Lyme Disease-endemic Regions Research Articles

Prevalence and Knowledge of Tick-Borne Disease Among Forest Management Workers in Santa Cruz, California.

Background: In Lyme-endemic areas, limited research has investigated the risk of tick-borne diseases among frontline workers in fire management. This study aimed to compare the exposure histories to ticks and tick-borne pathogens, knowledge, and prevention practices between individuals engaged in fire-related forest management and those participating in recreational activities within Santa Cruz County, CA, in an area of high risk of tick exposure. Methods: Blood samples from 55 forest workers and 58 members of the public were tested for bacterial DNA of and antibodies to Borrelia burgdorferi, Anaplasma phagocytophilum, and Rickettsia species. In addition, a questionnaire was administered to 54 workers and 84 members of the public to identify gaps in knowledge and prevention practices. Results: Although workers had a higher percentage of positive B. burgdorferi antibodies than the public (5.5% compared with 1.7%), the difference was not statistically significant. Conversely, rickettsial antibodies were more prevalent among the public (17.2% versus 3.6% for workers), but specificity to pathogenic bacteria could not be confirmed. No DNA for the three pathogens or antibodies against A. phagocytophilum were detected. Many workers and members of the public reported tick bites (67.4% of participants), with a notable 11% increase among workers in the odds of being bitten for each additional year spent working in forests. Although workers took greater precautions, significant knowledge and practice gaps were identified among both populations, such as an inability to distinguish tick species from common arthropods (mites, spiders, fleas), overestimating the size of ticks, and inappropriate tick-removal techniques. Conclusion: This study underscores the risk of tick-borne diseases faced by fire management workers in Lyme disease-endemic regions. The findings emphasize the necessity for future studies of Lyme disease within this population, and highlight the urgent need for enhanced training programs to minimize these risks.

Biomarkers for Pediatric Bacterial Musculoskeletal Infections in Lyme Disease–Endemic Regions

OBJECTIVES Bacterial musculoskeletal infections (MSKIs) are challenging to diagnose because of the clinical overlap with other conditions, including Lyme arthritis. We evaluated the performance of blood biomarkers for the diagnosis of MSKIs in Lyme disease–endemic regions. METHODS We conducted a secondary analysis of a prospective cohort study of children 1 to 21 years old with monoarthritis presenting to 1 of 8 Pedi Lyme Net emergency departments for evaluation of potential Lyme disease. Our primary outcome was an MSKI, which was defined as septic arthritis, osteomyelitis or pyomyositis. We compared the diagnostic accuracy of routinely available biomarkers (absolute neutrophil count, C-reactive protein, erythrocyte sedimentation rate, and procalcitonin) to white blood cells for the identification of an MSKI using the area under the receiver operating characteristic curve (AUC). RESULTS We identified 1423 children with monoarthritis, of which 82 (5.8%) had an MSKI, 405 (28.5%) Lyme arthritis, and 936 (65.8%) other inflammatory arthritis. When compared with white blood cell count (AUC, 0.63; 95% confidence interval [CI], 0.55–0.71), C-reactive protein (0.84; 95% CI, 0.80–0.89; P < .05), procalcitonin (0.82; 95% CI, 0.77–0.88; P < .05), and erythrocyte sedimentation rate (0.77; 95% CI, 0.71–0.82; P < .05) had higher AUCs, whereas absolute neutrophil count (0.67; 95% CI, 0.61–0.74; P < .11) had a similar AUC. CONCLUSIONS Commonly available biomarkers can assist in the initial approach to a potential MSKI in a child. However, no single biomarker has high enough accuracy to be used in isolation, especially in Lyme disease–endemic areas.

Clinical manifestations of Lyme neuroborreliosis in children: a review.

Lyme neuroborreliosis (LNB) is a manifestation of Lyme disease involving the central and peripheral nervous system. It is caused by the spirochete Borrelia burgdorferi, transmitted by tick bites to a human host. Clinical signs of LNB develop after the dissemination of the pathogen to the nervous system. The infection occurs in children and adults, but the clinical manifestations differ. In adults, painful meningoradicultis is the most common manifestation of LNB, while children often present with facial nerve palsy and/or subacute meningitis. Subacute headache can be the only manifestation of LNB in children, especially during the summer months in Lyme disease-endemic regions. Non-specific symptoms, such as loss of appetite, fatigue or mood changes, may also occur, especially in young children. A high level of suspicion and early recognition of the various clinical manifestations presented by children with LNB is essential to minimize delay in diagnosis and optimize management. This review provides an overview of the spectrum of clinical manifestations, and discusses diagnosis, antibiotic treatment, and clinical outcome of LNB in children.

