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Ewa Bojkiewicz,1 Kacper Toczylowski,1 Dawid Lewandowski,1 Diana Martonik,2 Robert Flisiak,2 Artur Sulik1 1Department of Pediatric Infectious Diseases, Medical University of Bialystok, Bialystok, Poland; 2Department of Infectious Diseases and Hepatology, Medical University of Bialystok, Bialystok, PolandCorrespondence: Kacper Toczylowski, Email kacper.toczylowski@umb.edu.plBackground: Chitinase 3-like-1 (CHI3L1), also known as YKL-40, is a potential biomarker for neuroinflammatory conditions. It is upregulated in Alzheimer’s disease, multiple sclerosis, and traumatic brain injury. However, its involvement in pediatric tick-borne encephalitis (TBE) has not been addressed yet. This study aimed to evaluate CHI3L1 and its relationship with other inflammatory cytokines, blood-brain barrier (BBB) integrity, immune response, and disease severity in pediatric patients with TBE.Patients and Methods: A total of 22 pediatric TBE patients hospitalized in Bialystok, Poland were included in this study. Participants were categorized as having meningoencephalitis (n=6) or meningitis (n=16). The integrity of the brain-blood barrier (BBB) was assessed using the albumin quotient (albQ). Biomarker indices were calculated to account for variations in BBB permeability. The concentrations of CHI3L1, CCL2, chemerin, CXCL2, IFN-γ, IL-1-β, IL-4, IL-6, IL-13, and TNF-α in both serum and CSF, were measured using the Luminex Multiplex Assay od admission and two weeks later when symptoms resolved.Results: CSF and serum concentrations of CHI3L1 did not differ between the encephalitis and meningitis cases. After adjusting for BBB permeability, the CHI3L1 index was 2.4-fold lower in patients with encephalitis than in those with meningitis (P=0.008). There was a post-treatment reduction of CHI3L1, IL-6, and TNF-α CSF concentrations. We also found and improvement in BBB permeability in younger children but in older albQ remained abnormal. Correlation analysis revealed associations between CHI3L1 levels and pro-inflammatory markers, notably chemerin, IL-6, and TNF-α, across both clinical groups.Conclusion: Our findings suggest that CHI3L1 CSF levels reflect the inflammatory activity in pediatric TBE and may help to differentiate between meningoencephalitis and meningitis. The observed interactions between CHI3L1 and other cytokines underscore its potential involvement in inflammatory response to the virus. The prolonged disruption in BBB integrity in older children might reflect age-dependent differences in the severity of TBE. These insights advance our understanding of TBE pathogenesis in children and support further investigation of CHI3L1 as a biomarker for TBE diagnosis and management.Keywords: chitinase-3-like-1, tick-borne encephalitis, blood-brain barrier, ticks, chemokines

Purpose: The aim of this study was to analyze treatment outcomes and their predictors in children hospitalized due to varicella complicated by bacterial superinfections after pandemic of COVID-19., Methods: This retrospective study analyzed data collected in a multicenter, nationwide, observational database dedicated for children aged 0-17 years hospitalized due to bacterial complications of varicella in 9 Polish tertiary healthcare inpatient centers. The primary endpoint of this study was the treatment outcome established after the end of hospital management assessed at a 4-point scale. The secondary endpoint was defined as the necessity of surgical intervention., Results: There were 458 patients with a median age of 4 (IQR 2-6) years. After the completed treatment, 319 (69%) participants were found fully recovered; 132 (29%) had transient complications; 2 (0.5%) had persistent complications; and 1 child (0.5%) died. Multivariate analysis revealed that implementation of ibuprofen in pre-treatment management of a child with varicella was associated with a 4.07-fold (2.50-6.60) increase in risk of complications after the treatment and it was associated with 2.87 times (1.39-5.89) higher risk of surgical intervention necessity. For other pre-hospital interventions (implementation of acyclovir, antibiotics or antihistaminics) no significant impact was observed. GAS infection increased the necessity of surgical intervention by 7.51 (3.64-15.49) times., Conclusions: One-third of patients treated for bacterial complications of varicella have post-treatment complications, most of them transient. GAS infection increases the need for surgical intervention. The use of ibuprofen in the treatment of varicella significantly increases the risk of complications and the need for surgical intervention., Competing Interests: Declarations. Conflict of interest: The authors declare no conflicts of interests., (© 2024. The Author(s).)

