Lyme Disease Diagnosis: Serology

Lyme Disease Confirmatory Western Blot Is Redundant for Screen Negative Samples in Low Endemic Areas, British Columbia, Canada

Background: Borrelia burgdorferi sensu stricto is the causative agent of Lyme disease (LD). Possible early symptoms include flu-like symptoms and erythema migrans and later, the risk of disruption of the nervous system, joints, and heart. A two-tiered testing method is employed for serological diagnostics. The Public Health Agency of Canada guidelines recommend that samples tested negative on first-tiered test need not be confirmed by second-tiered test. Due to the challenging nature of diagnosis leading to misconceptions among physicians about false negatives, confirmatory testing is requested despite the initial negative result. Methods: Hundred screen-negative Lyme patient samples from 2007 to 2016 were tested by Western blot (WB) second-tiered confirmatory test upon physician's request in British Columbia to study the first-tiered screening test sufficiency. Results: Those negative for first-tiered enzyme-linked immunosorbent assay were also negative by WB. Conclusion: Results demonstrate that confirmatory testing is not necessary on screen-negative samples. Hence, first-tiered test is sufficient to rule out LD.

Establishing a Pregnancy Lyme Disease Biobank

Availability of relevant biological samples supports both basic science research and patient-centered clinical studies. Establishing a biorepository faces challenges at multiple levels. These tasks include defining mission definition and scope; selection of subjects and sample types; recruitment strategies; timing of collection in the patient's journey; sample logistics and processing; determining what clinical data to collect; ensuring sample integrity on transport, processing, and storage; defining governance structures and oversight responsibilities; clarifying sample provenance and ownership; establishing procedures for sample and data access; selecting testing to be performed routinely versus upon request, and management of results; data security; funding sources; and regulatory compliance. Establishing and maintaining a biorepository therefore requires careful planning, diligent and sustained execution, technical and financial resources, stakeholder support, and flexible and resilient management to respond to changing environments and needs.

The history of Lyme disease in Italy and its spread in the Italian territory

Lyme borreliosis (LB) is the most common vector-borne zoonotic inflammatory disease in the Northern Hemisphere. In Italy, the first case was diagnosed in 1985 in a woman in Liguria, while the second, in 1986 in Friuli-Venezia Giulia, documenting the infection in northern Italy. Both diagnoses were confirmed by serological assessment by an indirect immunofluorescence (IFI) technique. Borrelia cultivation from both Ixodes ricinus ticks and human lesions in Trieste (Friuli-Venezia Giulia) identified Borrelia afzelii as the prevalent genospecies; nevertheless, Borrelia garinii, Borrelia burgdorferi (sensu stricto), and Borrelia valaisiana (VS116 Group) were also detected, although less frequently. LB was also documented in other Italian regions: in Tuscany (1991), Trentino-Alto Adige (1995-1996), Emilia-Romagna (1998), Abruzzo (1998), and more recently, Lombardy. Nevertheless, data on LB in other Italian regions, especially in southern Italy and islands, are poor. The aim of this study is to document the spread of LB in Italy through the collection of data from LB patients in eight Italian hospitals located in different Italian regions. Diagnostic criteria for LB diagnosis are as follows: i) the presence of erythema migrans (EM) or ii) a clinical picture suggestive of LB, confirmed by serological tests and/or PCR positivity for Borrelia detection. In addition, data also included the place of residence (town and region) and the place where patients became infected. During the observation period, 1,260 cases were gathered from the participating centers. Although different in extent from northern Italy to central/southern Italy, this study shows that LB is widespread throughout Italy.

Borrelia miyamotoi: A Comprehensive Review

Borrelia miyamotoi is an emerging tick-borne pathogen in the Northern Hemisphere and is the causative agent of Borrelia miyamotoi disease (BMD). Borrelia miyamotoi is vectored by the same hard-bodied ticks as Lyme disease Borrelia, yet phylogenetically groups with relapsing fever Borrelia, and thus, has been uniquely labeled a hard tick-borne relapsing fever Borrelia. Burgeoning research has uncovered new aspects of B. miyamotoi in human patients, nature, and the lab. Of particular interest are novel findings on disease pathology, prevalence, diagnostic methods, ecological maintenance, transmission, and genetic characteristics. Herein, we review recent literature on B. miyamotoi, discuss how findings adapt to current Borrelia doctrines, and briefly consider what remains unknown about B. miyamotoi.

