Manifestations of Lyme carditis

The role of vector-borne pathogens and cardiac Striatin genotype on survival in boxer dogs with arrhythmogenic right ventricular cardiomyopathy

INTRODUCTION/OBJECTIVES

Risk factors for severe disease in boxer dogs with arrhythmogenic right ventricular cardiomyopathy (ARVC) are not well understood. This study's objective was to determine whether Striatin genotype or canine vector-borne pathogen (CVBP) exposure/infection in boxer dogs with ARVC was associated with disease severity or survival.

ANIMALS

Sixty-four client-owned, adult boxer dogs with ARVC were included in the study.

MATERIALS AND METHODS

This was a prospective descriptive study. Disease severity was determined by echocardiography and Holter monitoring. Potential risk factors included CVBP exposure/infection (Anaplasma spp., Babesia spp., Bartonella spp., Borrelia burgdorferi, Dirofilaria immitis, Ehrlichia spp., and Rickettsia spp.) and Striatin genotype.

RESULTS

The median survival time after enrollment was 270 days (95% confidence interval [CI]: 226-798 days), and the median age at the time of death or censoring was 11 years (95% CI: 10.3-11.7 years). Striatin mutation genotype results included 31 homozygous-negative, 26 heterozygous-positive, and seven homozygous-positive boxer dogs. Ten boxer dogs had exposure to Bartonella spp., four to Rickettsia, two to Ehrlichia spp., and one to Anaplasma spp. Striatin homozygous-positive boxer dogs had a shorter median survival time (93 days vs. 373 days for heterozygous [P=0.010] and 214 days for homozygous negative [P=0.036]). Exposure/infection to CVBP was not associated with median survival time or age at the time of death.

DISCUSSION

Striatin homozygous positive boxer dogs with ARVC had shorter survival times and were younger at the time of death. Exposure or infection with CVBP did not appear to influence survival time.

STUDY LIMITATIONS

Selection bias for more severe disease limited the ability to assess the relationship between CVBP infection/exposure and disease severity, and overall small sample size limited statistical power. Extracardiac disease and treatment protocols were not controlled.

CONCLUSIONS

Striatin genotype screening can be considered for prognostic information. Exposure/infection to CVBP appears unlikely to influence survival time for boxer dogs with ARVC.

Cardiac Manifestations of Lyme Disease

Lyme disease (LD) is an inflammatory disorder caused by an infectious bacterial agent and is the most common tick-borne illness in the United States and Europe. About 1.5-10% of adults infected with LD develop cardiac complications. This review summarizes the current knowledge of the epidemiology, pathophysiology, and diagnosis of Lyme carditis (LC), as well as the different manifestations of LD in the cardiovascular system. This review will primarily highlight the effect of LD on the cardiac conduction system and also discuss its effect on the myocardium, pericardium, valves, and coronary arteries. The management and prognosis of LC will be reviewed here as well. While this is a comprehensive review of the current literature on LC, there remain many questions regarding the complex relationship between LD and the heart.

Evidence for the Presence of Borrelia burgdorferi Biofilm in Infected Mouse Heart Tissues

Borrelia burgdorferi, the bacterium responsible for Lyme disease, has been shown to form antimicrobial-tolerant biofilms, which protect it from unfavorable conditions. Bacterial biofilms are known to significantly contribute to severe inflammation, such as carditis, a common manifestation of Lyme disease. However, the role of B. burgdorferi biofilms in the development of Lyme carditis has not been thoroughly investigated due to the absence of an appropriate model system. In this study, we examined heart tissues from mice infected with B. burgdorferi for the presence of biofilms and inflammatory markers using immunohistochemistry (IHC), combined fluorescence in situ hybridization FISH/IHC, 3D microscopy, and atomic force microscopy techniques. Our results reveal that B. burgdorferi spirochetes form aggregates with a known biofilm marker (alginate) in mouse heart tissues. Furthermore, these biofilms induce inflammation, as indicated by elevated levels of murine C-reactive protein near the biofilms. This research provides evidence that B. burgdorferi can form biofilms in mouse heart tissue and trigger inflammatory processes, suggesting that the mouse model is a valuable tool for future studies on B. burgdorferi biofilms.

A Comprehensive Review of Lyme Disease: A Focus on Cardiovascular Manifestations

Lyme disease is a tick-borne illness known for its ability to cause multi-systemic manifestations. It can affect several different systems, including neurological, musculoskeletal, and dermatological systems. However, one of the most concerning biological systems affected is the cardiac system. Lyme carditis typically presents with varying degrees of atrioventricular (AV) block. Additionally, current literature also endorses atypical manifestations, including but not limited to atrial fibrillation and bundle branch blocks. These atypical manifestations are important as they can be the first presenting symptoms in patients with Lyme disease. Therefore, educating clinicians on various signs, symptoms, and manifestations of Lyme carditis remains paramount in reducing morbidity and mortality. We conducted a literature review using PubMed, MEDLINE, and CINAHL, collecting a total of 13 articles to gather information on atypical manifestations of Lyme carditis. This literature review serves to summarize the current research and studies describing these cardiac manifestations and the cardiac pathophysiology associated with Lyme disease. These findings aim to contribute to the expanding understanding of Lyme carditis, subsequently preventing long-term effects through prompt diagnosis and treatment.

