Clinical practice. Lyme disease

A 32-year-old pregnant woman from southeastern Connecticut presents to her physician in July at 26 weeks' gestation because of a skin lesion. She reports she has had fatigue, arthralgia, and headache for 2 days and a rash in her left axilla for 1 day. She lives in a wooded area and works in her garden frequently. Six weeks earlier, she had removed a small tick that was attached behind her right knee. On physical examination, she is afebrile. She has an erythematous, oval macular lesion, 7 to 8 cm in diameter, in her left axilla, with enhanced central erythema; no other abnormalities are noted. How should her case be managed?

[Isolation of Borrelia burgdorferi in ixodes from four counties, in North Xinjiang]

OBJECTIVE

To identify ticks and determine the Borrelia (B.) burgdorferi genotype from four counties of northern Xinjiang.

METHODS

Sheep ticks were collected from 6 surveillance sites in four counties including Shihezi, Shawan,Yining and Chabuchaer. All ticks were initially screened out based on morphological methods and 16S rRNA sequence analysis. B. burgdorferi was detected and cultivated with BSK-H medium. Combined with nested PCR, silver nitrate staining was employed to detect B. burgdorferi. Genotype of isolated B. burgdorferi was determined by Sequencing and phylogenic analysis based on 11 conference sequences.

RESULTS

Hyalomma asiaticum asiaticum, Haemaphysalis punctata, Dermacentor marginatus and Rhipicephalus turanicus were identified from more than 900 ticks. Out of 24 tubes from 102 representative tick specimens, 16 tube were positive for B. burgdorfer. Sequencing of 5S-23S rRNA intergenic spacer showed 98.6%-99.5% identities to B. burgdorferi Sensu Stricto(B31). Results from the analysis of OspC genotype showed consistent with that of 5S-23S rRNA intergenic spacer.

CONCLUSIONS

16 strains of B. burgdorferi Sensu Stricto were isolated in four counties, from northern Xinjiang. Additionally, B. burgdorferi Sensu Stricto was isolated from Rhipicephalus turanicus first time in China.

[Combatting Lyme disease]

The prevalence of ticks seems to have increased with time, and the number of patients with Lyme disease in the Netherlands is also increasing. Lyme disease and other tick-transmitted diseases now attract a lot of attention. Several national initiatives at different levels are now in progress, with the aim of suppressing Lyme disease and providing better care for patients with indications of having these diseases. A more uniform approach between different treatment centres, joint research and further expansion of education and continuing education for physicians and the public could lead to further improvement.

[Lyme disease: how widespread is the problem?]

Lyme disease is the cause of a lot of anxiety and discussion. Patients are demanding more preventive actions to avoid tick bites, and earlier and better diagnosis of Lyme disease. However, only a minority of people bitten by a tick go on to develop Lyme disease. Although physician delay may lead to a late diagnosis of disseminated Lyme disease, these patients are still treatable and even in bad cases, symptoms will subside within a few years. While we know that serious complications of late disseminated Lyme, e.g. neuroborreliosis, are very rare, there is still uncertainty about how often Lyme disease occurs, and how often the diagnosis is delayed. The high prevalence of seropositive people in the population suggests that many people clear the infection without any symptoms and without any treatment. Some decades ago mononucleosis infectiosa also had a bad reputation but this largely disappeared when it became clear that recovery is the rule. Lyme disease may also shed its reputation once the facts are known.

Activity of the tick Ixodes ricinus monitored in a suburban park in Brno, Czech Republic, in association with the evaluation of selected repellents

The ever-increasing number of Lyme borreliosis patients led us to consider more effective procedures for disease prevention. The aim of our study was to monitor the annual activity and infectivity of Ixodes ricinus ticks in the Pisárky region, City of Brno, CR, and to test the responses of the locally-captured ticks to selected repellents. The result of regular one-hour-per-week monitoring in 2011 was the collection of ticks that directly reflected the highest number of Lyme disease patients (4,835) detected throughout the period of recording in the Czech Republic. The ticks were examined for spirochaetes by dark field microscopy. The positive samples were identified by PCR analysis, confirming that 76% of these were infected with Borrelia burgdorferi sensu lato. Ticks were most abundant in May and June, with August having the highest risk for spirochaetal infection. Tick activity was statistically correlated with temperature. The moving-object-bioassay was used to study repellent efficiency on the Ixodes ricinus nymphs captured in the above-mentioned suburban park. Five selected commercial repellents based on DEET (N, N-diethyl-3-thylbenzamide) showed statistically different effects on the non-repellent control group.

