Tick bite and Lyme borreliosis risk at a recreational site in England.

The risk of tick bite and Lyme borreliosis in a forested area in England with public access was studied over a two-year period. Tick infestation levels were high with more than 1000 members of the public reporting for tick removal at a local clinic. Most of the attached ticks were nymphs (82%) and distinct differences in anatomical sites of attachment were observed in children and adults. Children sustained nymphal bites to the head, neck and axilla region much more frequently than adults (48 vs. 10%), whereas adults were bitten on the lower legs more frequently than children (46 vs. 9%). The vegetation was heavily infested with ticks and high numbers were particularly associated with areas used by deer. The average density of nymphs collected from the vegetation was 14.1 per 10 m2 (range 5.1-43.6). Infection rates of these nymphs determined by PCR and indirect IFA ranged from 5.2-17.0%, and the genospecies Borrelia valaisiana and B. garinii were detected, suggesting that birds may be important reservoir hosts in this area. It is estimated that, at the level of tick challenge observed here, at least 50 persons per year may be bitten by infected ticks at this site. However, no cases of Lyme borreliosis have been reported through the clinic follow-up procedure, and sera from 19 forest workers were negative for antibody to B. burgdorferi sensu lato. Despite the high challenge from tick bites, this particular recreational forest site poses a low risk of infection to the general public, and prophylactic antibiotic treatment or serological testing following a bite is not justified.

Limited role of rodents as reservoirs of Borrelia burgdorferi sensu lato in Ireland.

Despite the presence of Borrelia burgdorferi s.l.-infected Ixodes ricinus ticks in a west of Ireland location, very few small rodents from the same habitats were infected. Most of the infected ticks contained B. garinii or B. valaisiana, which implicates birds as the important reservoir hosts in this location.

Borrelia burgdorferi sensu lato in Ixodes ricinus ticks and rodents in a recreational park in south-western Ireland.

Ixodes ricinus ticks infected with Borrelia burgdorferi sensu lato were numerous on the edges of paths and roads in a recreational park in south-western Ireland. The abundance of ticks at different sites was related to the presence of deer, but a negative relationship was shown between tick abundance and tick infection rates. This is thought to be due to the deposition of large numbers of uninfected ticks by deer, which are apparently not good reservoir hosts of B. burgdorferi s.l. Blood meal analysis only detected deer DNA in uninfected nymphs. Reservoir competent rodents, Apodemus sylvaticus and Clethrionomys glareolus, were abundant at all sites and a high proportion of captured specimens were infested with larval ticks. However, very few rodents were infected with B. burgdorferi s.l. and none of the unfed infected nymphs analysed for the identity of their larval blood meal had fed on rodents. The spirochaetes detected in I. ricinus in the study area may be poorly adapted to rodents or are not transmitted readily because of the absence of nymphal infestation. The majority of spirochaetes in these ticks were apparently acquired from non-rodent hosts, such as birds.

Seroprevalence of Borrelia burgdorferi sensu lato infection in blood donors and park rangers in relation to local habitat.

Serum samples were obtained from blood donors in eleven selected locations in Ireland and tested for antibodies to Borrelia burgdorferi s.l. by enzyme immunoassay (EIA) and immunoblot (IB). The highest seroprevalence (8.7%) was found in Portumna, an area rated as high risk because of the presence of public access woodland harbouring both ticks and spirochaete reservoir hosts. The lowest seroprevalence (0.0%) was found in Ballina, an area where there is no suitable woodland though ticks are common on pastures grazed by cattle and sheep. These results support the findings of an earlier less extensive study and suggest that infection with B. burgdorferi s.l. in Ireland is mainly associated with mixed woodland containing deer and a variety of spirochaete reservoir hosts. The lack of association of tick-infested farmland with seropositive samples suggests that exposure to ticks alone is not a reliable indicator of risk of Lyme borreliosis. This is supported by the fact that none of 38 park rangers, all of whom are regularly bitten by ticks, were seropositive for B. burgdorferi s.l. The low overall seroprevalence of 3.4% in Ireland correlates with the rarity of clinical cases compared with continental European countries, and is due in part to the scarcity of high risk Lyme borreliosis habitat.

European interlaboratory comparison of Lyme borreliosis serology.

Serological testing for Lyme borreliosis was compared in 5 European reference laboratories with a total of 79 sera in order to determine variations in laboratory performance. A considerable range of methods were used and several laboratories employed 2 or 3 genomospecies of Borrelia burgdorferi sensu lato. No laboratory relied routinely on a single test and each weighted the significance of the findings of the various tests differently. A difference in strategy between laboratories in high and low prevalence areas was apparent in that laboratories in low prevalence areas emphasised specificity more than sensitivity and therefore produced fewer false positives, but also missed some cases. Overall agreement between the laboratories was poor and it was concluded that there is a need for a quality assurance scheme within Europe.

The European Union Concerted Action World Wide Web site for Lyme borreliosis.

This web site (URL http://www.dis.strath.ac.uk/vie/LymeEU/) provides information on Lyme borreliosis for physicians, scientists, health care workers, veterinarians and students. It consists of a review of the spirochaetes, vectors, reservoir hosts, diagnosis, treatment, epidemiology and prevention of the disease, as well as an account of the activities of EUCALB.

Lyme borreliosis habitat assessment.

Tick ecologists throughout Europe provided descriptions of Lyme borreliosis habitats according to a standardised format and data for 105 habitats in 16 countries were received. The data showed that high risk situations, as defined by the presence of large numbers of B. burgdorferi sensu lato-infected nymphal I. ricinus, occur in heterogeneous deciduous woodland, usually with a recreational function and with a diverse fauna, usually including deer. Large numbers of ticks occurred in some other habitats, but infection prevalence was usually low. The situation for adult I. ricinus was similar but less clearly defined. Tick infection rates were found to be lower in western Europe than in the east, and the infection rate in I. persulcatus, the most easterly vector species, was markedly higher than in I. ricinus. In the vast majority of habitats the infection rate in adult I. ricinus was greater than in nymphs. Larvae were rarely found to be infected.

The role of Chlamydia trachomatis and Neisseria gonorrhoeae in the aetiology of ectopic pregnancy in Gabon.

OBJECTIVE: To study the association between ectopic pregnancy and Chlamydia trachomatis and Neisseria gonorrhoeae. DESIGN: A prospective observational study with two comparison groups. SETTING: A general hospital in Franceville, Gabon. SUBJECTS: Forty-five women with ectopic pregnancies and two comparison groups each of 45 women, one at 5 to 12 and the other at 32 to 41 weeks gestation. MAIN OUTCOME MEASURES: Serum levels of IgG and IgA antibodies to C. trachomatis (L1 and rMOMP) and N. gonorrhoeae (pili) in all the women. In the women with ectopic pregnancy peritoneal adhesions were scored and in 40 women samples of tube were cultured for organisms being studied. RESULTS: IgG and IgA antibodies to C. trachomatis (L1) were detected in 84% of the ectopic group and 53 and 39% of the comparison groups (P less than 0.0001). IgG and IgA antibodies to N. gonorrhoeae occurred in 49, 28 and 18% and 49, 28 and 26% of the groups but the differences were not statistically significant. Adhesions were positively associated with the antibodies. C. trachomatis was cultured from the tubes of 71% of the women with ectopic pregnancy. CONCLUSIONS: Infection with chlamydia, and probably with N. gonorrhoeae, is an important factor in the causation of ectopic pregnancy in Gabon.