A Rare Presentation of Lyme Disease in an Immunocompromised Patient

Lyme disease is a progressive infectious disease caused by the Borrelia species that affects multiple organ systems, including the brain, heart, skin, and musculoskeletal systems. The cardiac manifestations of Lyme disease typically present with atrioventricular nodal conduction abnormalities and, more rarely, myocarditis. We report a case of an immunocompromised 57-year-old woman who presented with acute onset shortness of breath, hypervolemia, injective conjunctiva, and global vision loss of the left eye in the setting of a recent tick bite. Serologic testing confirmed borreliosis, and cardiac testing demonstrated acute isolated systolic heart failure without any cardiac conduction system abnormalities on the electrocardiogram. The diagnosis of Lyme carditis was made, and the patient was started on doxycycline with complete recovery of cardiac systolic function. This case demonstrates atypical cardiac manifestations of Lyme disease and highlights the difficulty in workup and understanding of Lyme carditis particularly in immunocompromised patients.

Paradigm shift in myocarditis treatment

Although most cases of myocarditis are self-limiting with a gradual improvement in cardiac function, the involvement of myocarditis in sudden cardiac death among children and young adults remains substantial, with rates of 3-17 % and 8.6-12 %, respectively. Moreover, the risk of developing chronic dilated cardiomyopathy ranges from 21 % to 30 % in all cases confirmed by biopsy. Current therapeutic strategies for myocarditis and its complications range from standard supportive care for heart failure and arrhythmias to etiologically oriented, case-based therapeutic options. For example, immunosuppression is indicated only in certain forms of acute myocarditis with clinical or endomyocardial biopsy evidence of immune checkpoint inhibitor-induced myocarditis and autoimmune diseases, including giant cell myocarditis, eosinophilic myocarditis, vasculitis, or cardiac sarcoidosis. However, our views on myocarditis treatment have changed considerably over the past two decades, thanks to the emergence of regenerative cells/tissues as well as drug and gene delivery systems. Cell-based therapies are now growing in popularity in any field of medicine. Studies evaluating the therapeutic efficacy of different stem cells in the treatment of acute myocarditis and its chronic complications have shown that although the experimental characteristics varied from study to study, in general, these strategies reduced inflammation and myocardial fibrosis while preventing myocarditis-induced systolic dysfunction and adverse remodeling in animal models.

Lyme-Associated Pericarditis: A Case Report and Literature Review

Lyme disease is caused by Borrelia burgdorferi (B. burgdorferi), which is a spirochete transmitted by ticks of the genus Ixodes. Complications related to the cardiovascular system usually occur in the early phase of infection, and the most common cardiovascular complication of Lyme disease is atrioventricular block, especially third-degree heart block. We report a case of a young Caucasian male patient who presented to the emergency department (ED) with complaints of chest pain and shortness of breath. Initial investigations, including chest X-ray, were negative. An EKG revealed ST elevation and PR depression with troponin elevation. The echocardiogram showed a normal ejection fraction with no pericardial effusion. Skin examination was positive for erythema migrans concerning Lyme. Initial Lyme testing was negative in the patient and it should be repeated after four to six weeks, according to the guidelines. This case report highlights the importance of keeping the differentials broad in these patients even if the initial testing is negative, especially since misdiagnosis or delayed diagnosis can cause cardiac complications.

Incidence of Lyme Carditis and Lyme Carditis as a Cause of Pacemaker Implantation: A Nationwide Registry-Based Case-Control Study

Background

Lyme borreliosis (LB) of the heart is called Lyme carditis (LC), which often manifests with high-grade atrioventricular block (AVB) requiring pacemaker implantation. LC is treated with antibiotics, and most patients recover fully after treatment. The overall incidence of LC, and of LC as a cause of pacemaker implantation, has not previously been systematically studied.

Methods

This was a case-control study based on data from Swedish national registers. The study was divided into two parts; part 1 including all patients diagnosed with AVB between 2001 and 2018, and part 2 including all patients who had received a pacemaker due to AVB between 2010 and 2018. Patients diagnosed with LB 90 days before and 180 days after the AVB diagnosis were identified among the patients and compared to matched control groups generated from the general population.

Results

Of 81 063 patients with AVB, 102 were diagnosed with LB. In the control group, 27 were diagnosed with LB. The yearly incidence of LC was 0.056 per 100 000 adults and year. Of 25 241 patients who had received a pacemaker for AVB, 31 were diagnosed with LB. In the control group, 8 were diagnosed with LB. The yearly incidence of LC as a cause of pacemaker implantation was 0.033 per 100 000 adults and year. The estimated risk for patients with LC to receive a permanent pacemaker was 59%.

Conclusions

LC is a rare cause of AVB. Nevertheless, more than half of patients with LC receive a permanent pacemaker for a condition that is easily cured with antibiotics.

A suspected case of Lyme disease causing complete heart block

Carditis is a rare complication of Lyme disease and usually presents in the early dissemination phase, several weeks after exposure to a tick bite. Conduction abnormalities are the most common manifestation of Lyme carditis. The presentation can vary from atrioventricular conduction delay (first-degree atrioventricular conduction block) to life-threatening situations, such as a complete heart block. Although such manifestations occur late, our case report describes an interesting case where the patient developed a complete heart block in the setting of acute Lyme disease. An elevated IgM with negative IgG Lyme serology titer, an unusual finding, initially led us to face a diagnostic dilemma. Our suspicion of a tick bite was affirmed when we detected a positive titer for Babesia microti, an organism carried by the same tick and a common co-infection with Lyme disease. The patient improved with antibiotic therapy and temporary pacemaker support during the initial few days of admission.