Evaluation of OspA vaccination-induced serological correlates of protection against Lyme borreliosis in a mouse model

BACKGROUND

For clinical development of a novel multivalent OspA vaccine against Lyme borreliosis, serological assays are required which can be used to establish immune correlates of protection against infection with Borrelia.

METHODS

Four assays (an OspA IgG ELISA, a competitive inhibition (CI) ELISA, a Borrelia surface-binding (SB) assay and a Borrelia killing assay) were used to evaluate the correlation between immune responses induced by rOspA 1/2 (a chimeric immunogen containing protective epitopes from OspA serotypes 1 and 2), and protective immunity against infection by B. burgdorferi s.s. (OspA-1) and B. afzelii (OspA-2). Mice were immunized with OspA 1/2 doses ranging from 0.3 ng to 100 ng, to induce a range of OspA antibody titers, and exposed to needle challenge with B. burgdorferi s.s. or tick challenge with B. afzelii. Receiver operator characteristics (ROC) curves were constructed for each assay, and the area under the curve (AUC), sensitivity, specificity and Youden Index were calculated. Potential cutoff antibody titers which could be used as correlates of vaccine-induced protection were derived from the maximum Youden Index.

RESULTS

Immunization with OspA-1/2 provided dose-dependent protection against infection with B. burgdorferi s.s. and B. afzelii. Antibody responses detected by all four assays were highly significantly correlated with protection from infection by either B. burgdorferi s.s. (p<0.0001 to 0.0062) or B. afzelii (p<0.0001). ROC analyses of the diagnostic effectiveness of each assay showed the AUC to range between 0.95 and 0.79, demonstrating that all assays distinguish well between infected and non-infected animals. Based on sensitivity, specificity and AUC, the OspA IgG ELISA and SB assays best discriminated between infected and non-infected animals.

CONCLUSIONS

All four assays differentiate well between Borrelia-infected and non-infected animals. The relatively simple, high throughput IgG ELISA would be suitable to establish immune correlates of protection for the novel OspA vaccine in clinical trials.

Lyme disease in Poland in 2011

INTRODUCTION

In Poland registration of all cases of Lyme disease is conducted by Epidemiological Unit of National Institute of Public Health - National Institute of Hygiene. Most cases of Lyme disease occur in the North- East region of Poland; however it is important to note that the disease is no longer solely a problem of this region of Poland.

OBJECTIVES

The aim of this work is the assessment of the epidemiological situation of Lyme disease in Poland in 2011 as compared to the situation in the previous years.

MATERIALS AND METHODS

Assessment of the epidemiological situation of Lyme disease in Poland was made on the basis of an analysis of individual notifications of suspected Lyme disease submitted to NIZP-NIH by the Provincial Sanitary- Epidemiological stations; as well as data from "Infectious diseases and poisoning in Poland in 2011" bulletin, and "Preventative vaccination in Poland in 2011" bulletin (MP Czarkowski and Co, Warsaw 2012, NIZP- PZH, GIS).

RESULTS

In 2011 there were 9 157 registered cases of Lyme disease and it is 2% higher than in the previous year. The overall incidence in the country amounted 23.8 per 100,000 population. The highest recorded in Podlaskie province 75.5 per 100,000 population. 2091 people were hospitalized due to Lyme disease.

SUMMARY AND CONCLUSIONS

In 2011 there was a tendency to slow down/inhibit the incidence of Lyme disease. The registered number of cases was comparable to the previous year. There is still fairly low percentage of confirmed cases by performing diagnostic test Western blot method.