After the first phase of the COVID-19 pandemic in Europe, a new highly pathogenic variant of echovirus 11 (E11) was detected. The aim of this study was to analyze the genetic diversity of Polish E11 environmental and clinical strains circulating between 2017 and 2023 as well as compare them with E11 strains isolated from severe neonatal sepsis cases reported in Europe between 2022 and 2023. Additionally, the study explores the effectiveness of environmental monitoring in tracking the spread of new variants. For this purpose, the complete sequences of the VP1 capsid protein gene were determined for 266 E11 strains isolated in Poland from 2017 to 2023, and phylogenetic analysis was performed. In the years 2017-2023, a significant increase in the detection of E11 strains was observed in both environmental and clinical samples in Poland. The Polish E11 strains represented three different genotypes, C3, D5 and E, and were characterized by a high diversity. In Poland, the intensive circulation of the new variant E11, responsible for severe neonatal infections with a high mortality in Europe, was detected in the years 2022-2023. This investigation demonstrates the important role of environmental surveillance in the tracking of enteroviruses circulation, especially in settings with limited clinical surveillance.

BACKGROUND COVID-19 manifests with varying degrees of severity across different age groups; adults typically experience more severe symptoms than children. Matrix metalloproteinases (MMPs), known for their role in tissue remodeling and immune responses, may contribute to the pathophysiological disparities observed between these groups. We sought to delineate differences in serum MMP profiles between adult and pediatric COVID-19 patients, assess the influence of anti-inflammatory treatment on MMP levels, and examine potential implications for long-term consequences. MATERIAL AND METHODS Serum samples from adult and pediatric COVID-19 patients, alongside controls, were analyzed for MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-10, MMP-12, MMP-13, EMMPRIN, TNF-alpha, TIMP-1, TIMP-2, TIMP-3, and TIMP-4. A subset of adult patients received treatment with glucocorticoids, tocilizumab, and convalescent plasma, and MMP levels were compared with those of untreated patients. RESULTS Elevated levels of MMP-1, MMP-7, TIMP-1, and TIMP-2 were observed in adult and pediatric patients. Adult patients displayed higher concentrations of MMP-3, MMP-8, MMP-9, TNF-alpha, and TIMP-4 than children. Post-treatment reduction in MMP-1, MMP-8, MMP-9 levels was observed, with median decreases from 21% to 70%. MMP-3 and MMP-7 remained largely unchanged, and MMP-2 concentrations increased after treatment. Notably, anti-inflammatory treatment correlated with reduced post-treatment MMP levels, suggesting potential therapeutic benefit. CONCLUSIONS Distinctive inflammatory responses in COVID-19 were evident between adults and children. While certain MMPs exhibited post-treatment reduction, the persistence of elevated levels raises concerns about potential long-term consequences, including lung fibrosis. Our findings emphasize the need for personalized treatment strategies and further investigation into the dynamics of MMP regulation in COVID-19.

BACKGROUND Respiratory tract infections (RTIs) in children often involve a complex interplay between viruses and bacteria. This study aimed to evaluate clinical presentation in children under 5 years old diagnosed with non-COVID-19 bacterial and viral respiratory tract co-infections between October 2021 and May 2022 in Białystok, Poland. MATERIAL AND METHODS We recruited 100 children under 5 years with RTIs who tested negative for SARS-CoV-2. Nasopharyngeal swabs were screened for 19 viruses and 7 bacterial strains using molecular assays. RESULTS Viral pathogens were detected in 71% of patients and bacterial pathogens were detected in 59%. The most common pathogens were Haemophilus influenzae (n=48), rhinoviruses (n=32), and Streptococcus pneumoniae (n=30). Single pathogens were detected in 36%, dual in 37%, triple in 15%, and quadruple in 2%. Bacterial pathogens were co-detected with viruses in 40 cases, mostly with rhinoviruses (n=15). Two different viruses were found in 14 children and the most common co-detection was adenovirus with rhinovirus (n=5); dyspnea (63% vs 11%) and wheezing (75% vs 22%) were more common in children with human bocavirus. Fever was a common symptom in children with human adenovirus (88% vs 58%). Detection of bacteria and multiple detections were more common in day-care attendees, but were not associated with clinical picture of RTI. CONCLUSIONS Consistent with previous studies, we found a high prevalence of rhinoviruses, despite ongoing implementation of non-pharmaceutical interventions to contain the COVID-19 pandemic. Co-detection of 2 different respiratory pathogens was frequent, but we found no evidence that this was associated with the severity of infections.

