Surveillance of Lyme disease in the United States, 1982

Self-reported tick exposure as an indicator of Lyme disease risk in an endemic region of Quebec, Canada

BACKGROUND

Lyme disease (LD) and other tick-borne diseases are emerging across Canada. Spatial and temporal LD risk is typically estimated using acarological surveillance and reported human cases, the former not considering human behavior leading to tick exposure and the latter occurring after infection.

OBJECTIVES

The primary objective was to explore, at the census subdivision level (CSD), the associations of self-reported tick exposure, alternative risk indicators (predicted tick density, eTick submissions, public health risk level), and ecological variables (Ixodes scapularis habitat suitability index and cumulative degree days > 0 °C) with incidence proportion of LD. A secondary objective was to explore which of these predictor variables were associated with self-reported tick exposure at the CSD level.

METHODS

Self-reported tick exposure was measured in a cross-sectional populational health survey conducted in 2018, among 10,790 respondents living in 116 CSDs of the Estrie region, Quebec, Canada. The number of reported LD cases per CSD in 2018 was obtained from the public health department. Generalized linear mixed-effets models accounting for spatial autocorrelation were built to fulfill the objectives.

RESULTS

Self-reported tick exposure ranged from 0.0 % to 61.5 % (median 8.9 %) and reported LD incidence rates ranged from 0 to 324 cases per 100,000 person-years, per CSD. A positive association was found between self-reported tick exposure and LD incidence proportion (ß = 0.08, CI = 0.04,0.11, p < 0.0001). The best-fit model included public health risk level (AIC: 144.2), followed by predicted tick density, ecological variables, self-reported tick exposure and eTick submissions (AIC: 158.4, 158.4, 160.4 and 170.1 respectively). Predicted tick density was the only significant predictor of self-reported tick exposure (ß = 0.83, CI = 0.16,1.50, p = 0.02).

DISCUSSION

This proof-of-concept study explores self-reported tick exposure as a potential indicator of LD risk using populational survey data. This approach may offer a low-cost and simple tool for evaluating LD risk and deserves further evaluation.

A Case of Anaplasmosis during a Warm Minnesota Fall

A healthy 33 year old male presented in December with a 3 week history of fever and fatigue. He had been deer-hunting in northern Minnesota 1 month prior and had sustained a tick bite. Extensive laboratory investigations and a lumbar puncture were conducted. He was empirically with doxycycline and had rapid improvement in his symptoms. Subsequently, PCR and serologic testing returned positive for Anaplasma phagocytophlium. Anaplasmosis is a tick-borne illness caused by the bacterium Anaplasma phagocytophilum and is typically seen in the warmer months. This patient’s presentation in December was uncommon for a tick-borne illness in Minnesota. Regional weather records demonstrated unseasonably warm temperatures during the patient’s trip. Ixodes ticks are known to be sensitive to temperature and humidity, which likely contributed to increased tick activity, leading to disease transmission. This case highlights the importance for clinicians to be aware of local weather patterns and how this might influence seasonal disease presentations.

Increasing Burden of Lyme Carditis in United States Children's Hospitals

We sought to characterize the shifting epidemiology and resource utilization of Lyme disease and associated carditis in US children's hospitals. We hypothesized that the Lyme carditis burden has increased and that hospitalizations for Lyme carditis are costlier than those for Lyme disease without carditis. The PHIS database was queried for Lyme disease encounters between January 1, 2007 and December 31, 2013. Additional diagnostic codes consistent with carditis identified Lyme carditis cases. Demographic, clinical, and resource utilization data were analyzed. All costs were adjusted to 2014 US dollars. Lyme disease was identified in 3620 encounters with 189 (5%) associated with carditis. Lyme disease (360 cases in 2007 vs. 672 in 2013, p = 0.01) and Lyme carditis (17 cases in 2007 vs. 40 in 2013, p = 0.03) both significantly increased in frequency. This is primarily accounted for by their increase within the Midwest region. Carditis frequency among cases of Lyme disease was stable (p = 0.15). Encounters for Lyme carditis are dramatically costlier than those for Lyme disease without carditis [median $9104 (3741-19,003) vs. 922 (238-4987), p < 0.001] The increase in Lyme carditis cases in US children's hospitals is associated with an increased Lyme disease incidence, suggesting that there has not been a change in its virulence or cardiac tropism. The increasing number of serious cardiac events and costs associated with Lyme disease emphasize the need for prevention and early detection of disease and control of its spread.