The Spectrum of Erythema Migrans in Early Lyme Disease: Can We Improve Its Recognition?

Background and objective Diagnosis of early Lyme disease (LD) often relies on clinical recognition of the skin lesion, erythema migrans (EM), a diagnostic sign of disease when laboratory testing is insensitive. Because EM can present in morphologically distinct forms, its recognition by clinicians can be challenging. This study aimed to characterize the clinical spectrum of lesions in patients presenting with suspected early LD in an ambulatory care setting to identify features that might help clinicians to be better prepared to recognize EM lesions. Methods Images of lesions from 69 participants suspected to have early LD were retrospectively evaluated by a dermatologist and a family practitioner with expertise in early LD. Reviewers made determinations on the diagnoses and morphological features of lesions. Agreement between reviewers and associations among lesion types and participant demographics, symptomology, and laboratory evidence of infection were examined using the kappa statistic and contingency tables, respectively. Results Challenges in diagnosing EM were evident in our study: initial concordance between reviewers was moderate [kappa statistic (95% CI): 0.45 (0.245 - 0.657)]. The final classification included 35 lesions (51%) that were agreed to be EM; 23 lesions (30%) were considered to be possible early EM or tick bite reactions, and 11 (16%) were thought not to be EM, but rather other diagnoses, including ringworm, allergic contact dermatitis, and mosquito bites. Only two lesions (6%) were observed with a classic bull's eye or ring-within-a-ring pattern. Most EM lesions were uniform (51%), pink (74%), oval lesions (63%), with well-demarcated borders (92%). Early EM or tick bite reactions were typically <5 cm in size (74%), red (52%), round lesions (61%), with a punctum present (100%). Lesions thought not to be EM also tended to be pink or red (64%), round (55%), or uniform (45%) lesions, but also had raised (25%) or irregular borders (33%), which were not commonly observed in the reviewer-classified EM or tick bite reaction lesions. Participants with lesions classified as EM reported that they had the lesions for more days (p = 0.043) and reported more symptoms (p = 0.017) than participants with other lesions. Only 14 (20%) participants overall had positive laboratory evidence for LD; these included 13 (37%) of the participants with EM-classified lesions. Conclusions EM commonly occurs in forms that are not the classic bull's eye. Patients often present with lesions that may represent the very early stage of EM or tick bite reactions, and most patients will test negative on currently available laboratory tests, challenging clinicians in making an LD diagnosis or treatment decisions. Additional studies to further characterize the morphological features of EM and how variation in skin lesions may be perceived among clinicians would be helpful for developing guidelines on improving clinician recognition of EM.

The Impact of Telemedicine in the Diagnosis of Erythema Migrans during the COVID Pandemic: A Comparison with In-Person Diagnosis in the Pre-COVID Era

Background: Erythema migrans (EM) is the hallmark manifestation of the Lyme borreliosis (LB), and therefore its presence and recognition are sufficient to make a diagnosis and to start proper antibiotic treatment to attempt to eradicate the infection. Methods: In this study we compared the clinical data of 439 patients who presented an EM either according to the diagnostic modality through physical assessment or through telemedicine. Conclusions: Our data clearly show that telemedicine for EM diagnosis is useful as it enables prompt administration of appropriate antibiotic therapy, which is critical to avoid complications, especially for neurologic and articular entities. Therefore, telemedicine is a tool that could be adopted for the diagnosis of Lyme disease both by specialized centers but also by general practitioners.

A focused review on Lyme disease diagnostic testing: An update on serology algorithms, current ordering practices, and practical considerations for laboratory implementation of a new testing algorithm

Lyme borreliosis or Lyme disease (LD) is the most prevalent tick-borne illness in the United States. Diagnosing LD can be challenging as symptoms can be nonspecific and the ability of laboratory tests to detect infection varies based on the duration of infection and the methodology used. To date, serology testing is the primary laboratory tool employed to aid in diagnosing LD. Since the mid-1990's, a two-tiered algorithm has been recommended for the optimization of specificity while maintaining high sensitivity. This mini-review aims to provide an overview of LD diagnostic testing in North America, with an emphasis on serologic algorithms, in particular the modified two-tiered testing (MTTT) algorithm, along with a discussion on provider ordering patterns and practical considerations for implementation of MTTT.

