uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Seroprevalence of Rickettsia spp. infection among tick-bitten patients and blood donors in Sweden
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Bacteriology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Center for Clinical Research Dalarna.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Infectious Diseases. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Center for Clinical Research Dalarna.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Bacteriology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Infectious Diseases.
2008 (English)In: Scandinavian Journal of Infectious Diseases, ISSN 0036-5548, E-ISSN 1651-1980, Vol. 40, no 1, 74-77 p.Article in journal (Refereed) Published
Abstract [en]

Serum samples from 236 Swedish patients with symptoms of infectious disease appearing after a tick bite were analysed for the presence of antibodies to Rickettsia helvetica, the only rickettsial species so far isolated from ticks in Sweden. Of these subjects, 137 had tested seropositive for Borrelia burgdorferi. For control purposes, sera from 161 healthy blood donors were examined. A total of 10/397 samples (2.6%) showed IgG-antibodies to R. helvetica at or above a titre of 1/80 as cut-off. 6/137 (4.4%) belonged to the Borrelia positive group, 3/99 (3.0%) to the tick-bitten but Borrelia negative group and 1/161 (0.6%) to the control group. The difference between the tick-exposed groups and the control group was significant in Pearson's 2-sided chi(2) test. In 1 serum sample the presence of antibodies to R. helvetica was further confirmed by Western immunoblot. The study shows that infection with Rickettsia spp. as well as coinfection with Lyme borreliosis needs to be considered in the diagnosis of tick-transmitted infections in Sweden. Owing to a known occurrence of immunological cross-reactivites, however, the results must be cautiously interpreted with regard to species of Rickettsia involved.

Place, publisher, year, edition, pages
2008. Vol. 40, no 1, 74-77 p.
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:uu:diva-103987DOI: 10.1080/00365540701509907ISI: 000252311200014PubMedID: 17852905OAI: oai:DiVA.org:uu-103987DiVA: diva2:219153
Available from: 2009-05-26 Created: 2009-05-26 Last updated: 2017-12-13Bibliographically approved
In thesis
1. Epidemiological and Bacteriological Aspects of Spotted Fever Rickettsioses in Humans, Vectors and Mammals in Sweden
Open this publication in new window or tab >>Epidemiological and Bacteriological Aspects of Spotted Fever Rickettsioses in Humans, Vectors and Mammals in Sweden
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Rickettsiae are obligate intracellular gram-negative bacteria transmitted by arthropod vectors. Rickettsiae sometimes cause disease in humans, typically with high fever, headache and occasionally an eschar.

In Sweden, Rickettsia helvetica, belonging to the spotted fever group, is the only tick-transmitted rickettsia found free in nature. The pathogenic roll of R. helvetica has not been fully investigated, but it has been implicated in aneruptive fever and cardiac disease.

This thesis describes parts of the transmission pathways of rickettsiae in Sweden. Rickettsia infection rates in ticks collected from birds were analysed, and the birds’ role as disseminators and reservoirs was studied. We found that more than one in ten ticks was infected with rickettsia bacteria, predominantly R. helvetica, and that migrating birds contribute not only to long-distance dispersion of bacteria, but also to an inflow of novel and potentially pathogenic rickettsia species, in this case R. monacensis and R. sp. strain Davousti-like species, into Sweden.

Further, wild and domestic animals were found to have seroreactivity against R. helvetica, which shows that they are exposed and susceptible to rickettsia. Their role as reservoirs has not been determined, yet they may indirectly be involved in transmission of rickettsia to humans by infected ticks feeding on them.

The seroreactivity in humans was also studied. Patients investigated for suspected Borrelioses and blood donors had detectable antibodies against Rickettsia spp., with the highest prevalence detected in the suspected Borreliosis group. This shows that humans in Sweden are exposed to and develop an immune response against rickettsia. The suspicion that R. helvetica may cause severe symptoms was verified by a patient with subacute meningitis where the bacterium was shown for the first time to cause an invasive infection with CNS involvement and where the bacterium was isolated from the patient’s cerebrospinal fluid.

Growth characteristics and morphology of R. helvetica were studied to better understand invasiveness and virulence. The findings indicate that the invasiveness is comparable with other rickettsia, though R. helvetica seems to have a stable but slightly slower growth. 

Rickettsia helvetica is endemic in Sweden and therefore needs to be considered when investigating disease after a tick bite.

Abstract [sv]

Rickettsia är en liten, strikt intracellulär, gramnegativ bakterie som sprids med vektorer som fästingar, löss och loppor. Bakterien kan orsaka Rickettsios hos människa, en sjukdom där de vanligaste symtomen är hög feber, huvudvärk, muskelvärk och i vissa fall ett bettmärke (eschar). I Sverige är Rickettsia helvetica, som tillhör spotted fever gruppen (SFG), den enda fästingöverförda rickettsia bakterien som hittats allmänt i naturen. Patogeniciteten för R. helvetica är ofullständigt utredd, men ”aneruptive fever” och hjärtmuskelinflammation har rapporterats.

Avhandlingen beskriver delar av smittkedjan för SFG rickettsia i Sverige. Bakteriernas förekomst i fästingar plockade från fåglar har studerats, likaså det ekologiska tryck som flyttfåglars bärarskap av infekterade fästingar bidrar med när de korsar olika världsdelar. Mer än var tionde fästing var infekterad med rickettsia bakterier, i huvudsak R. helvetica. Det visade sig att flyttfåglar bidrar inte bara till långväga spridning av bakterier utan även till införsel av nya potentiellt patogena rickettsiaarter, i detta fall identifierades R. monacensis och en R. sp strain Davousti liknande art.

