Tick-borne typhus

Related articles:

• Typhoid
• Epidemic typhus

Description of the disease

Typhus is a disease of infectious origin of species rickettsiosis disease caused by tick bites, with a relatively easy course with a lesion predominantly of the lymph nodes and skin rashes. Other names of the disease that occur in medical practice and everyday life can be tick-borne rickettsiosis, Siberian tick typhus, Oriental spotted fever.

The disease is a typical zoonosis, because the circulation of the pathogen and the incidence recorded only among small rodents in natural conditions. It can be squirrels, hamsters, field mice, chipmunks, voles. A person gets into this circle by accident after a tick bite. Therefore, tick-borne typhus is the disease with natural foci and is tied to certain areas, where it is constantly circulating pathogens. Is some region of Siberia, Krasnoyarsk, Khabarovsk, Primorsky Krai, Turkmenistan, Armenia, Kazakhstan, Mongolia.

The vectors between healthy and sick animals are ticks. The prevalence of the disease under natural conditions is so broad that every fifth representative of the ticks is infected. This explains the relatively high incidence of tick-borne typhus among people living in the pandemic zones. It is an average of 200-300 cases per 100 thousand population in a year. A significant number of people have persistent natural immunity, so ill mostly newcomers and persons with weakened immune systems.

The pathogenesis of the disease determine the pathogenic properties Rickettsia. They enter the human body through the wound of the skin, which remains after the tick bite. This place is called the primary affect because here there are the first inflammatory changes upon contact of the tissues with pathogens. When this occurs, the spread of pathogens via the lymphatic collectors in the lymph nodes of the regional order. The result of such processes may belimfangoit with the primary affect, and swollen lymph nodes. In them is the multiplication of Rickettsia with the regular release into the systemic circulation and posting throughout the body.

Feature of infectious agents in tick-borne spotted typhus in preservation of affinity for vascular endothelium, as in epidemic typhus fever, but much less pathogenic-toxigenic properties. The main pathogenetic links of the disease are microvascular disorders result from destruction of capillaries, inflammation in them and increased permeability, and slight intoxication occurring in the destruction of pathogens by the immune cells of the body. Therefore, their distribution in the body is relatively positive and never causes severe complications.

The symptoms of tick-borne typhus

The incubation period of pathogens of tick-borne typhus which lasts from the time of tick bite to the appearance of the first manifestations of the disease, ranging from 3-4 days to a week. At this time, other than a minor inflammation of the skin at the site of the bite, patients no longer worried. The clinical picture develops suddenly and acutely.

While there are symptoms of typhus:

1. Hyperthermic reaction. In most cases, temperature hectic (39% more), continuous or alternating. The duration of the febrile period may last up to two weeks if not treated the patient. A few days after the appearance of the figures temperature a little lower, it acquires consistency;

2. Light fever with muscle and headaches. Occur synchronously with hyperthermia and decrease with its reduction;

3. Mild puffiness of face on background of hyperemia;

4. The infiltrative inflammatory changes in the soft tissues in the area of the tick bite is the primary affect. It should never be after the tick bite that is not infected with a pathogenic Rickettsia. The very site of the bite turns into a small ulcer with a black scab, and around it are 2-to 3-mm stripe of hyperemia of the skin;

5. Hyperemia of the conjunctiva and mucosa of the oropharynx with power and congestive vascular pattern;

6. Skin rash. The true polymorphism primary elements: roseola, small papules, spots, in diameter to several millimeters. Their appearance is noted after 4-5 days after the appearance of temperature. Characteristic constant podsypanina new items. Hemorrhagic rash is not typical. The first rashes appear on the skin of the extremities, from where they spread to other areas;

7. Swollen lymph nodes, primarily, regional in relation to the site of the bite;

8. Tachycardia or bradycardia. Arrhythmias are rare. Blood pressure may decline slightly;

9. Symptoms of lesions of the nervous system: lethargy, headache, apathy, sleep disturbances. Dizziness and meningeal signs occur very rarely.

The causative agent of tick-borne typhus

Tick-borne typhoid is caused by pathogenic microorganisms from the group of Rickettsia. Specific the look of them – Rickettsia sibirica. She has a General properties characteristic of all representatives rickettsiae. The only difference is moderate virulent ability. Therefore, its ingestion causes severe manifestations.

According to the morphological structure of Rickettsia sibirica is a gram-negative Bacillus with aerobic type of metabolism. The only natural reservoir for it is the organism of rodents. Ticks serve as the vector that provides constant circulation in a certain area. This species of Rickettsia is very stable in the environment in relation to high and low temperatures. Different strains may have different virulence and pathogenic properties, defining the clinical course of the disease.

In most cases of Rickettsia sibirica in a timely manner verificarea immune cells in the body. Its destruction does not cause the release of dangerous endotoxins. This allows the body to cope with the pathogen, even in the absence of treatment. The result is a strong immunity in the form of antibodies to antigenic components of this type of Rickettsia, which remains for life.

Prevention of tick-borne typhus

To prevent tick-borne typhus can help such a complex nonspecific preventive measures:

1. Rodent control;

2. Preventing tick bitesduring the stay in the centers, pandemic on tick-borne typhus: the use of deterrents and chemical nature of essential oils, clothing should be possible to close the open parts of the body, periodic inspections of the surface of the garment to detect and remove ticks;

3. Reception of tetracycline in therapeutic doses with the development on the site of the tick bite primary affect;

Specific prophylaxis of tick-borne typhus does not exist.