Q fever outbreak in the terraced vineyards of Lavaux, Switzerland

Coxiella burnetii infection (Q fever) is a widespread zoonosis with low endemicity in Switzerland, therefore no mandatory public report was required. A cluster of initially ten human cases of acute Q fever infections characterized by prolonged fever, asthenia and mild hepatitis occurred in 2012 in the terraced vineyard of Lavaux. Epidemiological investigations based on patients' interviews and veterinary investigations included environmental sampling as well as Coxiella-specific serological assay and molecular examinations (real-time PCR in vaginal secretions) of suspected sheep. These investigations demonstrated that 43% of sheep carried the bacteria whereas 30% exhibited anti-Coxiella antibodies. Mitigation measures, including limiting human contacts with the flock, hygiene measures, flock vaccination and a public official alert, have permitted the detection of four additional human cases and the avoidance of a much larger outbreak. Since November 2012, mandatory reporting of Q fever to Swiss public health authorities has been reintroduced. A close follow up of human cases will be necessary to identify chronic Q fever.

[Tick-borne encephalitis: first autochtonous case and epidemiological surveillance in canton Valais, Switzerland]

Tick-borne encephalitis (TBE, in French MEVE) is a viral disease usually transmitted to man through an infected tick belonging to the genus Ixodes. Every year about 135 cases of TBE are reported to the Swiss Federal Office of Public Health. Emerging in north-east of Switzerland in the seventies, endemic areas have been slowly spreading. Actually 18 cantons out of 26 have been reached. In the western part of Switzerland, spared until not long ago, new endemic foci are spreading toward the lake of Geneva and recently in Valais. The precise exposure history of human cases, as well as the evaluation of collected tick samples allow the detection of endemic foci which are discontinuous and of variable size. New and more efficient methods are needed to monitor the changing epidemiology of TBE.

[Q fever: a cause of fever of unknown origin in Switzerland]

We describe two cases of Q fever in previously healthy women presenting with fever of unknown origin. The diagnosis was made after several days of investigations. Symptoms and signs of acute or chronic Coxiella burnetii infection are protean and non-specific. Q fever should be included in the differential diagnosis of fever of unknown origin and appropriate serologic studies should be done. We review the clinical presentation of Q fever. Use of serology for the diagnosis and the follow-up is discussed.

[Rickettsial diseases in Switzerland, update for the general practitioner]

Rickettsial diseases are arthropod-borne zoonosis. They are still misdiagnosed in Switzerland. Since development in molecular genetics, number of pathogenic species increased dramatically. In recent years, the incidence rise worldwide. Climatic conditions and development of tropical travels could explain it. In a near future, the Swiss general practitioner may face an increase of cases. Clinical presentation is unspecified. The eschar is the key diagnostic element but can be easily overlooked. Serology, the indirect immunofluorescence assay is the reference method. PCR can give the diagnosis in acute phase. However empirical treatment should be prescribed as soon as diagnosis is suspected. No vaccine is currently available and use of repellent is still the best way of prevention.

[Diseases and pathogenic agents transmitted by ticks in Switzerland]

Among the 20 tick species described in Switzerland, Ixodes ricinus, the most frequent one, is implicated in the transmission of pathogenic agents. Lyme borreliosis and tick-borne encephalitis (TBE) are the major tick-borne diseases transmitted to human. Presently 5 Borrelia species, belonging to the group Borrelia burgdorferi, are recognized as human pathogens. The risks of infection depend on the stage of the vector, the multiple hosts, the pathogenic agent, as well as human behavior in nature. The detection of other pathogenic agents in ticks: Anaplasma, Babesia and Rickettsia predispose to infections or co-infections. Results of sero-epidemiologic studies suggest human infections. Active surveillance by physicians is necessary and clinical studies are required to evaluate the importance of these infections in Switzerland.

[Atrioventricular heart block in Lyme disease]

Lyme disease is the most common tick-borne disease in Europe and in the United States. In comparison to dermatological, neurological and rheumatological manifestations, heart disease is quite rare. Atrioventricular heart block is nevertheless the most frequent cardiological manifestation. We hereby report the case of a patient with high degree heart block due to Lyme disease. We focus on the electrocardiographical evolution during antibiotic therapy, as well as on microbiological and diagnostic aspects. Lyme disease is a rare cause of conduction disturbances but it is treatable and potentially reversible.

Seroprevalence of Q-fever in febrile individuals in Mali

OBJECTIVES

We conducted a serological survey for Q-fever among febrile patients in Bamako and Mopti (Mali) and investigated the main risk factors for seroconversion.

METHODS

Blood samples from 156 febrile patients were collected in healthcare facilities of Bamako and Mopti and examined with the microimmunofluorescence test.

RESULTS

Forty per cent (n = 63) were seropositive for Q-fever, 28% in Bamako and 51% in Mopti. A more recent infection was suspected in 9.5% (n = 6) of all seropositive patients. This is the first time that Q-fever seropositivity is reported in febrile individuals in Mali. The patients' symptoms and diagnoses spanned a wide range of conditions; none had been diagnosed with Q fever by their treating physician. No risk factors for seropositivity could be identified with the exception of the city of residence and none could be identified with a logistic regression model with 'city' taken as random effect.

CONCLUSION

A high rate of seropositivity to C. burnetii was found among febrile urban patients in Mali but no risk factors for seropositivity could be identified in this study.

