- Email: [email protected]
Septicaemia with Rickettsia helvetica in a patient with acute febrile illness, rash and myasthenia
Journal of Infection (2009) 58, 79e82
www.elsevierhealth.com/journals/jinf
CASE REPORT
Septicaemia with Rickettsia helvetica in a patient with acute febrile illness, rash and myasthenia K. Nilsson a,b,c,d,e,* a
Section of Clinical Microbiology, Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden Section of Infectious Diseases, Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden c Department of Infectious Diseases, Falu Hospital, Falun, Sweden d Department of Clinical Bacteriology, Falu Hospital, Falun, Sweden e Centre for Clinical Research, Falu Hospital, Falun, Sweden b
Accepted 6 June 2008 Available online 22 July 2008
KEYWORDS Rickettsia; Septicaemia; Febrile illness; PCR; Rash
Summary The spotted fever rickettsia, Rickettsia helvetica, is mostly reported to present a flu-like self-limiting disease. In the present case, however, where the presence of R. helvetica in the blood was verified by PCR together with serologic evidence of infection, the patient presented a different clinical picture with acute febrile illness, rash and long-lasting myasthenia. ª 2008 The British Infection Society. Published by Elsevier Ltd. All rights reserved.
Introduction The spotted fever rickettsia, Rickettsia helvetica, has been described in several European countries as well as Japan, but recently also reported in Thailand and Laos.1,2 The tick Ixodes ricinus represents a potential vector and natural reservoir of R. helvetica, but in Japan the organism has also been isolated in other ticks.1 The pathogenic role of R. helvetica is debated and remains a matter of controversy. But R. helvetica has been implicated in acute perimyocarditis, unexplained febrile illness, sarcoidosis and fever following an Ixodes holocyclus bite.1,3e5 In Denmark, a serosurvey
* Department of Clinical Microbiology, Uppsala University Hospital, Uppsala, Sweden. Tel.: þ46 18 611 00 00; fax: þ46 18 50 81 27. E-mail address: [email protected]
of 168 Danish patients seropositive for borreliosis, demonstrated that a total of 12.5% (21/168) tick-bitten patients were seropositive for R. helvetica, and four cases of seroconversion were identified.6 Recently, eight patients from France, Italy and Thailand were reported, with serological evidence of infection associated with mild fever, myalgia and no cutaneous rash.1 In another study from Laos, serological analysis identified R. helvetica as the cause of fever in 2.6% of adults admitted to hospital, and in Sweden, a recent study shows that between 3 and 4.4% of patients with symptoms of infectious disease appearing after a tick bite had significant titres of antibodies to Rickettsia spp.2,7 Most reported patients have presented a flu-like self-limiting mild febrile disease, sometimes with prolonged fever and less frequently with a rash.1 Relevant studies using culture or PCR to confirm the causative role of R. helvetica in acute febrile illness are lacking, but in the present case,
0163-4453/$34 ª 2008 The British Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jinf.2008.06.005
80 the presence of R. helvetica in the blood was verified by PCR together with serological evidence of infection. All other reported cases of SFG rickettsiosis, possibly caused by R. helvetica, have been diagnosed using serological criteria including MIF, Western blotting and cross-absorption methods, and the causative role of R. helvetica has not previously been verified by isolation or, as in the present case, by PCR during the phase of active illness. The patient studied here also presented a different clinical picture, with fever and muscular symptoms that were found to be more severe and intense than previously described for this agent, together with a rash and a slow and delayed recovery.
