Tick season is in full swing. After removing a tick in Russia, many are faced with two pressing questions that are very difficult to give unequivocal answers: “Do I need to take a tick for analysis?” and “Do I need preventive treatment?” Moscow doctor Roman Shiyan answers them in detail on his blog:
“In recent days, acquaintances and patients have overwhelmed me with these questions. I do not have a short answer to these questions, but there is a long and boring one, I publish it here.
Russian regulatory documents and clinical recommendations suggest conducting laboratory testing of ticks and, depending on the results of such a study, introduce specific immunoglobulin against tick-borne encephalitis and / or carry out preventive antibacterial treatment to prevent Lyme disease (tick-borne borreliosis), anaplasmosis and ehrlichiosis.
European guidelines do not recommend conducting tick research and preventive treatment for tick bites, as there is no evidence of the effectiveness of such interventions and it is assumed that the possible harm from these interventions may well exceed their possible benefits.
For the same reasons, American guidelines do not recommend the study of ticks, and prophylactic treatment should be carried out only against Lyme disease (tick-borne borreliosis) in the presence of risk factors for infection, since the results of a tick study do not significantly affect the risk of a disease in a particular person, and their expectation is associated with a delay start treatment.
Bit of theory
The causative agent is tick-borne encephalitis virus. It is found in many regions of Europe and Asia. The list of endemic territories in Russia can be found in the letter of Rospotrebnadzor (link at the very end of the post).
70-98% of infected people develop asymptomatic infection (more often in children). The incubation period is from 2 to 28 days (most often 7-14 days). Of those who get sick, 70% of people have a spontaneous flu-like illness, the remaining 30% after this flu-like illness develops a second phase of the disease with damage to the nervous system (meningitis, meningoencephalitis, poliomyelitis). Among the identified cases, mortality from 1 to 40% (depending on the region). No specific treatment is known.
An effective vaccine exists for routine disease prevention. Vaccination for those living in tick-borne encephalitis endemic areas or planning trips to these territories is carried out twice with an interval of at least 1 month (in case of emergency vaccination, when the time is running out, with an interval of at least 2 weeks, but such vaccination may be somewhat less effective), then revaccination after 1 year, and then 1 time in 3 years. A person can be considered protected 2 weeks after the second vaccination, that is, vaccination must be carried out before the tick has bitten. The vaccine is approved for use from 1 year.
In Russia, people who do not have a full course of vaccination when detecting tick-borne encephalitis virus in a removed tick or when a tick is bitten in an endemic territory are given emergency prophylaxis: the introduction of a specific immunoglobulin no later than 4 days after tick suction.
In Europe, emergency prophylaxis with the use of specific immunoglobulin is not carried out due to the lack of evidence of the effectiveness of such treatment and theoretical concerns about the possibility of a more severe infection after the introduction of immunoglobulin or the development of a chronic form of the disease. But in Europe, due to the characteristics of the causative agents of the disease, tick-borne encephalitis as a whole more often occurs in mild forms and with less disability and mortality in comparison with Russia.
LYME DISEASE (TICK BORRELIOSIS)
The causative agents are bacteria of the genus Borrelia. It is found in many regions of Europe, Asia and North America. Borrelia causing disease and the ticks that carry them differ on the American and Eurasian continents.
In America, the transmission of the pathogen requires a tick suction duration of at least 36 hours, in Europe the transmission of the pathogen can occur in a shorter time (there is evidence of transmission of the pathogen 16 hours after suction, the minimum required suction time of the tick to transmit the infection in Europe and Asia is unknown )
The incubation period is from 3 to 30 days (most often 7-14 days). Most patients at the site of the bite develop a lesion of erythema migrans (an expanding lesion of red color, often with central enlightenment). At this stage, the disease is usually easily amenable to antibacterial treatment. Without treatment, some people may develop additional foci of migratory erythema, damage to the nervous system, heart, and joints in a few weeks or months, but even in these periods the treatment is effective in most cases.
In America, the disease as a whole has a more severe course and more frequent development of the second and third stages in comparison with Europe and Asia.
Regarding Lyme disease, there are several studies on prophylactic antibacterial treatment, and a meta-analysis and systematic review of these studies was carried out in 2010 (Warshafsky, 2010).
The authors of the review found 4 studies on the emergency prevention of Lyme disease.
1.Costello, 1989. USA, endemic area, 56 participants from 5 to 85 years old, of which 27 received penicillin for 10 days and 29 received a placebo. 21 ticks were suitable for the study, of which 6 (3 in each group) were positive for borrellia.
In the placebo group, one patient developed migratory erythema. Subsequently, she received treatment with doxycycline for 10 days and fully recovered. In the group receiving penicillin, tick-borne borreliosis was not affected, but in one patient, on the 5th day of prophylactic treatment, an itchy rash appeared on the hands, face and neck.
2.Shapiro, 1992. USA, endemic area, 387 participants, of which 205 received amoxicillin for 10 days and 182 received placebo. Of the 344 mites suitable for research, 53 (15%) were positive for borrelia.
In the placebo group, two patients developed migratory erythema. Subsequently, they received treatment with doxycycline for 10 days (female 35 years old) and amoxicillin for 10 days (female 4 years old) and fully recovered. The result of the study of a tick taken from a woman was positive, and from a child - doubtful. In the group receiving penicillin, tick-borne borreliosis no one became ill, but a rash appeared in two patients during prophylactic treatment. Long-term effects were not observed in any patient in both groups.
3. Agre, 1993. USA, endemic region, 179 participants from 3 to 19 years of whom 59 received penicillin 10 days, 30 received tetracycline 10 days and 90 received placebo.
In the placebo group, one patient had migratory erythema and one suffered a flu-like illness. In the group receiving penicillin, one patient had pharyngitis and conjunctivitis. One patient from the placebo group had urticaria, and there were no allergic reactions in the groups receiving treatment. Long-term effects were not observed in any patient in both groups.
4. Nadelman, 2001. USA, endemic area, 482 participants over 12 years old, of which 235 received doxycycline once and 247 received placebo.
In the placebo group, 8 patients had migratory erythema and 1 patient had a flu-like illness. In the group treated with doxycycline, migratory erythema appeared in 1 patient and in 1 patient a flu-like illness. The frequency of adverse reactions was higher in the doxycycline group (30%), the most common of which were nausea (15%) and vomiting (6%).
The authors of a systematic review estimate that per 100 people receiving preventive treatment, 2 cases of Lyme disease can be prevented, but 4 cases of a rash associated with taking amoxicillin or 15 cases of nausea associated with taking doxycycline will be created.
Based on the results of a recent study, the United States recommends a single dose of doxycycline 200 mg (or 4.4 mg per 1 kg of body weight for children weighing less than 45 kg) no later than 72 hours after removal of the tick if the bite occurred in a highly endemic area, the tick is identified as Ixodes scapularis and the duration of tick suction is 36 hours or more.
European guidelines do not recommend preventive treatment because it is not known to what extent the data obtained in a study in the USA can be transferred to Europe due to differences in the degree of tick infection, differences in carriers and pathogens of this disease, as well as differences in the course of the disease, and suggest that in Europe, the possible benefits of such treatment may not exceed the possible harm.
In Russia, various preventive treatment options are often used using 10-day courses of amoxicillin, amoxicillin / clavulanate, doxycycline, and even a three-day course of ceftriaxone intramuscularly.
ANAPLASMOSIS AND ERLICHIOSIS
The causative agents of these diseases, the bacteria anaplasma and ehrlichia, are very often excreted by ticks in many regions of the world, but in humans the disease develops infrequently, and these diseases are especially rare in children.
The incubation period is 5-14 days. Forms of the disease from mild self-passing to severe and critical. Symptoms of the disease include fever, headaches and muscle aches, often nausea and vomiting. Some patients have a rash. In rare cases, the development of meningoencephalitis, respiratory and renal failure, bleeding is possible. In treatment, doxycycline is highly effective. Mortality in the United States is 1-3% of the detected cases. In Europe, these diseases have a much milder course, severe forms are extremely rare. Prophylactic treatment is unknown.
Apparently, the benefits of the study of ticks are very doubtful, since the results of its analysis practically do not affect the risks of developing a disease in humans and the choice of further actions, but can lead to additional uncertainty, excessive anxiety, unnecessary additional examinations and treatments, and related possible adverse reactions. It seems reasonable to conduct a laboratory test not of ticks, and if necessary, conduct a study of a person in case of development of his disease.
AND NOW WHAT I CAN DO?
I don’t have a definite answer for everyone, but there are the variants of answers.
1. If you are among the people who “BUT WE SHOULD DO SOMETHING!”, then:
* If you are not vaccinated against tick-borne encephalitis, a tick bite occurred in an endemic area, you believed in the efficacy and safety of a specific immunoglobulin, you decided in advance that if you detect a pathogen in a tick, you will inject immunoglobulin, then you can pass the tick for examination (only for to detect tick-borne encephalitis virus and not to look for pathogens of other diseases in it), and if a positive result is obtained, enter immunoglobulin, or simply enter immunoglobulin without problems with a tick study.
* If a tick bite occurred in the territory of Lyme disease endemic, you decided that the possible benefits of preventive treatment are higher than the possible harm, you can discuss antibiotic prophylaxis with your doctor: doxycycline once (preferred option) or amoxicillin 10 days (less preferred option) ) without examining the tick.
2. In other cases, or if you are one of the people who prefer, in conditions of uncertainty, to avoid creating even more uncertainty, unnecessary anxiety, unnecessary examination and treatment, then:
* Get rid of the tick and continue your normal life, and if changes occur in the bite or flu-like illness within 30 days after the bite, consult a doctor and inform about the date of removal of the tick, if necessary undergo examination and receive the necessary treatment.