Risk of Borrelia burgdorferi infection in western Switzerland following a tick bite

The aim of this study was to define the risk of developing Lyme borreliosis after a tick bite. A survey was conducted from 1993 to 1995 in the western part of Switzerland in a group of patients who presented for treatment of a recent tick bite. Only patients with negative serological tests (enzyme-linked fluorescent assay screening test, and IgG and IgM immunoblots) at the first consultation and for whom a second blood sample was available 2 months later were included in the study. Of the 376 patients included, 266 had no clinical manifestation (group 1) and 110 had a small local cutaneous reaction (<2 cm) (group 2). The tick was available for 160 patients. Seroconversion was observed in 4.5% of 376 patients, 3.4% in group 1 and 7.2% in group 2. Typical erythema migrans, confirmed by seroconversion, was observed in three of 376 (0.8%) patients, while five of 376 (1.3%) patients developed a skin lesion without seroconversion. No other clinical manifestation of Lyme borreliosis was observed among these 376 patients. Borrelia detection in ticks did not correlate significantly with the risk of Lyme borreliosis. In conclusion, the risk of developing Lyme borreliosis in western Switzerland after a tick bite is low, and therefore, prophylactic antibiotics are not required.

[Fever after a tick bite: clinical manifestations and diagnosis of acute tick bite-associated infections in northeastern Switzerland]

BACKGROUND

Different tick-borne infections can cause an acute febrile illness. The study objectives were to investigate the clinical manifestations and diagnosis of infections among patients who presented with fever after a tick-bite, and to detect newly described pathogens, including Ehrlichia, Babesia and Rickettsia helvetica, in North-Eastern Switzerland.

PATIENTS AND METHODS

: We studied 75 patients (41 male, 34 female, median age 38 years, among them 10 children) who had fever within 3 weeks after a tick-bite. Paired sera were tested for antibodies to Borrelia burgdorferi, tick-borne encephalitis virus, Anaplasma (Ehrlichia) phagocytophila, Babesia microti, B. divergens, and Rickettsia helvetica. In addition, microscopy and polymerase chain reaction was used to detect Ehrlichia. Clinical data were obtained at baseline and at 1 and 2 year follow-up.

RESULTS

Tick-borne infections were confirmed or possible in 36 (48 %) patients: 7 (9 %) Erythema migrans, 6 (8 %) other specific manifestations of Lyme borreliosis, 6 (8 %) Lyme borreliosis presenting as non-specific febrile illness, 8 (11 %) tick-borne encephalitis, 7 (10 %) granulocytic ehrlichiosis, 1 B. microti infection in a traveler from the US and 6 (8 %) dual infections. In 8 (11 %) patients serological findings were suggesting possible acute or past R. helvetica infection.

CONCLUSION

Among patients with fever after a tick-bite, Lyme borreliosis was most frequently found. There was no evidence for babesiosis among the resident population. Serologic data suggest that human granulocytic ehrlichiosis and R. helvetica infections may be endemic in Switzerland. Among 50 % of the patients no tick-borne infections could be diagnosed.

Routine diagnosis of Borrelia burgdorferi (sensu lato) infections using a real-time PCR assay

OBJECTIVE

To establish a one-tube fluorogenic real-time PCR assay for routine detection of Borrelia burgdorferi (sensu lato) DNA in various clinical specimens.

METHODS

A fragment of the flagellin gene sequence was amplified with the TaqMan chemistry using primers and a probe common to Borrelia burgdorferi sensu stricto, Borrelia afzelii, Borrelia garinii and Borrelia valaisiana. A recombinant plasmid containing the chromosomal gene coding for the flagellin protein was used as standard.

RESULTS

The specificity of the assay was documented with 48 different clinically relevant Borrelia burgdorferi strains. No cross-reaction occurred with unrelated bacteria, viruses and fungi. At an analytic sensitivity of 10 copies, excellent precision within runs and between runs was observed. The potential presence of inhibitors of the Taq DNA polymerase was monitored by spiking aliquots of each sample with a plasmid containing the target sequence. Among 56 cerebrospinal fluid samples taken from 54 patients with clinical suspicion of neuroborreliosis, one (1.8%) tested positive for Borrelia burgdorferi sensu lato DNA. Borrelia burgdorferi DNA was also detected in five (17.9%) of 28 synovial fluid specimens and in one (20%) of five synovial membrane biopsies obtained from 31 patients with arthropathies. In order to test for the absence of false-positive results, 84 samples from 83 patients without evidence of Lyme disease were investigated. None of these samples showed measurable amounts of Borrelia burgdorferi DNA.

CONCLUSION

By its established features, such as speed, reliability, sensitivity, specificity, the inclusion of carryover prevention and the monitoring of inhibitors in individual test tubes, this real-time PCR assay has proved to be a potent tool for the detection of Borrelia burgdorferi DNA under routine conditions in diagnostic laboratories.

