Genotype determines phenotype in experimental Lyme borreliosis

Influence of ecological and climatic conditions on the spread of Borrelia burgdorferi in domestic dogs in Ukraine

Lyme-borreliosis is a zoonotic, infectious disease that has a complex chain of transmission of the pathogen Borrelia burgdorferi sensu lato and includes the relationship between ixodid ticks, vertebrate hosts, humans and companion animals in the environment. The article shows general trends in the prevalence of canine Lyme-borreliosis in Ukraine depending on environmental, climatic and physiographic factors. The results of a comparative cartographic analysis of the prevalence of Lyme borreliosis among domestic dogs in Ukraine are presented by systematizing, mathematical and statistical processing of the data obtained by surveying veterinarians engaged in clinical veterinary practice. The paper includes generalized data on the clinical manifestations, methods of diagnosis and treatment of Lyme borreliosis in dogs. We determined the dependence of the prevalence of Lyme borreliosis in dogs on the types of physical and geographical territories – natural zones of Ukraine. Each of the natural zones differs in types of relief, climatic conditions, soil types, composition of fauna and flora, which affect the epizootic chain of Lyme disease. There is a clear correlation between the incidence of Lyme borreliosis in dogs and the types of natural areas. The highest incidence of Lyme borreliosis in dogs was observed in the forest-steppe zone and the zone of broad-leaved forests. A sharp decrease in the incidence of dogs was recorded in areas of mixed forests, the Ukrainian Carpathians and in the South of Ukraine in the steppe zone. The study also confirmed that the prevalence of Lyme disease among domestic dogs was influenced by the climatic factors, in particular: gross moisture of territories, average annual air temperature and soil temperature. In Ukraine, veterinarians in the vast majority of cases use serological diagnostic methods: immunochromatographic analysis, immunoenzymatic assay, and western blot, which are insufficient, since the presence of antibodies to the Lyme borreliosis pathogen is only a confirmation of the animal's contact with the antigen and may not indicate the presence of the disease in the clinical form. The generalized data on the use of antimicrobial drugs in the treatment of Lyme borreliosis in dogs indicate the predominant use of tetracycline antibiotics and cephalosporins. The majority of veterinarians reported symptoms of Lyme arthritis, somewhat fewer reported Lyme nephritis, neuroborreliosis, Lyme carditis and in rare cases, veterinarians observed erythema at the site of tick bite. About half of the veterinarians in Ukraine observed an increase in the incidence of Lyme disease in dogs, indicating a probable deterioration of the epizootic and epidemiological situation regarding Lyme borreliosis, especially in areas with favourable conditions for the circulation of Lyme borreliosis pathogens in natural and urban ecotopes. The results substantiate the need for the further study of the circulation of Borrelia burgdorferi sensu lato and their ability to cause disease in humans and animals, as well as the need to implement the principles of the One Health concept for the control and management of Lyme borreliosis.

Lack of Convincing Evidence that Borrelia burgdorferi Infection Causes Either Alzheimer's Disease or Lewy Body Dementia

The role that microorganisms might have in the development of Alzheimer's disease is a topic of considerable interest. In this article we discuss whether there is credible evidence that Lyme disease is a cause of Alzheimer's disease and critically review a recent publication claiming that Borrelia burgdorferi sensu stricto infection, the primary cause of Lyme disease in the United States, may cause Lewy body dementia. We conclude that no convincing evidence exists that Lyme disease is a cause of either Alzheimer's disease or Lewy body dementia.

Monitoring Risk: Tick and Borrelia burgdorferi Public Participatory Surveillance in the Canadian Maritimes, 2012-2020

