Rickettsia species in Dermacentor reticulatus ticks feeding on human skin and clinical manifestations of tick-borne infections after tick bite.

Dermacentor reticulatus ticks are sporadically removed from human skin and therefore the medical consequences of their feeding are neglected compared to Ixodes ricinus. We investigated the prevalence of pathogens in D. reticulatus removed from human skin and possible clinical manifestations suggestive of tick-borne diseases after a tick bite. A total of 2153 ticks were studied and of these only 34 were D. reticulatus. The mean prevalence of Rickettsia in D. reticulatus was 50.0% and R. raoultii was identified in 82.4% of infected D. reticulatus ticks. We confirmed the first case of R. aeschlimannii infection in D. reticulatus ticks. Among participants bitten by D. reticulatus, 13.3% reported reddening around the tick bite site and flu-like symptoms, including lymphadenopathy and 3.3% reported eschar on the tick site bite. All of the participants with flu-like symptoms after tick removal were bitten by ticks infected with R. raoultii. The results of this study indicate that even though D. reticulatus ticks bite humans sporadically, pathogenic Rickettsia have a remarkably high prevalence in this tick species. We can expect that the incidence of tick-borne lymphadenopathy might increase with the reported expansion of the D. reticulatus into new areas and its growing abundance in Central Europe.

Associations of the cerebrospinal fluid lymphocyte population with a clinical presentation of tick-borne encephalitis.

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.

The Detectability of the Viral RNA in Blood and Cerebrospinal Fluid of Patients with Tick-Borne Encephalitis.

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.

Differences in the plasma phospholipid profile of patients infected with tick-borne encephalitis virus and co-infected with bacteria.

Tick-borne encephalitis (TBE) is an infectious viral disease, the pathogenesis of which is still not fully understood. Additionally, TBE can be complicated by co-infections with various bacteria that are also transmitted by ticks, which can affect the proper diagnosis and treatment. Therefore, the aim of the study was to evaluate changes in the plasma phospholipid (PL) and ceramide (CER) profile of patients with TBE and patients with bacterial co-infection (B. burgdorferi or A. phagocytophilum) in relation to healthy subjects. For this purpose, a high-resolution LC-QTOF-MS/MS platform as well as univariate and multivariate statistics were used. The results of this study showed that the levels of phosphatidylcholines (PC) and lysophosphatidylcholines (LPC) species were increased in the plasma of patients with TBE and patients with TBE co-infected with bacteria. On the other hand, observed differences in the content of phosphoethanolamines (PE) and sphingomyelins (SM) make it possible to distinguish TBE patients from patients with co-infections. The opposite direction of changes was also observed in the CER content. This study showed significant modifications to the metabolic pathways of linoleic (LA) and arachidonic acid (AA), as confirmed by the quantitative analysis of these fatty acids. The obtained results allow to distinguish the pathomechanism of TBE from TBE with bacterial co-infection, and consequently may improve the diagnostic process and enable more efficient pharmacotherapy against both pathogens.

Anti-TBE Intrathecal Synthesis as a Prediction Marker in TBE Patients.

Tick-borne encephalitis (TBE) is an emerging vector-borne disease in Europe caused by tick-borne encephalitis virus (TBEV), which belongs to Flaviviridae. Although most of the patients quickly recover from TBE, some require further neurological and psychiatric treatment due to persistent symptoms. The aim of the study was to evaluate the usefulness of an antibodies index for predicting the course of the disease and potential persistent sequalae. Sixty-six patients (49 males and 17 females, mean age 45.97 ± 13.69 years) with TBE hospitalized in the Department of Infectious Diseases and Neuroinfections, Medical University of Bialystok, Poland, in years 2016-2019 were included to the study. TBE antibodies titer in serum and CSF samples were measured with an Anti-TBEV ELISA (IgM, IgG) EUROIMMUN test. Patients who developed persistent sequelae after TBE had significantly lower IgG intrathecal index at admission. Additionally, IgG2/IgG1was significantly higher in patients who developed sequelae. IgG intrathecal index might be a useful tool for the prediction of TBE sequelae development.