Specificities and sensitivities of four monoclonal antibodies for typing of Borrelia burgdorferi sensu lato isolates

Borrelia burgdorferi, the agent of Lyme borreliosis, is genetically more heterogeneous than previously thought. In Europe five genospecies have been described from the original B. burgdorferi sensu lato (sl): B. burgdorferi sensu stricto (ss), B. garinii, B. afzelii, B. lusitaniae, and B. valaisiana. In the United States, B. burgdorferi ss as well as B. bissettii in California and B. andersonii on the East Coast were differentiated. In Asia, B. japonica has been identified along, with B. garinii, B. afzelii, and B. valaisiana. In order to evaluate sensitivity and specificity of four species-specific monoclonal antibodies, we analyzed 210 B. burgdorferi sl isolates belonging to eight genospecies by immunoblot and confirmed genospecies by restriction fragment length polymorphism (RFLP) of rrf (5S)-rrl (23S) intergenic spacer amplicon. Monoclonal antibody H3TS had 100% sensitivity for 55 B. burgdorferi ss isolates but showed reactivity with all four isolates belonging to B. bissetii. Monoclonal antibody I 17.3 showed 100% specificity and sensitivity for 45 B. afzelii isolates. Monoclonal antibody D6 was 100% specific for B. garinii but missed 1 of 64 isolates (98.5% sensitivity). Monoclonal antibody A116k was 100% specific for B. valaisiana but was unreactive with 4 of 24 isolates (83.5% sensitivity). Genetic analysis correlated well with results of reactivity and confirmed efficacy of the phenotypic typing of these antibodies. Some isolates showed atypical RFLP. Therefore, both phenotypic and genotypic analyses are needed to characterize new Borrelia isolates.

A mutagenic PCR identifies isolates of Borrelia garinii responsible for Lyme borreliosis

Borrelia garinii is one of the three major Borreliae responsible for Lyme borreliosis in Europe. We have characterized a protein of B. garinii (VS102) and a genomic fragment from the gene encoding this protein was cloned. The DNA sequence of the fragment showed high homology with a known gene of B. burgdorferi sensu stricto. The protein encoded by this gene in B. burgdorferi sensu stricto is a phosphocarrier protein (histidine-containing protein). A mutation T to G polymorphism at codon 57 was found to be specific to B. garinii. A PCR-based approach that allows the rapid detection of this mutation made it possible to specifically discriminate B. garinii from other B. burgdorferi genospecies with high sensitivity and specificity.

[Epidemiology of Lyme borreliosis in French-speaking Switzerland]

The purpose of this study was to assess the number of cases and the clinical aspects of Lyme borreliosis in French-speaking Switzerland. From July 1996 to December 1997, all laboratories performing serological tests for Lyme borreliosis sent a questionnaire to the treating physicians whenever the tests were positive. In addition, the physicians who diagnosed a case on clinical grounds only were also asked to report these cases. During this period, 1460 positive serological tests were recorded among approximately 10,360 performed (14%). A total of 775 questionnaires were returned (53%). In 3/4 of the cases, the test was ordered because of an acute clinical manifestation or a tick bite. The rest related to chronic symptoms or follow-up. In 504 cases (65%), diagnosis was considered certain or probable. These were erythema migrans in 46%, clinical manifestations of stage II in 33% (26 facial palsy, 20 acute arthritis, 5 benign cutaneous lymphocytoma) and chronic symptoms in 21% (23 acrodermatitis, 26 neuropathies, and 8 arthritis). The adjusted incidence, estimated on the basis of the treating physician's place of residence, ranged from 9/100,000 in Valais to 95/100,000 in Neuchâtel. This study indicates that Lyme borreliosis is a diagnosis frequently looked for and established in French-speaking Switzerland. Although erythema migrans is the main clinical manifestation, symptoms of stage II and III indicate that Lyme borreliosis is also responsible for relatively major systemic morbidity.

[Serological diagnosis and nasopharyngeal washings in pediatric infections]

In the course of respiratory infections, the efficacy of microbiologic diagnosis has increased years after years, in term of specificity, sensitivity and rapidity. New pathogenic agents have been described such as: Legionella pneumophila, Chlamydia pneumoniae, Hantavirus. Some viruses have been well characterized as responsible for seasonal outbreaks using rapid tools for identification. Needs for efficient diagnostic tools became more obvious when specific antiviral drugs appeared on the market. So technologic developments improved the efficacy of microbiologic diagnosis and anticipate a better specificity as well as sensitivity with the help of molecular biology. Respiratory syncytial virus is one of the major infectious agents found in respiratory infections in young children and newborns. On the whole it was detected in more than one third of pediatric nasopharyngeal aspirations received in our laboratory and more than 50% during the peak of the winter epidemics. The method of direct antigen detection by immunofluorescence with the help of monoclonal antibodies allowed us to establish an incidence curve of these recurrent outbreaks, beginning in December to stop usually by the end of April. During this same period, influenza A virus, seldom influenza B virus, were detected in many nasopharyngeal specimens. Other viruses, parainfluenza 1 to 3 and Adenovirus, were irregularly detected all along the year. In the great majority of nasopharyngeal aspirations with a positive virus detection, one virus only was observed. Antigen detection methods were also developed for some bacteria such as Chlamydia pneumoniae, Legionella pneumophila. Although serology is not frequently used by pediatricians, it is still necessary for the diagnosis of Mycoplasma pneumoniae infections. A direct antigen detection test is now available, but its sensitivity needs to be evaluated. On the other hand serologic diagnosis may be extremely useful when long lasting or treatment resistant respiratory infections occur. Seroconversion or four-fold increasing titers to one pathogen may be observed when a second serum sample is tested together with the first serum of this patient. The diagnostic yield will be all the more efficient that time between both samples is long. Molecular biology techniques will significantly change the way to investigate an infection. Presently these methods are used in research laboratories, but automated technologies will facilitate routine laboratory workload. Screening methods using multiplex PCR are also promising.