Case report A 57-year-old, healthy and immunocompetent man, living on the eastern coast of Sweden, a tick-endemic area, was admitted to the Department of Infectious Diseases in Falun, Sweden, on May 17, 2003, with septicaemic fever, myalgias, arthralgias, severe headache and photophobia of unknown aetiology. A prominent neck muscle myalgia with subjective neck stiffness was one reason for initial suspicion of meningitis. The fever had begun on May 11 and 1e2 days after onset of illness, a 1e2-mm macular rash similar to that caused by measles appeared on the lower parts of the legs and arms. He was unaware of any tick bites, but had observed and removed several ticks from his cats. On physical examination, the rash and fever (39.2 C) were observed, but no lymphadenopathy or inoculation eschar was found. Results of laboratory tests included an accelerated sedimentation rate (18 mm, first hour); elevated C-reactive protein (34e81 mg/L); elevated leukocyte count of 10.7 (109/L); platelets 165e266 (109/L); serum-creatinin 93 (mmol/L); and increased rates of serum-AST 1.0 (<0.80 IU/L). Blood cultures taken on May 17 were negative. Antibodies against Borrelia burgdorferi (serum and cerebrospinal fluid (CSF)), Anaplasma phagocytophilum, Q-fever, HIV 1 þ 2, EBV, CMV, herpes simplex virus 1 and 2 (serum and PCR of cerebrospinal fluid), nephropathia epidemica, hepatitis B and C, antinuclear antibodies and rheumatoid factor were all negative. Parvovirus, B-19, HHV-6, Brucella and Chlamydial agents had not been included in the original investigation. Lumbar puncture showed normal values. X-ray examination of the lungs revealed nothing abnormal, nor did computerized tomographic (CT) and magnetic resonance scanning (NMR) of the brain. No cause of the febrile disease was found, and the patient received (May 18) ex juvantibus, antibiotic treatment with 200 mg doxycycline/day for 14 days. The fever disappeared within 3e4 days and he slowly recovered, but extreme muscular weakness and pain together with headache remained for several months, resulting in treatment with steroids (prednisone) based on suspicion of arteritis. Steroids resulted in an obvious symptom relief and general recovery, but the steroid therapy could not be ended until 8 months later, as dose reduction immediately resulted in symptom aggravation. Further investigation, however, did not verify the suspicion of arteritis or other autoimmune diseases. Sera collected day 7 (I), 18 (II) and 27 (III) days after onset of symptoms (May 11) were frozen at 70 C. By coincidence,
K. Nilsson 2 years later, a suspicion of rickettsiosis was raised, and the sera were reinvestigated for the presence of rickettsial antibodies and DNA. The three sera (IeIII) were centrifuged at 12.500 rpm for 30 min. The pellets were redissolved in 200 ml of the original serum sample, respectively, and DNA was extracted in a MagnaPure LC robot (Roche Diagnostics, Mannheim, Germany) using the MagnaPure DNA Isolation Kit, according to the manufacturer’s instructions. The input and output volumes were set to 200 ml and 100 ml, respectively. Two sets of primers for nested PCR that amplify 17-kDa and Omp B gene sequences of spotted fever group and typhus group of rickettsiae were chosen as previously described.8,9 The PCR products were analysed using gel electrophoresis (2% agarose). Confirmation of fragment sizes was based on a standard DNA molecular weight marker (Invitrogen). The DNA-sequence analysis was performed at the Center for Genomics and Bioinformatics, KI, Stockholm (KI Seq) and used direct cycle sequencing analysis of both strands. Only Serum I, collected on day 7, was PCR-positive, and PCR amplification of the rickettsial 17 kDa- and Omp B genes yielded two fragments of which a 156- and 232-bp fragment was complete and showed 100% sequence similarity with the corresponding gene fragments of R. helvetica (EF202825, EF202824) and significant nucleotide differences from the other rickettsia in the spotted fever group. For the microimmunofluorescence assay (MIF), antigen prepared from Vero cell-grown isolates of R. helvetica from I. ricinus ticks was applied by dip-pen point to microscope slides, dried, fixed in acetone and incubated with serial dilutions of serum, as previously described.3,7,10 The three sera from the patient were tested in two-fold serial dilutions from 1/20 to 1/640. Immunoglobulin G (IgG) antibodies were detected by fluorescein isothiocyanate-conjugated (FITC) g-chain-specific polyclonal rabbit anti-human IgG (Dako, Denmark). A human serum with an end-point titre of 1/160 for R. conorii, confirmed at the Swedish Royal Institute in Stockholm, was used as the positive control. As the negative control a serum from a blood donor with no history of tick bites was used. The serological analyses showed in Serum I an end-titre of 1/40 and in Sera II and III end-titres of 1/160, respectively. Western blot immunoassay of Sera I and III was performed as previously described7,10 and revealed development of an IgG-antibody response to a high molecular weight protein of R. helvetica demonstrated in Serum III (Fig. 1). The secondary antibody alone, used as negative control, did not bind to any proteins.
