration [citraglucosolan, rehydron (dextrose + potassium chloride + sodium chloride + sodium citrate)] or for intravenous administration, taking into account age, body weight, the state of the circulatory and urinary systems, in a volume of 200-400 ml to 1.5-2 l [sodium chloride complex solution (potassium chloride + calcium chloride + sodium chloride), trisol (sodium bicarbonate + sodium chloride + potassium chloride), disol (sodium acetate + sodium chloride), acesol (sodium acetate + sodium chloride + potassium chloride)]. In case of severe hemorrhagic syndrome (for example, profuse hemorrhagic rash, bleeding gums, nosebleeds) and the presence of thrombocytopenia, ascorutin (ascorbic acid + rutoside), calcium gluconate, menadione sodium bisulfite, ascorbic acid, calcium chloride, gelatin, aminocaproic acid are prescribed.

Clinical examination

Patients are discharged 8-12 days after temperature has returned to normal.

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How is Marseille fever prevented?

Specific prevention of Marseilles fever has not been developed.

In epidemic foci, possible tick habitats are treated with insecticides (for example, dogs, dog kennels), and stray dogs are captured.

What is the prognosis for Marseille fever?

Marseilles fever has a favorable prognosis. Fatal outcomes are rare.