Context matters: Contrasting behavioral and residential risk factors for Lyme disease between high-incidence states in the Northeastern and Midwestern United States

The dynamics of zoonotic vector-borne diseases are determined by a complex set of parameters including human behavior that may vary with socio-ecological contexts. Lyme disease is the most common vector-borne disease in the United States. The Northeast and upper Midwest are the regions most affected - two areas with differing levels of urbanization and differing sociocultural settings. The probability of being infected with Lyme disease is related to the risk of encounters with Ixodes scapularis ticks infected with Borrelia burgdorferi sensu lato, which reflects both the environmental tick hazard and human behaviors. Herein, we compare behavioral and peridomestic risk factors perceived to influence the risk for human-tick encounters between two high-incidence states in the Northeast (New York and New Jersey) and one high-incidence state in the Midwest (Wisconsin). We used a smartphone application, The Tick App, as a novel survey tool, during spring and summer of 2018. Adaptive human behavior was identified in the relationship between outdoor activities and the use of methods to prevent tick bites. More frequent recreational outdoor activities and gardening (a peridomestic activity) were associated with a 1.4–2.3 times increased likelihood of using personal protective measures to prevent tick bites, when accounting for demographics and previous Lyme diagnosis. Most outdoor activities were more frequently reported by participants from the Midwest (n = 697), representing an older demographic, than the Northeast (n = 396). Participants from the Northeast were less likely to report use of personal protective measures to prevent tick bites, but a larger proportion of participants from the Northeast reported application of environmental pesticides targeting ticks or mosquitoes or other insects on their property (34 % of 279 versus 22 % of 616 participants) and interventions to reduce the presence of peridomestic deer compared to participants from the Midwest (e.g. 20 % of 278 versus 7% of 615 participants reported having a deer proof fence). Participants from the Midwest were more likely to kill rodents on their property (28 % versus 13 %). These differences illustrate the need for further assessment of personal behavior and tick exposure in these two Lyme disease-endemic regions to aid in targeted public health messaging to reduce tick-borne diseases.

Post-treatment Lyme Disease as a Model for Persistent Symptoms in Lyme Disease.

It has long been observed in clinical practice that a subset of patients with Lyme disease report a constellation of symptoms such as fatigue, cognitive difficulties, and musculoskeletal pain, which may last for a significant period of time. These symptoms, which can range from mild to severe, have been reported throughout the literature in both prospective and population-based studies in Lyme disease endemic regions. The etiology of these symptoms is unknown, however several illness-causing mechanisms have been hypothesized, including microbial persistence, host immune dysregulation through inflammatory or secondary autoimmune pathways, or altered neural networks, as in central sensitization. Evaluation and characterization of persistent symptoms in Lyme disease is complicated by potential independent, repeat exposures to B. burgdorferi, as well as the potential for co-morbid diseases with overlapping symptom profiles. Antibody testing for B. burgdorferi is an insensitive measure after treatment, and no other FDA-approved tests currently exist. As such, diagnosis presents a complex challenge for physicians, while the lived experience for patients is one marked by uncertainty and often illness invalidation. Currently, there are no FDA-approved pharmaceutical therapies, and the safety and efficacy of off-label and/or complementary therapies have not been well studied and are not agreed-upon within the medical community. Post-treatment Lyme disease represents a narrow, defined, mechanistically-neutral subset of this larger, more heterogeneous group of patients, and is a useful definition in research settings as an initial subgroup of study. The aim of this paper is to review the current literature on the diagnosis, etiology, risk factors, and treatment of patients with persistent symptoms in the context of Lyme disease. The meaning and relevance of existing patient subgroups will be discussed, as will future research priorities, including the need to develop illness biomarkers, elucidate the biologic mechanisms of disease, and drive improvements in therapeutic options.

Positive 2-Tiered Lyme Disease Serology is Uncommon in Asymptomatic Children Living in Endemic Areas of the United States.

Knowing the frequency of positive Lyme disease serology in children without signs of infection facilitates test interpretation. Of 315 asymptomatic children from Lyme disease endemic regions, 32 had positive or equivocal C6 enzyme-linked immunoassays, but only 5 had positive IgG or IgM supplemental immunoblots (1.6%; 95% confidence interval: 0.7%-3.7%).