Leveraging the Expertise of the New Jersey Mosquito Control Community to Jump Start Standardized Tick Surveillance

Despite the rising incidence of tick-borne diseases (TBD) in the northeastern United States (US), information and expertise needed to assess risk, inform the public and respond proactively is highly variable across states. Standardized and well-designed tick surveillance by trained personnel can facilitate the development of useful risk maps and help target resources, but requires nontrivial start-up costs. To address this challenge, we tested whether existing personnel in New Jersey’s 21 county mosquito control agencies could be trained and interested to participate in a one-day collection of American dog ticks (Dermacentor variabilis), a presumably widespread species never before surveyed in this state. A workshop was held offering training in basic tick biology, identification, and standard operating procedures (SOPs) for surveillance, followed by a one-day simultaneous collection of D. variabilis across the state (the “NJ Tick Blitz”). In total, 498 D. variabilis were collected from 21 counties and follow-up participant surveys demonstrated an increase in knowledge and interest in ticks: 41.7% of respondents reported collecting ticks outside the Tick Blitz. We hope that the success of this initiative may provide a template for researchers and officials in other states with tick-borne disease concerns to obtain baseline tick surveillance data by training and partnering with existing personnel.

Lyme disease: why the controversy?

Some Australians have become convinced of the existence of locally acquired Lyme disease (LD). The history of LD, since its recognition in the early 1970s, is reviewed as a model for investigative approaches to unknown syndromes. Australian Management Guidelines for LD include the requirement for diagnostic testing by National Association of Testing Authorities-accredited laboratories using Therapeutic Goods Administration-licensed tests, which result in the efficient diagnosis of LD in overseas travellers. Despite this, patients who have not left Australia pay many thousands of dollars for non-specialist consultations and testing at overseas laboratories. Unproven long-term therapy with multiple antibiotics has resulted in serious complications, including allergies, line sepsis, pancreatitis and pseudomembranous colitis. Studies have shown that LD vectors are not found in Australia, and Lyme Borrelia has not been found in Australian vectors, animals or patients with autochthonous illnesses. I propose that (i) A non-controversial name for the chronic syndrome should be adopted, 'Australian Multisystem Disorder'. (ii) Research funding should enable the development of a consensus case definition and studies of the epidemiology of this syndrome with laboratory investigations to identify an aetiology and surrogate markers of disease. Prospective, randomised treatment studies could then be undertaken using ethical protocols.

Dermatologic Problems in the Intensive Care Unit: Part III

In this third part of our review of skin problems seen in critically ill patients, we focus on a number of life-threatening systemic disorders in which cutaneous findings are prominent. We discuss purpura fulminans, toxic shock syndrome, systemic lupus erythematosus, acquired immunodeficiency syndrome, Lyme disease, graft-versus-host disease, and Rocky Mountain spotted fever.

GIS and Remote Sensing Use in the Exploration of Lyme Disease Epidemiology

Given the relatively recent recognition of Lyme disease (LD) by CDC in 1990 as a nationally notifiable infectious condition, the rise of reported human cases every year argues for a better understanding of its geographic scope. The aim of this inquiry was to explore research conducted on spatiotemporal patterns of Lyme disease in order to identify strategies for implementing vector and reservoir-targeted interventions. The focus of this review is on the use of GIS-based methods to study populations of the reservoir hosts, vectors and humans in addition to the spatiotemporal interactions between these populations. New GIS-based studies are monitoring occurrence at the macro-level, and helping pinpoint areas of occurrence at the micro-level, where spread within populations of reservoir hosts, clusters of infected ticks and tick to human transmission may be better understood.

Prevalence Rates of Borrelia burgdorferi (Spirochaetales: Spirochaetaceae), Anaplasma phagocytophilum (Rickettsiales: Anaplasmataceae), and Babesia microti (Piroplasmida: Babesiidae) in Host-Seeking Ixodes scapularis (Acari: Ixodidae) from Pennsylvania