In tick-borne encephalitis (TBE), lymphocytes infiltrating central nervous system are indispensable for the infection control, but also potentially immunopathogenic. To clarify their roles, we have evaluated cerebrospinal fluid (CSF) count of the main lymphocyte populations (considered as a proxy of the brain parenchyma lymphocytic infiltrate) in TBE patients and analyzed if they associate with clinical presentation, blood-brain barrier disruption and intrathecal antibody synthesis. We have studied CSF from 96 adults with TBE (50 with meningitis, 40 with meningoencephalitis, 6 with meningoencephalomyelitis), 17 children and adolescents with TBE and 27 adults with non-TBE lymphocytic meningitis. Th CD3+CD4+, Tc CD3+CD8+, double positive T CD3+CD4+CD8+, B CD19+ and NK CD16+/56+ cells were counted cytometrically with a commercial fluorochrome-stained monoclonal antibody set. The associations between the counts and fractions of these cells and clinical parameters were analyzed with non-parametric tests, p<0.05 considered significant. The TBE patients had lower pleocytosis with similar proportions of the lymphocyte populations compared to non-TBE meningitis. The different lymphocyte populations correlated positively with one another, as well as with CSF albumin, IgG and IgM quotients. The higher pleocytosis and expansion of Th, Tc and B cells associated with a more severe disease and neurologic involvement: Th with encephalopathy, myelitis and weakly with cerebellar syndrome, Tc with myelitis and weakly with encephalopathy, B with myelitis and with at least moderately severe encephalopathy. The double-positive T lymphocytes associated with myelitis, but not with other forms of CNS involvement. The fraction of double positive T cells decreased in encephalopathy and the fraction of NK in patients with neurologic deficits. In children with TBE, Tc and B counts were increased at the expense of Th lymphocytes in comparison with adults. The concerted intrathecal immune response, involving the main lymphocyte populations, increases with the clinical severity of TBE, with no evidently protective or pathogenic elements distinguishable. However, the particular populations including B, Th and Tc cells associate with different, though overlapping, spectra of CNS manifestations, suggesting they may be specifically related to TBE manifesting as myelitis, encephalopathy and cerebellitis. The double-positive T and NK cells do not expand evidently with severity and may be most closely associated with the protective anti-TBEV response., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests regarding this manuscript., (Copyright © 2023 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Background: This study aimed to analyze the differences in the epidemiologic and clinical characteristics of coronavirus disease 2019 (COVID-19) in children hospitalized in 2021, when the severe acute respiratory syndrome coronavirus 2 variants B.1.1.7 (alpha) and B.1.617.2 (delta) dominated, compared with 2020., Methods: In this multicenter study based on the pediatric part of the national SARSTer register (SARSTer-PED), we included 2771 children (0-18 years) with COVID-19 diagnosed between March 1, 2020, and December 31, 2021, from 14 Polish inpatient centers. An electronic questionnaire, which addressed epidemiologic and clinical data, was used., Results: Children hospitalized in 2021 were younger compared with those reported in 2020 (mean 4.1 vs. 6.8 years, P = 0 .01). Underlying comorbidities were reported in 22% of the patients. The clinical course was usually mild (70%). A significant difference in the clinical course assessment between 2020 and 2021 was found, with more asymptomatic patients in 2020 and more severely ill children in 2021. In total, 5% of patients were severely or critically ill, including <3% of the participants in 2020 and 7% in 2021. The calculated mortality rate was 0.1% in general and 0.2% in 2021., Conclusion: Infections with severe acute respiratory syndrome coronavirus 2 variants alpha and delta lead to a more severe course of COVID-19 with more pronounced clinical presentation and higher fatality rates than infection with an original strain. Most of the children requiring hospitalization due to COVID-19 do not have underlying comorbidities., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

