Marseille fever
Description
Marseille fever is an acute rickettsial zoonosis with a transmissible mechanism of spread, characterized by a benign course and the appearance of a generalized maculopapular rash.
What is it caused by?
The infectious disease is caused by the rod-shaped gram-negative bacterium Rickettsia conorii. Obligate intracellular parasite: reproduces in tissue culture /in the yolk sac of a chick embryo/ and when infecting laboratory animals /in the cells of the mesothelium/.
It is pathogenic for guinea pigs, monkeys, rabbits, lalugers, white mice and white rats. Its antigenic properties are similar to other tick-borne pathogens of spotted fever.
They can parasitize 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 environment, the bacterium is unstable.
What are the symptoms?
The infectious disease has an incubation period that lasts 3-7 days.
The disease is divided into 4 stages:
• Incubation;
• Initial – before the appearance of the rash;
• The actual disease;
• Recovery;
Before the appearance of the rash in most patients, the skin around the site of the tick bite is covered with a dark crust, in the center of which an ulcer with a diameter of 2-3 mm appears.
The size of the primary ulcer increases to about 5-10 mm. until the beginning of the febrile period. The crust falls off on its own about 5-7 days after the normalization of the body temperature.
And the open skin ulcer epithelializes after about 8-12 days, but the place remains pigmented. This primary rash can also appear in several places on the skin, usually in the areas of skin covered by clothing.
The patients do not have any complaints such as pain or irritation from the primary rash that appeared. About 1/3 of them have regional lymphadenitis with slight swelling and tenderness of the lymph nodes.
The disease begins acutely, the body temperature rises very quickly to 38-40 degrees Celsius. The fever lasts constantly for 3-10 days, and the body temperature gradually decreases.
Fever is accompanied by severe headache, general weakness, severe myalgia, arthralgia and insomnia. Vomiting is also possible. On examination, hyperemia and certain puffiness of the face, ruptured blood vessels in the sclera and mucous membranes of the throat are found.
The actual disease is characterized by the appearance of a characteristic rash, most often 2-4 days after the appearance of the initial symptoms. The rash first appears on the chest and abdomen, and then develops on the face, neck and limbs.
Skin lesions are usually in the form of spots and papules, but some transform into hemorrhages. In many patients, vesicles appear in place of the papules – fluid-filled blisters.
The rash is most concentrated on the legs – there the papules or vesicles are larger and brighter in color. The skin lesions disappear after 8-10 days, but the skin remains pigmented in the places where they were for about 2-3 months.
Bradycardia usually develops and blood pressure drops slightly. Serious respiratory disorders occur. The abdomen is soft or in some cases moderately swollen, painless on palpation.
In 50% of patients during the fever period, the frequency of bowel movements decreases and diarrhea develops less often. In some patients, an enlargement of the liver and less often of the spleen is observed.
The amount of diuresis decreases and sometimes proteinuria appears, especially in the first week of the disease. During the recovery period, the general condition improves and the symptoms disappear.
Treatment of Marseilles fever
Like other rickettsioses, the antibiotic tetracycline is most effective. It is prescribed for internal administration 300-400 mg. four times a day for 4-5 days. Doxycycline 200 mg is also prescribed. the first day and 100 mg. in the following days – up to 3 days after the temperature stabilizes.
In case of intolerance to tetracyclines, chloramphenicol 500-750 mg is administered. 4 times a day for 4-5 days.