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.

Global Transcriptome Analysis Identifies a Diagnostic Signature for Early Disseminated Lyme Disease and Its Resolution

A bioinformatics approach was employed to identify transcriptome alterations in the peripheral blood mononuclear cells of well-characterized human subjects who were diagnosed with early disseminated Lyme disease (LD) based on stringent microbiological and clinical criteria. Transcriptomes were assessed at the time of presentation and also at approximately 1 month (early convalescence) and 6 months (late convalescence) after initiation of an appropriate antibiotic regimen. Comparative transcriptomics identified 335 transcripts, representing 233 unique genes, with significant alterations of at least 2-fold expression in acute- or convalescent-phase blood samples from LD subjects relative to healthy donors. Acute-phase blood samples from LD subjects had the largest number of differentially expressed transcripts (187 induced, 54 repressed). This transcriptional profile, which was dominated by interferon-regulated genes, was sustained during early convalescence. 6 months after antibiotic treatment the transcriptome of LD subjects was indistinguishable from that of healthy controls based on two separate methods of analysis. Return of the LD expression profile to levels found in control subjects was concordant with disease outcome; 82% of subjects with LD experienced at least one symptom at the baseline visit compared to 43% at the early convalescence time point and only a single patient (9%) at the 6-month convalescence time point. Using the random forest machine learning algorithm, we developed an efficient computational framework to identify sets of 20 classifier genes that discriminated LD from other bacterial and viral infections. These novel LD biomarkers not only differentiated subjects with acute disseminated LD from healthy controls with 96% accuracy but also distinguished between subjects with acute and resolved (late convalescent) disease with 97% accuracy.IMPORTANCE Lyme disease (LD), caused by Borrelia burgdorferi, is the most common tick-borne infectious disease in the United States. We examined gene expression patterns in the blood of individuals with early disseminated LD at the time of diagnosis (acute) and also at approximately 1 month and 6 months following antibiotic treatment. A distinct acute LD profile was observed that was sustained during early convalescence (1 month) but returned to control levels 6 months after treatment. Using a computer learning algorithm, we identified sets of 20 classifier genes that discriminate LD from other bacterial and viral infections. In addition, these novel LD biomarkers are highly accurate in distinguishing patients with acute LD from healthy subjects and in discriminating between individuals with active and resolved infection. This computational approach offers the potential for more accurate diagnosis of early disseminated Lyme disease. It may also allow improved monitoring of treatment efficacy and disease resolution.

Borrelia burgdorferi as a risk factor for Alzheimer's dementia and mild cognitive impairment

OBJECTIVE

To determine the association of Borrelia burgdorferi infection with Alzheimer's disease or mild cognitive impairment (MCI) in older adults.

METHODS

Case-control study. Patients older than 60 years, both sexes, were included. Three groups were created: with probable Alzheimer's disease cases with NINCDS-ADRDA criteria, MCI cases in those not meeting NINCDS-ADRDA criteria for dementia, but who had an abnormal cognitive evaluation and independence in instrumental activities of daily living (IADL), cognitively healthy controls were diagnosed with normal cognitive evaluation and independence in IADL were identified in the community. Western blot IgG against B. burgdorferi in serum was done in all the participants. Non-conditional logistic regression was applied to estimate the association of Alzheimer's disease or MCI and seropositive to B. burgdorferi.

RESULTS

Thirty-eight patients with Alzheimer's disease, mean age of 75.6 ± 3.4 years, 69% were females, education 8.3 ± 4.8 years. 39 patients with MCI, mean age of 72.2 ± 6.8 years, 85% were females, education 11.2 ± 4.2 years. A total of 11/38 (29%) were positive to B. burgdorferi with Alzheimer's disease, 9/39 (23%) with MCI, and 11/108 (10%) of controls. In patients with Alzheimer's disease, an adjusted odds ratio (aOR) = 3.65 (95% CI 1.2-11.1) adjusted for education and a history of cerebrovascular disease (CVD) was estimated, and in patients with MCI an aOR = 3.2 (95% CI 1.1-9.1) for a history of diabetes mellitus and CVD was estimated.