Seroprevalence of tick-borne infections in military working dogs in the Republic of Korea

In this study we endeavored to determine the seroprevalence of tick-borne infections in the military working dog (MWD) population in the Republic of Korea (ROK). Our sample population consisted of 182 serum samples from MWDs for 3 different years (1996, 2002, and 2007). In addition, 63 whole blood samples from 2007 were available for polymerase chain reaction (PCR). Serum samples were evaluated by a commercially available enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA) for Ehrlichia canis and Anaplasma phagocytophilum, and by ELISA only for Borrelia burgdorferi. PCR amplification of DNA was performed to screen for Ehrlichia canis, E. chaffeensis, E. ewingii, Anaplasma phagocytophilum, A. platys, Borrelia burgdorferi, and Rickettsia rickettsii, as well as Babesia and Theileria species using previously published primers and probes. A total of 56 (30.8%) MWDs were positive by at least one serologic test. Seroprevalences for Anaplasma and Ehrlichia were 4.4% and 0.6% based on the ELISA, and 24.7% and 22.5% based on the IFA, respectively. ELISA testing for Borrelia yielded 2 (1.1%) positive results. In parallel testing using both the ELISA and IFA tests, the percentages of dogs with one or more positive results were 34.1%, 25.9%, and 28.4%, for 1996, 2002, and 2007, respectively. There was no significant differences in seroprevalence based on location, year, breed, or sex of the MWD. There was poor agreement between IFA and ELISA test results. No MWD sample had a positive PCR result. MWDs stationed in Korea had serologic evidence of exposure to several tick-borne pathogens, but PCR testing did not identify any active infections.

Efficacy and environmental persistence of nootkatone for the control of the blacklegged tick (Acari: Ixodidae) in residential landscapes

The ability of the plant-derived compound nootkatone to control nymphs of the blacklegged tick, Ixodes scapularis Say, was evaluated at lawn perimeter plots at homes in Lyme disease endemic areas of Connecticut. Three formulations of nootkatone ranging from 0.05 to 0.84% (0.06 - 1.03 g AI/m2) were applied by a hydraulic sprayer from 2008 to 2010. In 2008, the 0.84% emulsifiable nootkatone formulation provided 100% control of I. scapularis through week 1, but declined to 49 and 0% by 2 and 3 wk posttreatment, respectively. A combination of 0.05% nootkatone and entomopathogenic fungus, Metarhizium brunneum Petch F52, resulted in 50% control for the first week posttreatment and no control in subsequent weeks. The 0.84% emulsifiable nootkatone formulation was phytotoxic, although no damage was observed with the 0.05% formulation with Metarhizium. Residual analysis of nootkatone collected on filter paper disks showed that > or = 95% of the emulsified nootkatone for both formulations was lost within 7 d after application. A lignin-encapsulated nootkatone formulation (0.56 and 0.46% in 2009 and 2010, respectively) provided 100% control of I. scapularis for 8 wk in 2009 and, in 2010, 67% control at approximately 1 wk posttreatment with respect to the pretreatment counts, although there was no difference in tick abundance posttreatment. A 0.60% Maillard-reaction encapsulated nootkatone formulation in 2010 provided a similar level of control (62%). Nootkatone in the lignin and Maillard formulations were more persistent than the emulsifiable formulation. Little or no phytotoxicity was observed with the encapsulated formulations. Encapsulating nootkatone reduced phytotoxicity and appeared to reduce environmental loss. While nootkatone can provide effective tick control, further work is needed to refine formulations to address phytotoxicity, yet provide sufficient material to control ticks.

The rise and fall of the lyme disease vaccines: a cautionary tale for risk interventions in American medicine and public health

CONTEXT

Two vaccines to prevent Lyme disease (LD) were developed and tested in the 1990s. Despite evidence of their safety and efficacy in clinical trials and initial postmarketing surveillance, one vaccine was withdrawn before the regulatory review and the other after only three years on the market. An investigation of their history can illuminate (1) the challenges faced by many new risk-reducing products and practices and (2) the important role played by their social and psychological, as distinct from their biomedical or scientific, efficacy in how they are used, and their ultimate market success or failure.