PIP: A general hospital in Franceville, Gabon was the site for this prospective, observational study with 2 comparison groups which studied the association between ectopic pregnancy and Chlamydia trachomatous and Neisseria gonorrhoea. 45 women with ectopic pregnancies and 2 comparison groups, each with 45 women, were part of the study, 1 group from 5-12 weeks and the other at 32-41 weeks gestation. Serum levels of IgG and IgA antibodies to C. trachomatous (L1 and rMOMP) and gonorrhoea (pili) in all of the women were measured. In women with ectopic pregnancy, peritoneal adhesions were scored and in 40 women, samples of tube were cultured for organisms under study. IgG and IgA antibodies to C. trachomatous (L1) were detected in 84% of the ectopic group and 53% and 39% of the comparison groups (p0.001). IgG and IgA antibodies to N. gonorrhoea occurred in 49, 28, and 18%, and 49, 28, and 26% for the groups but the differences were not statistically significant. Adhesions were positively associated with the antibodies. C. trachomatous was cultured from the tubes of 71% of the women with ectopic pregnancies. It was concluded that infection with chlamydia, and probably with N. gonorrhoea, is an important factor in the causation of ectopic pregnancy in Gabon.

Gonococcal and chlamydial antibodies in ectopic and intrauterine pregnancy.

Sera from 50 women with ectopic pregnancy and 50 age-matched control women with intrauterine pregnancy were tested by enzyme-linked immunosorbent assay (ELISA) using C. trachomatis and N. gonorrhoeae pili as antigens. In the ectopic pregnancy group 76% had IgG antibodies to C. trachomatis compared with 38% in the controls. The prevalence of gonococcal IgG antibody was 32% in the ectopic pregnancy group and 4% in the controls. The prevalences of IgA antibodies to the two organisms ranged from 2 to 12% and were similar in the two groups; cultures for C. trachomatis from cervical swabs from the ectopic pregnancy group were negative. Chlamydial antigen was detected (by ELISA) in exfoliated cervical cells of only one patient in this group.

Detection of Chlamydia trachomatis by enzyme immunoassay in patients with trachoma.

Trachoma control necessitates identification of individuals shedding ocular chlamydiae. Conventional techniques of chlamydial culture are unsuitable for large field surveys in developing countries. In this study an enzyme immunoassay (EIA) developed for the detection of chlamydial antigen in genital-tract infection was used in trachoma. Conjunctival swabs were taken for chlamydial antigen detection from 1225 subjects in a Gambian village with endemic trachoma. Of these, 997 had insignificant or no disease and 172 had mild, 30 moderate, and 26 severe disease. Chlamydial antigen was detected in 5.0%, 20.3%, 46.7%, and 26.9% of subjects in these four categories, respectively. Samples for chlamydial isolation were obtained from 259 subjects. The corresponding rates of detection obtained by chlamydial isolation were 3/90 (3.3%), 16/129 (12.4%), 7/21 (33.3%), and 7/19 (36.8%). If isolation is taken as the "gold standard", the EIA technique had a sensitivity of 70.6% and a specificity of 90%. A substantial proportion of subjects with severe conjunctival scarring, from whom chlamydiae cannot generally be isolated, were antigen positive by EIA, implying that persistent chlamydial antigen plays a part in the pathogenesis of the late sequelae of trachoma.

Chlamydial and gonococcal antibodies in sera of infertile women with tubal obstruction.

Sera from 48 infertile women with tubal pathology and from 77 infertile women with normal fallopian tubes were tested by enzyme linked immunosorbent assay (ELISA) using Chlamydia trachomatis and Neisseria gonorrhoeae antigens. Control sera were obtained from women undergoing abortion, sterilisation, and from women practising barrier contraception. The results of ELISA for antibodies to chlamydiae were in close agreement with results published previously of an immunofluorescence test on these sera. Antibodies to C trachomatis were found in 73% of the infertile women with tubal pathology, significantly more than in any of the control groups. Only a very low prevalence (2-5%) of antibodies to gonococcal pili was found in all groups, except women undergoing abortion (16%).

Tubal infertility in the Gambia: chlamydial and gonococcal serology in women with tubal occlusion compared with pregnant controls.