Lyme neuroborreliosis: A case report

Key Clinical Message

Lyme neuroborreliosis is the manifestation of Lyme borreliosis that impacts the nervous system. It gives rise to various neurological and psychiatric conditions, and its diagnosis is challenging. The timely administration of antibiotics is effective.

Abstract

A male patient, aged 55, was admitted to the emergency department due to the sudden onset of tonic-clonic seizures. All standard laboratory examinations yielded unremarkable outcomes, except a favorable Wright and 2-mercaptoethanol test. The examination of cerebrospinal fluid revealed the presence of 380 white blood cells per milliliter. The protein level was also elevated, while the glucose level was within the normal range. The results of the serologic tests indicated the presence of both IgG and IgM antibodies to Borrelia burgdorferi. Following the administration of ceftriaxone, a significant improvement was observed in the patient's medical status, and he was subsequently discharged. Lyme neuroborreliosis is the manifestation of Lyme borreliosis that impacts the nervous system. It gives rise to various neurological and psychiatric conditions, and its diagnosis is challenging. The timely administration of antibiotics is effective in treating patients.

SYNCOPE: A RARE PRESENTATION OF LYME DISEASE

BACKGROUND

Lyme disease is one of the most common vector-borne illnesses in the United States. It is caused by Borrelia burgdorferi infection transmitted via the Ixodes tick. Rarely, it can progress to early disseminated Lyme disease with cardiac or neurologic manifestations, or both.

CASE REPORT

A 41-year-old previously healthy man presented to the emergency department (ED) by ambulance after an episode of syncope. Electrocardiogram revealed right bundle branch block with borderline first-degree atrioventricular nodal block. During his admission he was noted to have night sweats and elevated procalcitonin. Infectious workup revealed positive Borrelia enzyme-linked immunosorbent assay. Further testing revealed positive Borrelia immunoglobulin M with negative immunoglobulin G, indicating a recent infection. Why should an emergency physician be aware of this? Lyme disease should be on the differential for patients presenting with vague, flu-like symptoms in the summer months in endemic areas. Treatment of early Lyme disease with doxycycline can prevent progression to secondary Lyme, which can present as a true cardiac or neurologic emergency.

Tick-Borne Myopericarditis With Positive Anaplasma, Lyme, and Epstein Barr Virus (EBV) Serology: A Case Report

Myopericarditis has been reported only rarely in those with anaplasmosis and is typically difficult to diagnose. Lyme carditis can also be difficult to diagnose as it is relatively rare but potentially fatal and usually has nonspecific manifestations. We are presenting a 61-year-old male patient who presented in New Jersey, United States with unremitting fever, chills, and myalgia for two weeks along with nausea, vomiting, and diarrhea. Investigations were suggestive of perimyocarditis as was indicated by diffuse ST segment elevation on electrocardiography (EKG) with the presence of small pericardial effusion on echocardiography. A mild troponin leakage was also seen. This progressed to septic shock that required vasopressor therapy. Further history-taking revealed recent tick exposure and prompted empirical initiation of doxycycline. This proved to be successful with fever defervescence and clinical improvement. Serological tests confirmed both acute Lyme and anaplasma infections along with positive serology of Epstein Barr virus (EBV). This case highlights an uncommon presentation of carditis in acute Lyme and anaplasma infections with the associated false-positive serology of EBV.

An Atypical Case of Lyme Disease Presenting With Lyme Carditis

Lyme carditis is a rare but serious manifestation of Lyme disease presenting in the early disseminated stage of the disease often after a diagnosis has already been discovered. The classic case of Lyme disease presents a patient who had been participating in outdoor activities in a Lyme-endemic region and was found to have a tick bite. These patients often present in the early localized stage, within the first 1-2 weeks with the well-recognized erythema-migrans rash or with generalized flu-like symptoms. Here we describe a case of a 70-year-old male who presented to the hospital without any typical Lyme disease prodrome but instead with generalized symptoms of progressive orthopnea and dyspnea on exertion. His original diagnoses were not of infectious origin however after incidentally being found to have a second degree, Mobitz type 1 atrioventricular (AV) block; Lyme tests were ordered, and a diagnosis was confirmed. This incidence shows the importance of having a Lyme disease diagnosis when regionally appropriate for patients who may present with no other signs or symptoms other than an AV block. As in this case, after a diagnosis has been made the management becomes the treatment of the infection rather than the treatment of the symptoms themselves.

Serologic Status of Borrelia burgdorferi sensu lato in Patients with Cardiovascular Changes

Cardiovascular diseases, particularly coronary heart disease (CHD) caused by atherosclerosis, have the highest worldwide incidence and mortality rate of any type of disease. Aside from risk factors associated with lifestyle and comorbidities, infectious agents such as Borrelia burgdorferi sensu lato spirochetes, which cause Lyme disease, may also play a role in the development of cardiovascular disease. A growing number of scientific papers have mentioned Lyme carditis. The aim of this study was to find the level of anti-Borrelia IgG antibodies in the blood serum of patients with advanced coronary heart disease. Materials and methods: The study group included 70 patients undergoing coronary artery bypass grafting (CABG) and off-pump coronary artery bypass (OPCAB) surgery aged 50 to 82 (average 68.26). The ELISA test was used to detect anti-Borrelia/IgG antibodies in the blood serum. Serological testing revealed seropositivity in 34.29% of patients and 'borderline results' in 17.14% of patients. We found a link between antibody levels and tick bites but not with other risk factors for the development of CHD. Conclusions: These findings support the idea that, as one of many factors, the contact with spirochetal antigens may indicate a potential positive correlation with the formation of cardiovascular changes. More research, not only at the diagnostic level but also at the advanced research level, is needed.

