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Lyme borreliosis, caused by the tick-borne bacterium Borrelia burgdorferi, has become the most common vector-borne disease in North America over the last three decades. To understand the dynamics of the epizootic spread and to predict the evolutionary trajectories of B. burgdorferi, accurate information on the population structure and the evolutionary relationships of the pathogen is crucial. We, therefore, developed a multilocus sequence typing (MLST) scheme for B. burgdorferi based on eight chromosomal housekeeping genes. We validated the MLST scheme on B. burgdorferi specimens from North America and Europe, comprising both cultured isolates and infected ticks. These data were compared with sequences for the commonly used genetic markers rrs-rrlA intergenic spacer (IGS) and the gene encoding the outer surface protein C (ospC). The study demonstrates that the concatenated sequences of the housekeeping genes of B. burgdorferi provide highly resolved phylogenetic signals and that the housekeeping genes evolve differently compared with the IGS locus and ospC. Using sequence data, the study reveals that North American and European populations of B, burgdorferi correspond to genetically distinct populations. Importantly, the MLST data suggest that B. burgdorferi originated in Europe rather than in North America as proposed previously. evolution | Lyme borreliosis | ticks

A study to determine the effect on patients following administration of intravenous methcathinone is conducted. Results reveal that patients manifested a parkinsonian syndrome due to the effects of methcathinone raising incidence of acquired immunodeficiency syndrome (AIDS) and human immunodeficiency virus (HIV) besides elevated levels of blood manganese causing a neurological disorder.

Different host characteristics of ticks determine which genospecies of Borrelia burgdorferi sensu lato will infect the tick. When more than one genospecies is present in ticks, B. garinii and B. valaisiana segregate from B. afzelii.

Many plastic monomers are known to cause serious health effects. However, when these monomers are chemically reacted to form the familiar plastic polymers, they are generally harmless. The plastic monomer acrylamide is known to cause damage to the peripheral nerves. Few reports exist indicating any serious hazard associated with methyl methacrylate monomer. This substance is in much more common use, and the polymer acrylic plastic is a familiar household item to many. Methyl methacrylate is also used in making various prostheses used in dentistry and orthopedic surgery. There have been some reports that some dentists, technicians, and orthopedic surgeons who mold methyl methacrylate monomer products without using gloves may develop sensory abnormalities in their fingers. Now, however, a patient has been seen with generalized peripheral nerve damage that may be the result of exposure to methyl methacrylate monomer. The patient noticed mild leg weakness on walking at the age of 55 which progressed over the next several years. Electrophysiological studies revealed a defect in conduction in the peripheral nerves, and a nerve biopsy revealed a reduced density of myelinated nerve fibers in a peripheral nerve. The observed changes were similar to those which have been observed in factory workers exposed to acrylamide. This patient had been a dental technician for 30 years, and it is estimated that during that time he made 10 pairs of dentures each week and repaired 15 more. During these tasks, he was exposed to methyl methacrylate not only through his fingers, but by breathing the vapors as well. Of course, a single case is insufficient to establish methyl methacrylate as the cause of the peripheral nerve disorder in this patient. Nevertheless, the case strongly suggests that long-term exposure to this plastic monomer carries with it a strong risk of peripheral nerve degeneration. (Consumer Summary produced by Reliance Medical Information, Inc.)

Research has been conducted on Borrelia burgdorferi genospecies. The authors report their study of sensu lato distribution of these genospecies in questing Ixodes ticks from ecological habitats in Latvia.

Edited by GERARD SAID (Pp 200, £24.95). Published by Martin Dunitz, London, 2000. ISBN 1 85317 758 X. Over the past decade the introduction of high dose intravenous immunoglobulin (IvIg) [...]

Michael Donaghy was born in New York in 1954 to Irish parents, but he has lived for most of his writing life in London where he is a member of […]

Introduction to Clinical Neurology. By DOUGLAS J GELD (Pp86, £22.50). Published by Butterworth Heinemann, Oxford, 2000. ISBN 0-7506-7202-1. This is the second edition of Gelb's systematic approach to the neurological [...]

Proposed: That the electrode lies as it sparks the scent of Vicks from the cortex; and the bedroom's fevered wallpaper strafed by headlights, the rain, the tires' hiss through rain, [...]

We taped it under the seats, packed it into the door panels, drove it over the mountains in July, and the other two hadn't a word of the language, not [...]

It's shut. And after such a climb! A caustic drizzle slicks the abandoned funicular railway as the lights come on below in the abandoned weekend. The distant band's just tuning [...]

Byline: Mark Busby (1), Kannan Nithi (1), Kerry Mills (1), Michael Donaghy (1) Author Affiliation: (1) University Department of Clinical Neurology, Radcliffe Infirmary, Oxford OX2 6HE, UK, GB Article note: Received: 16 November 2000, Received in revised form: 12 October 2002, Accepted: 14 October 2002 Correspondence to M. Donaghy

Edited by C Sommer (Pp 202, us$170.50). Published by Karger, Basel, 2001. ISBN 3-8055-7268-9 Despite having a subspeciality interest in peripheral nerve disease, often I am perplexed by patients with [...]

THE WHIP Sometimes your writing's a soft tangle of subtleties undercutting one another, blurring the paths and you arrive at a washed out bridge or rockslide. Leave it. Don't try [...]

THE NEW GREY It's black, it says here, but not jet, not shiny, more the charcoal black old family snapshots burn, the dark of the cathedral vault aswarm with pigeons [...]

THE SWEAR BOX They open, at forty, cabinets their father locked, boys again, whispering bad words beneath blankets, girls spitting the big verbs at their mirrors. Something sharp and rusty [...]

By M Victor and A H Ropper (Pp 547, US$39.95). Published by McGraw-Hill Companies, New York, 2002. ISBN 0-07-137351-9 Nearly 20 years ago I used books to learn my neurology [...]