The etiological agents responsible for Lyme disease (Borrelia burgdorferi), human granulocytic anaplasmosis (Anaplasma phagocytophilum), and babesiosis (Babesia microti) are primarily transmitted by the blacklegged tick, Ixodes scapularis Say. Despite Pennsylvania having in recent years reported the highest number of Lyme disease cases in the United States, relatively little is known regarding the geographic distribution of the vector and its pathogens in the state. Previous attempts at climate-based predictive modeling of I. scapularis occurrence have not coincided with the high human incidence rates in parts of the state. To elucidate the distribution and pathogen infection rates of I. scapularis, we collected and tested 1,855 adult ticks statewide from 2012 to 2014. The presence of I. scapularis and B. burgdorferi was confirmed from all 67 Pennsylvania counties. Analyses were performed on 1,363 ticks collected in the fall of 2013 to avoid temporal bias across years. Infection rates were highest for B. burgdorferi (47.4%), followed by Ba. microti (3.5%) and A. phagocytophilum (3.3%). Coinfections included B. burgdorferi+Ba. microti (2.0%), B. burgdorferi+A. phagocytophilum (1.5%) and one tick positive for A. phagocytophilum+Ba. microti. Infection rates for B. burgdorferi were lower in the western region of the state. Our findings substantiate that Lyme disease risk is high throughout Pennsylvania.

Disease risk in a dynamic environment: the spread of tick-borne pathogens in Minnesota, USA

As humans and climate change alter the landscape, novel disease risk scenarios emerge. Understanding the complexities of pathogen emergence and subsequent spread as shaped by landscape heterogeneity is crucial to understanding disease emergence, pinpointing high-risk areas, and mitigating emerging disease threats in a dynamic environment. Tick-borne diseases present an important public health concern and incidence of many of these diseases are increasing in the United States. The complex epidemiology of tick-borne diseases includes strong ties with environmental factors that influence host availability, vector abundance, and pathogen transmission. Here, we used 16 years of case data from the Minnesota Department of Health to report spatial and temporal trends in Lyme disease (LD), human anaplasmosis, and babesiosis. We then used a spatial regression framework to evaluate the impact of landscape and climate factors on the spread of LD. Finally, we use the fitted model, and landscape and climate datasets projected under varying climate change scenarios, to predict future changes in tick-borne pathogen risk. Both forested habitat and temperature were important drivers of LD spread in Minnesota. Dramatic changes in future temperature regimes and forest communities predict rising risk of tick-borne disease.

Electrocardiograph Abnormalities in Children With Lyme Meningitis

OBJECTIVE

The objective of the study was to estimate the prevalence of and identify risk factors for electrocardiographic (ECG) changes in children presenting with Lyme meningitis.

DESIGN

This was a cross-sectional study.

SETTING

The study was set in three large urban pediatric tertiary care centers.

PARTICIPANTS

Children who were diagnosed with Lyme meningitis and underwent ECG testing were included.

OUTCOME MEASURE

The presence of an ECG abnormality associated with early-disseminated Lyme infection was the outcome measure.

RESULTS

Multivariable logistic regression was used to identify factors independently associated with ECG abnormalities. ECG testing was performed in 103 (66%) of 157 children with Lyme meningitis. The median age of these children was 10.8 years; 68% were male. ECG abnormalities, identified in 34 (33%) subjects, included one or more of the following: atrioventricular block (n = 16; 16%), ST-T wave changes (n = 14; 14%), and prolongation of the corrected QT interval (n = 11; 11%). In multivariate analysis, age ≥13 years and fever for ≥5 days were independently associated with ECG abnormalities. The probability of ECG abnormalities was greater than 50% in those with fever for ≥5 days or age ≥13 years, and if a subject fulfilled both criteria, the probability of ECG abnormalities was 83% (95% confidence interval: 50%-96%).

CONCLUSIONS

Electrocardiographic abnormalities occur commonly in children with Lyme meningitis. While older children with prolonged fever were most likely to have such abnormalities, the clinical consequences of asymptomatic ECG abnormalities in children with Lyme meningitis are not known.

Lyme carditis

Cardiovascular manifestations of Lyme disease were first reported nearly 30 years ago. This article describes Lyme carditis, its epidemiology, pathophysiology, methods of diagnosis, and treatment options.

Cardiac manifestations of Lyme disease

Lyme disease is a vector-borne illness that can affect numerous organ systems during the early disseminated phase, including the heart. The clinical course of Lyme carditis is usually benign with most patients recovering completely. In rare instances, death from Lyme carditis has been reported. The cardinal manifestation of Lyme carditis is conduction system disease, which generally is self-limited. Heart block occurs usually at the level of the atrioventricular node but often is unresponsive to atropine sulfate. Temporary pacing may be necessary in more than 30% of patients, but permanent heart block rarely develops. Myocardial and pericardial involvement can occur but generally is mild and self-limited. Diagnosis is made by associating the clinical and historical features of borreliosis, such as previous tick bite, EM, or neurologic involvement, with electrocardiographic abnormalities and symptoms such as chest pain, palpitations, syncope, and dyspnea. Serologic studies and endomyocardial biopsy can support the diagnosis in the correct clinical setting, and MR imaging, echocardiography, and gallium scanning have utility in selected circumstances. No treatment has been shown clearly to attenuate or prevent the development of Lyme carditis, but mild carditis generally is treated with oral antibiotics and severe carditis with intravenous antibiotics in an effort to eradicate the infection and prevent late complications of Lyme disease. There is conflicting evidence regarding the role that B. burgdorferi plays in the development and progression of chronic congestive heart failure. Because of the significant false-positive ELISA rate in this population and the unclear benefit of antibiotic therapy, confirmatory Western blot analysis is recommended. Routine therapy and screening of patients with idiopathic dilated cardiomyopathy is of limited utility and should be reserved for patients with clear history of antecedent Lyme disease or tick bite.

