Infectious diseases are a group of pathological conditions that are highly contagious. These diseases are caused by certain bacteria and viruses. All infections share common characteristics. These include: epidemiology, transmission routes and clinical manifestations. One of the infectious diseases is tick-borne rickettsiosis. There are several varieties of this pathology. Combine all rickettsiosis signs such as fever, intoxication syndrome, primary skin affect and vascular damage. The main route of transmission of these diseases is transmissible. That is, through the bites of insects common in specific climatic conditions.
Description of tick-borne rickettsiosis
Tick-borne rickettsiosis is an infectious pathology characterized by skin manifestations, widespread vasculitis and intoxication syndrome. The disease is characterized by transmissible transmission. Ticks and lice carry the infection. There are several variants of the course of rickettsiosis. The main difference between these pathologies is the type of pathogen. Somerickettsiosis is common in steppe and desert regions, others in tropical climates. Nevertheless, all these pathologies have a similar clinical picture. The disease can be suspected by characteristic symptoms, as well as due to epidemiological characteristics. The main diagnostic method is a serological study, which allows you to accurately determine the type of pathogen.
What are rickettsial diseases?
As you know, rickettsiosis is a large group of diseases. They are distributed throughout the world. The following species are considered the most common:
- Rickettsia prowazekii - This pathogen causes typhus. This disease is transmitted transmissibly (through lice bites).
- Rickettsia typhi is the causative agent of endemic typhus. It is transmitted by rodent and flea bites.
- Rickettsia sibirica. This pathogen causes the disease North Asian tick-borne rickettsiosis.
- Rickettsia burneti. When this pathogen enters the human body, Q fever develops. The disease is transmitted by transmissible way - through the bites of ixodid ticks.
- Rickettsia orientalis. Like the previous varieties of rickettsiosis, this pathology is transmitted by tick bites.
In addition to the listed diseases, there are many more infections caused by various strains of this pathogen.
Epidemiological characteristics of rickettsiosis
Rickettsiosesdiffer among themselves not only by the type of pathogen, but also by epidemiological characteristics. Despite the wide prevalence throughout the world, each disease is common in a particular area. For example, epidemic typhus is also called prison or ship fever, since this pathology is transmitted through the bites of lice, which were widespread among prisoners and sailors. A similar disease, but caused by the pathogen Rickettsia typhi, is more often recorded in regions with a warm climate. It is especially common in rural areas during the summer.
Tick-borne rickettsiosis is common in the habitats of these insects. This group of infectious pathologies is found in North Asia, Japan, Australia, and mountainous regions. Most rickettsioses are zoonotic diseases. Wild and domestic animals, rodents are considered an intermediate reservoir of infection. Rickettsiosis vectors are various types of ticks. Since these insects breed in the summer (May-September), the incidence increases sharply during this period. Most often, the infection affects people working on the street (dachas, vegetable gardens, pastures) and in contact with animals.
Cause of rickettsiosis
The etiological factor in the occurrence of the disease is a microorganism - rickettsia. This infectious agent can be attributed to bacteria or viruses. This phenomenon is explained by the fact that, despite the structure of the microorganism (rods or cocci), rickettsia has the ability tointracellular parasitism. The causative agent is unstable in the environment. Rickettsia die when exposed to high temperatures or disinfectants. Nevertheless, they can remain viable for a long time in cold and arid climates. In addition to the transmissible route of transmission, rickettsia can enter the body through blood transfusion, from the mother during childbirth. For some diseases of this group, other ways of infection are also characteristic. Among them are alimentary and airborne infection. The factors provoking tick-borne rickettsiosis include:
- Contact with rural domestic animals, dogs.
- Poor personal hygiene.
- Contact with infected people and carriers of pathology.