Lyme Carditis Presenting With Complete Heart Block and Wide Complex Escape Rhythm

A 19-year-old woman with newly diagnosed Lyme disease presented with complete heart block and an accompanying escape rhythm with a right bundle branch block morphology. With antibiotics, her dysrhythmia resolved completely within 24 hours of presentation. This case highlights an unusual electrocardiographic manifestation of Lyme carditis.

Infection with Borrelia burgdorferi Increases the Replication and Dissemination of Coinfecting Powassan Virus in Ixodes scapularis Ticks

Powassan virus (POWV) is a tick-borne neuroinvasive flavivirus endemic to North America. It is generally transmitted by the tick, Ixodes scapularis. This species also transmits Borrelia burgdorferi, the causative agent of Lyme disease. Infection with B. burgdorferi can result in arthritis, carditis, and neuroborreliosis. These pathogens experience sylvatic overlap. To determine the risk of human exposure to coinfected ticks, the interactions between POWV and B. burgdorferi are assessed in laboratory-infected I. scapularis. Adult male and female I. scapularis ticks are orally inoculated with either both pathogens, POWV only, B. burgdorferi only, or uninfected media. After twenty-one days, the ticks are dissected, and RNA is extracted from their midguts and salivary glands. In infected midguts, the quantity of POWV in coinfected ticks was elevated compared to those with only POWV. In addition, the salivary glands of ticks with infected midguts had increased POWV dissemination to those with only POWV. RNA sequencing is performed to identify the potential mechanism for this pattern, which varies between the organs. Ixodes scapularis ticks are found to be capable of harboring both POWV and B. burgdorferi with a benefit to POWV replication and dissemination.

Neurological Pain, Psychological Symptoms, and Diagnostic Struggles among Patients with Tick-Borne Diseases

Public health reports contain limited information regarding the psychological and neurological symptoms of tick-borne diseases (TBDs). Employing a mixed-method approach, this analysis triangulates three sources of symptomology and provides a comparison of official public health information, case reports, medical literature, and the self-reported symptoms of patients with Lyme disease and other TBDs. Out of the fifteen neuropsychiatric symptoms reported in the medical literature for common TBDs, headaches and fatigue and/or malaise are the only two symptoms fully recognized by public health officials. Of TBDs, Lyme disease is the least recognized by public health officials for presenting with neuropsychiatric symptoms; only headaches and fatigue are recognized as overlapping symptoms of Lyme disease. Comparisons from a patient symptoms survey indicate that self-reports of TBDs and the associated symptoms align with medical and case reports. Anxiety, depression, panic attacks, hallucinations, delusions, and pain—ranging from headaches to neck stiffness and arthritis—are common among patients who report a TBD diagnosis. Given the multitude of non-specific patient symptoms, and the number and range of neuropsychiatric presentations that do not align with public health guidance, this study indicates the need for a revised approach to TBD diagnosis and for improved communication from official public health sources regarding the wide range of associated symptoms.

Lyme Carditis: From Pathophysiology to Clinical Management

Cardiac involvement is a rare but relevant manifestation of Lyme disease that frequently presents as atrioventricular block (AVB). Immune-mediated injury has been implicated in the pathogenesis of Lyme carditis due to possible cross-reaction between Borrelia burgdorferi antigens and cardiac epitopes. The degree of the AVB can fluctuate rapidly, with two-thirds of patients progressing to complete AVB. Thus, continuous heart rhythm monitoring is essential, and a temporary pacemaker may be necessary. Routinely permanent pacemaker implantation, however, is contraindicated because of the frequent transient nature of the condition. Antibiotic therapy should be initiated as soon as the clinical suspicion of Lyme carditis arises to reduce the duration of the disease and minimize the risk of complications. Diagnosis is challenging and is based on geographical epidemiology, clinical history, signs and symptoms, serological testing, ECG and echocardiographic findings, and exclusion of other pathologies. This paper aims to explain the pathophysiological basis of Lyme carditis, describe its clinical features, and delineate the treatment principles.

Cat Ownership and Rural Residence Are Associated with Lyme Disease Prevalence in the Northeastern United States

Lyme disease (LD) is the most common vector-borne disease in the USA. Beyond its tick-borne nature, however, risk factors for LD are poorly understood. We used an online questionnaire to compare LD patients and non-LD counterparts and elucidate factors associated with LD. We investigated demographic, lifestyle, and household characteristics and use of prevention measures. Associations with LD were modeled using logistic regression, and average marginal effects were estimated. In total, 185 active or past LD patients and 139 non-patients participated. The majority of respondents were white (95%) and female (65%). Controlling for age, sex, and type of residential area, pet ownership was associated with an 11.1% (p = 0.038) increase in the probability of LD. This effect was limited to cat owners (OR: 2.143, p = 0.007; dog owners, OR: 1.398, p = 0.221). Living in rural areas was associated with a 36% (p = 0.001) increase in the probability of LD compared to living in an urban area. Participants who reported knowing someone with Lyme Disease were more likely to wear insect repellant and perform tick checks. This study suggests opportunities for improved LD prevention, including advising cat owners of their increased risk. Although patterns in adoption of LD prevention methods remain poorly understood, concern about LD risk does motivate their use.

