Cost-effectiveness of a potential anti-tick vaccine with combined protection against Lyme borreliosis and tick-borne encephalitis in Slovenia.

This study assessed cost-effectiveness of a potential anti-tick vaccine that would protect against both Lyme borreliosis (LB) and tick-borne encephalitis (TBE) in a highly endemic setting of Slovenia. A Markov model was developed to estimate cost-effectiveness of a vaccine with potential combined protection against LB and TBE from the societal perspective. The model expressed time in annual cycles, followed a target population through their lifetime, and applied an annual discounting of 3%. A target population entered the model in a susceptible state, with time dependent probabilities to acquire LB/TBE. Disease manifestations were either resolved within one cycle, or a patient developed LB/TBE sequelae. The vaccination consisted of initial immunization and one revaccination. Estimates of LB/TBE direct and indirect costs, and data on natural course of LB/TBE were obtained from Slovenian databases. Effectiveness of the vaccine with potential combined protection against LB/TBE was derived from studies on existing TBE and LB vaccines, while utility estimates were collected from various literature sources. A vaccine with potential combined protection against LB/TBE was predicted to have an incremental cost of €771,300 per 10,000 vaccinated persons, an incremental utility of 17QALYs and a base-case incremental cost-effectiveness ratio (ICER) of 46,061€/QALY. Vaccine cost, effectiveness and discount rates were identified as the most influential model parameters. A wholesale price for a vaccine shot of €9.13 would lead to cost savings followed by health gains for the vaccination strategy. The base-case ICER was below commonly accepted thresholds of cost-effectiveness, indicating that a combined LB/TBE vaccine might be a cost-effective option in Slovenia. With early Health Technology Assessment becoming increasingly important, this analysis still represents a rare example of cost-effectiveness assessment prior to market authorisation. Although obviously in such a situation some key parameters are unknown, our model sets up a tool to analyse pharmacoeconomic criteria that can help development of a cost-effective health technology, in this case a combined tick-borne diseases vaccine.

[Dilemma: to test or not to test for Lyme borreliosis in general practice]. / Dilemma: wel of niet testen op lymeziekte in de huisartsenpraktijk?

There is no such thing as a perfect diagnostic test and the value of a test depends on the situation in which the test is being used. Here, we discuss two options for dealing with the diagnostic process for Lyme borreliosis in general practice. One option is to manage, treat or refer according to clinical signs and symptoms, in accordance with Dutch practice guidelines. The other option is to use laboratory tests to guide further patient management (treatment or referral). The choice depends on currently unknown factors, such as the pre-test probability of Lyme disease in patients presenting to general practitioners. Furthermore, clarity is required about how to proceed after a positive or negative test result. The consequences of a false test result will depend on the patient's status, possible alternative diagnoses and treatment options. Both physician and patient should be aware of the shortcomings of diagnostic tests.

The diagnostic accuracy of serological tests for Lyme borreliosis in Europe: a systematic review and meta-analysis.

BACKGROUND: Interpretation of serological assays in Lyme borreliosis requires an understanding of the clinical indications and the limitations of the currently available tests. We therefore systematically reviewed the accuracy of serological tests for the diagnosis of Lyme borreliosis in Europe. METHODS: We searched EMBASE en MEDLINE and contacted experts. Studies evaluating the diagnostic accuracy of serological assays for Lyme borreliosis in Europe were eligible. Study selection and data-extraction were done by two authors independently. We assessed study quality using the QUADAS-2 checklist. We used a hierarchical summary ROC meta-regression method for the meta-analyses. Potential sources of heterogeneity were test-type, commercial or in-house, Ig-type, antigen type and study quality. These were added as covariates to the model, to assess their effect on test accuracy. RESULTS: Seventy-eight studies evaluating an Enzyme-Linked ImmunoSorbent assay (ELISA) or an immunoblot assay against a reference standard of clinical criteria were included. None of the studies had low risk of bias for all QUADAS-2 domains. Sensitivity was highly heterogeneous, with summary estimates: erythema migrans 50% (95% CI 40% to 61%); neuroborreliosis 77% (95% CI 67% to 85%); acrodermatitis chronica atrophicans 97% (95% CI 94% to 99%); unspecified Lyme borreliosis 73% (95% CI 53% to 87%). Specificity was around 95% in studies with healthy controls, but around 80% in cross-sectional studies. Two-tiered algorithms or antibody indices did not outperform single test approaches. CONCLUSIONS: The observed heterogeneity and risk of bias complicate the extrapolation of our results to clinical practice. The usefulness of the serological tests for Lyme disease depends on the pre-test probability and subsequent predictive values in the setting where the tests are being used. Future diagnostic accuracy studies should be prospectively planned cross-sectional studies, done in settings where the test will be used in practice.

Ticking the right boxes: classification of patients suspected of Lyme borreliosis at an academic referral center in the Netherlands.