CONCLUSIONS

In our study, there was an increased risk of Alzheimer's disease and MCI in seropositive IgG patients to B. burgdorferi.

Evaluation of Modified Two-Tiered Testing Algorithms for Lyme Disease Laboratory Diagnosis Using Well-Characterized Serum Samples

Standard two-tiered testing (STTT) is the recommended algorithm for laboratory diagnosis of Lyme disease (LD). Several limitations are associated with STTT that include low sensitivity in the early stages of disease, as well as technical complexity and subjectivity associated with second-tier immunoblotting; therefore, modified two-tiered testing (MTTT) algorithms that utilize two sequential first-tier tests and eliminate immunoblotting have been evaluated. Recently, a novel MTTT that uses a VlsE chemiluminescence immunoassay followed by a C6 enzyme immunoassay has been proposed. The purpose of this study was to evaluate the performance of the VlsE/C6 MTTT using well-characterized serum samples. Serum samples from the CDC Lyme Serum Repository were tested using three MTTTs, VlsE/C6, whole-cell sonicate (WCS)/C6, and WCS/VlsE, and three STTTs (immunoblotting preceded by three different first-tier assays: VlsE, C6, and WCS). Significant differences were not observed between the results of the MTTTs assessed; however, the VlsE/C6 MTTT resulted in the highest specificity (100%) when other diseases were tested and the lowest sensitivity (75%) for LD samples. Significant differences were present between the results for various MTTTs and STTTs evaluated. Specifically, all MTTTs resulted in higher sensitivities than the STTTs for all LD groups combined and were significantly more accurate (i.e., higher proportion of correct classifications) for this group, with the exception of the WCS/ViraStripe STTT. Additionally, when other diseases were tested, only the results of the VlsE/C6 MTTT differed significantly from those of the WCS/ViraStripe STTT, with the VlsE/C6 MTTT resulting in a 6.2% higher accuracy. Overall, the VlsE/C6 MTTT offers an additional laboratory testing algorithm for LD with equivalent or enhanced performance compared to that of the other MTTTs and STTTs evaluated in this study.

An estimate of Lyme borreliosis incidence in Western Europe†

Background

Lyme borreliosis (LB) is the most common zoonotic disease transmitted by ticks in the USA and Europe. This review aims to estimate the regional burden of LB in Western Europe. Data from previous publications will be used to calculate the mean incidence. The mean incidence rates will then be combined to estimate the regional burden and a population-weighted regional burden of disease based on the standardized incidence rate from the included studies and the total population at risk.

Methods

Reviews and surveillance reports identified by the initial database search were assessed for eligibility first by their title and abstract and subsequently by a more detailed review of the source by two independent authors for the most recent data regarding LB. Eleven sources of incidence data were included in the review representing 17 countries in total. Incidence estimates were calculated from reported values and population data.

Results

Countries in Western Europe have a large variance in the incidence rates. The highest reported incidences for LB were reported in southern Sweden with 464/100 000 and the lowest in Italy of 0.001/100 000. The unweighted mean for the included data provided an incidence rate of 56.3/100 000 persons per year, equating to ∼232 125 cases in 1 year throughout the region. The calculated population-weighted average incidence rate for the regional burden of LB in Western Europe was 22.05 cases per 100 000 person-years.

Conclusions

LB is a continually emerging disease and the most common zoonotic infection in Western Europe approaching endemic proportions in many European countries. The population-weighted incidence rate has been estimated by this study to be 22.04/100 000 person-years. Concordant and well-conducted surveillance and disease awareness should continue to be encouraged to monitor LB, as tick numbers and activity are increasing, leading to greater risks of infection.

[Cutaneous manifestations of Lyme disease : Pitfalls in the serological diagnostic workup]

Serology, the detection of B. burgdorferi-specific IgM and IgG serum antibodies, is the most common laboratory test to diagnose cutaneous manifestations of Lyme disease. In a two-tiered approach, an ELISA is used as a screening test. A positive or equivocal ELISA result needs confirmation by a specific immunoblot. The sensitivity of this approach reaches 80-95%. The diagnosis of erythema migrans is based on its typical clinical appearance. Serology is only indicated in atypical cases. In contrast, serology is mandatory in the diagnostic workup of borrelial lymphocytoma and acrodermatitis chronica atrophicans. A positive serology can persist for many years, even after adequate antibiotic treatment. A positive serology is no indication for antibiotic treatment if typical symptoms of Lyme disease are absent.