Discussion In addition to high fever, the patient had severe headache, subjective neck stiffness, photophobia and a macular rash involving the arms and legs, a clinical picture that differs from previous observations of R. helvetica. Owing to the prominent neck muscle myalgia, meningitis or meningoencephalitis was suspected, but could be ruled out. Notably, in African tick bite fever and Rocky Mountain spotted fever (RMSF), neck myalgia is thought to indicate a central nervous system affection. However, both the laboratory
Septicaemia with Rickettsia helvetica in a patient
Figure 1 Western immunoblot assay showing an IgG-antibody response in Serum III against a high molecular protein in the 110e145 kDa-region of R. helvetica. Lanes A and B: Sera I and III.
analysis and the X-ray examination, in the present case, did not result in any findings indicating such affection. Based on other SFG rickettsioses studies, early treatment is known to be of importance for the outcome.1 The present patient arrived at hospital after 1 week’s illness, but no severe manifestations, including pulmonary, cardiac or renal failure, were observed. The patient showed a four-fold rise of rickettsial antibodies in MIF and specific protein antibodies were demonstrated by Western blot analysis. Because of known immunological cross reactivities the results, however, must be cautiously interpreted with regards to species of Rickettsia involved. The sensitivity of the nested PCR assays used here has a documented detection sensitivity of fewer than 10 rickettsial particles per assay8,9 but because rickettsiae are intracellular, whole blood or buffy coat samples are considered preferable for the PCR assays. No such samples were available in the present case. To date, I. ricinus, which is widespread in Sweden, has been demonstrated to harbour three rickettsial species, i.e., R. helvetica, second, a genetically characterized spotted fever rickettsia reported from Slovakia and, third, R. monacensis, isolated in Germany.11,12 Both nucleotide sequences yielded in this case were long enough to exclude other related rickettsial species (EF202825, EF202824). For example, for the 17-kDa
81 and Omp B gene fragments, the differences from R. monacensis was 5 and 6 nucleotides, respectively, and for R. slovaca 8 nucleotides differed (Omp B). The present patient had a macular rash, only seen in three other cases with serological findings indicating an SFG rickettsiosis, possibly caused by R. helvetica.1,13,14 The macular rash was similar to that caused by measles, with small spots that after some days began to blend together, but the distribution was different and covered only the lower parts of the arms and legs. Another clinical observation was a very slow recovery to health, with symptoms of headache and muscular weakness lasting 7e8 months. The reduced muscular strength affected both legs and the left hand and resulted in problems with walking and driving a car, but steroids helped to reduce the symptoms. The initial prednisone dose was 40 þ 40 mg and was slowly reduced over 6 weeks until a daily dose of 10 mg was reached, at which point a relapse of headache and muscular weakness made it necessary to restart with the initial dose. Only by reducing the dose by 2.5 mg per week could he remain symptom free, and the treatment was finally ended after 8 months. Anaplasma phagocytophilum has been reported to cause similar symptoms, but in the present case was negative in serology. Patients with chronic illness has recently also been reported to show markers of exposure to spotted fever rickettsiae demonstrated in Australian patients with R. honei infection.15 The suspicion of autoimmune disease or arteritis that was raised during the early investigation of our case, was not verified during the course of the disease, and the patient recovered. He is, however, enrolled in a prospective long-term study in case signs of chronic disease or sequelae should develop.