A Case of Lyme Carditis With Variable Heart Block Successfully Treated With Oral Doxycycline

A 39-year-old male without significant past medical history presented with three weeks of worsening fatigue, migratory arthralgia, rash, and unilateral facial weakness after spending three months in Vermont. Serology showed positive Lyme titers 1:64 for both IgM and IgG. EKG on presentation showed a P-R interval of 384 ms, and the patient was admitted for concern of Lyme carditis. Serial EKGs obtained throughout his stay demonstrated variability between first- and second-degree heart blocks. After consultation with Infectious Disease, he was transitioned to oral doxycycline to complete a 21-day course. The patient’s heart block and other symptoms had resolved on follow-up after the treatment course had been completed.

Fulminant Lyme myocarditis without any other signs of Lyme disease in a 37-year-old male patient with microscopic polyangiitis-a case report

Background

Lyme disease is a tick-borne multisystem infection. The most common cardiac manifestation is an acute presentation of Lyme carditis, which often manifests as conduction disorder and rarely as myocarditis.

Case summary

We report the case of a 37-year-old male with a history of microscopic polyangiitis receiving immunosuppressive therapy. He was admitted for severe dyspnoea secondary to acute heart failure. Echocardiography and cardiac magnetic resonance imaging indicated a severely reduced left ventricular ejection fraction (LVEF) with global hypokinesia. Coronary heart disease was excluded, and endomyocardial biopsies (EMB) were performed. The left ventricular EMB revealed a rare case of fulminant Lyme carditis with evidence of typical lymphocytic myocarditis. Borrelia afzelii-DNA was detected without any relevant atrioventricular blockage or systemic signs of Lyme disease. The patient had no clinically apparent tick-borne infection or self-reported history of a tick bite. Immunological testing revealed a positive ELISA and Immunoblot for anti-Borrelia immunoglobulin G antibodies. After specific intravenous antibiotic therapy and optimized medical therapy for heart failure, the LVEF recovered, and the patient could be discharged in an improved condition. Repeat EMB a few months later revealed a dramatic regression of the cardiac inflammation and absence of Borrelia DNA in the myocardium.

Discussion

A severely reduced LVEF can be the primary manifestation of Lyme disease even without typical systemic findings and can have a favourable prognosis with antibiotic treatment. A thorough workup for Lyme carditis is required in patients with unexplained heart failure, particularly with EMB, especially in immunosuppressed patients.

Tick magnets: The occupational risk of tick-borne disease exposure in forestry workers in New York

BACKGROUND

Outdoor workers, such as forestry workers, are at an increased risk for contracting tick-borne diseases due to their prolonged time spent in tick habitats. Although well studied in Europe, no studies have been conducted with forestry workers in the Northeastern United States since 1990s.

METHODS

Full-time forestry workers and two comparison groups (volunteer firefighter/first responders and indoor/healthcare workers) within New York State Department of Environmental Conservation Regions 3, 4, 5, 6, and 7 were recruited for this cross-sectional seroprevalence study. Blood draws were conducted to test for antibodies to Lyme, anaplasmosis, babesiosis, and ehrlichiosis. Surveys were administered to determine personal risk factors and protective behaviors.

RESULTS

Between November 2020 and May 2021, 256 (105 forestry, 101 firefighter/first responder, and 50 indoor/healthcare) workers participated in this study. Forestry workers had a probability of testing positive nearly twice as high for any tick-borne disease (14%) compared to firefighter/first responders (8%) and to indoor workers (6%); however, this difference was not statistically significant (P = .140). Forestry workers were more likely to find embedded ticks on themselves (f = 33.26, P < .0001 vs both comparison groups) and to have been previously diagnosed with a tick-borne disease (P = .001 vs firefighter/first responders, P = .090 vs indoor/healthcare workers).

CONCLUSIONS

This pilot study suggests a higher proportion of tick-borne disease risk among forestry workers compared to firefighters/first responders and indoor/healthcare workers with lesser exposure. A larger study to confirm or refute this pilot data could help optimize mitigation/prevention strategies.

Lyme Carditis Manifesting as Wenckebach Heart Block

Lyme disease caused by Borrelia burgdorferi is a multisystem disease and can lead to Lyme carditis. The most common presentation of Lyme carditis is conduction system disturbances such as atrioventricular (AV) block. A 72-year-old male with a past medical history of gastroesophageal reflux disease (GERD) and prostate cancer presented with chest tightness, lightheadedness, and presyncope. During hospitalization, he developed bradycardia with heart rates ranging between 30 and 40 beats per minute and Wenckebach heart block. Lyme serology was consistent with a recent Lyme infection. He was treated with antibiotics and was eventually discharged home without requiring pacemaker implantation.

The burden of zoonoses in Paraguay: A systematic review

INTRODUCTION

Underestimation of zoonoses is exacerbated in low and middle-income countries due mainly to inequalities with serious consequences in healthcare. This is difficult to gauge and reduce the impact of those diseases. Our study focuses on Paraguay, where the livestock industry is one of the major components of the country's economy. Therefore, the rationale of this study was to develop a case study in Paraguay to estimate the dual impact of zoonotic diseases on both the human health and animal health sector and thus determine the societal burden of such diseases.