Ticks are vectors of many diseases, including Lyme disease (Ld). Lyme disease is an emerging disease in Canada caused by infection with the Lyme borreliosis (Lb) members of the Borrelia genus of spirochaete bacteria, of which Borrelia burgdorferi is regionally the most prevalent. The primary tick vector in central and eastern Canada, Ixodes scapularis, is increasing in numbers and in the geographical extent of established populations. This study documents the distribution of ticks recovered by passive surveillance, and their B. burgdorferi infection prevalence, in three Canadian Maritime provinces from 2012-2020. These regions represent areas in which tick populations are widely established, establishing, and considered non-established. Using a community science approach by partnering with veterinarians and members of the public, we collected over 7000 ticks from the 3 provinces. The three species found most often on companion animals and humans were I. scapularis (76.9%), Ixodes cookei (10.4%) and Dermacentor variabilis (8.9%). The most common hosts were dogs (60.5%), cats (16.8%) and humans (17.6%). As is typical of passive surveillance tick collections, the majority of ticks recovered were adult females; for I. scapularis 90.2%, 5.3%, 3.9% and 0.6% of the total of 5630 ticks recovered for this species were adult females, adult males, nymphs and larvae, respectively. The majority of B. burgdorferi-infected ticks were I. scapularis, as expected. Borrelia infection prevalence in I scapularis was higher in Nova Scotia (20.9%), the province with the most endemic regions, than New Brunswick (14.1%) and Prince Edward Island (9.1%), provinces thought to have established and non-established tick populations, respectively. The province-wide Borrelia infection prevalence generally increased in these latter tow provinces over the course of the study. The host did not have a significant effect on B. burgdorferi infection prevalence; I. scapularis ticks from dogs, cats, humans was, 13.3% (n = 3622), 15.6% (n = 817), 17.9% (n = 730), respectively. No I. scapularis larvae were found infected (n = 33) but B. burgdorferi was detected in 14.8% of both adults (n = 5140) and nymphs (n = 215). The incidence of B. burgdorferi infection also did not differ by engorgement status 15.0% (n = 367), 15.1% (n = 3101) and 14.4% (n = 1958) of non-engorged, engorged and highly engorged ticks, respectively, were infected. In New Brunswick, at the advancing front of tick population establishment, the province-wide infection percentages generally increased over the nine-year study period and all health district regions showed increased tick recoveries and a trend of increased percentages of Borrelia-infected ticks over the course of the study. Within New Brunswick, tick recoveries but not Borrelia infection prevalence were significantly different from endemic and non-endemic regions, suggesting cryptic endemic regions existed prior to their designation as a risk area. Over the 9 years of the study, tick recoveries increased in New Brunswick, the primary study region, and I. scapularis recoveries spread northwards and along the coast, most but not all new sites of recoveries were predicted by climate-based models, indicating that ongoing tick surveillance is necessary to accurately detect all areas of risk. Comparison of tick recoveries and public health risk areas indicates a lag in identification of risk areas. Accurate and timely information on tick distribution and the incidence of Borrelia and other infections are essential for keeping the public informed of risk and to support disease prevention behaviors.

Outer surface protein polymorphisms linked to host-spirochete association in Lyme borreliae

Lyme borreliosis is caused by multiple species of the spirochete bacteria Borrelia burgdorferi sensu lato. The spirochetes are transmitted by ticks to vertebrate hosts, including small- and medium-sized mammals, birds, reptiles, and humans. Strain-to-strain variation in host-specific infectivity has been documented, but the molecular basis that drives this differentiation is still unclear. Spirochetes possess the ability to evade host immune responses and colonize host tissues to establish infection in vertebrate hosts. In turn, hosts have developed distinct levels of immune responses when invaded by different species/strains of Lyme borreliae. Similarly, the ability of Lyme borreliae to colonize host tissues varies among different spirochete species/strains. One potential mechanism that drives this strain-to-strain variation of immune evasion and colonization is the polymorphic outer surface proteins produced by Lyme borreliae. In this review, we summarize research on strain-to-strain variation in host competence and discuss the evidence that supports the role of spirochete-produced protein polymorphisms in driving this variation in host specialization. Such information will provide greater insights into the adaptive mechanisms driving host and Lyme borreliae association, which will lead to the development of interventions to block pathogen spread and eventually reduce Lyme borreliosis health burden.

Identification of Borrelia bissettii in Ixodes scapularis ticks from New Brunswick, Canada

Lyme disease is a tick-borne disease that is emerging in Canada. The disease is caused by spirochetes of the Lyme borreliosis group, which is expanding as new species are discovered. In Canada, Lyme disease risk has so far been assessed primarily by detection of Borrelia burgdorferi sensu stricto. Of Ixodes scapularis ticks collected between 2014 and 2016 in New Brunswick, Canada, 7 were shown to be infected with Borrelia bissettii by nested PCR and sequencing of 5 B. bissettii genes. Since different Borrelia species are associated with different clinical manifestations and are not detected with the same diagnostic tests, the identification of a previously undocumented or underreported pathogenic Borrelia species has important implications for public and veterinary medicine.

Risk factors for a non-favorable outcome after treated European neuroborreliosis

AIM

To identify possible risk factors for reduced health-related quality of life (HRQoL) and fatigue after treated Lyme neuroborreliosis (LNB).

METHODS

We included 50 patients with LNB and analyzed associations between their demographic, clinical, and laboratory characteristics at baseline and outcome at 30 months assessed by the self-report questionnaires Short Form-36 (SF-36) and Fatigue Severity Scale (FSS).

