Landscape Epidemiology of Tularemia Outbreaks in Sweden

Svensson, Kerstin; Bäck, Erik; Eliasson, Henrik; Berglund, Lennart; Granberg, Malin; Karlsson, Linda; Larsson, Pär; Forsman, Mats; Johansson, Anders

doi:10.3201/eid1512.090487

Cited by 82 publications

(92 citation statements)

References 23 publications

(43 reference statements)

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“…The range of arthropod vectors connected with tularemia has expanded to include ticks [19,40,[53][54][55][56][57][58][59][60], mosquitoes [56,61], horse flies [56], fleas [62] and gamasid mites [3]. In Europe, much of the research on the role of arthropod vectors in the transmission of F. tularensis subsp.…”

Section: Tularemia In Vectorsmentioning

confidence: 99%

The status of tularemia in Europe in a one-health context: a review

et al. 2014

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SUMMARYThe bacterium Francisella tularensis causes the vector-borne zoonotic disease tularemia, and may infect a wide range of hosts including invertebrates, mammals and birds. Transmission to humans occurs through contact with infected animals or contaminated environments, or through arthropod vectors. Tularemia has a broad geographical distribution, and there is evidence which suggests local emergence or re-emergence of this disease in Europe. This review was developed to provide an update on the geographical distribution of F. tularensis in humans, wildlife, domestic animals and vector species, to identify potential public health hazards, and to characterize the epidemiology of tularemia in Europe. Information was collated on cases in humans, domestic animals and wildlife, and on reports of detection of the bacterium in arthropod vectors, from 38 European countries for the period 1992-2012. Multiple international databases on human and animal health were consulted, as well as published reports in the literature. Tularemia is a disease of complex epidemiology that is challenging to understand and therefore to control. Many aspects of this disease remain poorly understood. Better understanding is needed of the epidemiological role of animal hosts, potential vectors, mechanisms of maintenance in the different ecosystems, and routes of transmission of the disease.

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Section: Tularemia In Vectorsmentioning

confidence: 99%

The status of tularemia in Europe in a one-health context: a review

et al. 2014

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“…Recent studies in Sweden have indicated phylogeographical patterns both in local outbreaks and across larger geographical distances. These studies from Sweden also identified areas where F. tularensis persisted over several years and spatial associations of certain genetic subpopulations [16]. Little is known about phylogeographical patterns of F. tularensis in Norway.…”

Section: Introductionmentioning

confidence: 99%

Phylogeographical pattern of Francisella tularensis in a nationwide outbreak of tularaemia in Norway, 2011

et al. 2015

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In 2011, a nationwide outbreak of tularaemia occurred in Norway with 180 recorded cases. It was associated with the largest peak in lemming density seen in 40 years. Francisella tularensis was isolated from 18 patients. To study the geographical distribution of F. tularensis genotypes in Norway and correlate genotype with epidemiology and clinical presentation, we performed whole genome sequencing of patient isolates. All 18 genomes from the outbreak carried genetic signatures of F. tularensis subsp. holarctica and were assigned to genetic clades using canonical single nucleotide polymorphisms. Ten isolates were assigned to major genetic clade B.6 (subclade B.7), seven to clade B.12, and one to clade B.4. The B.6 subclade B.7 was most common in southern and central Norway, while clade B.12 was evenly distributed between the southern, central and northern parts of the country. There was no association between genotype and clinical presentation of tularaemia, time of year or specimen type. We found extensive sequence similarity with F. tularensis subsp. holarctica genomes from high-endemic tularaemia areas in Sweden. Finding nearly identical genomes across large geographical distances in Norway and Sweden imply a life cycle of the bacterium without replication between the outbreaks and raise new questions about long-range migration mechanisms.

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“…These pathogens may cause anthrax, tularemia, plague, brucellosis, glanders, melioidosis, and Q fever, respectively. In most parts of the world, the natural prevalence of these agents is low, even though some of these agents cause outbreaks in human and animal populations from time to time (5)(6)(7)(8). The intentional release of these agents, however, can result in severe public health consequences, as was shown in the Unites States in 2001 (9,10).…”

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Identification of Highly Pathogenic Microorganisms by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: Results of an Interlaboratory Ring Trial

et al. 2015

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mIn the case of a release of highly pathogenic bacteria (HPB), there is an urgent need for rapid, accurate, and reliable diagnostics. MALDI-TOF mass spectrometry is a rapid, accurate, and relatively inexpensive technique that is becoming increasingly important in microbiological diagnostics to complement classical microbiology, PCR, and genotyping of HPB. In the present study, the results of a joint exercise with 11 partner institutions from nine European countries are presented. In this exercise, 10 distinct microbial samples, among them five HPB, Bacillus anthracis, Brucella canis, Burkholderia mallei, Burkholderia pseudomallei, and Yersinia pestis, were characterized under blinded conditions. Microbial strains were inactivated by high-dose gamma irradiation before shipment. Preparatory investigations ensured that this type of inactivation induced only subtle spectral changes with negligible influence on the quality of the diagnosis. Furthermore, pilot tests on nonpathogenic strains were systematically conducted to ensure the suitability of sample preparation and to optimize and standardize the workflow for microbial identification. The analysis of the microbial mass spectra was carried out by the individual laboratories on the basis of spectral libraries available on site. All mass spectra were also tested against an in-house HPB library at the Robert Koch Institute (RKI). The averaged identification accuracy was 77% in the first case and improved to >93% when the spectral diagnoses were obtained on the basis of the RKI library. The compilation of complete and comprehensive databases with spectra from a broad strain collection is therefore considered of paramount importance for accurate microbial identification. Highly pathogenic bacteria (HPB) are risk group 3 bacteria, which are defined as biological agents that can cause severe human disease and present a serious hazard to health care workers. This may present a risk of spreading to the community, but there is usually effective prophylaxis or treatment available (1). To this group belong bacteria such as Bacillus anthracis, Francisella tularensis subsp. tularensis (type A), Yersinia pestis, species of the Brucella melitensis group, Burkholderia mallei, and Burkholderia pseudomallei. HPB have the potential to be used in bioterrorist attacks (2, 3). The Centers for Disease Control and Prevention (CDC, Atlanta, GA) have classified B. anthracis, F. tularensis, and Y. pestis as category A and Brucella species, B. mallei, B. pseudomallei, and Coxiella burnetii as category B, comprising the main pathogens of concern for use in bioterrorist attacks (4). These pathogens may cause anthrax, tularemia, plague, brucellosis, glanders, melioidosis, and Q fever, respectively. In most parts of the world, the natural prevalence of these agents is low, even though some of these agents cause outbreaks in human and animal populations from time to time (5-8). The intentional release of these agents, however, can result in severe public health consequences, as was shown in the U...

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Landscape Epidemiology of Tularemia Outbreaks in Sweden

Abstract: Transmission sites of specific Francisella tularensis genotypes were highly localized during natural outbreaks of human tularemia.

Cited by 82 publications

References 23 publications

The status of tularemia in Europe in a one-health context: a review

The status of tularemia in Europe in a one-health context: a review

Phylogeographical pattern of Francisella tularensis in a nationwide outbreak of tularaemia in Norway, 2011

Identification of Highly Pathogenic Microorganisms by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: Results of an Interlaboratory Ring Trial

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