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Prevalence of Rickettsia spp., Anaplasma phagocytophilum and Coxiella burnetii in adult Ixodes ricinus ticks from 29 study areas in central and southern Sweden
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Bacteriology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Systematic Biology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Systematic Biology.
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. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Center for Clinical Research Dalarna.
2012 (English)In: Ticks and Tick-borne Diseases, ISSN 1877-959X, E-ISSN 1877-9603, Vol. 3, no 2, 100-106 p.Article in journal (Refereed) Published
Abstract [en]

A total of 887 adult Ixodes ricinus ticks (469 females and 418 males) from 29 different localities in Sweden were screened for Rickettsia, Anaplasma, and Coxiella DNA using PCR and then subjected to gene sequencing. Rickettsial DNA was detected in 9.5–9.6% of the ticks. Most of the positive ticks were infected with Rickettsia helvetica. One tick harbored another spotted fever rickettsia, closely related to or identical with R. sibirica not previously found in I. ricinus nor in Sweden. Six of the ticks (0.7%) were infected with an Anaplasma sp., presumably A. phagocytophilum. Coxiella burnetii DNA was not detected in any of the ticks. The detection of R. helvetica and A. phagocytophilum in several of the localities sampled suggests that these potentially human-pathogenic agents are common in Sweden.

Place, publisher, year, edition, pages
2012. Vol. 3, no 2, 100-106 p.
Keyword [en]
Ixodes ricinus, Rickettsia, Anaplasma, Coxiella, PCR
National Category
Microbiology in the medical area
Research subject
Microbiology
Identifiers
URN: urn:nbn:se:uu:diva-168814DOI: 10.1016/j.ttbdis.2011.11.003ISI: 000304570200006OAI: oai:DiVA.org:uu-168814DiVA: diva2:503484
Note

De två första författarna delar förstaförfattarskapet.

Available from: 2012-02-15 Created: 2012-02-15 Last updated: 2017-12-07Bibliographically approved
In thesis
1. The Origin of the Genus Flavivirus and the Ecology of Tick-Borne Pathogens
Open this publication in new window or tab >>The Origin of the Genus Flavivirus and the Ecology of Tick-Borne Pathogens
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The present thesis examines questions related to the temporal origin of the Flavivirus genus and the ecology of tick-borne pathogens. In the first study, we date the origin and divergence time of the Flavivirus genus. It has been argued that the first flaviviruses originated after the last glacial maximum. This has been contradicted by recent analyses estimating that the tick-borne flaviviruses emerged at least before 16,000 years ago. It has also been argued that the Powassan virus was introduced into North America at the time between the opening and splitting of the Beringian land bridge. Supported by tip date and biogeographical calibration, our results suggest that this genus originated circa 120,000 (156,100–322,700) years ago if the Tamana bat virus is included in the genus, or circa 85,000 (63,700–109,600) years ago excluding the Tamana bat virus. In the second study we estimate the prevalence of tick-borne encephalitis virus (TBEV) in host-seeking Ixodes ricinus from 29 localities in Sweden and compare our data with those of neighbouring countries. Nymphs and adult ticks were screened for TBEV using a real-time PCR assay. The mean TBEV prevalence for all tick stages combined was 0.26% for Sweden and 0.28% for all Scandinavian countries, excluding Iceland. The low prevalence of TBEV in nature may partly be explained by the fact that TBEV occurs in spatially small foci and that the inclusion of ticks from non-infected foci will reduce the prevalence estimate. In the third and fourth study, we conducted the first large-scale investigations to estimate the prevalence and geographical distribution of Anaplasma spp. and Rickettsia spp. in host-seeking larvae, nymphs and adults of I. ricinus ticks in Sweden. Ticks were collected from several localities in central and southern Sweden and were subsequently screened for the presence of Anaplasma spp. and Rickettsia spp. using a real-time PCR assay. For all active tick stages combined, the mean prevalence of Anaplasma spp. and Rickettsia spp. in I. ricinus in Sweden was estimated to 1.1% and 4.8%, respectively. It was also shown that A. phagocytophilum and R. helvetica are the main Anaplasma and Rickettsia species occurring in Sweden.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. 60 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1100
Keyword
Flavivirus, Virus dating, Molecular dating, Biogeography, Ixodes ricinus, Minimum infection rate, TBE, Tick-borne encephalitis virus, Rickettsia helvetica, Anaplasma phagocytophilum, Infection prevalence, RT-PCR
National Category
Biological Sciences
Research subject
Biology with specialization in Systematics
Identifiers
urn:nbn:se:uu:diva-211090 (URN)978-91-554-8814-7 (ISBN)
Public defence
2014-01-10, Zootissalen, EBC, Villavägen 9, Uppsala, 13:00 (English)
Opponent
Supervisors
Available from: 2013-12-10 Created: 2013-11-19 Last updated: 2014-01-24
2. Studies of Spotted Fever Rickettsia - Distribution, Detection, Diagnosis and Clinical Context: With a Focus on Vectors and Patients in Sweden
Open this publication in new window or tab >>Studies of Spotted Fever Rickettsia - Distribution, Detection, Diagnosis and Clinical Context: With a Focus on Vectors and Patients in Sweden
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The spotted fever rickettsia, Rickettsia helvetica, is an endemic tick-borne bacteria in Sweden. It causes infections in humans, manifested as aneruptive fever, headache, arthralgia and myalgia, and sometimes an inoculation eschar or a rash. There have also been two known cases of human infections with R. felis in Sweden.