Bartonellaspp. Bacteremia and Rheumatic Symptoms in Patients from Lyme Disease–endemic Region

<i>Bartonella</i>spp. Bacteremia and Rheumatic Symptoms in Patients from Lyme Disease–endemic Region

Bartonellaspp. Bacteremia and Rheumatic Symptoms in Patients from Lyme Disease–endemic Region

To the Editor: We believe the recent article by Maggi et al. (1) contains serious flaws in content and underlying message, including a poorly defined study population, lack of appropriate controls, improper use of the term bacteremia, and incongruent laboratory findings. Selection criteria were vague: the authors state only that participants were a “biased” collection of “patients selected by a rheumatologist,” with no control population included for comparison. The diagnosis of Lyme disease and other previously diagnosed conditions was solely by self-report. Although blood samples were collected from every participant, the authors apparently neglected to perform standardized testing for Borrelia burgdorferi or other conditions.

Bartonellaspp. Bacteremia and Rheumatic Symptoms in Patients from Lyme Disease–endemic Region

<i>Bartonella</i>spp. Bacteremia and Rheumatic Symptoms in Patients from Lyme Disease–endemic Region

Bell palsy in Lyme disease–endemic regions of Canada: a cautionary case of occult bilateral peripheral facial nerve palsy due to Lyme disease

Lyme disease caused by the spirochete Borrelia burgdorferi is a multisystem disorder characterized by three clinical stages: dermatologic, neurologic, and rheumatologic. The number of known Lyme disease-endemic areas in Canada is increasing as the range of the vector Ixodes scapularis expands into the eastern and central provinces. Southern Ontario, Nova Scotia, southern Manitoba, New Brunswick, and southern Quebec are now considered Lyme disease-endemic regions in Canada. The use of field surveillance to map risk and endemic regions suggests that these geographic areas are growing, in part due to the effects of climate warming. Peripheral facial nerve palsy is the most common neurologic abnormality in the second stage of Lyme borreliosis, with up to 25% of Bell palsy (idiopathic peripheral facial nerve palsy) occurring due to Lyme disease. Here we present a case of occult bilateral facial nerve palsy due to Lyme disease initially diagnosed as Bell palsy. In Lyme disease-endemic regions of Canada, patients presenting with unilateral or bilateral peripheral facial nerve palsy should be evaluated for Lyme disease with serologic testing to avoid misdiagnosis. Serologic testing should not delay initiation of appropriate treatment for presumed Bell palsy.

Bartonellaspp. Bacteremia and Rheumatic Symptoms in Patients from Lyme Disease–endemic Region

Bartonella spp. infection has been reported in association with an expanding spectrum of symptoms and lesions. Among 296 patients examined by a rheumatologist, prevalence of antibodies against Bartonella henselae, B. koehlerae, or B. vinsonii subsp. berkhoffii (185 [62%]) and Bartonella spp. bacteremia (122 [41.1%]) was high. Conditions diagnosed before referral included Lyme disease (46.6%), arthralgia/arthritis (20.6%), chronic fatigue (19.6%), and fibromyalgia (6.1%). B. henselae bacteremia was significantly associated with prior referral to a neurologist, most often for blurred vision, subcortical neurologic deficits, or numbness in the extremities, whereas B. koehlerae bacteremia was associated with examination by an infectious disease physician. This cross-sectional study cannot establish a causal link between Bartonella spp. infection and the high frequency of neurologic symptoms, myalgia, joint pain, or progressive arthropathy in this population; however, the contribution of Bartonella spp. infection, if any, to these symptoms should be systematically investigated.

Prevalence of Lyme Meningitis in Children With Aseptic Meningitis in a Lyme Disease-endemic Region

This study determined the prevalence of Lyme meningitis in children with undifferentiated aseptic meningitis from April to December in a Lyme disease-endemic region. Of the 60 children, 8 were seropositive (prevalence 13.3%; 95% confidence interval: 6.3-25.1%), with another probable case having high cerebrospinal fluid antibody titers. Clinicians in endemic regions should evaluate children with undifferentiated aseptic meningitis for Lyme meningitis in appropriate seasons.

Prospective Validation of a Clinical Prediction Model for Lyme Meningitis in Children

Lyme meningitis is difficult to differentiate from other causes of aseptic meningitis in Lyme disease-endemic regions. Parenteral antibiotics are indicated for Lyme meningitis but not viral causes of aseptic meningitis. A clinical prediction model was developed to distinguish Lyme meningitis from other causes of aseptic meningitis. Our objective was to prospectively validate this model. Children between 2 and 18 years of age presenting to Hasbro Children's Hospital from April through October of 2006 and 2007 were enrolled if a lumbar puncture for meningitis showed a cerebrospinal fluid white blood cell count of >8 cells per microL. Cerebrospinal fluid was sent for Lyme antibody testing. The probability of Lyme meningitis was calculated by using the percentage of cerebrospinal fluid mononuclear cells, duration of headache, and presence of cranial neuropathy by using the prediction model. Definite Lyme meningitis cases were defined as cerebrospinal fluid pleocytosis with (1) positive Lyme serology confirmed by immunoblot or (2) erythema migrans rash. Possible Lyme meningitis cases were defined as cerebrospinal fluid pleocytosis with positive cerebrospinal fluid Lyme antibody. Sensitivity, specificity, and likelihood ratios for definite and possible Lyme meningitis were determined by using 10% increments of calculated probability of Lyme meningitis. Fifty children were enrolled, including 14 children with definite Lyme meningitis, 6 with possible Lyme meningitis, and 30 with aseptic meningitis. A calculated probability of <10% for Lyme meningitis had a negative likelihood ratio of 0.006 for definite and possible Lyme meningitis cases. A calculated probability of >50% for Lyme meningitis had a positive likelihood ratio of 100 using these definitions. A clinical prediction model using the percentage of cerebrospinal fluid mononuclear cells, headache duration, and presence of cranial neuropathy can differentiate children with Lyme meningitis from children with aseptic meningitis. Our findings suggest categories of low (<10%), indeterminate (10%-50%), and high (>50%) probability of Lyme meningitis.

Transmission Dynamics of &lt;I&gt;Borrelia burgdorferi&lt;/I&gt; s.s. During the Key Third Day of Feeding by Nymphal &lt;I&gt;Ixodes scapularis&lt;/I&gt; (Acari: Ixodidae)

Nymphal Ixodes scapularis Say are the principal vectors of Lyme disease spirochetes (Borrelia burgdorferi sensu stricto) in the eastern United States. Physicians frequently face the decision of whether or not to administer prophylactic antibiotics to human tick bite victims in Lyme disease endemic regions, based on the overall probability that such bites will result in infection with B. burgdorferi s.s. We evaluated the transmission dynamics of B. burgdorferi s.s. during the key third day of nymphal I. scapularis feeding, when the risk of transmission rapidly increases. The cumulative probability that 50% of infected ticks transmitted B. burgdorferi s.s. occurred at 68 h of tick attachment and our overall estimate that a human tick bite would result in transmission of B. burgdorferi s.s. was 2.4%.

Transmission Dynamics ofBorrelia burgdorferis.s. During the Key Third Day of Feeding by NymphalIxodes scapularis(Acari: Ixodidae)

Nymphal Ixodes scapularis Say are the principal vectors of Lyme disease spirochetes (Borrelia burgdorferi sensu stricto) in the eastern United States. Physicians frequently face the decision of whether or not to administer prophylactic antibiotics to human tick bite victims in Lyme disease endemic regions, based on the overall probability that such bites will result in infection with B. burgdorferi s.s. We evaluated the transmission dynamics of B. burgdorferi s.s. during the key third day of nymphal I. scapularis feeding, when the risk of transmission rapidly increases. The cumulative probability that 50% of infected ticks transmitted B. burgdorferi s.s. occurred at 68 h of tick attachment and our overall estimate that a human tick bite would result in transmission of B. burgdorferi s.s. was 2.4%.

Response of nymphal Ixodes scapularis, the primary tick vector of Lyme disease spirochetes in North America, to barriers derived from wood products or related home and garden items

Forest products were tested to see if they functioned as a barrier to nymphal Ixodes scapularis. These products could potentially be used to define a border between high density and low density tick zones on residential properties in Lyme disease endemic regions of North America. Common home and garden items were also tested. Three wood products effectively acted as barriers to nymphal I. scapularis: Alaska Yellow Cedar sawdust, Alaska Yellow Cedar woodchips, and cellulose. These three products were then weathered to determine how long they remained active. Cellulose and Alaska Yellow Cedar woodchips lost their activity almost immediately (within three days); in contrast, Alaska Yellow Cedar sawdust impeded crossing by nymphal ticks for up to one month. Creating barriers at the woods-lawn interface may someday play a role in integrated campaigns to prevent Lyme disease but will not serve as a stand-alone measure to block transmission of Lyme disease spirochetes.