Vidare analyserades seroreaktivitet mot Rickettsia helvetica hos både tamdjur och vilda djur, vilket visade på antikroppsutveckling, som uttryck för smittexposition, i mer än vart femte djur. Djurens roll som reservoar för bakterien är inte klarlagd, men oavsett är djuren indirekt involverade i spridningen av bakterien till människa via infekterade fästingar som suger blod.

Seroreaktivitet hos människa har också studerats. Patienter, provtagna på grund av misstanke om borreliainfektion, samt blodgivare hade detekterbara antikroppar mot Rickettsiae, med högst prevalens i gruppen med misstänkt borreliainfektion. Fynden visar att människor i Sverige är exponerade för och utvecklar en immunreaktion mot rickettsia. Att R. helvetica skulle kunna ge allvarlig sjukdom verifieras av ett patientfall med subakut meningit där bakterien för första gången visats ge invasiv infektion med påverkan på nervsystemet (CNS engagemang) och där bakterien isolerats från patientens ryggmärgsvätska. 

Morfologi och tillväxtegenskaper för R. helvetica undersöktes för att bättre förstå bakteriens invasivitet och virulens. Fynden indikerar att invasiviteten är jämförbar med andra rickettsiaarter men R. helvetica verkar ha en stabil men något långsammare tillväxt.

Rickettsia helvetica är endemisk i Sverige och måste tas i beaktande vid sjukdomsutredning efter ett fästingbett.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. 52 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 888
Keyword
Rickettsia helvetica, ticks, cultivation, serology, polymerase chain reaction (PCR), DNA sequencing, western blot, electron microscopy, meningitis, seroprevalence
National Category
Clinical Laboratory Medicine Microbiology Microbiology in the medical area
Identifiers
urn:nbn:se:uu:diva-197277 (URN)978-91-554-8639-6 (ISBN)
Public defence
2013-05-22, Hörsalen, Klinisk Mikrobiologi, Akademiska Sjukhuset, Dag Hammarskjöldsväg 17, Ing D1, Uppsala, 13:00 (Swedish)
Opponent
Supervisors
Available from: 2013-04-26 Created: 2013-03-21 Last updated: 2013-08-30Bibliographically approved
2. Spotted Fever Rickettsioses in Sweden: Aspects of Epidemiology, Clinical Manifestations and Co-infections
Open this publication in new window or tab >>Spotted Fever Rickettsioses in Sweden: Aspects of Epidemiology, Clinical Manifestations and Co-infections
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The spotted fever group rickettsiae are emerging diseases. They cause damage in their hosts by invading the endothelium in small to medium-sized blood vessels, which results in vasculitis that can cause clinical manifestations from most organs.

The present thesis describes the prevalence of Rickettsia helvetica in ticks, the incidence of rickettsial infection based on seroreactivity and seroconversion in humans and their symptoms, from different parts of Sweden and the Åland Islands in Finland. This was accomplished through serological analysis of both retrospective and prospective serum samples from confirmed and suspected tick-bitten individuals compared to individuals with no knowledge of tick exposure (blood donors). We found a comparable seroprevalence to Rickettsia spp. in different geographical areas where ticks are present; it was also comparable to the seroprevalence of Borrelia spp. Seroprevalence was also more common, as suspected, in the tick-exposed group compared to blood donors. In comparison with co-infections with other tick-borne infections (Anaplasma spp. and Borrelia spp.), we could conclude that co-infections do exist and that, based on clinical findings, it is difficult to distinguish which microorganism causes certain clinical manifestations. For reliable conclusions regarding the causative microorganism, the diagnosis should basically rely on diagnostic tests. In comparison with Borrelia spp., seroconversion to Rickettisa spp. was more common in the areas we investigated, indicating that rickettsiosis is a common tick-borne infection in Sweden and most likely underdiagnosed.

When investigating patients with meningitis, we found R. felis in cerebrospinal fluid from two patients with subacute meningitis. This was the first report in which R. felis was found and diagnosed in patients in Sweden. The patients recovered without sequelae and without causal treatment. To provide guidelines on when to treat Rickettisa spp. infections, more investigations are needed.

The present thesis shows that Rickettsia spp. are common in ticks and do infect humans. Rickettsial infection should be considered in both non-specific or specific symptoms after a tick bite. It was also shown in the thesis that flea-borne rickettsiosis (R. felis) occurs in Sweden and may cause invasive infections

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. 64 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 1253
Keyword
Rickettsia helvetica, Rickettsia felis, co-infection, erythema migrans, meningitis, serology, PCR, western blot
National Category
Infectious Medicine
Research subject
Infectious Diseases
Identifiers
urn:nbn:se:uu:diva-302137 (URN)978-91-554-9677-7 (ISBN)
Public defence
2016-10-26, Mikrobiologens hörsal, Dag Hammarskjöldsväg 17, Uppsala, 13:15 (Swedish)
Opponent
Supervisors
Available from: 2016-10-03 Created: 2016-08-30 Last updated: 2016-10-11

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Authority records BETA

Lindblom, Anders

Search in DiVA

By author/editor
Lindblom, Anders
By organisation
Clinical BacteriologyCenter for Clinical Research DalarnaInfectious Diseases
In the same journal
Scandinavian Journal of Infectious Diseases
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 506 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf