Ticks are one of the largest reservoirs of disease pathogens in the world of parasites. Their natural habitat is green areas in Central Europe, the Eastern United States and Russia. Ticks transmit many bacterial and viral diseases, in Poland the most important are bacterial Lyme disease and viral tick-borne encephalitis.
The tick’s organism provides ideal conditions for the transmission of pathogenic microorganisms. The ease of transmission of infection is due to:
- The way of eating. A tick uses many hosts, usually wild animals, during its life cycle. Maintaining long-term, direct contact with the blood of many potentially infected organisms means that the risk of contamination of a random host, which is humans, is relatively high.
- Longevity. Ticks are relatively long-living animals. A tick infected with tick-borne encephalitis can wait up to 5 years for its victim.
- Traveling. Some species of ticks travel with their host – migratory birds. This fact promotes the transmission of diseases to areas that are theoretically free from tick-borne diseases.
Lyme disease is the most common bacterial disease transmitted in Poland by ticks. It is easily treatable, provided that antibiotic therapy is implemented quickly. The risk of Lyme infection following a bite increases with the duration of parasitization on the host and with the intensity of unskilled methods of removing the parasite from the skin. There are 3 stages of the disease, each stage has different symptoms and treatment.
- Early limited stage – appears about 7 days after a tick bite. It is characterized by flu-like symptoms and a characteristic erythema creeping. Erythema is a painless, non-itchy skin lesion with the characteristic shape of a shooting target (a red spot with a red rim over 5 cm in diameter). Symptoms in the case of not taking antibiotics disappear after about 4 weeks. A rare symptom of limited early stage is the appearance of cutaneous lymphocytic lymphoma. In the absence of effective treatment, the disease may progress to the next phase.
- Early disseminated stage – develops within weeks to months of infection. It is characterized by pathological involvement of the joints, heart muscle and nervous system (neuroborreliosis). Symptoms of the stage include joint pain, heart rhythm disturbances and paralysis of the cranial nerves (paralysis is manifested, for example, by paresis of the facial muscles).
Late stage – appears several years after infection. It is characterized by atrophic limb dermatitis, chronic arthritis, permanent damage to muscles and tendons, and severe symptoms of Lyme disease.
The diagnosis of Lyme disease is made using serological tests – the detection of specific antibodies. Performing an antibody test in the absence of clinical symptoms is not recommended, antibiotic therapy (the only effective treatment method) is justified only in the presence of symptoms.
Antibiotic therapy is based on the administration of chemotherapeutic agents adapted to the phase of the disease for a period of 2 to 4 weeks.
In the presence of erythema migrans or other symptoms of the early phase of the disease, the most commonly used drugs are amoxicillin given orally 3 times a day or doxycycline given twice or once a day.
Infection with tick-borne encephalitis virus occurs suddenly and in two phases. The diagnosis is made, as in Lyme disease, on the basis of serological tests.
The first stage, about 7 days after the bite, is a harbinger. It is characterized by flu-like symptoms, nausea, vomiting and diarrhea. Most patients heal spontaneously after about a week.
Sometimes, a few days after the end of the prodromal phase, neuroinfection occurs. The course of neuroinfection is characterized by inflammation of the brain, cerebellum or spinal cord. The disease mortality is about 1%.
Treatment of tick-borne encephalitis is only symptomatic, there is no effective specific treatment for the disease. However, effective vaccination is possible. Vaccination is usually carried out with 3 doses of the vaccine intramuscularly. More about vaccination at the link.
In order to minimize the risk of infection by ticks, you should take steps such as:
- Covering the skin during a stay in the woods or meadows
- The use of repellants – tick repellants
- Whole body skin inspection after returning from forest areas
- Remove the tick as soon as possible in the event of a bite
- Protection of pets through the use of repellants and animal skin control.
If you suspect symptoms of Lyme disease or tick-borne encephalitis, especially in the case of a tick bite, you should seek medical attention. It should be remembered that a tick bite can be overlooked, the lack of a detected bite does not exclude the appearance of tick-borne diseases.
Szczeklik, P. Gajewski, Interna Szczeklik.
Antoni Deryło, et al., Medical parasitology and acroentomology