Prediction of Lyme Meningitis in Children From a Lyme Disease–Endemic Region: A Logistic-Regression Model Using History, Physical, and Laboratory Findings

Differentiating Lyme meningitis (LM) from other forms of aseptic meningitis (AM) in children is a common diagnostic dilemma in Lyme disease-endemic regions. Prior studies have compared clinical characteristics of patients with LM versus patients with documented enteroviral infections. No large studies have compared patients with LM to all patients presenting with AM and attempted to define a clinical prediction model. To create a statistical model to predict LM versus AM in children based on history, physical, and laboratory findings during the initial presentation of meningitis. Children older than 2 years presenting to the Alfred I. duPont Hospital for Children between October 1999 and September 2004 were identified if both Lyme serology and cerebrospinal fluid (CSF) were collected during the same hospital encounter. Patients were considered to have Lyme disease only if they met Centers for Disease Control and Prevention criteria (documented erythema migrans and/or positive Lyme serology). Patients were eligible for study inclusion if they had documented meningitis (CSF white blood cell count: >8 per mm3). Retrospective chart review abstracted duration of headache and cranial neuritis (papilledema or cranial nerve palsy) on physical examination and percent CSF mononuclear cells. Using logistic-regression analysis, the type of meningitis (LM versus AM) was simultaneously regressed on these 3 variables. The Hosmer-Lemeshow test was performed and the area under the receiver operating characteristic curve was calculated. A total of 175 children with meningitis were included in the final statistical model. Logistic-regression analysis included 27 patients with LM and 148 patients classified as having AM. Duration of headache, cranial neuritis, and percent CSF mononuclear cells independently predicted LM. The Hosmer-Lemeshow test revealed a good fit for the model, and the Nagelkerke R2 effect size demonstrated good predictive efficacy. Odds ratios based on the logistic-regression results were calculated for these variables. The final model was transformed into a clinical prediction model that allows practitioners to calculate the probability of a child having LM. Longer duration of headache, presence of cranial neuritis, and predominance of CSF mononuclear cells are predictive of LM in children presenting with meningitis in a Lyme disease-endemic region. The clinical prediction model can help guide the clinician about the need for parenteral antibiotics while awaiting serology results.

Hypersensitivity to Ticks and Lyme Disease Risk

Although residents of Lyme disease-endemic regions describe frequent exposure to ticks, Lyme disease develops in relatively few. To determine whether people who experience cutaneous hypersensitivity against tick bite have fewer episodes of Lyme disease than those who do not, we examined several factors that might restrict the incidence of Lyme disease among residents of Block Island, Rhode Island. Of 1,498 study participants, 27% (95% confidence interval [CI] 23%-31%) reported > or = 1 tick bites, and 17% (95% CI 13%-21%) reported itch associated with tick bite in the previous year. Borrelia burgdorferi infected 23% (95% CI 20%-26%) of 135 nymphal Ixodes scapularis (I. dammini) ticks. The likelihood of Lyme disease infection decreased with >3 reports of tick-associated itch (odds ratio 0.14, 95% CI 0.94-0.03, p = 0.01). Prior exposure to uninfected vector ticks protects residents of disease-endemic sites from Lyme disease.

Ixodes scapularis(Acari: Ixodidae): Abundance and Rate of Infection withBorrelia burgdorferiin Four State Parks in Wisconsin

Four state parks located in Lyme disease endemic regions of Wisconsin were surveyed for the presence of Ixodes scapularis Say during May and June of 1998 by drag sampling along hiking trails. Nymphal abundance varied between parks, with the average number of nymphs encountered in 1 h ranging from 6.2 +/- 3.8-47.1 +/- 36.3 (mean +/- SD). Questing nymphs were tested for the presence of Borrelia burgdorferi by culture in BSK medium and 7-12% was found to be infected. The average risk of encountering an infected nymph (entomologic risk index) ranged from 0.5 to 5.2 infected nymphs per hour. The highest entomological risk index was recorded from a small island park in northwestern Wisconsin during the last week in May (8.0 infected nymphs per hour). These results indicate a lower risk for human Lyme disease exposure in Wisconsin state parks in comparison with highly endemic areas of the northeastern United States.