METHODOLOGY/PRINCIPAL FINDINGS

We conducted a systemic review (including a meta-analysis) to assess the burden of zoonoses in Paraguay, including official reports and grey literature of disease incidence and prevalence. We estimated the Disability Adjusted Life Years (DALYs) and Zoonosis Disability Adjusted Life Years (zDALYs) to measure the difference between the current health status and the desired health situation of animals and the Paraguayan population based on 50 zoonotic diseases suggested by the WHO (World Health Organization), OIE (World Organization for Animal Health) and the National Health in Paraguay. The total DALYs represent 19,384 (95% CI: from 15,805 to 29,733), and zDALYs, 62,178 (95% CI: from 48,696 to 77,188). According to the results, the priority pathogens for DALYs are E. coli, Trypanosoma cruzi, Leishmania spp, and Toxoplasma gondii. When we include the additional animal health burden, the most important pathogens are Brucella spp, E. coli, Trypanosoma cruzi, and Fasciola hepatica for zDALYs.

CONCLUSION/SIGNIFICANCE

This is the first study to integrate DALYs and zDALYs with important clues related to the health status of Paraguay. Through DALYs and zDALYs, our perspective becomes more complete because we consider not only human health but also animal health. This is important for setting priorities in disease control, especially in a society where livestock contribute significantly to the economy and to human well-being.

Multiple roles of cardiac macrophages in heart homeostasis and failure

Macrophages are essential components of the immune system and play a role in the normal functioning of the cardiovascular system. Depending on their origin and phenotype, cardiac macrophages perform various functions. In a steady-state, these cells play a beneficial role in maintaining cardiac homeostasis by defending the body from pathogens and eliminating apoptotic cells, participating in electrical conduction, vessel patrolling, and arterial tone regulation. However, macrophages also take part in adverse cardiac remodeling that could lead to the development and progression of heart failure (HF) in such HF comorbidities as hypertension, obesity, diabetes, and myocardial infarction. Nevertheless, studies on detailed mechanisms of cardiac macrophage function are still in progress, and could enable potential therapeutic applications of these cells. This review aims to present the latest reports on the origin, heterogeneity, and functions of cardiac macrophages in the healthy heart and in cardiovascular diseases leading to HF. The potential therapeutic use of macrophages is also briefly discussed.

Diagnosis, treatment and predictors of prognosis of myocarditis. A narrative review

Although it has been recognized for almost two centuries, myocarditis is still a challenging diagnosis due to the wide heterogeneity of its clinical manifestations and evolution. Moreover, the diagnostic gold standard, endomyocardial biopsy (EMB), is infrequently used, making hard to determine the exact incidence of myocarditis. Clinical presentation includes a wide range of symptoms, ranging from asymptomatic or subclinical disease with mild dyspnea and chest pain to sudden death, due to cardiogenic shock or malignant ventricular arrhythmias. Equally, the evolution of myocarditis largely varies: albeit short-term prognosis is usually good, with complete or partial recovery, dilated cardiomyopathy with chronic heart failure is the major long-term consequence of myocarditis, developing often several years after the acute onset. This narrative review aims to summarize the current knowledge about myocarditis, with a particular attention to predictors of short- and long-term prognosis, in order to provide a rational and practical approach to the diagnosis, evaluation and treatment of suspected myocarditis.

Lyme Disease among Patients at an Ambulatory Unit in a Highly Endemic Country: Lithuania

Background and objectives: Lyme disease is the most common tick-borne infectious disease in Europe, caused by the spirocheta bacteria of Borrelia burgdorferi. Several genospecies of B. burgdorferi are pathogenic to humans. B. burgdorferi sensu stricto, which is prevalent in North America, causes reactive arthritis, whereas B. garinii and B. afzelii, common in Europe, can affect the skin, heart, or nervous system; it has been shown that the clinical symptoms of the disease may be very different. The objective of this study was to identify the baseline characteristics of Lyme disease and to elucidate the frequency of different Lyme disease syndromes in Lithuania. Materials and Methods: Patients who were diagnosed with Lyme disease during an ambulatory visit to the Center of Infectious Diseases, Vilnius University Santaros clinics, from 2014 to 2016, were enrolled in this study. A retrospective material analysis was conducted. Results: In total, 1005 patients were enrolled with the following prevalence of clinical syndromes: erythema migrans (EM), 945 (94.02%); Lyme arthritis, 32 (3.18%); neuroborreliosis, 23 (2.28%); Lyme carditis, 4 (0.39%); and acrodermatitis, 1 (0.09%). Erythema migrans was dominant among middle-aged women, with a rash appearing mainly on the lower extremities. Lyme arthritis mainly manifested among middle-aged women as an oligoarthritis, mostly affecting the knee joint. Neuroborreliosis was seen more often in middle-aged women than men and the main symptom was nervus facialis neuropathy. Lyme carditis, manifested as an atrioventricular block, with a male/female ratio of 3:1, and the median age was 51. Acrodermatitis was diagnosed in a 61-year-old woman, as a painful, red rash on the hand. Conclusions: According to the prevalence of B. garinii and B. afzelii in Europe, previously it was thought that Lyme disease presented as erythema migrans, and less frequently as neuroborreliosis; however, this study revealed that other syndromes may also be seen. In addition, we revealed that the longer it takes for erythema migrans to appear, the greater the likelihood of Lyme arthritis developing.