RESULTS

Lower scores in the SF-36 domain Physical Component Summary were associated with pretreatment symptom duration >6 weeks (B = -11.0, P = 0.001) and non-complete recovery at 4 months (B = -5.5, P = 0.037) (R(2) = 0.35). Lower scores in the SF-36 domain Mental Component Summary were associated with non-complete recovery at 4 months (B = -8.9, P = 0.01 (R(2) = 0.14). Higher FSS scores were associated with pretreatment symptom duration >6 weeks (B = 1.4, P = 0.006), high scores on the composite clinical score pretreatment (B = 0.1, P = 0.003), and non-complete recovery at 4 months (B = 1.6, P = 0.005) (R(2) = 0.46). No laboratory test results were associated with these predefined outcomes.

CONCLUSIONS

Delayed treatment start, more symptoms and findings before treatment, and non-complete recovery at 4 months after treatment are possible predictors of a poorer HRQoL and more fatigue 30 months after treated LNB. We did not find age, gender, educational level, involvement of the central nervous system, coexisting diseases, or cerebrospinal fluid findings to be associated with reduced HRQoL or fatigue. Our findings should be replicated in future studies before any conclusions can be drawn.

Lyme neuroborreliosis

Lyme neuroborreliosis (LNB) designates the nervous system disorders caused by the tick-borne spirochete Borrelia burgdorferi (Bb). The clinical syndromes are usually distinct and are classified as early and the rare late or chronic LNB. Early LNB occurs 3-6 weeks after infection most frequently as a lymphocytic meningoradiculoneuritis (LMR). Symptoms are mainly due to a painful sensory radiculitis and a multifocal motor radiculo-neuritis. Fifty percent have cranial nerve involvement predominantly uni- or bilateral facial nerve palsies. Meningitic symptoms occur primarily in children. Nerve biopsies, autopsies, animal models, and nerve conduction studies showed that the pathology is a lymphocytic perineuritis leading to multisegmental axonal injury of nerve roots, spinal ganglia, and distal nerve segments. Due to meningeal and root inflammation cerebrospinal fluid (CSF) shows lymphocytic inflammation. The only evidence that Bb causes peripheral neuropathy without CSF inflammation is seen in patients with acrodermatitis chronica atrophicans (ACA), a chronic dermatoborreliosis. In the rare chronic or late LNB the pathology and thus the clinical presentation is primarily due to chronic meningitis and meningovascular CNS involvement, whereas the peripheral nervous system is not primarily affected. In early and late LNB the diagnosis is based on a characteristic clinical appearance and CSF inflammation with Bb-specific intrathecal antibody production. Both conditions, but not the ACA-associated neuropathy, respond to antibiotic therapy.

Detection of Borrelia burgdorferi sensu lato in endomyocardial biopsy specimens in individuals with recent-onset dilated cardiomyopathy

AIMS

Recent studies in patients with dilated cardiomyopathy (DCM) have detected the genome of Borrelia burgdorferi sensu lato (BBSL) in endomyocardial biopsy (EMB) specimens using a qualitative polymerase chain reaction (PCR), suggesting a causal link between Lyme disease and DCM in areas in which Lyme disease is endemic. We aimed to study this relationship using a comprehensive molecular analysis detecting BBSL in EMB samples.

METHODS AND RESULTS

We performed a comprehensive histopathological, immunohistochemical, ultrastructural, and molecular analysis targeting cardiotropic viruses and BBSL in EMB specimens of 41 individuals with recent-onset DCM and 15 controls with end-stage coronary artery disease. Specifically, quantitative PCR and electron microscopy of EMB specimens were employed. In addition, autoantibodies and manifestation of autoimmune diseases were evaluated in both groups. Individuals with recent-onset DCM presented more frequently with myocardial BBSL persistence as compared with the control group (24% vs. 0%, P = 0.035). In contrast, the prevalence of parvovirus B19 and cytomegalovirus was similar in both groups. Sequence analysis of borrelial DNA revealed the following genospecies: Borrelia burgdorferi sensu stricto in three patients (30%), Borrelia afzelii in two patients (20%), and Borrelia garinii in four patients (40%), the results being inconclusive in one case. BBSL-positive DCM patients had a higher prevalence of organ-specific autoimmune diseases in comparison with the remaining DCM patients (50% vs. 16%, P = 0.030).

CONCLUSION

Myocardial persistence of BBSL may be involved in the pathophysiology of DCM in individuals living in areas in which Lyme disease is endemic.

Infectivity of Borrelia burgdorferi sensu lato is unaltered in C3-deficient mice

B. burgdorferi, B. afzelii, and B. bavariensis show resistance to mouse and human complement. B. garinii and B. valaisiana are sensitive to mouse and human complement. We evaluated whether the absence of C3 in mice influenced infectivity and pathogenicity of different Borrelia species. C3 knockout mice (C3-/-) and syngeneic C57Bl/6 wild-type (WT) mice were challenged with 5 different Borrelia species. After 2 weeks, quantitative PCR (qPCR), culture, histopathology, and immunofluorescence were performed on heart, joint, brain, bladder, and skin. Spirochaetes were detected by qPCR after infection with B. burgdorferi, B. afzelii, or B. bavariensis strains. In joints of C3-/-, but not WT mice challenged with B. burgdorferi, spirochaetes were detected by qPCR. No other significant differences between C3-/- and WT mice were seen. Histopathology demonstrated concordance between borrelia load and inflammation score. Only after B. burgdorferi and B. afzelii infection, spirochaetes were detected by immunofluorescence microscopy. B. burgdorferi was cultured from heart, joint, bladder, and skin from all mice within 2 weeks. B. afzelii and B. bavariensis grew only from heart tissue from both C3-/- and WT mice after 2-6 weeks. The infectivity and pathogenicity of complement-resistant Borrelia strains is unchanged in complement-deficient mice. Complement-susceptible strains do not become infectious in the absence of C3.

Expression of Fas receptor on human T lymphocytes under stimulation with Borrelia burgdorferi sensu lato - preliminary results

PURPOSE

Apoptosis of activated T lymphocytes is essential to immunoregulation and its abnormalities have been observed in immune system disorders and persistent infections. To asses Borrelia burgdorferi influence on the susceptibility of T lymphocytes to apoptosis, we have measured expression of the Fas death receptor on these cells after incubation with live B. burgdorferi.

MATERIAL AND METHODS

Peripheral blood mononuclear cells from 23 LD patients (18 with Lyme arthritis, 5 with neuroborreliosis) and 13 healthy controls (C) were incubated for 48 hours with and without live B. burgdorferi spirochetes: B. afzelii, B. garinii or B. burgdorferi sensu stricto. After incubation, Fas expression on CD3+ cells was measured cytometrically with FITC-labeled monoclonal antibody.

RESULTS

Median fraction of Fas-expressing T lymphocytes increased under incubation with B. burgdorferi, with more cells expressing Fas after incubation with B. burgdorferi sensu stricto than with B. garinii. There was a tendency for a higher expression of Fas on T lymphocytes from LD patients then from controls, both in unstimulated and B. burgdorferi-stimulated cultures, but it did not reach a level of statistical significance.

CONCLUSIONS

B. burgdorferi seems to increase Fas expression on CD3+ T lymphocytes, which may render these cells more susceptible to apoptosis. This effect is stronger for B. burgdorferi s.s. than for B. garinii genospecies.

Tick-Borne Bacterial, Rickettsial, Spirochetal, and Protozoal Diseases

Approximately 900 tick species exist worldwide, parasitizing a broad array of mammals, including humans, and thereby playing a significant role in the transmission of infectious diseases (1). In the United States, tick-borne diseases are generally seasonal and geographically distributed. They occur mostly during the spring and summer but can occur throughout the year.

Interleukin 10 protects the brain microcirculation from spirochetal injury

Spirochetal infections are an important cause of neurological disease. In previous studies of the pathogenesis of spirochetal brain infection, mice inoculated with Borrelia turicatae, an agent of tick-borne relapsing fever in North America, developed mild meningitis and parenchymal activation/infiltration by interleukin 10 (IL-10)-producing microglia/macrophages. Here, we investigated the neuroprotective effects of IL-10 during spirochetal infection by comparing the outcomes of B. turicatae infection in wild-type and IL-10-deficient RAG2-deficient mice. Mice were infected with either serotype 1 (Bt1), which causes more brain infection but lower bacteremia, or Bt2, which causes less brain infection but higher bacteremia. Interleukin 10 deficiency resulted in early death from subarachnoid/intraparenchymal brain hemorrhage in Bt2-infected mice. These mice had marked apoptosis of brain microvascular endothelial cells as assessed by terminal transferase-mediated DNA nick end-labeling staining. In contrast, Bt1 infection caused milder subarachnoid hemorrhage. Neuronal apoptosis was observed in mice infected with both serotypes and was prominent in the cerebellum. Neutralization of tumor necrosis factor prevented death and reduced morbidity and brain injury in mice infected by both serotypes. We conclude that IL-10 plays a critical role protecting the cerebral microcirculation from spirochetal injury possibly by inhibition effects of tumor necrosis factor.