Analysis of Clinical Course and Vaccination Influence on Serological Response in COVID-19 Convalescents.

Our goal was to assess the anti-SARS-CoV-2 antibodies presence in COVID-19 convalescents and assess the differences in anti-SARS-CoV-2 antibodies production regarding the disease severity, sex, vaccination, and assess the correlation between anti-SARS-CoV-2 antibodies production and inflammatory parameters. Three hundred twenty-two COVID-19 patients (282 hospitalized and 40 patients with oligosymptomatic COVID-19 isolated at homes) were included in the study. Blood was taken at 4 time points: during hospitalization, 1 month, 3 months, and 6 months. Detection of SARS-CoV-2 antibodies was performed with LIAISON SARS-CoV-2 S1/S2 IgG tests (DiaSorin, Italy). Clinical and laboratory parameters were compared. Significant differences between higher anti-SARS-CoV-2 antibodies titer in symptomatic patients 3 months after infection (III sample) and significantly higher ratio II/I in symptomatic patients were observed. Subgroup analysis based on sex showed differences only in laboratory tests, not in serological. Analysis of the results of serological tests showed significant differences in ratio IV/I and a significant increase in antibodies level after vaccination. The most significant rise was observed between the 3rd and 6th month when the patients received a vaccination. Immunological response after COVID-19 infection lasted over 6 months in all patients, although antibodies titers were significantly higher in patients with a history of severe COVID-19 and vaccinated patients. Immunological response after COVID-19 infection did not depend on sex. There was a significant correlation between anti-SARS-CoV-2 antibodies production and the degree of inflammation in the acute phase of the disease (inflammatory parameters in blood and severity of lung affection in CT). IMPORTANCE The results of our study confirm the knowledge on immune response in the Polish population and add new information regarding correlations with the severity of the disease. The data in the literature concerning the correlation between antibodies response and sex are ambiguous, and we did not observe differences between antibodies production and gender, which also adds new information.

Prevalence of Tick-Borne Pathogens in Questing Ixodes ricinus and Dermacentor reticulatus Ticks Collected from Recreational Areas in Northeastern Poland with Analysis of Environmental Factors.

Ticks, such as Ixodes ricinus and Dermacentor reticulatus, act as vectors for multiple pathogens posing a threat to both human and animal health. As the process of urbanization is progressing, those arachnids are being more commonly encountered in urban surroundings. In total, 1112 I. ricinus (n = 842) and D. reticulatus (n = 270) ticks were collected from several sites, including recreational urban parks, located in Augustów and Bialystok, Poland. Afterwards, the specimens were examined for the presence of Borrelia spp., Babesia spp., Anaplasma phagocytophilum, Rickettsia spp., Bartonella spp., and Coxiella burnetii using the PCR method. Overall obtained infection rate reached 22.4% (249/1112). In total, 26.7% (225/842) of I. ricinus was infected, namely with Borrelia spp. (25.2%; 212/842), Babesia spp. (2.0%; 17/842), and A. phagocytophilum (1.2%; 10/842). Among D. reticulatus ticks, 8.9% (24/270) were infected, specifically with Babesia spp. (7.0%; 19/270), A. phagocytophilum (1.1%; 3/270), and Borrelia burgdorferi s.l. (0.7%; 2/270). No specimen tested positively for Rickettsia spp., Bartonella spp., or Coxiella burnetii. Co-infections were detected in 14 specimens. Results obtained in this study confirm that I. ricinus and D. reticulatus ticks found within the study sites of northeastern Poland are infected with at least three pathogens. Evaluation of the prevalence of pathogens in ticks collected from urban environments provides valuable information, especially in light of the growing number of tick-borne infections in humans and domesticated animals.

The Lack of the Association of the CCR5 Genotype with the Clinical Presentation and Frequency of Tick-Borne Encephalitis in the Polish Population.

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%) CCR5Δ32 heterozygotes and 3 (1.5%) homozygotes in the TBE group, with no statistically significant difference in comparison with the controls. The CCR5Δ32 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 CCR5Δ32 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.