Borrelia burgdorferi-specific IgA in Lyme Disease

The laboratory diagnosis of Lyme disease is currently dependent on the detection of IgM and IgG antibodies against Borrelia burgdorferi, the causative agent of the disease. The significance of serum IgA against B. burgdorferi remains unclear. The production of intrathecal IgA has been noted in patients with the late Lyme disease manifestation, neuroborreliosis, but production of antigen-specific IgA during early disease has not been evaluated. In the current study, we assessed serum IgA binding to the B. burgdorferi peptide antigens, C6, the target of the FDA-cleared C6 EIA, and FlaB(211-223)-modVlsE(275-291), a peptide containing a Borrelia flagellin epitope linked to a modified VlsE sequence, in patients with early and late Lyme disease. Specific IgA was detected in 59 of 152 serum samples (38.8%) from early Lyme disease patients. Approximately 50% of early Lyme disease patients who were seropositive for peptide-specific IgM and/or IgG were also seropositive for peptide-specific IgA. In a subpopulation of patients, high peptide-specific IgA could be correlated with disseminated disease, defined as multiple erythema migrans lesions, and neurological disease complications. These results suggest that there may be an association between elevated levels of antigen-specific IgA and particular disease manifestations in some patients with early Lyme disease.

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Approximately one-third of all patients diagnosed with early Lyme disease have significant levels of antigen-specific IgA

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Approximately one-half of patients seropositive for IgM and/or IgG are also seropositive for IgA

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Antigen-specific IgA correlated with disseminated disease and neurological symptoms in patients with early Lyme disease

The significance of serum IgA production in patients with early Lyme disease has not been previously evaluated. In the present study, we demonstrated that IgA antibodies against Borrelia burgdorferi, the causative agent of Lyme disease, were present in ~ 33% of patients diagnosed with early disease. Anti-B. burgdorferi IgA production correlated with disseminated disease as well as neurological manifestations in a subset of these patients. Though further study is necessary, these results suggest that monitoring serum IgA could have potential diagnostic and/or prognostic value in early Lyme disease.

Evaluation of bioMérieux's Dissociated Vidas Lyme IgM II and IgG II as a First-Tier Diagnostic Assay for Lyme Disease

The recommended laboratory diagnostic approach for Lyme disease is a standard two-tiered testing (STTT) algorithm where the first tier is typically an enzyme immunoassay (EIA) that if positive or equivocal is reflexed to Western immunoblotting as the second tier. bioMérieux manufactures one of the most commonly used first-tier EIAs in the United States, the combined IgM/IgG Vidas test (LYT). Recently, bioMérieux launched its dissociated first-tier tests, the Vidas Lyme IgM II (LYM) and IgG II (LYG) EIAs, which use purified recombinant test antigens and a different algorithm than STTT. The dissociated LYM/LYG EIAs were evaluated against the combined LYT EIA using samples from 471 well-characterized Lyme patients and controls. Statistical analyses were conducted to assess the performance of these EIAs as first-tier tests and when used in two-tiered algorithms, including a modified two-tiered testing (MTTT) approach where the second-tier test was a C6 EIA. Similar sensitivities and specificities were obtained for the two testing strategies (LYT versus LYM/LYG) when used as first-tier tests (sensitivity, 83 to 85%; specificity, 85 to 88%) with an observed agreement of 80%. Sensitivities of 68 to 69% and 76 to 77% and specificities of 97% and 98 to 99% resulted when the two EIA strategies were followed by Western immunoblotting and when used in an MTTT, respectively. The MTTT approach resulted in significantly higher sensitivities than did STTT. Overall, the LYM/LYG EIAs performed equivalently to the LYT EIA in test-to-test comparisons or as first-tier assays in STTT or MTTT with few exceptions.

HtrA, a Temperature- and Stationary Phase-Activated Protease Involved in Maturation of a Key Microbial Virulence Determinant, Facilitates Borrelia burgdorferi Infection in Mammalian Hosts

High-temperature requirement protease A (HtrA) represents a family of serine proteases that play important roles in microbial biology. Unlike the genomes of most organisms, that of Borrelia burgdorferi notably encodes a single HtrA gene product, termed BbHtrA. Previous studies identified a few substrates of BbHtrA; however, their physiological relevance could not be ascertained, as targeted deletion of the gene has not been successful. Here we show that BbhtrA transcripts are induced during spirochete growth either in the stationary phase or at elevated temperature. Successful generation of a BbhtrA deletion mutant and restoration by genetic complementation suggest a nonessential role for this protease in microbial viability; however, its remarkable growth, morphological, and structural defects during cultivation at 37°C confirm a high-temperature requirement for protease activation and function. The BbhtrA-deficient spirochetes were unable to establish infection of mice, as evidenced by assessment of culture, PCR, and serology. We show that transcript abundance as well as proteolytic processing of a borrelial protein required for cell fission and infectivity, BB0323, is impaired in BbhtrA mutants grown at 37°C, which likely contributed to their inability to survive in a mammalian host. Together, these results demonstrate the physiological relevance of a unique temperature-regulated borrelial protease, BbHtrA, which further enlightens our knowledge of intriguing aspects of spirochete biology and infectivity.

Diagnosis, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: A Review

IMPORTANCE

Lyme disease, human granulocytic anaplasmosis (HGA), and babesiosis are emerging tick-borne infections.

OBJECTIVE

To provide an update on diagnosis, treatment, and prevention of tick-borne infections.

EVIDENCE REVIEW

Search of PubMed and Scopus for articles on diagnosis, treatment, and prevention of tick-borne infections published in English from January 2005 through December 2015.

FINDINGS

The search yielded 3550 articles for diagnosis and treatment and 752 articles for prevention. Of these articles, 361 were reviewed in depth. Evidence supports the use of US Food and Drug Administration-approved serologic tests, such as an enzyme immunoassay (EIA), followed by Western blot testing, to diagnose extracutaneous manifestations of Lyme disease. Microscopy and polymerase chain reaction assay of blood specimens are used to diagnose active HGA and babesiosis. The efficacy of oral doxycycline, amoxicillin, and cefuroxime axetil for treating Lyme disease has been established in multiple trials. Ceftriaxone is recommended when parenteral antibiotic therapy is recommended. Multiple trials have shown efficacy for a 10-day course of oral doxycycline for treatment of erythema migrans and for a 14-day course for treatment of early neurologic Lyme disease in ambulatory patients. Evidence indicates that a 10-day course of oral doxycycline is effective for HGA and that a 7- to 10-day course of azithromycin plus atovaquone is effective for mild babesiosis. Based on multiple case reports, a 7- to 10-day course of clindamycin plus quinine is often used to treat severe babesiosis. A recent study supports a minimum of 6 weeks of antibiotics for highly immunocompromised patients with babesiosis, with no parasites detected on blood smear for at least the final 2 weeks of treatment.

CONCLUSIONS AND RELEVANCE

Evidence is evolving regarding the diagnosis, treatment, and prevention of Lyme disease, HGA, and babesiosis. Recent evidence supports treating patients with erythema migrans for no longer than 10 days when doxycycline is used and prescription of a 14-day course of oral doxycycline for early neurologic Lyme disease in ambulatory patients. The duration of antimicrobial therapy for babesiosis in severely immunocompromised patients should be extended to 6 weeks or longer.

Nervous System Lyme Disease

Nervous system involvement occurs in 10% to 15% of patients infected with the tick-borne spirochetes Borrelia burgdorferi, B afzelii, and B garinii. Peripheral nervous system involvement is common. Central nervous system (CNS) involvement, most commonly presenting with lymphocytic meningitis, causes modest cerebrospinal fluid (CSF) pleocytosis. Parenchymal CNS infection is rare. If the CNS is invaded, however, measuring local production of anti-B burgdorferi antibodies in the CSF provides a useful marker of infection. Most cases of neuroborreliosis can be cured with oral doxycycline; parenteral regimens should be reserved for patients with particularly severe disease.