Macaque models of human infectious disease

Macaques have served as models for more than 70 human infectious diseases of diverse etiologies, including a multitude of agents—bacteria, viruses, fungi, parasites, prions. The remarkable diversity of human infectious diseases that have been modeled in the macaque includes global, childhood, and tropical diseases as well as newly emergent, sexually transmitted, oncogenic, degenerative neurologic, potential bioterrorism, and miscellaneous other diseases. Historically, macaques played a major role in establishing the etiology of yellow fever, polio, and prion diseases. With rare exceptions (Chagas disease, bartonellosis), all of the infectious diseases in this review are of Old World origin. Perhaps most surprising is the large number of tropical (16), newly emergent (7), and bioterrorism diseases (9) that have been modeled in macaques. Many of these human diseases (e.g., AIDS, hepatitis E, bartonellosis) are a consequence of zoonotic infection. However, infectious agents of certain diseases, including measles and tuberculosis, can sometimes go both ways, and thus several human pathogens are threats to nonhuman primates including macaques. Through experimental studies in macaques, researchers have gained insight into pathogenic mechanisms and novel treatment and vaccine approaches for many human infectious diseases, most notably acquired immunodeficiency syndrome (AIDS), which is caused by infection with human immunodeficiency virus (HIV). Other infectious agents for which macaques have been a uniquely valuable resource for biomedical research, and particularly vaccinology, include influenza virus, paramyxoviruses, flaviviruses, arenaviruses, hepatitis E virus, papillomavirus, smallpox virus, Mycobacteria, Bacillus anthracis, Helicobacter pylori, Yersinia pestis, and Plasmodium species. This review summarizes the extensive past and present research on macaque models of human infectious disease.

Higher mRNA levels of chemokines and cytokines associated with macrophage activation in erythema migrans skin lesions in patients from the United States than in patients from Austria with Lyme borreliosis

BACKGROUND

Erythema migrans (EM) is caused primarily by Borrelia afzelii in Europe and solely by Borrelia burgdorferi in the United States. B. burgdorferi infection in the United States has previously been associated with faster expansion of EM lesions and with more associated symptoms, compared with B. afzelii infection in Europe. However, reasons for these differences are not yet known.

METHODS

We determined the Borrelia species infecting 67 US or Austrian patients with EM. The clinical pictures and chemokine and cytokine mRNA levels in lesional skin were then compared in the 19 B. burgdorferi-infected US patients and the 37 B. afzelii-infected Austrian patients, the 2 largest groups.

RESULTS

The 19 B. burgdorferi-infected US patients had faster-expanding EM lesions and a median of 4 associated signs and symptoms, whereas the 37 B. afzelii-infected Austrian patients had slower-expanding lesions and usually did not experience associated symptoms. Compared with the EM lesions of B. afzelii-infected Austrian patients, those of B. burgdorferi-infected US patients had significantly higher mRNA levels of chemokines associated with activation of macrophages, including chemoattractants for neutrophils (CXCL1), macrophages (CCL3 and CCL4), and T helper 1 cells (CXCL9, CXCL10, and CXCL11). In addition, compared with the EM lesions of Austrian patients, the EM lesions of US patients tended to have higher mRNA levels of the macrophage-associated proinflammatory cytokines interleukin 1beta and tumor necrosis factor alpha, and they had significantly higher mRNA expression of the antiinflammatory cytokines interleukin 10 and transforming growth factor beta.

CONCLUSIONS

The EM lesions of B. burgdorferi-infected US patients expanded faster, were associated with more symptoms, and had higher mRNA levels of macrophage-associated chemokines and cytokines than did the EM lesions of B. afzelii-infected Austrian patients.

Lyme neuroborreliosis: infection, immunity, and inflammation

Lyme neuroborreliosis (LNB), the neurological manifestation of systemic infection with the complex spirochaete Borrelia burgdorferi, can pose a challenge for practising neurologists. This Review is a summary of clinical presentation, diagnosis, and therapy, as well as of recent advances in our understanding of LNB. Many new insights have been gained through work in experimental models of the disease. An appreciation of the genetic heterogeneity of the causative pathogen has helped clinicians in their understanding of the diverse presentations of LNB.

Lyme borreliosis--an update

Lyme borreliosis is the most common tick-borne, infectious disease in the northern hemisphere. Disease manifestations in the United States and Europe vary as a result of geographic distribution of different species within the genospecies Borrelia burgdorferi sensu lato, which in turn are host-specific. Certain toxigenic B. burgdorferi strains cause early disseminated disease. The ability of Borrelial organisms to break down the extracellular matrix also promotes dissemination. B. burgdorferi are eliminated by complement-mediated lysis and by T and B cell activity of the specific immune response. Yet, B. burgdorferi can evade humoral immunity by means of type of protective mechanism by which it adheres to the proteoglycan decorin in the joints and skin. A further factor in the persistence of the pathogen is altered antigen expression. Re-infection usually occurs with a different strain, although repeated infection with the same strain is also possible after a certain period of latency. New developments in serologic testing include the use of recombinant native antigen as well as antigens produced in vivo such as VlsE (variable major protein-like sequence, expressed) or decorin-binding protein A. Diagnosis continues to be complicated by seropositivity of healthy individuals, the persistence of antibodies after therapy, and a lacking humoral immune response in patients with erythema migrans.

The mammalian host response to borrelia infection

Tick-borne relapsing fever (RF) and Lyme disease (LD) are spirochetal infections of humans caused by different Borrelia species in endemic areas throughout the world. Our laboratory is studying the response of mammalian hosts to borrelia infection in RF and LD. For this, we use mice and non-human primates infected with B. burgdorferi sensu stricto strain N40 (N40) and the Oz1 strain of Borrelia turicatae (Bt), agents of LD and RF in North America, respectively. Our results have revealed that outbred non-human primates are significantly less susceptible than outbred mice to persistent infection with N40. In contrast, the majority of mice inoculated with the RF agent B. turicatae clear the infection, with the notable exception of residual brain or blood infection in up to 25% of cases. Little if any tissue injury occurs in immunocompetent animals with either LD or RF. In contrast, impairment of specific antibody production results in significant tissue injury, most notably in the heart, in both LD and RF. The inflammatory infiltrate is rich in plasma cells, activated macrophages and T cells, and there is significant deposition of antibody and complement, including membrane attack complex, in inflamed tissues and spirochetes. Significant loss of cardiomyocytes with apoptosis and caspase activation was observed in the heart of immunosuppressed non-human primates infected with N40 and in B cell-deficient mice infected with B. turicatae. Unlike the heart, the brain of B cell-deficient mice infected with B. turicatae showed prominent microglial activation but no detectable tissue injury. Tissues from immunosuppressed non-human primates infected with N40 produce large amounts of immunoglobulin and the B cell chemokine CXCL13, both of which significantly correlate with the spirochetal load. We conclude that the main response of mammalian hosts in LD and RF is the production of specific antibody to clear the infection. Failure of this response leads to persistent infection, which can lead to tissue injury, most notably in the heart.

Cerebrospinal fluid-infiltrating CD4+ T cells recognize Borrelia burgdorferi lysine-enriched protein domains and central nervous system autoantigens in early lyme encephalitis

Neurological manifestations of Lyme disease are usually accompanied by inflammatory changes in the cerebrospinal fluid (CSF) and the recruitment of activated T cells into the CSF compartment. In order to characterize the phenotype and identify target antigens of CSF-infiltrating T cells in early neuroborreliosis with central nervous system (CNS) involvement, we combined T-cell cloning, functional testing of T-cell responses with positional scanning synthetic combinatorial peptide libraries, and biometric data analysis. We demonstrate that CD4+ gamma interferon-producing T cells specifically responding to Borrelia burgdorferi lysate were present in the CSF of a patient with acute Lyme encephalitis. Some T-cell clones recognized previously uncharacterized B. burgdorferi epitopes which show a specific enrichment for lysine, such as the heat shock-induced chaperone HSP90. Degenerate T-cell recognition that included T-cell responses to borrelia-specific and CNS-specific autoantigens derived from the myelin protein 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) could be demonstrated for one representative clone. Our results show that spirochetal antigen-specific and Th1-polarized CD4+ lymphocytes infiltrate the CSF during monophasic CNS symptoms of Lyme disease and demonstrate that cross-recognition of CNS antigens by B. burgdorferi-specific T cells is not restricted to chronic and treatment-resistant manifestations.

Longitudinal analysis of tick densities and Borrelia, Anaplasma, and Ehrlichia infections of Ixodes ricinus ticks in different habitat areas in The Netherlands

From 2000 to 2004, ticks were collected by dragging a blanket in four habitat areas in The Netherlands: dunes, heather, forest, and a city park. Tick densities were calculated, and infection with Borrelia burgdorferi and Anaplasma and Ehrlichia species was investigated by reverse line blot analysis. The lowest tick density was observed in the heather area (1 to 8/100 m2). In the oak forest and city park, the tick densities ranged from 26 to 45/100 m2. The highest tick density was found in the dune area (139 to 551/100 m2). The infection rates varied significantly for the four study areas and years, ranging from 0.8 to 11. 5% for Borrelia spp. and 1 to 16% for Ehrlichia or Anaplasma (Ehrlichia/Anaplasma) spp. Borrelia infection rates were highest in the dunes, followed by the forest, the city park, and heather area. In contrast, Ehrlichia/Anaplasma was found most often in the forest and less often in the city park. The following Borrelia species were found: Borrelia sensu lato strains not identified to the species level (2.5%), B. afzelii (2.5%), B. valaisiana (0.9%), B. burgdorferi sensu stricto (0.13%), and B. garinii (0.13%). For Ehrlichia/Anaplasma species, Ehrlichia and Anaplasma spp. not identified to the species level (2.5%), Anaplasma schotti variant (3.5%), Anaplasma phagocytophilum variant (0.3%), and Ehrlichia canis (0.19%) were found. E. canis is reported for the first time in ticks in The Netherlands in this study. Borrelia lusitaniae, Ehrlichia chaffeensis, and the human granylocytic anaplasmosis agent were not detected. About 1.6% of the ticks were infected with both Borrelia and Ehrlichia/Anaplasma, which was higher than the frequency predicted from the individual infection rates, suggesting hosts with multiple infections or a possible selective advantage of coinfection.

Interaction of a neurotropic strain of Borrelia turicatae with the cerebral microcirculation system

Relapsing fever (RF) is a spirochetal infection characterized by relapses of a febrile illness and spirochetemia due to the sequential appearance and disappearance of isogenic serotypes in the blood. The only difference between isogenic serotypes is the variable major outer membrane lipoprotein. In the absence of specific antibody, established serotypes cause persistent infection. Studies in our laboratory indicate that another consequence of serotype switching in RF is a change in neuroinvasiveness. As the next step to elucidate this phenomenon, we studied the interaction of the neurotropic Oz1 strain of the RF agent Borrelia turicatae with the cerebral microcirculation. During persistent infection of antibody-deficient mice, we found that serotype 1 entered the brain in larger numbers and caused more severe cerebral microgliosis than isogenic serotype 2. Microscopic examination revealed binding of B. turicatae to brain microvascular endothelial cells in vivo. In vitro we found that B. turicatae associated with brain microvascular endothelial cells (BMEC) significantly more than with fibroblasts or arachnoidal cells. The binding was completely eliminated by pretreatment of BMEC with proteinase K. Using transwell chambers with BMEC barriers, we found that serotype 1 crossed into the lower compartment significantly better than serotype 2. Heat killing significantly reduced BMEC crossing but not binding. We concluded that the interaction of B. turicatae with the cerebral microcirculation involves both binding and crossing brain microvascular endothelial cells, with significant differences among isogenic serotypes.

Persistent joint swelling and borrelia-specific antibodies in Borrelia garinii-infected mice after eradication of vegetative spirochetes with antibiotic treatment

We wanted to study the pathogenesis and the long-term manifestations of Borrelia garinii infection in SJL and C3H/He mice. We report here that B. garinii A218 causes a persisting infection in these mouse strains. Mice infected with intracutaneous inoculation of B. garinii at 4-5 weeks of age developed a disseminated infection and joint swelling within 2 weeks of inoculation and remained infected with joint symptoms until the end of follow-ups of up to 52 weeks. Treatment with ceftriaxone or ampicillin at 18 or 44 weeks of infection did not affect the joint swelling during the follow-ups of 19 and 8 weeks, respectively. However, B. garinii could not be cultured from any of the post mortem tissue samples of the treated mice, whereas the spirochete grew from samples of all untreated infected animals. Borrelia-specific IgG antibodies were detectable after 2 weeks of infection, and in late infection, all mice had high anti-borrelia IgG levels. Antibiotic treatment had no effect on antibody levels. Histology showed only slight changes in the joints of the infected mice with occasional lymphocyte infiltration, synovial proliferation and slight involvement of the Achilles' tendon. No difference was seen in the findings between ceftriaxone-treated and untreated mice. The results suggest that the presence of vegetative spirochetes is no prerequisite for persisting joint symptoms and elevated anti-borrelia IgG levels in these B. garinii-infected mice.

Mycosis fungoides: is it a Borrelia burgdorferi-associated disease?

Mycosis fungoides (MF) is the most frequently found cutaneous T-cell lymphoma with an unknown aetiology. Several aetiopathogenetic mechanisms have been postulated, including persistent viral or bacterial infections. We looked for evidence of Borrelia burgdorferi (Bb), the aetiologic agent of Lyme disease (LD), in a case study of MF patients from Northeastern Italy, an area with endemic LD. Polymerase chain reaction for the flagellin gene of Bb was used to study formalin-fixed paraffin-embedded lesional skin biopsies from 83 patients with MF and 83 sex- and age-matched healthy controls with homolocalised cutaneous nevi. Borrelia burgdorferi-specific sequence was detected in 15 out of 83 skin samples of patients with MF (18.1%), but in none out of 83 matched healthy controls (P<0.0001). The Bb positivity rates detected in this study support a possible role for Bb in the aetiopathogenesis of MF in a population endemic for LD.