Conclusion The present case indicates that R. helvetica may also present a more acute febrile illness with rash and long-lasting muscular symptoms, and it is therefore important that this agent be taken into consideration in cases of FUO or symptoms of infection appearing after a tick bite. PCR may be a tool that makes early diagnosis possible.
Acknowledgement This study was supported by grants from the Dalarna Research Foundation (project no. 99285) and the Center for Clinical Research Dalarna (project no. 420016).
References 1. Parola P, Paddock CD, Raoult D. Tick-borne rickettsioses around the world: emerging diseases challenging old concepts. Clin Microbiol Rev 2005;18:719e56. 2. Phongmany S, Rolain JC, Phetsouvanh R, Blacksell SD, Soukkhaseum V, Rasachack B, et al. Rickettsial infections and fever, Vientiane, Laos. Emerging Infect Dis 2006;12:256e8. 3. Nilsson K, Lindquist O, Pa ˚hlson C. Association of Rickettsia helvetica with chronic perimyocarditis in sudden cardiac death. Lancet 1999;354:1169e73.
82 4. Parola P, Raoult D. Ticks and tickborne bacterial diseases in humans: an emerging infectious threat. Clin Infect Dis 2001;32: 397e430. 5. Nilsson K, Pa ˚hlson C, Lukinius A, Eriksson L, Nilsson L, Lindquist O. Presence of Rickettsia helvetica in granulomatous tissue from patients with sarcoidosis. J Infect Dis 2002;185:1128e38. 6. Nielsen H, Fournier PE, Pedersen IS, Krarup H, Ejlertsen T, Raoult D. Serological and molecular evidence of Rickettsia helvetica in Denmark. Scand J Infect Dis 2004;36:559e63. 7. Elfving K, Lindblom A, Nilsson K. Seroprevalence of Rickettsia spp. infection among tick-bitten patients and blood-donors in Sweden. Scand J Infect Dis 2008;40:74e7. 8. Leitner M, Yitzhaki S, Rzotkiewicz S, Keysary A. Polymerase chain reaction-based diagnosis of Mediterranean spotted fever in serum and tissue samples. Am J Trop Med 2002;67:166e9. 9. Choi YJ, Lee SH, Park KH, Koh YS, Lee KH, Baik HS, et al. Evaluation of PCR-based assay for diagnosis of spotted fever group rickettsiosis in human serum samples. Clin Diagn Lab Immunol 2005;12:759e63. 10. Nilsson K, Lukinius A, Pa ˚hlson C, Moron C, Hajem N, Olsson B, et al. Evidence of Rickettsia spp. infection in Sweden:
K. Nilsson
11.
12.
13.
14.
15.
a clinical, ultrastructural and serological study. APMIS 2005; 113:126e34. Sekeyova ´ Z, Fournier PE, Reha ´cek J, Raoult D. Characterization of a new spotted fever group rickettsia detected in Ixodes ricinus (Acari: Ixodidae) collected in Slovakia. J Med Entomol 2000;37:707e13. Simser JA, Palmer AT, Fingerle V, Wilske B, Kurtti TJ, Munderloh UG. Rickettisa monacensis sp. nov., a spotted fever group rickettsia, from ticks (Ixodes ricinus) collected in a European city park. Appl Environ Microbiol 2003;68:4559e66. Parola P, Miller S, McDaniel P, Telford 3rd SR, Rolain JM, Wongsrichanalai C, et al. Emerging rickettsioses of the ThaiMyanmar border. Emerging Infect Dis 2003;9:592e5. Fournier PE, Allombert C, Supputamongkol Y, Caruso G, Brouqui P, Raoult D. Aneruptive fever associated with antibodies to Rickettsia helvetica in Europe and Thailand. J Clin Microbiol 2004;42:816e8. Unsworth N, Graves S, Nguyen C, Kemp G, Graham J, Stenos J. Markers of exposure to spotted fever rickettsiae in patients with chronic illness, including fatigue, in two Australian populations. QJM Feb 19, 2008 [E-pub ahead of print].