Scored antibody reactivity determined by immunoblotting shows an association between clinical manifestations and presence of Borrelia burgdorferi sensu stricto, B. garinii, B. afzelii, and B. Valaisiana in humans

An immunoglobulin G immunoblot was developed with antigenic extracts of Borrelia burgdorferi sensu stricto, B. garinii, B. afzelii, and B. valaisiana genospecies and was reacted with sera from patients with neuroborreliosis, acrodermatitis, and Lyme arthritis. A detailed analysis of the reactivities of the protein bands was performed, and a two-step scoring procedure was selected to determine the preferential reactivity of sera to one particular genospecies. The discriminative potential of 5 proteins (12-kDa, 16-kDa, 18-kDa, OspA, and 66-kDa proteins) was used as a rapid first-step scoring method, followed by scoring of 14 additional protein bands if necessary. The advantage of this procedure is the low percentage of serum samples with inconclusive results for one of the four species (10% for patients with neuroborreliosis, 6% for patients with acrodermatitis chronica atrophicans, and 6% for patients with Lyme arthritis). Among 31 serum samples from patients with neuroborreliosis, 16 were more reactive to B. garinii, 7 were more reactive to B. afzelii, 3 were more reactive to B. valaisiana, and 2 were more reactive to B. burgdorferi sensu stricto. Of 31 serum samples from patients with acrodermatitis, 26 showed a higher level of reactivity to B. afzelii. Of 34 serum samples from patients with Lyme arthritis, 21 were more reactive to B. burgdorferi sensu stricto, 10 were more reactive to B. afzelii, and 1 was more reactive to B. valaisiana. Our results suggest an organotropism of Borrelia species and provide some evidence of a pathogenic potential of B. valaisiana in humans.

No serological evidence of association between chlamydia pneumonia infection and acute coronary heart disease

Today's medical literature shows more and more evidence that Chlamydia pneumoniae plays a role in coronary atherosclerotic disease. This cross-sectional study examines the serostatus for C. pneumoniae of patients with an acute cardiovascular event. A total of 58 patients with acute myocardial infarction or with proven unstable angina (occlusion > or = 70% of at least 1 vessel at coronary angiography) ('patients') were compared with 58 age- and sex-matched patients without a cardiovascular event ('controls'). Serological testing for C. pneumoniae was performed by a microimmunofluorescence test during the first week of the event and 4-6 weeks later. Although more patients from the cardiovascular event group showed a positive history of a respiratory tract infection during 6 weeks preceding hospitalization (18/58 patients, 8/58 controls, p = 0.03), there was no significant difference between the two groups for an acute, chronic or past infection by C. pneumoniae (19/58 patients, 24/58 controls, p = 0.93). In conclusion, contrary to previous published papers, this study could not confirm an association of C. pneumoniae infection with an acute coronary event. Serological testing alone may not be the best way to demonstrate this association. An acute infection by C. pneumoniae, which should have been detected by serological testing, is probably not the origin of the rupture of an atheromatous plaque.

Long term vascular complications of Coxiella burnetii infection in Switzerland: cohort study

OBJECTIVE

To evaluate the range of long term vascular manifestations of Coxiella burnetii infection.

DESIGN

Cohort study in Switzerland of people affected in 1983 by the largest reported outbreak of Q fever and who were followed up 12 years later. Follow up information about possible vascular disease and endocarditis was obtained through a mailed questionnaire and death certificates.

SETTING

Val de Bagnes, a rural Alpine valley in Switzerland.

PARTICIPANTS

2044 (87%) of 2355 people who had serum testing for Coxiella burnetii infection in 1983: 1247 were classed as not having been infected, 411 were classed as having been acutely infected, and 386 were classed as having been infected before 1983.

MAIN OUTCOME MEASURES

Relative risk controlled for age and sex and 12 year risk of vascular diseases and endocarditis among infected participants as compared with those who had never been infected.

RESULTS

The 12 year risk of endocarditis or venous thromboembolic disease was not increased among those who had been acutely infected. The 12 year risk of arterial disease was significantly higher among those who had been acutely infected (7%) as compared with those who had never been infected (4%) (relative risk 2.2, 95% confidence interval 1.4 to 3.6). Specifically, there was an increased risk of developing a cerebrovascular accident (relative risk 3.7, 1.6 to 8.4) and cardiac ischaemia (relative risk 1.9, 1.04 to 3.4). 12 year mortality was significantly higher among the 411 people who had been acutely infected in 1983 (9.7%; age adjusted relative risk 1.8, 1.2 to 2.6) when compared with the 1247 participants who had remained serologically negative in 1983 (7.0%).

CONCLUSIONS

Coxiella burnetii infection may cause long term complications including vascular disease.

Vector competence of Ixodes scapularis and Ixodes ricinus (Acari: Ixodidae) for three genospecies of Borrelia burgdorferi

The vector competence of 2 tick species, Ixodes ricinus (L.) and Ixodes scapularis Say, was determined and compared for 3 genospecies of Borrelia burgdorferi. The 3 genospecies of B. burgdorferi used in the following experiments were Borrelia burgdorferi sensu stricto (B-31 and B-31.D1 clone), Borrelia afzelii (strain Pgau. C3), and Borrelia garinii (strain VS286 and VSBP). Spirochetes from all 5 strains were inoculated intradermally into outbred mice; larval ticks of both species were subsequently fed on those mice and replete larvae were assayed for infection by culture in BSK-H media every 7 d for 4 wk. Infection frequencies in I. scapularis exposed to the 5 strains were as follows: B-31 (90%), B-31.D1 (83%), Pgau.C3 (87%), VS286 (10%), and VSBP (5%). The comparable infection frequencies for I. ricinus were B-31 (3%), B-31.D1 (3%), Pgau.C3 (90%), VS286 (5%), and VSBP (3%). Resultant nymphal I. scapularis successfully transmitted B-31, B-31,D1, Pgau.C3, and VS286 to outbred mice. I. ricinus nymphs transmitted Pgau.C3 and VS286. Both species failed to transmit strain VSBP.