Borrelia burgdorferi infection induces long-term memory-like responses in macrophages with tissue-wide consequences in the heart

Lyme carditis is an extracutaneous manifestation of Lyme disease characterized by episodes of atrioventricular block of varying degrees and additional, less reported cardiomyopathies. The molecular changes associated with the response to Borrelia burgdorferi over the course of infection are poorly understood. Here, we identify broad transcriptomic and proteomic changes in the heart during infection that reveal a profound down-regulation of mitochondrial components. We also describe the long-term functional modulation of macrophages exposed to live bacteria, characterized by an augmented glycolytic output, increased spirochetal binding and internalization, and reduced inflammatory responses. In vitro, glycolysis inhibition reduces the production of tumor necrosis factor (TNF) by memory macrophages, whereas in vivo, it produces the reversion of the memory phenotype, the recovery of tissue mitochondrial components, and decreased inflammation and spirochetal burdens. These results show that B. burgdorferi induces long-term, memory-like responses in macrophages with tissue-wide consequences that are amenable to be manipulated in vivo.

Lyme carditis is a manifestation of Lyme disease characterized by episodes of atrioventricular block and additional cardiomyopathies. This study describes the proteomic and transcriptomic changes in the heart upon infection with Borrelia burgdorferi, and identifies innate immune memory hallmarks specific to the response to the spirochete that are amenable to therapeutic manipulation.

An ultra-high-density protein microarray for high throughput single-tier serological detection of Lyme disease

Current serological immunoassays have inherent limitations for certain infectious diseases such as Lyme disease, a bacterial infection caused by Borrelia burgdorferi in North America. Here we report a novel method of manufacturing high-density multiplexed protein microarrays with the capacity to detect low levels of antibodies accurately from small blood volumes in a fully automated system. A panel of multiple serological markers for Lyme disease are measured using a protein microarray system, Lyme Immunochip, in a single step but interpreted adhering to the standard two-tiered testing algorithm (enzyme immunoassay followed by Western blot). Furthermore, an enhanced IgM assay was supplemented to improve the test's detection sensitivity for early Lyme disease. With a training cohort (n = 40) and a blinded validation cohort (n = 90) acquired from CDC, the Lyme Immunochip identified a higher proportion of Lyme disease patients than the two-tiered testing (82.4% vs 70.6% in the training set, 66.7% vs 60.0% in the validation set, respectively). Additionally, the Immunochip improved sensitivity to 100% while having a lower specificity of 95.2% using a set of investigational antigens which are being further evaluated with a large cohort of blinded samples from the CDC and Columbia University. This universal microarray platform provides an unprecedented opportunity to resolve a broad range of issues with diagnostic tests, including multiplexing, workflow simplicity, and reduced turnaround time and cost.

Third-Degree Atrioventricular Block as the Initial Presentation of Lyme Disease

Lyme disease is a multisystemic infection that can present as localized disease, early disseminated, or late disease. During the early disseminated phase of Lyme disease, the hematogenous spread can result in extracutaneous manifestations, including cardiac, neurological, and joint. Lyme carditis is an uncommon manifestation occurring in patients with untreated Lyme disease. Third-degree atrioventricular (AV) block is a rarer entity. We present a case of a 21-year-old female with no significant past medical history admitted with third-degree AV block and thereby highlighting this uncommon presentation. 

A Practical Approach to the Diagnosis of Lyme Borreliosis: From Clinical Heterogeneity to Laboratory Methods

Clinical evaluation of Lyme Borreliosis (LB) is the starting point for its diagnosis. The patient's medical history and clinical symptoms are fundamental for disease recognition. The heterogeneity in clinical manifestations of LB can be related to different causes, including the different strains of Borrelia, possible co-infection with other tick transmitted pathogens, and its interactions with the human host. This review aims at describing the heterogeneous symptoms of Lyme Borreliosis, as well as offering a practical approach for recognition of the disease, both in terms of clinical features and diagnostic/research tools.

Early Disseminated Lyme Carditis Inducing High-Degree Atrioventricular Block

Lyme disease is the most common tick-borne illness in the United States due to Borrelia burgdorferi infection. This case demonstrates a 20-year-old male patient presenting with complaints of annular skin rash, malaise, fever, and lightheadedness after significant outdoor exposure. Physical exam revealed multiple large targetoid lesions on the back and extremities. The rash had raised borders and centralized clearing consistent with erythema migrans chronicum. Electrocardiogram (ECG) revealed a high-degree atrioventricular (AV) block. The patient was started on intravenous ceftriaxone due to clinical suspicion for Lyme carditis. ELISA and Western blot tests were reactive for Lyme IgM and IgG, confirming the diagnosis. The AV block resolved by hospital day four and the patient was discharged with outpatient follow-up. Early identification of disease allowed for effective treatment with no adverse outcomes or sequelae.

History of Lyme Disease as a Predictor of Atrial Fibrillation

In many cases, atrial fibrillation (AF) is associated with a history of cardiac inflammation. One of the potential pathogens responsible for atrial inflammation might be Borrelia burgdorferi - a pathogen involved in Lyme carditis. This study aimed to assess whether the serological history of Borrelia infection was associated with the risk of AF. The study included 113 AF patients and 109 patients in sinus rhythm. All patients underwent a clinical evaluation, echocardiography and had their blood taken for the assessment of anti-Borrelia IgG antibodies. Patients with AF compared with the non-AF group had more often serological signs of Borrelia infection (34.5% vs 6.4%; p <0.0001). The multivariate analysis showed that positive results for anti-Borrelia IgG antibodies were a strong independent predictor of AF (odds ratio 8.21; 95% confidence interval 3.08 to 21.88; p < 0.0001). In conclusion, presented data show that exposure to Borrelia spp. infection is associated with an increased risk of AF. Whether the early treatment of Lyme disease lowers the risk of AF development remains to be explored.

