"The peak of the number will be reached in June": a specialist of Rospotrebnadzor - about the activity of ticks this year and the prevention of bites

- Lyudmila Stanislavovna, the regional department of Rospotrebnadzor reported that in the Kuban the number of victims of tick bites has doubled compared to last year. An unusual invasion of ticks is observed this year in other regions - for example, residents of Vladimir complain about this. Is there really a lot of ticks this year? If so, what is the reason for this?

- This year, weather conditions really contribute to the fact that ticks are more active in search of food. Ticks get out of the forest floor and climb onto the grass, where they lie in wait for people and animals. The ideal conditions for ticks are moderate humidity and heat. They do not like heat and dryness.

At the same time, such weather is conducive to the fact that people often get out into nature, outside the city, where the grass is not treated for ticks, as in the city.

The increase in the number of contacts of people with ticks this year is associated with these factors, this does not mean that there are more ticks. At the same time, it is too early to make predictions about how the summer of 2023 will go as a whole, because ticks will reach their peak numbers only in June. And even then it will be possible to estimate what this season will be in terms of the number of infections transmitted by ticks, and which diseases will prevail.

As a rule, the June rise in the number of ticks is followed by a decline, which lasts until about the beginning or middle of August. And the second increase in the European part of Russia begins in August-September - however, it is less than in June.

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- Is it possible to solve this problem by cultivating the territories? And if so, are these measures being sufficiently taken in Russia today? Why has the tick situation worsened over the past decades?

- The point here is this: in the 1970s, ticks were less common, because then they were treated with a long-acting drug that remained in the soil for a long time. Due to concerns about the accumulation of toxic substances in plants, animals and humans, this drug was eventually banned for use, and over time, we switched to shorter-acting drugs.

It is impossible to process all forests and fields with them, such treatments are prescribed to be carried out at certain facilities - in medical institutions, children's camps, recreation centers, etc. This is controlled by state bodies. But the territory of your own dacha needs to be treated from ticks on your own.

- How to choose drugs for such self-treatment of the infield?

- In the regional Centers of Hygiene and Epidemiology of Rospotrebnadzor, you can clarify which drugs can be used independently and how exactly to do it. In general, ticks rarely appear on the site if people constantly live in the house, most often ticks are brought to the site in the fall by rodents. So if you carry out acaricidal treatment of the site at the beginning of the season or simply collect hungry ticks on a white cloth from the surface of the grass for a week, be sure to cut the grass regularly, then, in principle, such actions can rid your site of ticks for the whole summer.

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- Probably the most dangerous disease carried by ixodid ticks is encephalitis. How wide is the range of this virus, as well as the ticks that carry it?

- Rospotrebnadzor regularly updates the map of areas endemic for tick-borne viral encephalitis. For example, in the Tver region, out of 37 administrative territories, 12 are endemic, in Moscow - two, in the Yaroslavl region encephalitis occurs in 18 territories out of 23, etc. Endemic territory is an area where the virus is constantly detected in ticks, and not single, but regular cases of the disease among people are recorded. This means that there are permanent natural foci of the virus in the area.

In general, tick-borne viral encephalitis "prefers" temperate latitudes, far in the north and south it is almost never found, with the exception of the Crimea, where 25 out of 10 administrative territories are endemic. But the most dangerous in terms of the incidence of tick-borne encephalitis are many regions of Siberia, as well as a number of territories of the Volga region and the northwestern regions of Russia.

- How do ticks become infected with the tick-borne encephalitis virus?

- The tick-borne encephalitis virus enters the body of a tick, when it feeds on a feeding animal, in which the virus is currently circulating in the blood. Or a tick can become infected by feeding on an animal next to another, already infected tick. In addition, the tick transmits the virus to its offspring.

- And how is the virus transmitted to humans?

- Most often, a person becomes infected by sucking on an infected tick, less often by eating the milk of goats or cows. The pathogen immediately enters the skin and subcutaneous tissue, as it is contained in the saliva of a hungry tick. But it is also important to remember that as blood enters the tick's body, the virus also multiplies. And the longer the tick is on a person, the greater the dose of the virus he will transmit to him. Therefore, it is better to immediately remove the tick from the body as soon as you notice it.

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- What other dangerous infections can be obtained after an ixodid tick bite, except for encephalitis and borreliosis?

- Ticks are carriers of pathogens of a number of diseases. For example, ticks can transmit rickettsia, anaplasma, ehrlichia, bartonella. These are all pathogens of bacterial vector-borne infections. Although very rare, it is possible to become infected with protozoa - babesia, as a result of which a person may develop a clinically pronounced disease. In the south, ticks can also become infected with Crimean-Congo hemorrhagic fever, a serious disease that can also be transmitted from person to person through contact with the patient's body fluids. Most often, medical workers who care for patients become infected in this way.

- Is there a vaccine against Crimean-Congo hemorrhagic fever?

- In Russia, such a vaccine was developed many years ago, but its effectiveness in those years could not be tested, because at the time of clinical trials there was no outbreak of the disease. But there is such a vaccine in Bulgaria. In general, Crimean-Congo hemorrhagic fever, in addition to Russia, is registered in Southern Europe, Asia and Africa.

- Earlier in Russia, three new species of ticks were discovered, which, allegedly, can be carriers of diseases such as plague, hemorrhagic fever with renal syndrome and West Nile fever. According to scientists, new types of parasites are widespread in Siberia and Mongolia. What is known about these species and should we be afraid of the spread of the diseases they carry?

- In the original scientific article, the authors do not say anything about the epidemic significance of new species. The mention that they can carry infections was already made in the commentary of the author, associate professor of the Tyumen Medical University Marina Orlova. Moreover, the author presented information common to ticks of this family, and not just recently discovered species. Therefore, it is not necessary to draw any specific conclusions regarding the epidemic danger of open species. The main vectors of West Nile fever are mosquitoes. There are no documented cases of human disease with West Nile fever after a tick bite. Hemorrhagic fever with renal syndrome, which was also mentioned in the commentary, is transmitted to a person by inhalation of dust, which contains particles of dried excrement and urine of rodents, and not through mites, although infectious agents can be found in them. As for the plague, its main carrier is also not a tick, but a flea.

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- What are the basic rules to follow to reduce the risk of a tick bite?

- If you go to the forest, then wear light-colored clothes, tuck your trousers into socks, and after the hike, inspect yourself for ticks. It is also necessary to inspect animals after walks, because they can bring ticks into the house. And if the tick does not stick to the dog, it can go to humans. Clothes before going to the forest can be treated with special acaricidal preparations that kill ticks. They can not be applied to the skin, only to clothing. Of course, if you live or plan to travel to areas endemic for tick-borne encephalitis, it is recommended to get vaccinated in advance.

Well, if the tick has already sucked, and the causative agent of encephalitis is not found in it, the infectious disease doctor may prescribe a short course of antibiotics to suppress the development of bacterial infections. If the encephalitis virus is found in the tick, then there is no delay - anti-tick immunoglobulin is administered within 72 hours if the person is not vaccinated.