[Q fever with endocarditis: clinical presentation and serologic follow-up of 21 patients]

AIM OF THE STUDY

The purpose of this study was to analyse the clinical and serological follow-up in 21 patients with Q fever endocarditis in Switzerland from 1981 to 1993.

PATIENTS AND METHODS

Criteria for Q fever endocarditis were the following: Coxiella burnetii phase I IgG > 1 : 2560 and IgA > 1 : 20 by indirect immunofluorescence. Methods to confirm the diagnosis include immunohistochemical demonstration of C. burnetii by microscopy in valvular material (1 case) and inoculation of this material in experimental animals (10 cases). Information on clinical course of the disease, laboratory abnormalities and treatment were obtained by chart review and a questionnaire sent to physicians who requested the serological tests for Q fever.

RESULTS

The average age of the patients was 47 years (15 men and 6 women). 64% of patients had a history of environmental exposure to C. burnetii. The median time of symptomatology before diagnosis was 5 months (1-108). 19/21 patients had valvular lesions, and 2/21 vascular Dacron prosthesis. Most patients presented with fever (18/21), congestive cardiac failure (14/21), weight loss (12/21), anemia (6/19), or thrombocytopenia (6/19). All the patients required antibiotic treatment. Cardiac surgery was performed in 15/21 patients. For 10 patients the geometric mean serological follow-up included at least titers at time of diagnosis (IgG anti-phase I antibodies 1 : 27024, IgA anti-phase I antibodies 1 : 685), at the end of therapy (IgG anti-phase I antibodies 1 : 2941, IgA anti-phase I antibodies 1 : 153) and 6 months after the end of therapy (IgG anti-phase I antibodies 1 : 368, IgA anti-phase I antibodies 1 : 40). The fall in anti-phase I titers was significant. During the clinical and serological outcome (median of 60 months and 69 months respectively) there was no recurrence of endocarditis and antibody titers to C. burnetii phase I remained low. Two patients died during the observation period, one from lung cancer, while the cause of death in the other was unknown.

CONCLUSIONS

Serology is the key to Q fever diagnosis. The duration of treatment, and the values to be used to establish cure of endocarditis, are not clearly defined. During the clinical and serological outcome (median of 60 months and 69 months respectively) there was no recurrence of endocarditis and antibody titers to C. burnetii phase I remained low.

Matrix metalloproteinases in the cerebrospinal fluid of patients with Lyme neuroborreliosis

Neurologic manifestations of Lyme disease include meningitis, encephalopathy, and cranial and peripheral neuropathy. There are no sensitive markers for neuroborreliosis, and diagnosis is often based on clinical presentation and cerebrospinal fluid (CSF) abnormalities, including intrathecal antibody production. Matrix metalloproteinase (MMP) activity in CSF was compared in patients with neuroborreliosis, patients with diverse neurologic disorders, and healthy controls. The CSF of 17 of 18 healthy subjects and 33 of 37 patients with neurologic symptoms and normal CSF and imaging studies contained only MMP2. The CSF of several patients with neurologic disorders contained MMP2, MMP9, and gelatinolytic activity at 130 and 250 kDa. The 130-kDa MMP was found without the 92-kDa MMP9 in the CSF of 11 (79%) of 14 patients with neuroborreliosis and only 7 (6%) of 118 control patients (P < .001). This pattern of CSF gelatinase activity may be a useful marker for neuroborreliosis.

Tick zoonoses in the southern part of Switzerland (Canton Ticino): occurrence of Borrelia burgdorferi sensu lato and Rickettsia sp

The diversity and the distribution of tick species and their infection rates by the pathogenic micro-organism Borrelia burgdorferi sensu lato, the etiologic agent of Lyme borreliosis, and Rickettsia sp., were studied in Canton Ticino (the southern part of Switzerland). Ticks specimens collected from animals and humans were classified and analysed for the presence of both pathogens. In particular, PCR analysis was performed for the detection of Borrelia spirochetes in Ixodes ricinus and Ixodes hexagonus, and the hemolymph test was done on Rhipicephalus sanguineus for the detection of Rickettsia sp. PCR assays, performed on 424 of the 989 collected ticks, revealed a low rate of infection (around 2%) of both vectors I. ricinus and I. hexagonus by B. burgdorferi sensu lato. These results are in agreement with the modest number of Lyme borreliosis cases yearly recorded in Ticino. Further, through analysis of DNA sequences, the strains carried by the infected ticks were identified as belonging to the genomic group VS116. The widespread finding of the Mediterranean species Rhipicephalus sanguineus in different locations from July 1994 to October 1995 demonstrates its establishment in Ticino. Of the 210 specimens collected, 70 were analysed and one was infected by Rickettsia sp.

Occurrence of different genospecies of Borrelia burgdorferi sensu lato in ixodid ticks of Valais, Switzerland

A total of 825 adult ticks (727 Ixodes ricinus, 72 Dermacentor marginatus and 26 Haemaphysalis punctata) was collected from vegetation in Valais (Switzerland) in 1987 to 1992. They were examined for the presence of Borrelia burgdorferi sensu lato, the etiologic agent of Lyme borreliosis. B. burgdorferi sensu lato was detected by indirect immunofluorescence assay, dark field microscopy and/or culture in 221 out of 727 I. ricinus (30.4%) and none in the other two species. From these 221 infected ticks we obtained 50 isolates. Indirect immunofluorescence assay and culture were used for all ticks but dark field examination has also been performed and compared to the two above mentioned methods for 231 I. ricinus. Indirect immunofluorescence assay and culture were used for all ticks but dark field examination has also been performed and compared to the two above mentioned methods for 231 I. ricinus. Indirect immunofluorescence was found the most efficient method for the detection of Borrelia in ticks with 54 positive out of 231, followed by dark field examination with 35 positive and culture with 12 isolates. We found no site free of Borrelia where I. ricinus is present. The rate of infection varied from 9.7 to 47.5%, as detected by the addition of the three methods. Typing of the 50 isolates revealed also a nonhomogeneous distribution of the Borrelia species. Based on the electrophoretic mobility of the OspA and B and immunostaining with species specific monoclonal antibodies (H3TS for B. burgdorferi sensu stricto, D6 for B. garinii and J8.3 for B. afzelii) 4 groups could be observed. Half of the isolates (n = 26) were typed as B. burgdorferi sensu stricto, 19 as B. garinii, 3 as B. afzelii and 2 as group VS116. This forth group formed of two isolates from one location is genetically distinct from the 3 former species described in Europe so far. The Borreliae of this group are unreactive with any of the three monoclonal antibodies used.

Confirmation that Rickettsia helvetica sp. nov. is a distinct species of the spotted fever group of rickettsiae

We propose the name Rickettsia helvetica sp. nov. for a rickettsial serotype of unknown pathogenicity isolated in 1979 in Switzerland from Ixodes ricinus ticks and designated the Swiss agent. The growth characteristics and the results of microimmunofluorescence serologic typing, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting (immunoblotting) with specific mice sera, and a polymerase chain reaction followed by restriction fragment length polymorphism analysis confirmed previously reported preliminary findings which suggested that this rickettsia, to which a name was given provisionally, does represent a new member of the spotted fever group of rickettsiae. The type strain is C3 (Reference Center for Rickettsioses, Marseille, France).

Genotypic and phenotypic diversity among nine Swiss isolates of Borrelia burgdorferi

Nine strains of Borrelia burgdorferi isolated from ticks in the canton of Valais (Switzerland) were characterized genotypically by determining restriction fragment length polymorphisms (RFLP) and plasmid profiles. The strains were also compared with respect to presence and electrophoretic mobility of the outer surface proteins OspA and OspB, and immunoreactivity of OspA and a 12 kD antigen. By both approaches, three different patterns were observed resulting in identical grouping of the strains. However, RFLP's allowed determination of relationships among strains within a group and have shown that geographic distribution does not correlate with genotype.

[Isolation of Borrelia burgdorferi in the cerebrospinal fluid of 3 children with neurological involvement]

Isolation of Borrelia burgdorferi from the CSF is relatively rare. The present report describes the first three isolations in Switzerland. Clinically, our first observation confirmed the frequent association of B. burgdorferi with peripheral facial paresis in children. The other two cases illustrate the variety of symptoms in neuro-borreliosis. In the first case the culture was positive after 6 weeks. The results of serologic tests (indirect immunofluorescence and ELISA) for detection of antibodies against B. burgdorferi were negative or non-significant in this child's serum. On the other hand, specific antibodies (IgG) were detected in the serum by western blot. Culture of the second CSF already showed Borrelia growth after 10 days. Immunofluorescence revealed high antibody titers (1/256) against B. burgdorferi in this patient's serum. IgG showed a weakly positive reaction in western blot. The reliability of this result was confirmed by isolation of Borrelia. In neither of the two CSF could intrathecal synthesis of specific antibodies be demonstrated. In the third case, however, immunofluorescence showed IgG antibody titers of 1/128 in the CSF and 1/512 in serum. Intrathecal synthesis of specific antibodies was demonstrated with an index of 13.4 (norm < 2). Western blot confirmed the specificity of the reactions observed with the serum and CSF IgG. Culture of CSF produced significant growth of Borrelia within 7 days. Protein profile and reactions with poly- and monoclonal antibodies confirmed that the three strains belonged to B. burgdorferi.(ABSTRACT TRUNCATED AT 250 WORDS)

Q fever endocarditis: diagnostic approaches and monitoring of therapeutic effects

The scope of current diagnostic methods for Q fever endocarditis includes serology, direct demonstration of Coxiella burnetii in the resected heart valve tissue, and animal inoculation studies. Illustrated by a clinical case report, the different methods are presented and discussed. Serology represents the primary method, using the techniques of complement fixation, indirect immunofluorescence, and enzyme-linked immunosorbent assay (ELISA). The latter two techniques allow the detection of immunoglobulins G, M, and A to the phase I and II antigens of C. burnetii. After cardiac surgery, we visualized C. burnetii on smears and specifically stained it on histologic sections of the resected heart valve by light and electron microscopic immunohistochemistry. In addition, seroconversion in animals after inoculation with valve specimens confirmed the presence of C. burnetii in the heart valve. The antibody titers determined by ELISA correlated well with the patient's clinical course during the treatment period. Therefore it is suggested that its usefulness for monitoring the efficacy of antimicrobial agents in patients with Q fever endocarditis should be further evaluated.