Seasonal distribution of borreliae in Ixodes ricinus ticks

Ixodes ricinus ticks were collected by flagging vegetation of a mixed oak forest in South Moravia (Czech Republic) at regular two-month intervals from March 1991 to March 1992 and examined for borreliae by darkfield microscopy. Mean annual proportions of infected ticks were 17.2% (15.4% to 21.2% monthly) in females (F), 18.6% (11.8% to 25.9%) in males (M), and 16.3% (12.4% to 20.9%) in nymphs (N); the differences among monthly values were insignificant. However, monthly proportions of intensively infected ticks containing more than 100 borreliae fluctuated widely, from 0.0% to 7.7% (annual mean 3.3%) in F, from 0.0% to 5.6% (mean 2.4%) in M, and from 0.0% to 5.7% (mean 1.9%) in N; the differences among months were significant, and the peak prevalence values were found in July (F, M) or November (N). Mean numbers of borreliae per infected tick reached their peak in September for both adult and nymphal ticks while they were generally low in spring. The highest risk of infection with tick-borne borreliae for vertebrates (including man) occurred in the study area during the month of July; in that month, one either female or nymphal I. ricinus containing more than 100 borreliae was encountered, on the average, every 92 minutes of flagging.

Cardiovascular manifestations of Lyme disease

Although the cardiac manifestations of Lyme disease may be diverse, in general they are treatable with currently available therapies. A high index of suspicion is required to make a diagnosis, especially for patients who may lack a suggestive history of tick exposure or residence in an endemic region. Lyme disease-related heart block may require pacemaker insertion and supportive care. The efficacy of antibiotics in the therapy of acute and chronic cardiac Lyme disease will require further study. Serologic testing and cardiac histopathology are the most precise methods of diagnosis. There is a need to develop more sensitive and specific diagnostic tests for Lyme disease and for Lyme carditis in particular.

Dogs as sentinels for Lyme disease in Massachusetts

BACKGROUND

An investigation of the relationship between incident human cases of Lyme disease and seroprevalence of antibodies to B. burgdorferi in dogs was undertaken in order to determine whether dogs might serve as sentinels for Lyme disease.

METHODS

3011 canine serum samples were analyzed by ELISA for antibody to B. burgdorferi. Records of incident human cases of Lyme disease were obtained from the Massachusetts Department of Public Health.

RESULTS

Regression analyses of the relationship between the log10 (mean incidence in people 1985-1989) and canine seroprevalence from July 1988-August 1989 revealed that canine seroprevalence was highly predictive of incidence (R2 = 0.86, p less than .0001). A logistic regression model that incorporates the altitude of the town where each dog was resident, the date of sampling, and information on each dog's age, sex, and breed adequately explained the risk of canine seropositivity. Dogs resident at altitudes less than 200 feet, of sporting or large mixed breeds, and greater than two years of age were five times, four times, and almost three times more likely, respectively, to exhibit seropositivity than were other dogs.

CONCLUSIONS

Estimates of the prevalence of antibody to B. burgdorferi in dog populations offers a sensitive, reliable, and convenient measure of the potential risk to people of B. burgdorferi in the environment. Risk factors for canine seropositivity may directly or indirectly illuminate certain aspects of the epidemiology of human Lyme disease.