Intrathecal antibody production in a mouse model of Lyme neuroborreliosis

Intrathecal antibody (ITAb) production is a common feature of neurological diseases, yet very little is known about its mechanisms. Because ITAb is prominent in human Lyme neuroborreliosis (LNB), in the present study we established a mouse model of LNB to study ITAb production. We injected different strains of Borrelia burgdorferi into a variety of mouse strains by the intracerebral (i.c.) route to develop the model. Spirochetal infection and ITAb production were identified by complementary methods. This study demonstrates that the mouse model of LNB can be utilized to test hypotheses related to the mechanisms of ITAb production.

Heterozygous Arg753Gln polymorphism of human TLR-2 impairs immune activation by Borrelia burgdorferi and protects from late stage Lyme disease

Lyme disease (LD) is caused by Borrelia burgdorferi and displays different stages, including localized, early disseminated, and persistent infection, all of which are associated with profound inflammatory reactions in the host. Induction of proinflammatory cytokines by B. burgdorferi is mainly mediated by outer surface proteins interacting with TLR-2/TLR-1 heterodimers. In this study, we show that TNF-alpha induction by Borrelia lysate was impaired in heterozygous TLR-2 knockout mice, while reactivity to lipoteichoic acid, another TLR-2 ligand signaling via TLR-2/TLR-6 heterodimers, was unaffected. Blood from individuals heterozygous for the TLR-2 polymorphism Arg753Gln was tested for cytokine release upon stimulation with Borrelia lysate, and induction of TNF-alpha and IFN-gamma was significantly lower as compared with individuals not exhibiting this variation. Overexpression of TLR-2 carrying the Arg753Gln polymorphism in HEK 293 cells led to a significantly stronger impairment of activation by TLR-2/TLR-1 ligands as compared with TLR-2/TLR-6 ligands. To study whether heterozygosity for the Arg753Gln variant of TLR-2 influenced susceptibility for LD, we analyzed 155 patients for this polymorphism. The Arg753Gln variant occurs at a significantly lower frequency in LD patients as compared with matched controls (5.8 vs 13.5%, odds ratio 0.393, 95% confidence interval 0.17-0.89, p = 0.033), with an even more pronounced difference when late stage disease was observed (2.3 vs 12.5%, odds ratio 0.163, 95% confidence interval 0.04-0.76, p = 0.018). These data suggest that Arg753Gln may protect from the development of late stage LD due to a reduced signaling via TLR-2/TLR-1.

The nervous system as ectopic germinal center: CXCL13 and IgG in lyme neuroborreliosis

Lyme neuroborreliosis (LNB) is a chronic infection in which B-cell activation, plasma cell infiltration, and enhanced Ig production in infected tissue are prominent feature. However, little is known about how B cells and plasma cells invade and persist in target organs. To assess this issue, we developed real-time PCR measurements of IgG and CXCL13 production. We used these RNA assays and specific enzyme-linked immunosorbent assays for protein and demonstrated that human peripheral blood mononuclear cells (PBMCs), stimulated by Borrelia burgdorferi sonicate, produced CXCL13 and IgG. Magnetic separation of PBMC populations and flow cytometry showed that CXCL13 is produced by dendritic cells. We then measure the expression of CXCL13 and IgG in tissues and correlated the expression of these host genes with spirochetal load. We also measured expression of dbpA and BBK32, two spirochetal genes important in chronic infection. There was a strong correlation between host immune response gene expression (CXCL13 and IgG) and spirochetal load. Immunohistochemistry of infected nonhuman primates tissue confirmed that CXCL13 is expressed in the nervous system. We conclude that persistent production of CXCL13 and IgG within infected tissue, two characteristics of ectopic germinal centers, are definitive features of LNB.

The Therapy of Lyme Neuroborreliosis

The challenge for the neurologist in the treatment of Lyme neuroborreliosis is not in the treatment per se, but in the diagnosis. Neurological manifestations of Lyme disease can present in many forms, and diagnostic techniques which detect the spirochete directly; the culture or polymerase chain reaction of the spirochete in cerebrospinal fluid, are of disappointingly low yield. Therefore, the diagnosis is frequently not easy. After the diagnosis is made, antibiotic therapy is straightforward; Lyme neuroborreliosis should be treated with at least 2 weeks of antibiotics. In the United States, intravenous therapy with ceftriaxone or penicillin for 2 weeks is the standard, whereas in Europe oral doxycycline therapy is commonly administered. Either is effective, and my choice of therapy generally depends on the patient. Many patients have symptoms which continue after antibiotic therapy referable to persistent inflammation, and, for those patients, I will commonly prescribe nonsteroidal anti-inflammatory medications.