Mechanism of disease progression
The disease develops a few days after the introduction of the tick into the skin. The duration of the incubation period depends on the type of pathogen and the immune response of the body. When a tick bites, a local reaction occurs. The skin becomes edematous, hyperemic, soreness is noted. The infiltrate occurs due to the accumulation of cells of the immune system at the site of the introduction of the insect. From there, the causative agents of the disease - rickettsia - penetrate into the lymphatic vessels and nodes. There they temporarily settle and multiply. Given that the lymph nodes belong to the organs of the immune system, they increase markedly. Cells are activated and proliferated to fight bacterial agents. Later, rickettsia fall intoblood vessels. Bacteremia and toxinemia occur. First of all, the veins and arteries of the skin are affected. An inflammatory reaction develops in the walls of the vessels, leading to destructive changes in the endothelium. In addition, rickettsia often penetrate the arteries and veins of the brain. As a result, signs of CNS damage, meningitis and encephalitis develop, possibly an acute circulatory disorder. The mechanism of infection development determines the clinical picture of the pathology of tick-borne rickettsiosis. ICD-10 is an international classification that includes all diseases. This infection is no exception. In addition, pathological complications such as meningitis, encephalitis and vascular disease are coded separately in the ICD-10. The underlying disease has code A77.
Tick-borne rickettsiosis: symptoms of pathology
Despite the fact that tick-borne rickettsiosis differs from each other, they all have common clinical manifestations. The duration of the incubation period averages from 3 to 7 days. Often the penetration of mites into the skin goes unnoticed at the onset of the disease. Sometimes there is marked infiltration and regional lymphadenitis. The primary affect is characterized by induration, in the center of which there is skin necrosis (brown), and on the periphery - hyperemia (red corolla). After 2-3 days, an intoxication syndrome and a fever of a permanent nature join. The patient complains of body aches, fever up to 39 degrees, muscle pain, general weakness. The feverish period is about 1-2 weeks. Beyond the symptomsintoxication, rashes appear at the beginning of the disease. They have a roseolous-papular character. The rash first occurs on the limbs, later spreading to the trunk. The background of the skin does not change. These signs are characterized by tick-borne rickettsiosis. Photos of skin manifestations can be found in the special literature. It is very important to distinguish between rashes for the diagnosis of infectious pathologies.
Detection of tick-borne rickettsiosis
You cannot rely on the clinical picture alone to identify tick-borne rickettsiosis. Diagnosis of the disease should include laboratory tests. After all, the symptoms of pathology can resemble many other infections. To make an accurate diagnosis with an indication of the type of pathogen, serological studies are carried out. Among them are enzyme immunoassay, complement fixation reaction, hemagglutination, etc. Microscopy of blood, cerebrospinal fluid, urine and separated infiltrate is also performed.
Tick-borne rickettsiosis: treatment of infection
Because the disease is a bacterial infection, treatment requires antibiotics. For this purpose, the drugs "Tetracycline" and "Levomycetin", as well as their analogues, are used. In severe cases of the disease, the patient should be hospitalized in an infectious diseases hospital. For the purpose of detoxification, a solution of 5% glucose with ascorbic acid is administered intravenously. When bradycardia is necessary to use vasopressor drugs. These include medicines "Atropine", "Caffeine". Symptomatic therapy is also carried out - antipyretic,antihistamines. Ticks are removed with tweezers. With the development of complications, specific treatment is carried out.
Consequences of tick-borne rickettsiosis
It is important to start treating tick-borne rickettsiosis as early as possible. The consequences of infection can be severe. With untimely access to a doctor, complications from the nervous, respiratory and cardiovascular systems develop. Among them are pneumonia, bronchitis, meningitis and encephalitis, myocarditis, etc. In severe cases, toxic shock develops.
Tick-borne rickettsiosis prevention
Non-specific prevention includes insect and rodent control, as well as personal hygiene. Typhus and Q fever are vaccinated against. If a disease is detected, it is necessary to sanitize the premises, as well as examine all persons who have been in contact with the patient. If the tick has already invaded the skin, but the symptoms of the infection have not developed, emergency medical prophylaxis is performed. Antibiotics "Doxycycline" and "Azithromycin" are used.