Polymorphism of outer surface proteins of Borrelia burgdorferi as a tool for classification

A total of 23 isolates of Borrelia burgdorferi were characterized by SDS-PAGE and immunoblot analysis. One isolate came from the CSF of a Lyme neuro-borreliosis patient in Valais (Switzerland) and 22 were tick isolates (2 from I. dammini of Shelter Island, USA and 20 from I. ricinus of Valais, Switzerland). Based on the electrophoretic mobility of outer surface proteins (OspA and OspB), four groups of B. burgdorferi could be defined. Group I isolates possess an OspA of 31 KD and an OspB of 34 KD. The group II isolate showed an OspA of 32 KD and OspB of 35 KD. Group III isolates have a 33 KD OspA and group IV a 33.5 KD OspA. This classification was confirmed by the reactivity of a monoclonal antibody (D6) to a 12 KD antigen that was recognized in group III only. A Lyme patient's serum showed a 2-band pattern (10 and 13 KD) for group I and a one-band pattern (12 KD) for the other 3 groups. Therefore OspA, OspB and other proteins of low molecular weight (10, 12, and 13 KD) seem to be important keys for the classification of B. burgdorferi isolates. This typing system correlates with genetic analysis.

[The diagnosis of Lyme borreliosis. Apropos of a neurological case]

The clinical diagnosis of Lyme borreliosis is easily established in the initial phase of the illness. Erythema chronicum migrans is pathognomonic of this infection. However, during further complications (neurological, cardiac or articular) the diagnosis is chiefly based on laboratory results. The detection of specific antibodies to B. burgdorferi is one of the effective means of confirming the diagnosis. Culture or isolation of this bacteria is not routinely performed due to its very low yield. In this article a case of serologically proved neuro-borreliosis is described and the methods of diagnosis are discussed. Intrathecal synthesis of antibodies observed in the cerebrospinal fluid of this patient and the specificity of serologic tests confirmed by Western-blot provide the diagnosis. However, the absence of locally synthesized antibodies in the cerebrospinal fluid is not sufficient to rule out neuro-borreliosis.

Isolation by a sensitive centrifugation cell culture system of 52 strains of spotted fever group rickettsiae from ticks collected in France

Boutonneuse fever caused by Rickettsia conorii is transmitted mainly by the brown dog tick, Rhipicephalus sanguineus. We collected 540 ticks in Marseille, France, and tried to isolate as many strains of rickettsia as possible. Ticks were evaluated for the presence of rickettsia by the hemolymph test and by a new culture system, the centrifugation-shell vial technique. We avoided contamination in the culture system. Prior to ticks being submitted to the hemolymph test, they were disinfected. Only 5.6% (27 of 478) of the cultures were contaminated. A drop of hemolymph from each of 478 R. sanguineus ticks was cultured in two shell vials, and another drop was stained by the Gimenez method or indirect immunofluorescence. Since Gimenez staining in our hands was not satisfactory, comparison of the hemolymph test and culture is based on the results of indirect immunofluorescence. Thus, 50 of 369 (13.5%) examined ticks were hemolymph test positive, and 44 (11.9%) cultures were positive. After disinfection, another pool of 62 ticks were examined by the hemolymph test. The ticks were kept individually in a sterile environment. A few days later, the hemolymph of these ticks was collected again and cultured. The contamination rate was not significantly higher (6.4%) than in the above-described conditions. It allowed us to isolate eight more strains. Thus, we recommend screening ticks with the hemolymph test and culturing only the hemolymph test-positive ticks.

Enzyme-linked immunosorbent assay for diagnosis of chronic Q fever

From 1982 through 1987 we diagnosed 13 chronic Q fever cases. Clinically these patients presented a culture-negative endocarditis, and all but two had high complement-fixing antibody titers to Coxiella burnetii phase I (reciprocal titer above 200). With the enzyme-linked immunosorbent assay (ELISA), titers of immunoglobulin G (IgG) to phases I and II of C. burnetii averaged 158,000 and 69,900, respectively, whereas they reached 300 and 3,200 in acute Q fever cases. Similarly, IgA to both phases of C. burnetii and IgM to phase I were consistently higher during chronic than acute Q fever. The serological follow-up of one patient with chronic Q fever over a 4-year period showed a good correlation between the titers of IgG and IgM antibody titers detected by ELISA and indirect fluorescent-antibody test (IFA) to both phases of C. burnetii. Few discrepancies appeared with IgA. Shortly after initiation of antibiotic treatment, a slow and steady decrease of the antibody titers to C. burnetii phases I and II was observed. The complement fixation, IFA, and ELISA tests showed the same type of antibody response. The ELISA proved to be an excellent diagnostic test for chronic Q fever. It distinguished negative from positive reactions clearly, and results were highly reproducible. The reading is objective, and the test is simple to perform and more sensitive than the IFA and complement fixation tests. The ELISA is recommended for serologic evaluation of patients with chronic Q fever.

Comparison of enzyme-linked immunosorbent assay and complement fixation and indirect fluorescent-antibody tests for detection of Coxiella burnetii antibody

An enzyme-linked immunosorbent assay (ELISA) was developed to detect immunoglobulin G to Coxiella burnetii phase II. Serum samples from 213 patients who had had Q fever 1 year previously and from 301 blood donors from six localities in Switzerland were tested by ELISA and by indirect fluorescent-antibody (IFA) and complement fixation (CF) tests. The ELISA and the IFA and CF tests detected antibody to C. burnetii in 202 (94.8%), 193 (90.6%), and 166 (77.8%) of the 213 Q fever patients, respectively. With the serum samples from blood donors, the ELISA yielded a higher percentage of positive sera than did the IFA and CF tests. The high specificity of the three tests was confirmed by analyzing paired serum samples from 36 patients suffering from acute pneumonia of viral or bacterial origin. In these cases, the serological results were negative by the three tests, except for three Q-fever cases included as positive control.