METHODS

This article reviewed medical and popular literature on LD vaccines, analyzed the regulatory hearings, and conducted interviews with key participants.

FINDINGS

Even if proved safe and effective, LD vaccines faced regulatory and market challenges because the disease was geographically limited, treatable, and preventable by other means. Pharmaceutical companies nevertheless hoped to appeal to consumers' desire for protection and control and to their widespread fear of the disease. The LD advocacy community initially supported the vaccines but soon became critical opponents. The vaccines' success was seen as threatening their central position that LD was chronic, protean, and difficult to treat. The activists' opposition flipped the vaccines' social and psychological efficacy. Instead of the vaccines restoring control and reducing fear, demand was undermined by beliefs that the vaccines caused an LD-like syndrome.

CONCLUSIONS

The social and psychological efficacy of many risk-reducing practices and products, such as new "personalized vaccines," is to provide insurance and reduce fear. Yet the actions of self-interested actors can easily undermine this appeal. In addition to evaluating the scientific efficacy and safety of these practices and products, policymakers and others need to understand, anticipate, and perhaps shape the potential social and psychological work they might do.

[Problems in the organization of epidemiological surveillance of natural focal infections and ways of their solution]

The spread of natural focal infections is determined by a set of interrelated and interdependent populations of warm-blooded animals, arthropods, and microorganisms. Real danger to humans makes their foci be included into environmental risk factors in this or that area.

Human risk of infection with Borrelia burgdorferi, the Lyme disease agent, in eastern United States

The geographic pattern of human risk for infection with Borrelia burgdorferi sensu stricto, the tick-borne pathogen that causes Lyme disease, was mapped for the eastern United States. The map is based on standardized field sampling in 304 sites of the density of Ixodes scapularis host-seeking nymphs infected with B. burgdorferi, which is closely associated with human infection risk. Risk factors for the presence and density of infected nymphs were used to model a continuous 8 km×8 km resolution predictive surface of human risk, including confidence intervals for each pixel. Discontinuous Lyme disease risk foci were identified in the Northeast and upper Midwest, with a transitional zone including sites with uninfected I. scapularis populations. Given frequent under- and over-diagnoses of Lyme disease, this map could act as a tool to guide surveillance, control, and prevention efforts and act as a baseline for studies tracking the spread of infection.

[Lyme borreliosis in Poland in 2010]

INTRODUCTION

Lyme borreliosis is an animal, affecting multiple systems infectious disease transmitted to humans by the ticks (vector) belonging to the genus Ixodes. The incidence of Lyme borreliosis is conterminous with the ticks habitat and covers the Northern Hemisphere. The Department of Epidemiology of National Institute of Public Health - National Institute of Hygiene (NIPH-NIH) is liable for the registration of Lyme borreliosis since 1996. The highest incidence of Lyme borreliosis is observed in the north-east region, but it should be noted that the disease is not only restricted to the aforesaid area of Poland.

OBJECTIVES

The aim of the present article is to analyze the epidemiological situation of Lyme borreliosis in Poland in 2010 with its comparison to the situation observed in the previous years.

MATERIAL AND METHODS

The epidemiological situation of Lyme borreliosis in Poland was analyzed on the basis of case-based questionnaires for Lyme borreliosis sent to Epidemiology Department NIPH-NIH by the Sanitary and Epidemiological Stations and the data from the bulletin--"Infectious diseases and poisonings in Poland in 2010" (MP Czarkowski et al., Warsaw 2011, NIPH-NIH, Chief Sanitary Inspectorate).

RESULTS

In 2010, 9005 Lyme borreliosis cases were registered in Poland, which constitutes a 13% decrease in the number of reported cases and incidence (23.6 per 100 000 population) in the comparison with the previous year. The highest incidence, accounting for 76.0 per 100 000 population, was reported in podlaskie voivodeship. 2318 persons were hospitalized due to Lyme borreliosis.

CONCLUSIONS

In 2010, for the first time in eight years, an increased tendency of the number of registered Lyme borreliosis cases was not observed. An approximately 13% decline in the number of notified cases was reported in comparison with the previous year. There is still a low number of Western blot tests performed to confirm the disease.

