The distribution of Borrelia burgdorferi sensu lato, the Lyme borreliosis agent, was surveyed in British ticks in the collection of the Natural History Museum, London. Alcohol-preserved specimens of eight species of ticks known to attack humans were studied: Ixodes ricinus, I. hexagonus, I. uriae, I. trianguliceps, Dermacentor reticulatus, Haemaphysalis punctata, Rhipicephalus sanguineus and Argas vespertilionis. The sample comprised all life stages and originated from a wide range of host species, collection dates (1896-1994) and geographical localities in England, Scotland and Wales. Borrelia burgdorferi s.l. DNA, detected by a polymerase chain reaction that targeted the outer surface protein A gene, was found in all eight species. The overall proportion of PCR-positive specimens ranged from 7.8% for I. hexagonus (mostly from mustelids and hedgehogs) to 98.3% for I. uriae (mostly from seabirds). Borrelia burgdorferi s.l. DNA was found for the first time in the bat parasite A. vespertilionis (85.3%). The spirochaete is newly recorded in British populations of I. trianguliceps (97.4%, mostly from voles, mice and shrews), D. reticulatus (12.5% from dog and man) and R. sanguineus (30% from dogs and human dwellings). Of the four tick species with larvae available for testing, examples of I. ricinus, I. uriae and A. vespertilionis were PCR positive, as were significantly more nymphs than adults of I. ricinus, I. hexagonus and A. vespertilionis. Analyses showed that B. burgdorferi s.l. has been consistently present in British tick populations since at least 1897. Ticks positive for B. burgdorferi s.l. DNA were collected in all months of the year, throughout Britain, and were found on a wide range of mammal and bird species. PCR positivity does not prove vector or reservoir competence, but the use of archived material has demonstrated an extensive range of host-tick relationships involving B. burgdorferi s.l. in Britain for > 100 years.

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Analyses of the gut contents of larvae of three species of Tanypodinae, collected from four sites in north-east England and Scotland, invariably showed small particles (1-1o µm2), predominantly of detritus, to be more abundant than large particles (totoo AM), mostly algae and diatoms . No animal remains, such as carapaces, head capsules and chaetae, or vascular plant fragments were found in any of the intestines . In contrast, food-choice and growth experiments suggested that animal food (particularly Tubificidae and Chironominae larvae) was important in the tanypod diet . In the food-choice experiments, six different foods offered to small (4-7 mm long) and to large (8-12 mm long) larvae of Procladius choreus Meigen, were chosen in the following order: live Tubificidae spp . ; detritus ; live Chironominae larvae ; a mixture of algae and diatoms ; live Ostracoda spp . ; and live Cladocera spp . However, when the results of the individual choices were examined, it was clear that the small larvae had consumed greater amounts of the small types of food (i.e . detritus, algae and diatoms) in comparison to the large larvae .

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Red squirrels (Sciurus vulgaris) found dead or dying on the Isle of Wight and the island of Jersey were suffering from exudative, ulcerative dermatitis and superficial staphylococcal pyoderma. The principal gross lesions were on the lips, eyelids and feet and showed similarities to those of squirrelpox. The histopathological lesions were also similar and, although there was no ballooning degeneration of epidermal cells, intracytoplasmic inclusions resembling those seen in poxvirus infections were present. Examination of lesions by electron microscopy failed to identify any virions, and PCR analysis for squirrelpox virus proved negative. The skin lesions also resembled those of mange, but although numerous mites were present in the fur these were mostly Dermacarus sciurinus with small numbers of Metalistrophorus pagenstecheri. The occurrence of these species on red squirrels in Britain is confirmed, but neither is pathogenic and they were not considered to have been involved in the pathogenesis of the dermatitis, the primary cause of which was not established.