To provide better care for patients suspected of having Lyme borreliosis (LB) we founded the Amsterdam Multidisciplinary Lyme borreliosis Center (AMLC). The AMLC reflects a collaborative effort of the departments of internal medicine/infectious diseases, rheumatology, neurology, dermatology, medical microbiology and psychiatry. In a retrospective case series, characteristics of 200 adult patients referred to the AMLC were recorded, and patients were classified as having LB, post-treatment LB syndrome (PTLBS), persistent Borrelia burgdorferi sensu lato (s.l.) infection despite antibiotic treatment or no LB. In addition, LB, PTLBS and persistent B. burgdorferi s.l. infection cases were classified as 'definite,' 'probable' or 'questionable.' Of the 200 patients, 120 (60%) did not have LB and 31 (16%) had a form of localized or disseminated LB, of which 12 were classified as definite, six as probable and 13 as questionable. In addition, 34 patients (17%) were diagnosed with PTLBS, of which 22 (11%) were probable and 12 (6%) questionable. A total of 15 patients (8%) were diagnosed with persistent B. burgdorferi s.l. infection, of which none was classified as definite, three as probable and 12 as questionable. In conclusion, in line with previous studies, the number of definite and probable (persisting) LB cases was low. The overall high number of questionable cases illustrates the fact that it can sometimes be challenging to either rule out or demonstrate an association with a B. burgdorferi s.l. infection, even in an academic setting. Finally, we were able to establish alternative diagnoses in a large proportion of patients.

High seroprevalence of Borrelia miyamotoi antibodies in forestry workers and individuals suspected of human granulocytic anaplasmosis in the Netherlands.

Substantial exposure to Borrelia miyamotoi occurs through bites from Ixodes ricinus ticks in the Netherlands, which also transmit Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum. Direct evidence for B. miyamotoi infection in European populations is scarce. A flu-like illness with high fever, resembling human granulocytic anaplasmosis, has been attributed to B. miyamotoi infections in relatively small groups. Borrelia miyamotoi infections associated with chronic meningoencephalitis have also been described in case reports. Assuming that an IgG antibody response against B. miyamotoi antigens reflects (endured) infection, the seroprevalence in different risk groups was examined. Sera from nine out of ten confirmed B. miyamotoi infections from Russia were found to be positive with the recombinant antigen used, and no significant cross-reactivity was observed in secondary syphilis patients. The seroprevalence in blood donors was set at 2.0% (95% CI 0.4-5.7%). Elevated seroprevalences in individuals with serologically confirmed, 7.4% (2.0-17.9%), or unconfirmed, 8.6% (1.8-23%), Lyme neuroborreliosis were not significantly different from those in blood donors. The prevalence of anti-B. miyamotoi antibodies among forestry workers was 10% (5.3-16.8%) and in patients with serologically unconfirmed but suspected human granulocytic anaplasmosis was 14.6% (9.0-21.8%); these were significantly higher compared with the seroprevalence in blood donors. Our findings indicate that infections with B. miyamotoi occur in tick-exposed individuals in the Netherlands. In addition, B. miyamotoi infections should be considered in patients reporting tick bites and febrile illness with unresolved aetiology in the Netherlands, and other countries where I. ricinus ticks are endemic.

Rapid outer-surface protein C DNA tattoo vaccination protects against Borrelia afzelii infection.

Borrelia afzelii is the predominant Borrelia species causing Lyme borreliosis in Europe. Currently there is no human vaccine against Lyme borreliosis, and most research focuses on recombinant protein vaccines against Borrelia burgdorferi sensu stricto. DNA tattooing is a novel vaccination method that can be applied in a rapid vaccination schedule. We vaccinated C3H/HeN mice with B. afzelii strain PKo OspC (outer-surface protein C) using a codon-optimized DNA vaccine tattoo and compared this with recombinant protein vaccination in a 0-2-4 week vaccination schedule. We also assessed protection by DNA tattoo in a 0-3-6 day schedule. DNA tattoo and recombinant OspC vaccination induced comparable total IgG responses, with a lower IgG1/IgG2a ratio after DNA tattoo. Two weeks after syringe-challenge with 5 × 10(5) B. afzelii spirochetes most vaccinated mice had negative B. afzelii tissue DNA loads and all were culture negative. Furthermore, DNA tattoo vaccination in a 0-3-6 day regimen also resulted in negative Borrelia loads and cultures after challenge. To conclude, DNA vaccination by tattoo was fully protective against B. afzelii challenge in mice in a rapid vaccination protocol, and induces a favorable humoral immunity compared to recombinant protein vaccination. Rapid DNA tattoo is a promising vaccination strategy against spirochetes.

Borrelia burgdorferi sensu lato serology in the Netherlands: guidelines versus daily practice.