What do we need to know about disease ecology to prevent Lyme disease in the northeastern United States?

Lyme disease is the most commonly reported vector-borne disease in the United States, with the majority of cases occurring in the Northeast. It has now been three decades since the etiological agent of the disease in North America, the spirochete Borrelia burgdorferi, and its primary North American vectors, the ticks Ixodes scapularis Say and I. pacificus Cooley & Kohls, were identified. Great strides have been made in our understanding of the ecology of the vectors and disease agent, and this knowledge has been used to design a wide range of prevention and control strategies. However, despite these advances, the number of Lyme disease cases have steadily increased. In this article, we assess potential reasons for the continued lack of success in prevention and control of Lyme disease in the northeastern United States, and identify conceptual areas where additional knowledge could be used to improve Lyme disease prevention and control strategies. Some of these areas include: 1) identifying critical host infestation rates required to maintain enzootic transmission of B. burgdorferi, 2) understanding how habitat diversity and forest fragmentation impacts acarological risk of exposure to B. burgdorferi and the ability of interventions to reduce risk, 3) quantifying the epidemiological outcomes of interventions focusing on ticks or vertebrate reservoirs, and 4) refining knowledge of how human behavior influences Lyme disease risk and identifying barriers to the adoption of personal protective measures and environmental tick management.

Borrelia burgdorferi BBA52 is a potential target for transmission blocking Lyme disease vaccine

The surface-exposed antigens of Borrelia burgdorferi represent important targets for induction of protective host immune responses. BBA52 is preferentially expressed by B. burgdorferi in the feeding tick, and a targeted deletion of bba52 interferes with vector-host transitions in vivo. In this study, we demonstrate that BBA52 is an outer membrane surface-exposed protein and that disulfide bridges take part in the homo-oligomeric assembly of native protein. BBA52 antibodies lack detectable borreliacidal activities in vitro. However, active immunization studies demonstrated that BBA52 vaccinated mice were significantly less susceptible to subsequent tick-borne challenge infection. Similarly, passive transfer of BBA52 antibodies in ticks completely blocked B. burgdorferi transmission from feeding ticks to naïve mice. Taken together, these studies highlight the role of BBA52 in spirochete dissemination from ticks to mice and demonstrate the potential of BBA52 antibody-mediated strategy to complement the ongoing efforts to develop vaccines for blocking the transmission of B. burgdorferi.

Synthesis and antigenicity of BBGL-2 glycolipids of Borrelia burgdorferi, the causative agent of Lyme disease

Borrelia burgdorferi is the etiological agent for Lyme disease (LD), the most common vector borne disease in the United States. There is no human vaccine against LD currently available. Our approach to a vaccine is based on its surface-exposed glycolipids. One group of these glycolipids termed BBGL-2 consists of 1,2-di-O-acyl-3-O-(α-d-galactopyranosyl)-sn-glycerol congeners having palmitic, oleic, stearic, linoleic, and myristic acids. In order to delineate the immunodominant region(s) of the BBGL-2 components, we embarked on a synthetic project to provide available structurally defined, homogeneous analogs of BBGL-2 that might help identify the best vaccine candidate. The antigenicity of the synthetic glycolipids was examined by dot-blot analysis using mice sera obtained by immunization with killed B. burgdorferi cells, with native BBGL-2 in complete Freund's adjuvant, as well as sera obtained from patients with Lyme disease. We found that the presence of two acyl groups in the glycerol moiety was essential for antigenicity. At least one of these groups must be an oleoyl moiety. Neither the anomeric configuration of the galactose nor the configuration of the glycerol at C-2 was a decisive factor. Based on these findings we designed an 'unnatural' BBGL-2 analog having the structure 3-O-(β-d-galactopyranosyl)-1,2-di-O-oleoyl-dl-glycerol which is easier and less expensive to synthesize than the other BBGL-2 congeners prepared in this study. This substance proved to be antigenic and is considered a candidate vaccine for Lyme disease.