PIP: Levels of immunoglobulin G (IgG) antibodies to Chlamydia trachomatis and Neisseria gonorrhoeae were determined by enzyme-linked immunosorbent assay (ELISA) in 37 infertile Gambian women with bilateral fallopian tube occlusion and in 37 pregnant controls matched for age, ethnic group, and domicile. The infertile women had a significantly higher prevalence of antibodies to C. trachomatis serotype L1 (P=0.1) and to purified N. gonorrhoeae pili, outer membrane, and Lipopolysaccharide antigens (P0.01 in each case). Serological studies of immunoglobulin A (IgA) antibodies to C. trachomatis were less sensitive than the IgG studies in discriminating between the pregnant and infertile groups, suggesting that much of the infertility due to chlamydiae was the result of past rather than current infection. Data suggest that both C. trachomatis and N. gonorrhoea are important causes of infertility due to tubal pathology in Gambian women. (author's)^ieng

The preparation and properties of alpha and beta pili from variants of Neisseria gonorrhoeae P9.

The alpha and beta type pili produced by variants of Neisseria gonorrhoeae P9 were isolated and characterized. The two types of pili showed clear differences in morphology, buoyant density (alpha, 1.292 g ml-1; beta, 1.282 g ml-1) and isoelectric point (alpha, pI 5.2; beta, pI 4.3). Amino acid analysis of alpha and beta pili showed that their overall composition was similar with the exception that beta pili had a higher content of glutamate and alanine residues. A high degree of structural homology was seen in two-dimensional peptide maps of tryptic hydrolysates of alpha and beta pili. The molecular differences between alpha and beta pili were reflected in their antigenic activity and in their ability to attach to human cells. The binding of alpha pili to buccal epithelial cells was pH dependent with a maximum binding of 49% at pH 6.5, whereas the attachment of beta pili showed no pH optimum. The binding of pili to erythrocytes differed from binding to buccal epithelial cells in that attachment of both pili was identical with no pH optimum. Data from attachment of pili to human cells suggest that erythrocytes lack receptors for binding gonococcal pili.

Biological properties of two distinct pilus types produced by isogenic variants of Neisseria gonorrhoeae P9.

Isogenic variants from a single strain of Neisseria gonorrhoeae were shown to produce two distinct types of pili. These pili, designated alpha and beta, differed in both subunit molecular weight and in ability to attach to buccal epithelial cells.

Protection by monospecific gonococcal antisera of the chicken embryo challenged with Neisseria gonorrhoeae.

The protective effects of monospecific gonococcal antisera on 11-day chick embryos challenged with a known lethal dose of gonococci were assessed. The monospecific antisera were prepared by immunisation of rabbits with purified gonococcal antigens, and removal of trace amounts of unwanted antibodies was achieved by absorption with antigen covalently bound to cyanogen bromide-activated Sepharose beads. The antisera were standardised for IgG by solid-phase radioimmunoassay. Antiserum raised against whole outer membrane was protective and antiserum raised against the lipopolysaccharide (LPS) was moderately protective. Outer-membrane antiserum from which the LPS component was removed by absorption was less protective than either of these sera. Investigation of the protective mechanism of anti-LPS antibodies indicated that in addition to any antitoxic effect, these antibodies inhibited the multiplication of gonococci. Antisera raised against individual outer-membrane proteins offered no protection in this test. Out of five antisera tested, antipilus serum gave the strongest protection when piliate gonococci were used as the challenge in this model; antipilus serum did not protect against challenge with non-piliate gonococci.

The preparation and properties of gonococcal pili.

Pili have been isolated from Neisseria gonorrhoeae by controlled homogenization followed by selective disaggregation in sucrose and purification by CsCl density gradient centrifugation. Pili from six gonococcal strains had buoyant densities of 1-30 to 1-31 g ml-1 on CsCl. The pili were immunologically distinct when tested with rabbit antisera to purified pili. The amino acid composition of pilin from strains P9 and 201 was very similar, consisting of 208 and 212 amino acid residues respectively giving molecular weights of 22 600 and 22352. The pili contained a high proportion (46%) of non-polar amino acids. Further analysis of strain P9 pili revealed the presence of 1 to 2 phosphate groups and 1 to 2 hexose groups per pilin subunit; no amino sugars were detected. Pili from strain P9 were resolved into two bands by equilibrium density gradient centrifugation or column isoelectric focusing, suggesting the presence of more than one kind of pilus.