Lyme Endocarditis as an Emerging Infectious Disease: A Review of the Literature

Lyme endocarditis is extremely rare manifestation of Lyme disease. The clinical manifestations of Lyme endocarditis are non-specific and can be very challenging diagnosis to make when it is the only manifestation of the disease. Until now, only a few cases where reported. Physicians should keep in mind the possibility of borrelial etiology of endocarditis in endemic areas. Appropriate valve tissue sample should be sent for histopathology, culture, and PCR especially in case of endocarditis of unknown origin PCR on heart valve samples is recommended. With more frequent PCR, Borrelia spp. may be increasingly found as a cause of infective endocarditis. Prompt diagnosis and treatment of Lyme carditis may prevent surgical treatment and pacemaker implantations. Due to climate change and global warming Lyme disease is a growing problem. Rising number of Lyme disease cases we can expect and rising number of Lyme endocarditis.

Diagnosis and Treatment of Lyme Carditis: JACC Review Topic of the Week

The incidence of Lyme disease, a tick-borne bacterial infection, is dramatically increasing in North America. The diagnosis of Lyme carditis (LC), an early disseminated manifestation of Lyme disease, has important implications for patient management and preventing further extracutaneous complications. High-degree atrioventricular block is the most common presentation of LC, and usually resolves with antibiotic therapy. A systematic approach to the diagnosis of LC in patients with high-degree atrioventricular block will facilitate the identification of this usually transient condition, thus preventing unnecessary implantation of permanent pacemakers in otherwise healthy young individuals.

Lyme aortitis

A 72-year-old man was admitted with complaints of sudden-onset oppressive precordial pain radiating to the back for 1 hour. He had hypotension, peripheral cyanosis and cold extremities. An initial assessment was done and acute coronary syndrome was excluded. After the patient was admitted, he developed fever and increased levels of inflammatory markers. Data obtained from CT angiography and transoesophageal echocardiogram revealed diffuse parietal thickening of the arch and the descending thoracic aorta, as well as dilatation of the aortic root and the proximal ascending aorta. In addition, the test for Borrelia burgdorferi was positive, and the patient was diagnosed with Lyme vasculitis of the thoracic aorta. He was treated with doxycycline for 3 weeks. Two months later, the patient exhibited a Stanford type A aortic dissection (clinically stable), which was treated by prosthesis replacement. The patient has remained asymptomatic for 1 year after the episode, performing his routine daily activities.

Powassan virus encephalitis, severe babesiosis and lyme carditis in a single patient

Ixodes scapularis is responsible for transmission of Borrelia burgdorferi, B. miyamotoi, Babesia microti, Anaplasma phagocytophilum and Powassan virus to humans. We present a case of an 87-year-old man who presented with fever and altered mental status. Initial workup revealed haemolytic anaemia, thrombocytopenia, mild hepatitis and acute kidney injury. Patient tested positive for B. burgdorferi and Babesia microti, and was started on doxycycline, atovaquone and azithromycin. He also underwent exchange transfusion twice. After some initial improvement, patient had acute deterioration of mental status and appearance of neurological findings like myoclonus and tremors. Therefore, testing for arboviruses was done and results were positive for Powassan virus. During a protracted course of hospitalisation, patient required intubation for respiratory failure and temporary pacemaker for unstable arrythmias from Lyme carditis. Patient developed permanent neurological deficits even after recovery from the acute illness.

Myocarditis in Humans and in Experimental Animal Models

Myocarditis is defined as an inflammation of the cardiac muscle. In humans, various infectious and non-infectious triggers induce myocarditis with a broad spectrum of histological presentations and clinical symptoms of the disease. Myocarditis often resolves spontaneously, but some patients develop heart failure and require organ transplantation. The need to understand cellular and molecular mechanisms of inflammatory heart diseases led to the development of mouse models for experimental myocarditis. It has been shown that pathogenic agents inducing myocarditis in humans can often trigger the disease in mice. Due to multiple etiologies of inflammatory heart diseases in humans, a number of different experimental approaches have been developed to induce myocarditis in mice. Accordingly, experimental myocarditis in mice can be induced by infection with cardiotropic agents, such as coxsackievirus B3 and protozoan parasite Trypanosoma cruzi or by activating autoimmune responses against heart-specific antigens. In certain models, myocarditis is followed by the phenotype of dilated cardiomyopathy and the end stage of heart failure. This review describes the most commonly used mouse models of experimental myocarditis with a focus on the role of the innate and adaptive immune systems in induction and progression of the disease. The review discusses also advantages and limitations of individual mouse models in the context of the clinical manifestation and the course of the disease in humans. Finally, animal-free alternatives in myocarditis research are outlined.

A Case of Lyme Carditis Presenting with Atrial Fibrillation

We report a case of a 20-year-old man who presented to our institution with a new arrhythmia on a routine EKG. Serial EKG tracings revealed various abnormal rhythms such as episodes of atrial fibrillation, profound first degree AV block, and type I second degree AV block. He was found to have positive serologies for Borrelia burgdorferi. After initiation of antibiotic therapy, the atrial arrhythmias and AV block resolved. Here, we present a case of Lyme carditis presenting with atrial fibrillation, a highly unusual presentation of Lyme carditis.