An important outbreak of human Q fever in a Swiss Alpine valley

We describe an important Q fever human epidemic involving 415 serologically confirmed cases in the Val de Bagnes (Valais, Switzerland) during the autumn of 1983. The ages of the 415 cases with acute Q fever ranged from 8 to 82 years with a mean of 35 years, of whom 58% (240) were men and 42% (175) were women. This outbreak started about three weeks after 12 flocks of sheep (between 850 and 900 animals) descended from the alpine pastures to the valley. Geographically, the epidemic reached all the villages in the lower part of the Val de Bagnes located along the road followed by the sheep. As a result, 21.1% of the population of these villages contracted Q fever during this period. In contrast (p less than 0.001), the inhabitants of the higher villages away from the road followed by the sheep were only slightly affected (2.9%). Better collaboration between physicians and veterinarians would prevent such outbreaks in the future.

Serological diagnosis of Q fever endocarditis

The diagnosis of Q fever endocarditis cannot be made by bacterial cultures and necessitates serological identification of specific antibodies to Coxiella burnetii which stimulates mainly the production of anti-phase II antibodies during the acute disease, but primarily anti-phase I antibodies in endocarditis. Indirect microimmunofluorescence allows rapid detection of specific IgA, IgG and IgM. The results of serological analyses of 191 acute cases of Q fever were compared with those of 8 cases of Coxiella burnetii endocarditis. All sera were evaluated by complement fixation and microimmunofluorescence tests. The highest titre differences between primary Q fever and Q fever endocarditis were observed with anti-phase I IgA and IgG antibodies measured by microimmunofluorescence followed by anti-phase I antibodies measured by complement fixation tests. Antiphase I IgG and IgM titres were consistently higher than anti-phase II titres in endocarditis. The reverse is true in acute Q fever. In addition, anti-phase I IgA appeared to be diagnostic for Coxiella burnetii endocarditis. Accordingly we recommend the testing of these specific IgA, IgG, and IgM by microimmunofluorescence in cases of culture-negative endocarditis. These tests could also prove useful for following the development of Coxiella burnetii endocarditis in patients under treatment.

Immunoglobulin responses in acute Q fever

Knowledge of the development of different classes of antibody during the course of acute Q fever is important to the clinician for interpreting a patient's serological test results. In the present study, the appearance of antibodies to Coxiella burnetii phases I and II was determined for a period of 1 year. A total of 683 sera from 191 patients with symptomatic Q fever were evaluated by the complement fixation and indirect immunofluorescence (immunoglobulins M and G [IgM, IgG]) tests. These patients had contracted acute Q fever in the fall of 1983 during an epidemic that resulted in 415 serologically confirmed cases of Q fever. As demonstrated by the complement fixation test, antibodies to C. burnetii phase II remained elevated throughout the entire study period, whereas antibodies to phase I were barely detectable. Although the immunofluorescence test was more sensitive than the complement fixation test, the specific anti-IgG response to C. burnetii to phases I and II gave the same general antibody profiles as did the complement fixation test. IgM anti-phase I and II titers appeared earlier but disappeared after 10 to 12 weeks. During this period, anti-phase II antibody levels were generally much higher than anti-phase I antibody levels.

Evaluation of the complement fixation and indirect immunofluorescence tests in the early diagnosis of primary Q fever

A comparison was made of the performance of the commonly used complement fixation test and the more recently developed indirect immunofluorescence test in the early diagnosis of Q fever. The 303 sera tested were from 181 patients who contracted Q fever during an outbreak in Switzerland in 1983. Specific IgM antibodies were detected by the immunofluorescence test in 53% and 89% of sera obtained during the first and second week respectively after onset of illness. With the complement fixation test, the diagnosis could not be made until the second week of illness. The immunofluorescence test proved to be superior to the complement fixation test in the early detection of Q fever. Not only was it more specific but also faster and simpler to perform, permitting an earlier diagnosis on the basis of results obtained with a single serum specimen.

[Clinical aspects observed during an epidemic of 415 cases of Q fever]

The clinical findings during a major epidemic of Q-fever which affected 415 people in the Val de Bagnes (Valais, Switzerland) in the autumn of 1983 are reported. Q-fever symptoms were evident in 191 cases but inconspicuous or absent in 224 cases. The symptoms most frequently reported were prolonged high fever, headaches, severe exhaustion, loss of appetite, cough and myalgia. Amongst disorders which accompany acute Q-fever, pneumonia and granulomatous hepatitis are very frequent, while myopericarditis and glomerulonephritis are less frequently observed. Endocarditis, a later complication of Q-fever, is a severe illness which more frequently affects patients with underlying valvular lesions. New serological techniques now permit more rapid and more accurate diagnosis of both acute and chronic Q-fever.

Rickettsia conorii isolated from Rhipicephalus sanguineus introduced into Switzerland on a pet dog

A tick/rickettsial survey in a household near Geneva, Switzerland, revealed that 30 (40%) of 75 nymphs and adults of the brown dog tick, Rhipicephalus sanguineus, were infected with a rickettsial agent biologically and antigenically indistinguishable from R. conorii, the causative agent of boutonneuse fever. Introduced in 1979 from either southern France or Italy by the family's pet dog, the tick infestation had steadily increased until 1981 when control measures were initiated. During 1980 and 1981, four persons associated with the household's pet dog contracted a febrile illness diagnosed as boutonneuse fever.