www.elsevierhealth.com/journals/jinf
CASE REPORT
Septicaemia with Rickettsia helvetica in a patient with acute febrile illness, rash and myasthenia K. Nilsson a,b,c,d,e,* a
Section of Clinical Microbiology, Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden Section of Infectious Diseases, Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden c Department of Infectious Diseases, Falu Hospital, Falun, Sweden d Department of Clinical Bacteriology, Falu Hospital, Falun, Sweden e Centre for Clinical Research, Falu Hospital, Falun, Sweden b
Accepted 6 June 2008 Available online 22 July 2008
KEYWORDS Rickettsia; Septicaemia; Febrile illness; PCR; Rash
Summary The spotted fever rickettsia, Rickettsia helvetica, is mostly reported to present a flu-like self-limiting disease. In the present case, however, where the presence of R. helvetica in the blood was verified by PCR together with serologic evidence of infection, the patient presented a different clinical picture with acute febrile illness, rash and long-lasting myasthenia. ª 2008 The British Infection Society. Published by Elsevier Ltd. All rights reserved.
Introduction The spotted fever rickettsia, Rickettsia helvetica, has been described in several European countries as well as Japan, but recently also reported in Thailand and Laos.1,2 The tick Ixodes ricinus represents a potential vector and natural reservoir of R. helvetica, but in Japan the organism has also been isolated in other ticks.1 The pathogenic role of R. helvetica is debated and remains a matter of controversy. But R. helvetica has been implicated in acute perimyocarditis, unexplained febrile illness, sarcoidosis and fever following an Ixodes holocyclus bite.1,3e5 In Denmark, a serosurvey
* Department of Clinical Microbiology, Uppsala University Hospital, Uppsala, Sweden. Tel.: þ46 18 611 00 00; fax: þ46 18 50 81 27. E-mail address: [email protected]
of 168 Danish patients seropositive for borreliosis, demonstrated that a total of 12.5% (21/168) tick-bitten patients were seropositive for R. helvetica, and four cases of seroconversion were identified.6 Recently, eight patients from France, Italy and Thailand were reported, with serological evidence of infection associated with mild fever, myalgia and no cutaneous rash.1 In another study from Laos, serological analysis identified R. helvetica as the cause of fever in 2.6% of adults admitted to hospital, and in Sweden, a recent study shows that between 3 and 4.4% of patients with symptoms of infectious disease appearing after a tick bite had significant titres of antibodies to Rickettsia spp.2,7 Most reported patients have presented a flu-like self-limiting mild febrile disease, sometimes with prolonged fever and less frequently with a rash.1 Relevant studies using culture or PCR to confirm the causative role of R. helvetica in acute febrile illness are lacking, but in the present case,
0163-4453/$34 ª 2008 The British Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jinf.2008.06.005
80 the presence of R. helvetica in the blood was verified by PCR together with serological evidence of infection. All other reported cases of SFG rickettsiosis, possibly caused by R. helvetica, have been diagnosed using serological criteria including MIF, Western blotting and cross-absorption methods, and the causative role of R. helvetica has not previously been verified by isolation or, as in the present case, by PCR during the phase of active illness. The patient studied here also presented a different clinical picture, with fever and muscular symptoms that were found to be more severe and intense than previously described for this agent, together with a rash and a slow and delayed recovery.
