Tick Activity Research Articles

Risk of Ixodes ricinus Bites in a Population of Forestry Workers in an Endemic Region in France.

The progressing worldwide increases in tick occurrence and tick-borne diseases calls for the development of new prevention strategies to reduce their impact on human and animal health. Defining the risk of exposure to tick bites is therefore essential. Forestry workers are at high risk of tick bites. We set up an explorative study among forestry workers in the Alsace region in eastern France to measure the different factors affecting the risk of Ixodes ricinus tick bites during their activities in forests. For one year, forestry workers recorded the presence of ticks on their clothes and tick bites every time they were working in teams in different forest ecosystems. Questions about the prevention measures they followed were also noted. Among the 32 participants, we were able to differentiate between groups having a high, neutral, or low risk of being bitten. The median tick bite number per year was 4 (0-8). We tried to identify individual as well as environmental factors affecting the risk of tick bites. Factors influencing the risk were the seasonal peak of tick activity in May and June, the time of exposure, and the forest ecosystems visited during the year. Additional factors potentially affecting the risk were also identified.

Circadian regulation of locomotion, respiration, and arousability in adult blacklegged ticks (Ixodes scapularis)

The blacklegged tick, Ixodes scapularis, is an ectoparasitic arachnid and vector for infectious diseases, including Lyme borreliosis. Here, we investigate the diurnal activity and respiration of wild-caught and lab-reared adult ticks with long-term video recording, multi-animal tracking and high-resolution respirometry. We find male and female ticks are in a more active, more arousable state during circadian night. We find respiration is augmented by light, with dark onset triggering more frequent bouts of discontinuous gas exchange and a higher overall volume of CO2 respired. Observed inactivity during the day meets the criteria of sleep: homeostatic in nature, rapidly reversible, a characteristic pose, and reduced arousal threshold. Our findings indicate that blacklegged ticks are in a distinct, heightened state of activity and arousability during night and in dark, suggesting this period may carry higher risk for tick bites and subsequent contraction of tick-borne diseases.

Tularemia: a case series from an endemic area in Hajnówka County, Norteast Poland.

Tularemia is a zoonotic disease caused by the bacterium Francisella tularensis. It may manifest itself in various clinical forms, but in Poland the ulcerative-glandular or glandular forms of tularemia predominate. One of the routes of infection with F. tularensis is through a tick or insect bite. A patient may show no symptoms or report flu-like symptoms and painful lumps adjacent to the bite site. The differential diagnosis of localized lymphadenopathy accompanied by flu-like symptoms should include tularemia, especially in endemic areas. Lymphadenitis usually requires surgical intervention and is often unsuccessfully treated with beta-lactam antibiotics before the diagnosis of tularemia is established. The aim of the study was to analyze and present the epidemiology and clinical presentation of tularemia in a highly endemic area, in which ticks are an important vector of F. tularensis. We have analyzed epidemiological and medical reports on the confirmed tularemia cases from Hajnówka County in 2014-2022. We describe three patients from the specific endemic area who were diagnosed with granular tularemia in 2022. We have found high local exposition to Francisella tularensis infection in the Narewka community, generally consistent with the seasonality of tick activity and human activity outdoors. The medical practitioner in such endemic areas must be aware that tularemia should be considered when diagnosing of flu-like symptoms accompanied by lymphadenopathy in patients bitten by ticks or insects in the summer and early autumn months. Early diagnosis and targeted antibiotic therapy are the basis for effective treatment of tularemia.

Lime for Lyme: Treatment of Leaf Litter with Dolomitic Lime Powder Impairs Activity of Immature Ixodes scapularis Ticks.

Background: Tick-borne diseases are an emerging threat to public health throughout the temperate world, leading to a growing field of research aimed at developing and testing intervention strategies for reducing human-tick encounters or prevalence of infection in ticks. Various wide-spectrum chemical acaricides have proven effective for controlling tick populations, but many of these have potential deleterious side-effects on health and the environment. In addition to chemical acaricides, certain compounds such as diatomaceous earth have been shown to have physical acaricidal properties. We hypothesized that dolomitic lime (CaMg(CO3)2, a corrosive, desiccant mineral that is already used extensively in agricultural and forestry contexts to balance the pH of soils, may affect ticks' locomotory activity, habitat position, or survival and that this should manifest as a reduction in the number of questing ticks collected by dragging. Objective: This study aimed to formally assess this hypothesis in a controlled laboratory setting. Methods: We carried out a microcosm experiment, with one control and three treated microcosm trays, each replicating the natural substrate characterizing I. scapularis habitat in northeastern North America. Each tray was infested with 200 living larvae and 50 nymphs, and then treated with 0 (control), 50, 100, or 500 g/m2 of lime powder. Ticks were collected by microdragging 24 and 72 h postliming. Results: Efficacy of liming at reducing the number of collected questing ticks ranged from 87% to 100% for larvae and 0% to 69% for nymphs 24 h postliming and from 91% to 93% for larvae and -47% to 65% for nymphs 72 postliming. Conclusion: This study provides the first experimental evidence of the potential efficacy of liming for impairing activity of questing immature ticks. Given that lime is a low-cost material, that methods for widespread application in deciduous woodlands already exist, and that it has been documented as having a limited negative impact on the environment, further assessment of lime application as a public health risk reduction intervention for tick-borne diseases is warranted.

Effects of rodent abundance on ticks and Borrelia: results from an experimental and observational study in an island system

BackgroundLyme borreliosis is the most common tick-borne disease in Europe and is often caused by Borrelia afzelii, which is transmitted by Ixodes ricinus ticks. The prevalence and abundance of infected ticks fluctuate in time and space, influencing human infection risk. Rodents are reservoir hosts for B. afzelii and important feeding hosts for larval ticks. In the study reported here, we examined how variation in rodent abundance is associated with B. afzelii infection prevalence in ticks, the density of nymphs (DON) and the density of infected nymphs (DIN) in the following year. We further analysed the relationships between the abundance of infected rodents and nymphal infection prevalence (NIP) and DIN.MethodsWe conducted a study that combined experimental and observational approaches on 15 islands (10 small islands and 5 large islands) in Finland. On all of the islands, ticks and rodents were monitored and sampled during the summer of 2019, with the monitoring of tick abundance and sampling continuing into the spring of 2020. On five of the 10 small islands, captured rodents were removed from the island (“removal” islands), and on the other five small islands, captured rodents were released back to the trapping site after marking and sampling (“control” islands). On the five large islands, captured rodents were released back to the trapping site after marking and sampling. The presence of B. afzelii from nymph and rodent samples was examined.ResultsThe results of the experimental study showed that neither treatment (removal), rodent abundance index nor abundance index of infected rodents in 2019 was associated with DON, NIP or DIN in 2020. Based on data from the observational study, the NIP in 2020 decreased with increasing rodent abundance index and abundance index of infected rodents in 2019. However, the DIN in 2020 was not associated with the rodent abundance index or the abundance index of infected rodents in 2019. In addition, in the observational study, DON in 2020 increased with increasing rodent abundance index.ConclusionsOur results suggest that low rodent abundance during the tick activity period is not sufficient for reducing the disease hazard and, hence, rodent removal may not be a feasible control measure in natural ecosystems.Graphical abstract

Polymeric films of corn starch enhance the lethal effects of thymol and carvacrol terpenes upon Rhipicephalus microplus ticks

The tick Rhipicephalus microplus is a parasite of great importance in cattle breeding. It is responsible for huge economic losses. The application of synthetic acaricides is used as a form of control. However, resistant strains have been selected over the years, making it necessary to search for new alternative formulations. The present study aimed to formulate biodegradable films impregnated with the terpenes carvacrol and thymol and evaluate their efficacy on larvae and adults of R. microplus through in vitro tests. The following formulations were prepared: Film 1 (starch based); Film 2 (based on starch and glycerol); Film 1 + Carvarcol or Thymol; Film 2 + Carvarcol or Thymol. Terpenes had a final concentration of 5.0 mg/mL. To evaluate the formulations on larvae, the immersion test was performed by dividing into six groups according to the concentration of terpenes: 5.0, 2.5, 1.25, 0.625, 0.313, 0.156 mg/mL and the control groups: 1% ethanol solution; 10% ethanol solution; Film 1; and Film 2. For the evaluations on adult ticks, ten experimental groups (n = 10) were used: 1) Carvacrol; 2) Film 1 + Carvacrol; 3) Film 2 + Carvacrol; 4) Thymol; 5) Film 1 + Thymol; 6) Film 2 + Thymol; 7) Distilled water; 8) 10% ethanol solution; 9) Film 1; and 10) Film 2. In experimental groups 1–6, carvacrol and thymol (free or incorporated in two different biodegradable film formulations) were evaluated at the same concentration (5.0 mg/mL). Each group of ticks was immersed in their respective solutions for five minutes. The results of the tests on larvae showed that the Film 1 + thymol and Film 2 + carvacrol formulations had the lowest lethal concentrations (0.076 and 0.255 mg/mL, respectively), values up to 9.0-fold lower than the monoterpenes tested outside the formulation. Carvacrol and thymol at the concentrations tested were effective in controlling engorged females with a percentage of 32.2% and 63.8%, respectively. When incorporated into biodegradable film formulations, these monoterpenes showed much greater efficacy. Film 1 + carvacrol and Film 2 + carvacrol with control percentages of 71.6% and 97.2%, respectively, while the formulations Film 1 + thymol and Film 2 + thymol showed values of 96.9% and 100.0%. The tick control activity of the biopolymer formulations with thymol and carvacrol was demonstrated through the high mortality rates of larvae and engorged females of the tick R. microplus. Therefore, the results obtained indicate that these formulations have great potential for tick control mainly because of the percentage of control up to 100% in engorged females in in vitro tests.

К изучению иксодовых клещей Большесосновского муниципального округа Пермского края

This article presents the results of studying the abundance, biotopic location and seasonal dynamics of ixodid ticks Dermacentor reticulatus Fabricius, 1794 and Ixodes persulcatus (Schulze, 1930) on the territory of the Bolshesosnovsky municipal District located in the south-west of Perm Krai. An analysis of the biotopic abundance of ticks showed that I. persulcatus prefers various types of forests (relative abundance per season ranged from 20 to 104 specimens/flago-km), and D. reticulatus prefers meadow stations (relative abundance per season ranged from 39 to 830 specimens/flago-km). Assessment of the influence of temperature and humidity on tick activity has shown that for each factor in all biotopes and for each species there is a moderate or noticeable correlation of environmental parameters with changes in tick activity. The analysis of the seasonal dynamics of the activity of the studied species revealed the following: in May or early June, on average, there is a high number of adult ticks of both species, in midsummer their activity drops to zero and only in D. reticulatus activity resumes in late summer and early autumn and becomes even higher than in spring.