Cerebrospinal fluid immune complexes in patients exposed to Borrelia burgdorferi: detection of Borrelia-specific and -nonspecific complexes

We analyzed cerebrospinal fluid (CSF) from 32 patients with neurological symptoms and evidence of Borrelia burgdorferi infection (29 were seropositive as determined by enzyme-linked immunosorbent assay, 2 were cell-mediated immune positive, and 1 had been seropositive as shown by enzyme-linked immunosorbent assay 9 months previously). CSF immune complexes were found in 22 (69%) of 32 patients; in 18, there was sufficient sample to isolate immune complexes. By enzyme-linked immunosorbent assay, isolated immune complexes from 10 of these 18 patients contained antibody specific for B. burgdorferi antigens. The isotypes were IgG (n = 8), IgM (n = 3), and IgA (n = 2). By immunoblot, these antibodies were directed against B. burgdorferi 41-kDa antigen and occasionally against the 33- and 17-kDa antigens. Anti-B. burgdorferi IgM was present in patients with acute neurological symptoms, was predominantly complexed rather than free, and decreased with clinical recovery in the one serial study. Three patients were nonreactive for free CSF antibodies, but had complexed antibodies to the organism. The preliminary finding of specific B. burgdorferi components in immune complexes in CSF suggests an active process triggered by the organism, even in the absence of other CSF abnormalities.

Epidemiology of Lyme disease in Virginia

Prior to January 1986, only one case of Lyme disease was reported from Virginia. In 1986-87, however, the Virginia Department of Health observed an increase in reports of suspected Lyme disease by physicians, despite the fact that Ixodes dammini is not highly prevalent in the Virginia tick population. Twenty-eight cases of Lyme disease were identified in Virginia, of which eight cases occurred in 1986 and 20 in 1987. Lyme disease appears to be increasing in frequency in Virginia and moving southward along the Eastern Atlantic Seaboard.

The many faces and phases of borreliosis. I. Lyme disease

Lyme disease is increasingly being reported throughout the United States and many parts of the world. Borrelia burgdorferi, the etiologic agent of Lyme disease, is a spirochete that, not unlike the treponema of syphilis, can cause a spectrum of disease from the initial skin lesion, through widely varied symptoms and signs, to chronic neurologic and arthritic disability. The borrelial spirochete and Lyme disease are the subject of this review. A subsequent article will review other definite and possible cutaneous manifestations of borreliosis.

The geographic distribution of Lyme disease in the United States

In 1982, national surveillance for Lyme disease was established by the Centers for Disease Control to monitor trends and determine endemic geographic areas. Initially, the endemic areas corresponded to the known distribution of Ixodes dammini, a five-state area of the northeastern seaboard (New York, New Jersey, Connecticut, Rhode Island, and Massachusetts) and Wisconsin and Minnesota. Increasing numbers of cases have been reported outside these areas, however, 86% of the provisional 5731 cases reported to CDC were acquired in these seven states. The number of reported cases increased from 491 in 1982 to approximately 1500 per year in 1984-1986, making Lyme disease the most commonly reported tick-borne illness in the United States. The apparently widening distribution of Lyme disease indicates that physicians in all regions of the country should be familiar with its signs and symptoms. Investigations of the vector in areas endemic for Lyme disease where Ixodes ticks are not found are warranted.

Lyme disease presenting as heart block

Lyme disease is now recognized as an infectious process capable of involving multiple organs including the cardiovascular system. We recently treated a boy whose complaints on admission related only to symptomatic heart block that was severe enough to require transvenous pacing. This boy was subsequently determined to have had Lyme Disease after his medical testing was reevaluated for possible tick exposure. In rare instances symptomatic heart block may be the sole presenting complaint of Lyme Disease in children.

Childhood Lyme arthritis: experience in an endemic area

We report 25 children with oligoarticular arthritis associated with Lyme disease. There were 16 boys (male/female ratio 1.8:1); ages ranged from 2 to 15 years. Thirteen (52%) children had no history of erythema chronicum migrans or other rash. Thirteen had temperatures as high as 41 degrees C for up to 2 months before the onset of arthritis. Twelve recalled definite tick bites. Ten (40%) children, of whom seven had no history of rash, were hospitalized for presumed septic arthritis. Another four had diagnoses of pauciarticular juvenile rheumatoid arthritis for as long as 3 years. Seven patients had less acute, recurrent episodes of synovitis. Two children had seventh nerve palsies 2 months before onset of arthritis. All patients had antibodies to the Lyme spirochete. In 14 patients, synovial fluid white blood cell counts ranged from 180 to 97,700/mm3 (greater than or equal to 76% polymorphonuclear leukocytes). Antibiotic therapy was effective in all patients; in 13, orally administered therapy alone resulted in elimination of synovitis and recurrent attacks. Lyme arthritis may be confused with acute bacterial septic arthritis or recurrent "pauciarticular juvenile rheumatoid arthritis," particularly when there is no history of erythema chronicum migrans.