This study aimed to analyze the differences in severity and clinical characteristics of COVID-19 in infants hospitalized in Poland in 2021, when the dominance of variants of concern (VOCs) alpha and delta was reported, compared to 2020, when original (wild) SARS-CoV-2 was dominant (III-IV vs. I-II waves of the pandemic, respectively). In addition, the influence of the presence of comorbidities on the clinical course of COVID-19 in infants was studied. This multicenter study, based on the pediatric part of the national SARSTer database (SARSTer-PED), included 940 infants with COVID-19 diagnosed between March 1, 2020, and December 31, 2021, from 13 Polish inpatient centers. An electronic questionnaire, which addressed epidemiological and clinical data, was used. The number of hospitalized infants was significantly higher in 2021 than in 2020 (651 vs. 289, respectively). The analysis showed similar lengths of infant hospitalization in 2020 and 2021, but significantly more children were hospitalized for more than 7 days in 2020 ( p < 0.009). In both analyzed periods, the most common route of infection for infants was household contact. There was an increase in the percentage of comorbidities, especially prematurity, in children hospitalized in 2021 compared to 2020. Among the clinical manifestations, fever was predominant among children hospitalized in 2021 and 2020. Cough, runny nose, and loss of appetite were significantly more frequently observed in 2021 ( p < 0.0001). Severe and critical conditions were significantly more common among children with comorbidities. More infants were hospitalized during the period of VOCs dominance, especially the delta variant, compared to the period of wild strain dominance, even though indications for hospitalization did not include asymptomatic patients during that period. The course of COVID-19 was mostly mild, characterized mainly by fever and respiratory symptoms. Comorbidities, particularly from the cardiovascular system and prematurity, were associated with a more severe course of the disease in infants.

Objectives: Multisystem inflammatory syndrome in children (MIS-C) is the result of an immune response triggered by a previous exposure to SARS-CoV-2. The clinical presentation of MIS-C overlaps with other life-threatening bacterial infections, in which antimicrobials are the mainstay therapy. The aim of study was to describe the use of antibiotics in children with MIS-C in Poland., Methods: The analysis of 345 children reported from 42 Polish cities to the national MultiOrgan Inflammatory Syndromes COVID-19 Related Study (MOIS-CoR Study) from June 2020 to April 2021., Results: At least one antibiotic was used in 310 (90%) children, mainly third-generation cephalosporin (251/310). Broad-spectrum antibiotics were used in 258 (75%) children and 224 (87%) received this treatment for more than 3 days. Concentrations of serum procalcitonin >2 µg/l and the presence of lower respiratory symptoms were associated with increased odds of receiving any antibiotic., Conclusion: Although bacterial infections in patients with MIS-C are uncommon, we show that MIS-C poses a challenge to clinicians who are faced with the decision to start, continue, or stop antimicrobial therapy. Antibiotic stewardship in patients with MIS-C should be improved to ensure that likely pathogens are treated and that antimicrobials are stopped when bacterial infections are excluded and the diagnosis of MIS-C is made., Competing Interests: Conflict of interest The authors have no competing interests to declare., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The detection rate of viral RNA in tick-borne encephalitis (TBE) is low and variable between studies, and its diagnostic/prognostic potential is not well defined. We attempted to detect RNA of TBE virus (TBEV) in body fluids of TBE patients., Methods: We studied 98 adults and 12 children with TBEV infection, stratified by the disease phase and presentation. EDTA blood and cerebrospinal fluid (CSF) samples were obtained upon hospital admission. RNA was extracted from freshly obtained plasma, concentrated leukocyte-enriched CSF, and whole blood samples, and real time PCR was performed with a Rotor-Gene Q thermocycler., Results: TBEV RNA was detected in (1) plasma of one (of the two studied) adult patients with an abortive infection, (2) plasma of two (of the two studied) adults in the peripheral phase of TBE, and (3) plasma and blood of an adult in the neurologic phase of TBE presenting as meningoencephalomyelitis. No CSF samples were TBEV RNA-positive., Conclusions: The detection of TBEV RNA in blood might be diagnostic in the peripheral phase of TBE. The lack of TBEV RNA in the CSF cellular fraction speaks against TBEV influx into the central nervous system with infiltrating leukocytes and is consistent with a relatively low intrathecal viral burden.