Case report A 57-year-old, healthy and immunocompetent man, living on the eastern coast of Sweden, a tick-endemic area, was admitted to the Department of Infectious Diseases in Falun, Sweden, on May 17, 2003, with septicaemic fever, myalgias, arthralgias, severe headache and photophobia of unknown aetiology. A prominent neck muscle myalgia with subjective neck stiffness was one reason for initial suspicion of meningitis. The fever had begun on May 11 and 1e2 days after onset of illness, a 1e2-mm macular rash similar to that caused by measles appeared on the lower parts of the legs and arms. He was unaware of any tick bites, but had observed and removed several ticks from his cats. On physical examination, the rash and fever (39.2 C) were observed, but no lymphadenopathy or inoculation eschar was found. Results of laboratory tests included an accelerated sedimentation rate (18 mm, first hour); elevated C-reactive protein (34e81 mg/L); elevated leukocyte count of 10.7 (109/L); platelets 165e266 (109/L); serum-creatinin 93 (mmol/L); and increased rates of serum-AST 1.0 (<0.80 IU/L). Blood cultures taken on May 17 were negative. Antibodies against Borrelia burgdorferi (serum and cerebrospinal fluid (CSF)), Anaplasma phagocytophilum, Q-fever, HIV 1 þ 2, EBV, CMV, herpes simplex virus 1 and 2 (serum and PCR of cerebrospinal fluid), nephropathia epidemica, hepatitis B and C, antinuclear antibodies and rheumatoid factor were all negative. Parvovirus, B-19, HHV-6, Brucella and Chlamydial agents had not been included in the original investigation. Lumbar puncture showed normal values. X-ray examination of the lungs revealed nothing abnormal, nor did computerized tomographic (CT) and magnetic resonance scanning (NMR) of the brain. No cause of the febrile disease was found, and the patient received (May 18) ex juvantibus, antibiotic treatment with 200 mg doxycycline/day for 14 days. The fever disappeared within 3e4 days and he slowly recovered, but extreme muscular weakness and pain together with headache remained for several months, resulting in treatment with steroids (prednisone) based on suspicion of arteritis. Steroids resulted in an obvious symptom relief and general recovery, but the steroid therapy could not be ended until 8 months later, as dose reduction immediately resulted in symptom aggravation. Further investigation, however, did not verify the suspicion of arteritis or other autoimmune diseases. Sera collected day 7 (I), 18 (II) and 27 (III) days after onset of symptoms (May 11) were frozen at 70 C. By coincidence,
K. Nilsson 2 years later, a suspicion of rickettsiosis was raised, and the sera were reinvestigated for the presence of rickettsial antibodies and DNA. The three sera (IeIII) were centrifuged at 12.500 rpm for 30 min. The pellets were redissolved in 200 ml of the original serum sample, respectively, and DNA was extracted in a MagnaPure LC robot (Roche Diagnostics, Mannheim, Germany) using the MagnaPure DNA Isolation Kit, according to the manufacturer’s instructions. The input and output volumes were set to 200 ml and 100 ml, respectively. Two sets of primers for nested PCR that amplify 17-kDa and Omp B gene sequences of spotted fever group and typhus group of rickettsiae were chosen as previously described.8,9 The PCR products were analysed using gel electrophoresis (2% agarose). Confirmation of fragment sizes was based on a standard DNA molecular weight marker (Invitrogen). The DNA-sequence analysis was performed at the Center for Genomics and Bioinformatics, KI, Stockholm (KI Seq) and used direct cycle sequencing analysis of both strands. Only Serum I, collected on day 7, was PCR-positive, and PCR amplification of the rickettsial 17 kDa- and Omp B genes yielded two fragments of which a 156- and 232-bp fragment was complete and showed 100% sequence similarity with the corresponding gene fragments of R. helvetica (EF202825, EF202824) and significant nucleotide differences from the other rickettsia in the spotted fever group. For the microimmunofluorescence assay (MIF), antigen prepared from Vero cell-grown isolates of R. helvetica from I. ricinus ticks was applied by dip-pen point to microscope slides, dried, fixed in acetone and incubated with serial dilutions of serum, as previously described.3,7,10 The three sera from the patient were tested in two-fold serial dilutions from 1/20 to 1/640. Immunoglobulin G (IgG) antibodies were detected by fluorescein isothiocyanate-conjugated (FITC) g-chain-specific polyclonal rabbit anti-human IgG (Dako, Denmark). A human serum with an end-point titre of 1/160 for R. conorii, confirmed at the Swedish Royal Institute in Stockholm, was used as the positive control. As the negative control a serum from a blood donor with no history of tick bites was used. The serological analyses showed in Serum I an end-titre of 1/40 and in Sera II and III end-titres of 1/160, respectively. Western blot immunoassay of Sera I and III was performed as previously described7,10 and revealed development of an IgG-antibody response to a high molecular weight protein of R. helvetica demonstrated in Serum III (Fig. 1). The secondary antibody alone, used as negative control, did not bind to any proteins.