The purpose of this study was to compare guideline recommendations and day-to-day practice of serological testing for Lyme borreliosis (LB) in a laboratory located in Amsterdam, the Netherlands, serving both regional hospitals and primary care physicians. By telephone interview, we obtained clinical information regarding 488 requests for LB serology. Screening for LB was performed with a C6-peptide EIA and confirmed by recombinant immunoblot. A total of 82 % of the requests were not supported by guideline's recommendations and either originated from patients with atypical symptoms and a low a priori chance for LB or from patients for which testing on LB was not recommended for other reasons. C6-EIA screening was positive in 5 % of patients with atypical symptoms, comparable to the seroprevalence in the Dutch population. Interestingly, 10 % of the requests were from patients with atypical skin lesions, of which 20 % was positive, suggesting that serological testing is of additional value in a selection of such patients. Strikingly, only 9 % of the requests were supported by recommendations by guidelines. The percentage of positive confirmatory IgM and/or IgG immunoblots did not differ substantially between the groups and ranged from 56 to 75 %. Guidelines for testing for LB are not adequately followed in the Netherlands. Better education and adherence to the guidelines by physicians could prevent unnecessary diagnostics and antibiotic treatment of supposed LB patients.

[Lyme disease]. / De ziekte van Lyme.

Lyme disease, or Lyme borreliosis, is the most prevalent vector-borne illness in the United States of America and Europe. In the Netherlands, the disease is endemic with an estimated yearly incidence of 133 cases per 100.000 inhabitants. Lyme disease is caused by spirochetes of Borrelia burgdorferi sensu lato and transmitted by Ixodes ticks. Diagnosing the different manifestations of Lyme disease is based on a history of possible exposure to ticks, the appearance of specific clinical symptoms, exclusion of other causes of the symptoms, whether or not combined with serological or other diagnostics tests. Antibiotics are effective in all Lyme disease manifestations and, generally, patients have a good prognosis.

Tired of Lyme borreliosis. Lyme borreliosis in the Netherlands.

Lyme borreliosis has become the most common vector-borne illness in North Eastern USA and Europe. It is a zoonotic disease, with well-defined symptoms, caused by B. burgdorferi sensu lato, and transmitted by ticks. Lyme borreliosis is endemic in the Netherlands with a yearly incidence of approximately 133 cases/100,000 inhabitants. Similar to another spirochetal disease, syphilis, it can be divided into three stages; early, early disseminated and late disseminated manifestations of disease, of which the specific clinical presentations will be discussed in detail. The diagnosis of Lyme borreliosis is based on a history of potential exposure to ticks and the risk of infection with B. burgdorferi s.l., development of specific symptoms, exclusion of other causes, and when appropriate, combined with serological and/or other diagnostic tests. The specific indications for, but also the limitations of, serology and other diagnostic tests, including the polymerase chain reaction (PCR), are detailed in this review. Lyme borreliosis is treated with antibiotics, which are usually highly effective. Recent literature discussing the indications for antibiotic treatment, the dosage, duration and type of antibiotic, as well as indications to withhold antibiotic treatment, are reviewed. This review presents the most recent, and when available Dutch, evidence-based information on the ecology, pathogenesis, clinical presentation, diagnosis, treatment and prevention of Lyme borreliosis, argues against the many misconceptions that surround the disease, and provides a framework for the Dutch physician confronted with a patient with putative Lyme borreliosis.

The (re)generation of splenic tissue.

A 48-year-old man with a history of a traumatic splenic rupture followed by splenectomy at the age of 5 years was referred to the outpatient clinic with markedly elevated liver enzymes. He was diagnosed with alcoholic liver cirrhosis. Ultrasound of the upper abdomen revealed hepatomegaly and suggested a central mass in the liver. Subsequent MRI of the abdomen did not show a hepatic mass, but revealed multiple intraperitoneal and retroperitoneal ovoid structures with a maximum diameter of 3 cm. A peripheral blood smear did not reveal Howell-Jolly bodies suggesting intact splenic function. The diagnosis splenosis-that is, autotransplantation of splenic tissue after iatrogenic/traumatic rupture of the spleen-was considered and confirmed by SPECT-CT with technetium-99m ((99m)Tc) labelled heat-denatured autologous red blood cells.

Identification of Salp15 homologues in Ixodes ricinus ticks.

The 15-kDa Ixodes scapularis salivary gland protein Salp15 protects Borrelia burgdorferi sensu stricto from antibody-mediated killing and facilitates infection of the mammalian host. In addition, Salp 15 has been shown to inhibit T-cell activation. We determined whether Ixodes ricinus, the major vector for Lyme borreliosis in Western Europe, also express salp15-related genes. We show that engorged I. ricinus express salp15 and we have identified three Salp15 homologues within these ticks by reverse transcriptase-polymerase chain reaction (RT-PCR). One of the predicted proteins showed 80% similarity to I. scapularis Salp15, evenly distributed over the entire amino acid sequence, whereas the two other predicted proteins showed approximately 60% similarity, mainly confined to the signal sequence and C-terminus. Comparison of the DNA and protein sequences with those deposited in several databases indicates that these proteins are part of a Salp15 family of which members are conserved among different Ixodes species, all capable of transmitting B. burgdorferi sensu lato. This suggests that these Salp15 homologues could also play a role in the transmission of diverse Borrelia species and in inhibition of T-cell activation.