Background: The host factors influencing the susceptibility to and the severity of tick-borne encephalitis (TBE) are poorly defined. The loss-of-function Δ32 mutation in the chemokine receptor gene CCR5 was identified as a risk factor for West Nile encephalitis and possibly for TBE, suggesting a protective role of CCR5 in Flavivirus encephalitis., Methods: We studied the CCR5 genotype in 205 TBE patients stratified by a clinical presentation and 257 controls from the same endemic area (Podlasie, Poland). The genotype distribution between the groups and differences between TBE patients with different genotypes were analyzed., Results: There were 36 (17.6%) CCR5 Δ32 heterozygotes and 3 (1.5%) homozygotes in the TBE group, with no statistically significant difference in comparison with the controls. The CCR5 Δ32 allele did not associate with the clinical presentation or the severity of TBE. The cerebrospinal fluid (CSF) inflammatory parameters did not differ between the wild-type ( wt/wt ) and wt/ Δ32 genotype patients. The TBE clinical presentation and CSF parameters in three Δ32/ Δ32 homozygotes were unremarkable., Conclusions: The lack of association of CCR5 Δ32 with the risk and clinical presentation of TBE challenges the suspected CCR5 protective role. CCR5 is not indispensable for the effective immune response against the TBE virus.

Background: Multisystem inflammatory syndrome (MIS-C) is a condition related to COVID-19. It's most significant feature is cardiac involvement., Methods: We have analyzed data from 42 hospitals in the Polish MIS-C Registry. To compare the effect of GCS on fever, we formed two groups: the first treated with IVIG and the second treated with IVIG+GCS., Results: There were 111 boys and 56 girls; the mean age was 8.57 years. All the patients were treated with IVIG: 76 patients with IVIG only, and 91 patients with IVIG+GCS. There were no statistically significant differences between the groups regarding age, gender, BMI, or inflammatory markers. Methylprednisolone was the most common drug (80%). Echocardiographic abnormalities on admission were more prevalent in the IVIG+GCS group. Mean time from IVIG infusion to subsidence of fever was 1.1 days, and 1.5 for those in the IVIG+GCS group., Conclusions: GCS are commonly used in the treatment of MIS-C patients in Poland. Various GCS regimens are used, from a single dose to a month-long therapy. Children with lower lymphocyte levels and cardiac abnormalities on an echocardiographic examination performed on admission were more likely to receive GCS+IVIG. The effect of GCS is difficult to access as patients were not randomly assigned to receive the treatment.

This prospective multicenter cohort study aimed to analyze the epidemiological and clinical characteristics of coronavirus disease 2019 (COVID-19) in children. The study, based on the pediatric part of the Polish SARSTer register, included 1283 children (0 to 18 years) who were diagnosed with COVID-19 between 1 March 2020 and 31 December 2020. Household contact was reported in 56% of cases, more frequently in younger children. Fever was the most common symptom (46%). The youngest children (0-5 years) more frequently presented with fever, rhinitis and diarrhea. Teenagers more often complained of headache, sore throat, anosmia/ageusia and weakness. One fifth of patients were reported to be asymptomatic. Pneumonia was diagnosed in 12% of patients, more frequently in younger children. During the second wave patients were younger than during the first wave (median age 53 vs. 102 months, p < 0.0001) and required longer hospitalization ( p < 0.0001). Significantly fewer asymptomatic patients were noted and pneumonia as well as gastrointestinal symptoms were more common. The epidemiological characteristics of pediatric patients and the clinical presentation of COVID-19 are age-related. Younger children were more frequently infected by close relatives, more often suffered from pneumonia and gastrointestinal symptoms and required hospitalization. Clinical courses differed significantly during the first two waves of the pandemic.