Discussion In addition to high fever, the patient had severe headache, subjective neck stiffness, photophobia and a macular rash involving the arms and legs, a clinical picture that differs from previous observations of R. helvetica. Owing to the prominent neck muscle myalgia, meningitis or meningoencephalitis was suspected, but could be ruled out. Notably, in African tick bite fever and Rocky Mountain spotted fever (RMSF), neck myalgia is thought to indicate a central nervous system affection. However, both the laboratory
Septicaemia with Rickettsia helvetica in a patient
Figure 1 Western immunoblot assay showing an IgG-antibody response in Serum III against a high molecular protein in the 110e145 kDa-region of R. helvetica. Lanes A and B: Sera I and III.
analysis and the X-ray examination, in the present case, did not result in any findings indicating such affection. Based on other SFG rickettsioses studies, early treatment is known to be of importance for the outcome.1 The present patient arrived at hospital after 1 week’s illness, but no severe manifestations, including pulmonary, cardiac or renal failure, were observed. The patient showed a four-fold rise of rickettsial antibodies in MIF and specific protein antibodies were demonstrated by Western blot analysis. Because of known immunological cross reactivities the results, however, must be cautiously interpreted with regards to species of Rickettsia involved. The sensitivity of the nested PCR assays used here has a documented detection sensitivity of fewer than 10 rickettsial particles per assay8,9 but because rickettsiae are intracellular, whole blood or buffy coat samples are considered preferable for the PCR assays. No such samples were available in the present case. To date, I. ricinus, which is widespread in Sweden, has been demonstrated to harbour three rickettsial species, i.e., R. helvetica, second, a genetically characterized spotted fever rickettsia reported from Slovakia and, third, R. monacensis, isolated in Germany.11,12 Both nucleotide sequences yielded in this case were long enough to exclude other related rickettsial species (EF202825, EF202824). For example, for the 17-kDa
81 and Omp B gene fragments, the differences from R. monacensis was 5 and 6 nucleotides, respectively, and for R. slovaca 8 nucleotides differed (Omp B). The present patient had a macular rash, only seen in three other cases with serological findings indicating an SFG rickettsiosis, possibly caused by R. helvetica.1,13,14 The macular rash was similar to that caused by measles, with small spots that after some days began to blend together, but the distribution was different and covered only the lower parts of the arms and legs. Another clinical observation was a very slow recovery to health, with symptoms of headache and muscular weakness lasting 7e8 months. The reduced muscular strength affected both legs and the left hand and resulted in problems with walking and driving a car, but steroids helped to reduce the symptoms. The initial prednisone dose was 40 þ 40 mg and was slowly reduced over 6 weeks until a daily dose of 10 mg was reached, at which point a relapse of headache and muscular weakness made it necessary to restart with the initial dose. Only by reducing the dose by 2.5 mg per week could he remain symptom free, and the treatment was finally ended after 8 months. Anaplasma phagocytophilum has been reported to cause similar symptoms, but in the present case was negative in serology. Patients with chronic illness has recently also been reported to show markers of exposure to spotted fever rickettsiae demonstrated in Australian patients with R. honei infection.15 The suspicion of autoimmune disease or arteritis that was raised during the early investigation of our case, was not verified during the course of the disease, and the patient recovered. He is, however, enrolled in a prospective long-term study in case signs of chronic disease or sequelae should develop.