The present thesis starts by investigating dispersal of ticks and Rickettsia spp. by migrating birds flying from Africa to Europe. Almost 15,000 birds were searched and 734 ticks collected, mainly of the species Hyalomma marginatum complex. Almost half (48%) of the ticks were infected with Rickettsia spp., 96% of which was R. aeschlimannii, the remaining R. africae and undefined species.

The next study focused on questing ticks over a large area in Sweden and determining the prevalence of Rickettsia spp., Anaplasma spp. and Coxiella burnetii. Rickettsia spp. was found in 9.5-9.6% of the ticks and A. phagocytophilum in 0.7%; no C. burnetii was found.

The last three papers in the thesis focused on the clinical presentation of rickettsiosis, the symptoms associated with the infection in general and particularly in patients with neurological complications. A tick-exposed population in Sweden was investigated to gain a better understanding of symptoms due to rickettsioses, also in relation to co-infections with other tick-borne bacteria. Based on symptoms, it was not possible to distinguish what pathogen caused the infections. Most patients had erythema migrans, some had serological reactions to Rickettsia spp., Borrelia spp. or co-infections by Rickettsia spp., Borrelia spp. and/or Anaplasma spp. In the fourth and fifth papers, we found associations between antibodies against Rickettsia spp. and sudden deafness (in 10-24% of patients) and facial nerve paralysis (in 8.3-25% of patients). In three patients R. felis was detected in the cerebrospinal fluids.   

Briefly, the thesis helps to clarify our knowledge about tick dispersal, shows a narrower prevalence estimate of Rickettsia spp. in Swedish ticks, and illuminates symptoms of rickettsioses and co-infections with other tick-borne infections. It also shows that presence of erythema migrans may be explained by more than Lyme disease and indicates a possible association between rickettsiosis and sudden deafness and facial nerve paralysis.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. 77 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 1195
Keyword
tick-borne infections, co-infections, ticks, Ixodes ricinus, zoonosis, Rickettsia helvetica, migrating birds, Bell’s pares, erythema migrans, Rickettsia aeschlimannii, sudden deafness, facial nerve paralysis, Hyalomma marginatum, Rickettsia africae, western blot, PCR, serology
National Category
Clinical Medicine Basic Medicine
Research subject
Clinical Bacteriology
Identifiers
urn:nbn:se:uu:diva-280667 (URN)978-91-554-9512-1 (ISBN)
Public defence
2016-05-04, Hörsalen, Klinisk Mikrobiologi, Akademiska sjukhuset, Ing D1, Dag Hammarskjöldsväg 17, Uppsala, 09:15 (Swedish)
Opponent
Supervisors
Available from: 2016-04-11 Created: 2016-03-14 Last updated: 2016-04-12

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Wallménius, KatarinaPettersson, John H-OJaenson, Thomas G.T.Nilsson, Kenneth

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