Introduction: Tick-borne encephalitis (TBE) is endemic in many parts of Eurasia including countries previously considered to be free from the disease. The incidence of TBE is changing owing to various ecological and climatic factors. The factors influencing the variability of the number of TBE cases are still under investigation. In 2020 the new coronavirus SARS-CoV-2 emerged causing COVID-19 pandemic. Governments have reorganized health care systems to contain a surge of COVID-19 cases and avoid hospital overload. Moreover, new measures have modified several aspects of social habits leading to a change in the incidence of numerous diseases. We aimed to evaluate the epidemiology of TBE in the last decade (2010-2019) and to demonstrate the impact of the surge of SARS-CoV-2 infections on the TBE incidence as reported to a national surveillance database., Material and Methods: We performed the analysis of the TBE notification from the epidemiologic reports in the years 2010-2019 and in the pandemic year 2020 at a national and regional level in Poland. We included data from two infectious disease departments located in the most TBE-prevalent province of Poland., Results: Most cases of TBE occur in two provinces of Northeastern Poland from May to December. The increasing temporal trend occurred in Poland in 2016-2017. The increased number of cases of COVID-19 coincided with a reduction of the number of the reported TBE cases in 2020., Conclusions: Tick-borne encephalitis virus activity in Poland is invariably concentrated in endemic regions of Northeastern Poland fluctuating considerably from year to year. The decrease of TBE incidence with surge of COVID-19 patients conceivably resulted from underreporting due to limited access to specialized diagnostics. In endemic areas, TBE should be included in the differential diagnostics in all the cases when the central nervous system infection in suspected., (© National Institute of Public Health – National Institute of Hygiene.)

In tick-borne encephalitis (TBE) the cerebrospinal fluid (CSF) cytosis is dominated by T CD3+CD4+ and T CD3+CD8+ lymphocytes, but their pathogenetic roles and mechanisms of migration into central nervous system (CNS) are unclear. Currently, we have studied CSF lymphocyte subsets and chemotactic axes in TBE patients stratified according to the clinical presentation. Blood and CSF were obtained from 51 patients with TBE (presenting as meningitis in 30, meningoencephalitis in 18 and meningoencephalomyelitis in 3), 20 with non-TBE meningitis and 11 healthy controls. We have studied: (1) abundances of the main lymphocyte subsets and (2) CXCR3 and CCR5 expression on CD3+CD4+ and CD3+CD8+ lymphocytes cytometrically with fluorochrome-stained monoclonal antibodies; (3) concentrations of chemotactic cytokines: CCL5 (CCR5 ligand), CXCL10 (CXCR3 ligand), IL-16, CCL2, CCL20 and CXCL5 with ELISA. Cytokine concentrations were additionally studied in 8 pediatric TBE patients. Data were analyzed with non-parametric tests, p < 0.05 considered significant. The higher CSF lymphocyte counts were associated with symptoms of CNS involvement, especially with altered consciousness (B, Th and Tc cells) and focal neurologic deficits (B cells). The minor fraction of double-positive T CD4+CD8+ cells was unique in associating negatively with encephalitis and altered consciousness. CSF CD3+CD4+ and CD3+CD8+ lymphocyte population was enriched in CCR5-positive cells and CCL5 concentration in CSF was increased and associated with a milder presentation. Although CXCL10 was vividly up-regulated intrathecally and correlated with CSF T lymphocyte counts, the CXCR3 expression in CSF T lymphocytes was low. Serum and CSF concentrations of CCL2, CXCL5 and IL-16 were increased in adult TBE patients, CCL2 created a chemotactic gradient towards CSF and both CCL2 and IL-16 concentrations correlated positively with CSF lymphocyte counts. The particular lymphoid cell populations in CSF associate differently with the clinical presentation of TBE, suggesting their distinct roles in pathogenesis. CCR5/CCL5 axis probably contributes to T lymphocyte migration into CNS. CXCL10 mediates the intrathecal immune response, but is probably not directly responsible for T cell migration. Additional chemotactic factors must be involved, probably including CCL2 and IL-16., (Copyright © 2020 Elsevier GmbH. All rights reserved.)

Despite the constant development of biotechnology, laboratory diagnostics of Lyme disease in children still poses a significant challenge. The aim of this article is to present the current methods of Lyme disease diagnosis and its future perspectives. A serological test is often the first step in supporting clinical diagnosis of Lyme disease in children. Recently, a new generation of enzyme-linked immunosorbent assays has been created. These assays use recombinant proteins or synthetic peptides in their antigenic spectrum. It is postulated that these tests may replace the classic immunoblot as the second step in the Lyme disease diagnostic protocol. Direct detection methods based on bacterial culture techniques or using the polymerase chain reaction (PCR) have inadequate sensitivity, which prevents their widespread use in clinical practice. Recently, a number of other tools have been developed that are of supportive importance. Among them, measuring of the CXCL13 chemokine concentration in the cerebrospinal fluid has the potential to become a routine procedure in the diagnosis of Lyme disease in children. Future diagnostic strategies of Lyme disease might include: innovative immunological tests using new antigens, combining serology with direct methods in order to increase sensitivity, standardization of selected unconventional tests, identification of host response biochemical metabolic markers or linking clinical symptoms reported by patients with appropriate test panels. In the absence a vaccine which protects against the disease, the preventive recommendations given to parents to prevent tick bites in children remain valid., (© National Institute of Public Health – National Institute of Hygiene.)

Tick-borne encephalitis virus (TBEV), which causes central nervous system infections, is a major health problem in Europe and Asia. This virus is transmitted mainly via the bite of a tick. However, an infection may also occur as a result of consuming raw milk. In 2018, a total of 3 092 cases of tick-borne encephalitis (TBE) were reported in EU countries. In recent years, TBE has emerged in previously unaffected regions; thus, new endemic areas have been identified. Most cases of TBE occur in spring and autumn, which correlates with increased tick activity. TBE is found in all age groups, including infants. The clinical presentation of TBE varies, but the severity of the infection and risk of complications increase with age. Post-encephalitic syndrome, which affects up to 50% of infected individuals, significantly reduces quality of life. Currently, there is no effective treatment for TBE, and supportive management is used in the acute phase of the disease. Therefore, anti-TBE immunization and the avoidance of tick bites are of key importance in preventing this infection., (© National Institute of Public Health – National Institute of Hygiene.)

Adipose tissue secretes a number of cytokines, referred to as adipokines. Intensive studies conducted over the last two decades showed that adipokines exert broad effects on cardiac metabolism and function. In addition, the available data strongly suggests that these cytokines play an important role in development of cardiovascular diseases. Epicardial adipose tissue (EAT) has special properties that distinguish it from other deposits of visceral fat. Overall, there appears to be a close functional and anatomic relationship between the EAT and the cardiac muscle. They share the same coronary blood supply, and there is no structure separating the adipose tissue from the myocardium or coronary arteries. The role of EAT in osierdziocardiac physiology remains unclear. Its putative functions include buffering coronary arteries against the torsion induced by the arterial pulse wave and cardiac contraction, regulating fatty acid homeostasis in the coronary microcirculation, thermogenesis, and neuroprotection of the cardiac autonomic ganglia and nerves. Obesity (particularly the abdominal phenotype) leads to elevated EAT content, and the available data suggests that high amount of this fat depot is associated with increased risk of ischemic heart disease, cardiac hypertrophy and diastolic dysfunction. The mass of EAT is small compared to other fat deposits in the body. Nevertheless, its close anatomic relationship to the heart suggests that this organ is highly exposed to EAT-derived adipokines which makes this tissue a very promising area of research. In this paper we review the current knowledge on the role of EAT in cardiac physiology and development of heart disease.