Conclusion The present case indicates that R. helvetica may also present a more acute febrile illness with rash and long-lasting muscular symptoms, and it is therefore important that this agent be taken into consideration in cases of FUO or symptoms of infection appearing after a tick bite. PCR may be a tool that makes early diagnosis possible.
Acknowledgement This study was supported by grants from the Dalarna Research Foundation (project no. 99285) and the Center for Clinical Research Dalarna (project no. 420016).
References 1. Parola P, Paddock CD, Raoult D. Tick-borne rickettsioses around the world: emerging diseases challenging old concepts. Clin Microbiol Rev 2005;18:719e56. 2. Phongmany S, Rolain JC, Phetsouvanh R, Blacksell SD, Soukkhaseum V, Rasachack B, et al. Rickettsial infections and fever, Vientiane, Laos. Emerging Infect Dis 2006;12:256e8. 3. Nilsson K, Lindquist O, Pa ˚hlson C. Association of Rickettsia helvetica with chronic perimyocarditis in sudden cardiac death. Lancet 1999;354:1169e73.
82 4. Parola P, Raoult D. Ticks and tickborne bacterial diseases in humans: an emerging infectious threat. Clin Infect Dis 2001;32: 397e430. 5. Nilsson K, Pa ˚hlson C, Lukinius A, Eriksson L, Nilsson L, Lindquist O. Presence of Rickettsia helvetica in granulomatous tissue from patients with sarcoidosis. J Infect Dis 2002;185:1128e38. 6. Nielsen H, Fournier PE, Pedersen IS, Krarup H, Ejlertsen T, Raoult D. Serological and molecular evidence of Rickettsia helvetica in Denmark. Scand J Infect Dis 2004;36:559e63. 7. Elfving K, Lindblom A, Nilsson K. Seroprevalence of Rickettsia spp. infection among tick-bitten patients and blood-donors in Sweden. Scand J Infect Dis 2008;40:74e7. 8. Leitner M, Yitzhaki S, Rzotkiewicz S, Keysary A. Polymerase chain reaction-based diagnosis of Mediterranean spotted fever in serum and tissue samples. Am J Trop Med 2002;67:166e9. 9. Choi YJ, Lee SH, Park KH, Koh YS, Lee KH, Baik HS, et al. Evaluation of PCR-based assay for diagnosis of spotted fever group rickettsiosis in human serum samples. Clin Diagn Lab Immunol 2005;12:759e63. 10. Nilsson K, Lukinius A, Pa ˚hlson C, Moron C, Hajem N, Olsson B, et al. Evidence of Rickettsia spp. infection in Sweden:
K. Nilsson
11.
12.
13.
14.
15.
a clinical, ultrastructural and serological study. APMIS 2005; 113:126e34. Sekeyova ´ Z, Fournier PE, Reha ´cek J, Raoult D. Characterization of a new spotted fever group rickettsia detected in Ixodes ricinus (Acari: Ixodidae) collected in Slovakia. J Med Entomol 2000;37:707e13. Simser JA, Palmer AT, Fingerle V, Wilske B, Kurtti TJ, Munderloh UG. Rickettisa monacensis sp. nov., a spotted fever group rickettsia, from ticks (Ixodes ricinus) collected in a European city park. Appl Environ Microbiol 2003;68:4559e66. Parola P, Miller S, McDaniel P, Telford 3rd SR, Rolain JM, Wongsrichanalai C, et al. Emerging rickettsioses of the ThaiMyanmar border. Emerging Infect Dis 2003;9:592e5. Fournier PE, Allombert C, Supputamongkol Y, Caruso G, Brouqui P, Raoult D. Aneruptive fever associated with antibodies to Rickettsia helvetica in Europe and Thailand. J Clin Microbiol 2004;42:816e8. Unsworth N, Graves S, Nguyen C, Kemp G, Graham J, Stenos J. Markers of exposure to spotted fever rickettsiae in patients with chronic illness, including fatigue, in two Australian populations. QJM Feb 19, 2008 [E-pub ahead of print].