PREVALENCE OF ANAPLASMOSIS IN SMALL RUMINANTS IN SOME SELECTED LIVESTOCK FARMS IN WUKARI METROPOLIS TARABA STATE NIGERIA

Anaplasmosis is a tick-borne haemo-parasitic disease that causes huge economic loss in small ruminant flocks. The pathogen, Anaplasma Spp destroys red blood cells resulting in anaemia. The study was aimed at determining the prevalence of Anaplasmosis in Goats and Sheep in Wukari metropolis, Taraba State, Nigeria and to determine the prevalence based on age and sex. A total of 100 small ruminants (n =50 sheep, n =50 goats) were randomly sampled. 5mls of blood were collected via jugular vein puncture stained with Giemsa, and examined under a microscope for the pathogen. An overall prevalence of 21% was obtained; goats had a prevalence of 32% while sheep had 10%. Based on age, the prevalence was observed higher in adults (>2yrs) than the young ones (≤ 2yrs), while prevalence based on sex was higher in females than in the males. Prevalence among the female animals was observed higher in pregnant ones in both goats and sheep and therefore, special veterinary and management care should be given to tick infested pregnant animals because of their prone to the disease due to their suppressed immunity during pregnancy. Also, adult animals that have gone through many ticks’ seasons with heavy tick infestation should also be given special veterinary and management attention. Veterinary care through prevention and control of ticks by chemical method either by fumigation of the animal farms with acaricides or regular treatment of tick infested animals with acaricides by direct application on the animal host is recommended. Also, management changes such as clearing bushes, keeping pastures mowed and avoiding tick habitats during the season of greatest tick activity may be helpful and therefore recommended. This will reduce the prevalence of the disease with the resultant effect of reduced economic loss.

Seasonal Activity of Adult Ticks Ixodes persulcatus (Acari, Ixodidae) in the North-West of the Distribution Area.

The taiga tick Ixodes persulcatus (Schulze, 1930) (Acari, Ixodidae) is the main vector of the tick-borne encephalitis virus and one of the most widespread species of ixodid ticks in the Palaearctic. In this paper, we present long-term data on the seasonal activity of adult ticks in the north-west of their distribution. The seasonal activity of Ixodes persulcatus was studied from 1982 to 1990 and from 2012 to 2023 in the middle taiga subzone of Karelia (N62.0697, E33.961). In the study area, adult ticks I. persulcatus demonstrate a pronounced spring-summer activity with a unimodal curve of abundance change. A comparison of the monitoring data from the 1980s and the 2010s showed a significant increase in the abundance of I. persulcatus in the study area. A tendency towards an earlier start of the tick activity, as compared to the 1980s, is now being observed.

Differential associations of horizontally and vertically transmitted symbionts on Ixodes ricinus behaviour and physiology

BackgroundIxodes ricinus ticks are infected with a large diversity of vertically and horizontally transmitted symbionts. While horizontally transmitted symbionts rely on a vertebrate host for their transmission, vertically transmitted symbionts rely more on the survival of their invertebrate host for transmission. We therefore hypothesized horizontally transmitted symbionts to be associated with increased tick activity to increase host contact rate and vertically transmitted symbionts to be associated with higher tick weight and lipid fraction to promote tick survival.MethodsWe used a behavioural assay to record the questing activity of I. ricinus ticks. In addition, we measured weight and lipid fraction and determined the presence of ten symbiont species in these ticks using qPCR, of which six were vertically transmitted and four horizontally transmitted.ResultsVertically transmitted symbionts (e.g. Midichloria mitochondrii) were associated with an increase in tick weight, whereas horizontally transmitted symbionts (e.g. Borrelia burgdorferi sensu lato) were often associated with lower weight and lipid fraction of ticks. Moreover, horizontally transmitted symbionts (e.g. B. burgdorferi s.l.) were associated with increased tick activity, which may benefit pathogen transmission and increases tick-borne disease hazard.ConclusionsOur study shows that horizontally and vertically transmitted symbionts differentially influence the behaviour and physiology of I. ricinus and warrants future research to study the underlying mechanisms and effects on transmission dynamics of tick-borne pathogens.Graphical abstract

Tick Activity, Host Range, and Tick-Borne Pathogen Prevalence in Mountain Habitats of the Western Carpathians, Poland.

In mountainous regions, diverse ecosystems provide a habitat for numerous species of organisms. In this study, we focused on ixodid ticks and their presence in the Western Carpathians, Poland. Our objectives were to investigate the impact of environmental factors on tick occurrence and activity, the prevalence of vectored pathogens, and tick hosts, and their role as reservoir organisms for tick-borne pathogens (TBPs). To this end, we collected ticks from the vegetation and from animals (Apodemus agrarius, A. flavicollis, Capreolus capreolus, Microtus spp., Myodes glareolus, Ovis aries). In addition, we collected blood samples from rodents. The collected material underwent molecular analysis, utilizing the high-throughput microfluidic real-time PCR technique, to detect the presence of TBPs. Our findings confirmed the occurrence of only two species of ixodid ticks in the study area: the dominant Ixodes ricinus, and Dermacentor reticulatus with very limited abundance. Temperature significantly influenced tick activity, and the number of I. ricinus nymphs varied with altitude. We also observed a circadian pattern of questing activity in I. ricinus ticks. The main hosts for juvenile tick stages were M. glareolus and A. agrarius, while adult stages were frequently found on C. capreolus. I. ricinus ticks collected from the vegetation were often infected with Rickettsia helvetica (up to 35.71%), Borrelia afzelii (up to 28.57%), and Ehrlichia spp. (up to 9.52%). In contrast, juvenile stages frequently carried Bartonella spp. (up to 10.00%), Mycoplasma spp. (up to 16.67%) and R. helvetica (up to 16.67%). Moreover, we detected genetic material of Mycoplasma spp. (up to 100.00%), Ehrlichia spp. (up to 35.71%), Bartonella spp. (up to 25.00%), and Borrelia spp. (up to 6.25%) in rodent blood samples. The obtained results indicate A. agrarius and M. glareolus as reservoir animals for TBPs in the studied region.

Tick-Bite "Meteo"-Prevention: An Evaluation of Public Responsiveness to Tick Activity Forecasts Available Online.

Until causal prophylaxis is available, the avoidance of ticks and personal protection provide the best insurance against contracting a tick-borne disease (TBD). To support public precaution, tick-activity forecasts (TAFs) based on weather projection are provided online for some regions/countries. This study-aimed at evaluating the efficacy of this preventative strategy-was conducted between 2015 and 2019, and included two countries where TAFs are issued regularly (Czech Republic, Germany) and two neighbouring countries for reference (Austria, Switzerland). Google Trends (GT) data were used to trace public concern with TAFs and related health information. GTs were compared with epidemiological data on TBD cases and tick bites, wherever available. Computer simulations of presumable effectiveness under various scenarios were performed. This study showed that public access to TAFs/preventive information is infrequent and not optimally distributed over the season. Interest arises very early in midwinter and then starts to fall in spring/summer when human-tick contacts culminate. Consequently, a greater number of TBD cases are contracted beyond the period of maximum public responsiveness to prevention guidance. Simulations, nevertheless, indicate that there is a potential for doubling the prevention yield if risk assessment, in addition to tick activity, subsumes the population's exposure, and a real-time surrogate is proposed.

Canine Babesiosis Caused by Large Babesia Species: Global Prevalence and Risk Factors-A Review.

Canine babesiosis is a disease caused by protozoan pathogens belonging to the genus Babesia. Four species of large Babesia cause canine babesiosis (B. canis, B. rossi, B. vogeli, and the informally named B. coco). Although canine babesiosis has a worldwide distribution, different species occur in specific regions: B. rossi in sub-Saharan Africa, B. canis in Europe and Asia, and B. coco in the Eastern Atlantic United States, while B. vogeli occurs in Africa, southern parts of Europe and Asia, northern Australia, southern regions of North America, and in South America. B. vogeli is the most prevalent large Babesia species globally. This results from its wide range of monotropic vector species, the mild or subclinical nature of infections, and likely the longest evolutionary association with dogs. The most important risk factors for infection by large Babesia spp. include living in rural areas, kennels or animal shelters, or regions endemic for the infection, the season of the year (which is associated with increased tick activity), infestation with ticks, and lack of treatment with acaricides.

Serologic Testing for Rocky Mountain Spotted Fever in a Low-Incidence Region.

Tick-borne diseases have grown in incidence over recent decades. As a result, diagnostic testing has become more common, often performed as broad antibody-based panels for multiple tick-transmitted pathogens. Rocky Mountain spotted fever (RMSF) is rare in our region yet may cause severe morbidity, leading to diagnostic screening in low-risk patients. We sought to describe trends in RMSF diagnostic testing, rate of IgG seropositivity, and clinical features of those tested. We performed a retrospective chart review of patients ≤21 years old undergoing testing for RMSF and/or with an ICD-9/10 code for RMSF. Patients were categorized by infection likelihood based on clinical and laboratory criteria adapted from Centers for Disease Control and Prevention's (CDC) case definition of spotted fever rickettsioses. Clinical data were collected and analyzed with descriptive statistics. One hundred and seventy patients were included. 5.8% met CDC criteria for rickettsial infection, 6.5% had an elevated IgG titer but lacked suggestive symptoms, and 87.6% had a negative IgG titer. Many patients tested were unlikely to have RMSF, including 50% lacking fever, 20% lacking any RMSF "classic triad" symptoms, 13% without acute illness, and 22% tested during months with low tick activity. Convalescent serology was performed in 7.6% of patients and none underwent Rickettsia rickettsii polymerase chain reaction (PCR) testing. Diagnostic testing was frequently performed in patients unlikely to have RMSF. We identified many opportunities for improving test utilization. Reserving testing for those with higher pretest probability, performing convalescent serology, and utilizing PCR may improve the accuracy of RMSF diagnosis and reduce clinical challenges stemming from inappropriate testing.

Winter activity of Ixodes ricinus in Sweden

BackgroundIn Europe, Ixodes ricinus (Acari: Ixodidae) is the most widespread and abundant tick species, acting as a vector for several microorganisms of medical and veterinary importance. In Northern and Central Europe, the tick has a bimodal activity pattern consisting of a peak in spring to the beginning of summer and a second peak at the end of summer. However, several findings of ticks on animals during winter have been reported, which raises the question of whether this is an overwintering strategy or whether ticks are active during winter in Scandinavia. The objectives of our study were to determine (i) whether ticks were active and finding hosts during winter, (ii) whether they parasitize their hosts, and (iii) what climatic factors—i.e., temperature, snow depth and precipitation—govern tick winter activity.MethodsThroughout three winter seasons, we examined wild-living and free-ranging roe deer (Capreolus capreolus) for ticks on 332 occasions. In total, 140 individual roe deer were captured in two climatically contrasting sites in south-central Sweden, Grimsö and the Bogesund research area, respectively. We re-examined individual roe deer up to 10 times within the same winter or approximately once a week (mean 10 days, median 7 days between re-examinations) and recorded the absence or presence of ticks on the animals, and tested to what extent meteorological factors affected tick activity. To determine the attachment day, we used the coxal/scutal index of 18 nymphs and 47 female ticks.ResultsIn total, 243 I. ricinus were collected from 301 roe deer captures between 14 December and 28 February at the Bogesund study site during three subsequent years (2013/2014–2015/2016). We found attached ticks every third to every second examination (32%, 48% and 32% of the examinations, respectively). However, we collected only three I. ricinus females from 31 roe deer captures at the Grimsö study site between 17 December 2015 and 26 February 2016. At the Bogesund study site, based on 192 captures of previously examined deer, we collected 121 ticks, and ticks were found at 33%, 48% and 26% of the examinations during the respective winters. The probability of finding an attached tick on a roe deer at a temperature of −5 °C was > 8% ± 5 (SE), and that probability increased to almost 20% ± 7 (SE) if the air temperature increased to 5 °C.ConclusionsTo the best of our knowledge, this is the first time that winter-active nymphs and female ticks have been documented to attach and feed on roe deer during winter (December to February) in Scandinavia. The main weather conditions regulating winter activity for females were temperature and precipitation, and the lowest estimated air temperature for finding an active tick was well below 5 °C. The behaviour of winter-active and blood-feeding ticks was documented over several winters and in two contrasting areas, implying that it is a common phenomenon that should be investigated more thoroughly, since it may have important consequences for the epidemiology of tick-borne pathogens.

Anomalous phenology of Ixodes scapularis (Ixodida: Ixodidae) in Mississippi.

The blacklegged tick, Ixodes scapularis Say, is one of the most important vectors of tick-borne disease agents in North America. Accordingly, it is crucial to know this species local composition, abundance, and seasonality (phenology) to help prevent tick-borne illnesses. The phenology of adult I. scapularis is reported in the scientific literature from October through May. Data from previous research in Mississippi have all supported this time frame for adult blacklegged tick activity. However, in this study, we report a collection of 13 I. scapularis from 9 widely separated areas in Mississippi during the summer and early fall of 2022 (June, July, and September). These findings are remarkable, even enigmatic, and should prompt further investigation.

Tick-Borne Encephalitis Virus: A Comprehensive Review of Transmission, Pathogenesis, Epidemiology, Clinical Manifestations, Diagnosis, and Prevention.

Tick-borne encephalitis virus (TBEV), a member of the Flaviviridae family, can cause serious infection of the central nervous system in humans, resulting in potential neurological complications and fatal outcomes. TBEV is primarily transmitted to humans through infected tick bites, and the viral agent circulates between ticks and animals, such as deer and small mammals. The occurrence of the infection aligns with the seasonal activity of ticks. As no specific antiviral therapy exists for TBEV infection, treatment approaches primarily focus on symptomatic relief and support. Active immunization is highly effective, especially for individuals in endemic areas. The burden of TBEV infections is increasing, posing a growing health concern. Reported incidence rates rose from 0.4 to 0.9 cases per 100,000 people between 2015 and 2020. The Baltic and Central European countries have the highest incidence, but TBE is endemic across a wide geographic area. Various factors, including social and environmental aspects, improved medical awareness, and advanced diagnostics, have contributed to the observed increase. Diagnosing TBEV infection can be challenging due to the non-specific nature of the initial symptoms and potential co-infections. Accurate diagnosis is crucial for appropriate management, prevention of complications, and effective control measures. In this comprehensive review, we summarize the molecular structure of TBEV, its transmission and circulation in natural environments, the pathogenesis of TBEV infection, the epidemiology and global distribution of the virus, associated risk factors, clinical manifestations, and diagnostic approaches. By improving understanding of these aspects, we aim to enhance knowledge and promote strategies for timely and accurate diagnosis, appropriate management, and the implementation of effective control measures against TBEV infections.

Puutiaisten (Ixodes ricinus ja Ixodes persulcatus) levinneisyyteen ja runsauteen vaikuttavat tekijät Suomessa

Hard ticks (Acari: Ixodidae) and tick-borne diseases are considered as a threat in several parts of Europe. In Finland, both Ixodes ricinus and Ixodes persulcatus have shifted northwards in recent decades, and they have become more abundant at the same time. This is thought to be due to global climate change and its effect directly on ticks or indirectly on their host animals. This review focuses on the factors that affect both tick activity and survival, and the factors that influence the life cycle of ticks. Both presence and availability of host animals and microclimatic conditions are factors that affect tick occurrence in any given area. For example, high temperatures or low humidity force the species to seek shelter from cooler and more humid microhabitats, as ticks are sensitive to desiccation. However, tick distribution is associated with a complex combination of environmental and climatic factors.

Etiological Structure, Clinical and Epidemiological Characteristics of Infections Transmitted by Ixodic Ticks in the Sverdlovsk Region at the Present Stage

Relevance. The Sverdlovsk region is a highly endemic territory for infections transmitted by ixodic ticks. The possibilities of laboratory diagnostics of tick–borne infections in the routine practice of a clinician in the region today are limited mainly by testing blood serum for antibodies to the tick-borne encephalitis virus (TBE virus) and Lyme disease (LD) pathogens – Borrelia burgdorferi sensu lato complex, therefore, among tick-borne infections in the region currently mainly TBE and LD are registered. In case of negative results for antibodies to the pathogens of the above infections, the diagnosis may remain unknown. Aims. To study the etiological structure of infections transmitted by ixodic ticks in the Sverdlovsk region at the present stage, as well as to characterize the epidemiological and clinical features of the course of tick-borne infections detected in conditions of a combination of natural foci. Materials and methods. The study included 227 patients undergoing inpatient or outpatient treatment during the epidemic season of tick activity in 2021 (June-August) at LLS MO "New Hospital" (Urban Center of Natural Focal Infections). The case histories (epidemiological, clinical and laboratory indicators) were studied from each patient, as well as the material (blood) was examined prospectively and retrospectively using molecular biological (PCR) and serological (ELISA, planar protein biochip) methods. Results and discussion. During the study, six diseases were identified among the examined patients: TBE, LD (erythematous and nonerythematous forms), Borrelia miyamotoi disease (BMD), human granulocytic anaplasmosis (HGA), human monocytic ehrlichiosis (HME), as well as "Viral fever transmitted by arthropods" (VFTA). Among the examined patients, the proportion of patients with monoinfection was 49,5%, with mixed infection – 50,5%. Additional studies conducted by us using specific PCR for the presence DNA rickettsia and the causative agent of Q-fever in the blood of patients gave negative results. The general epidemiological characteristics for the above identified infections were the vector-borne mechanism, the prevalence of diseases in groups of middle-aged and elderly people, the largest number of cases of infection with pathogens of any tick-borne infection occurred in Yekaterinburg and its surroundings, for all infections, the duration of tick bite in most cases did not exceed one day; there were differences by sex, incubation period. Clinical symptoms were similar, except for the erythematous form of LD (the presence of erythema migrans at the byte site of tick), because the vast majority of patients had a general infectious syndrome; general laboratory indicators varied. Confirmation of the diagnosis was based on the results of the complex application of molecular biological and serological research methods. Conclusions. The modern etiological structure of infections transmitted by ixodic ticks in the Sverdlovsk region is represented not only by TBE and LD, but also by new disease to our country, such as BMD, HGA, HME, while a high proportion of mixed infections in various combinations has been revealed.

Study on Hard and Soft Ticks of Domestic and Wild Animals in Western Iran.

Ticks are blood-sucking ectoparasites of many vertebrates and act as vectors of a wide range of vector-borne diseases. Alongside pathogens transmission, ticks also cause economic losses in animal industry such as production loss, physical damage, anemia, and poisoning. This study aimed to determine the fauna, geographical distribution and seasonal activity of ticks collected from animals in Lorestan Province, west of Iran. Ticks were collected from domestic animals including cattle, sheep, goats, chickens, turkeys, pigeons, as well as wild animals such as jackals in 2017-2018. Then, they were identified based on morphological characteristics using valid identification keys. Out of a total of 706 ticks, 433 (61.33%), 104 (14.73%), 33 (4.67%) and 136 (19.26%) ticks were collected in spring, summer, autumn and winter, respectively. In terms of hard ticks, 4 genera and 6 species were identified: Hyalomma asiaticum (22.80%), Hyalomma anatolicum (3.68%), Hyalomma marginatum (2.40%), Rhipicephalus sanguineus (0.84%), Dermacentor marginatus (1.13%), and Haemaphysalis sulcata (0.64%). Additionally, two genera and four species fell into soft ticks: Argas persicus (60.48%), Argas reflexus (6.65%), Ornithodoros canstrini (0.70%) and Ornithodoros erraticus (0.42%). There was significant variation in the seasonal activity and abundance of ticks in different seasons but in the tick abundancy among different regions. The present study provides a perspective of the distribution status of ticks in Lorestan Province, their seasonal activity and the likelihood of emergence of related diseases.