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Identification. differentiation and genotyping of Francisella tularensis in organ samples of wildlife and arthropods in Germany
Project
Project code: FLI-IBIZ-08-DA_0006
Contract period: 01.01.2001
- 31.12.2017
Purpose of research: Applied research
Tularemia is a disease caused by Francisella (F.) tularensis and called hare pest, rodent pest, lemming fever, deer flee fever, hunter sickness or Ohara disease too. It is the zoonosis caused by one of the most highly infectious bacteria are known. For this reason the infectious agent F. tularensis is declared as a biological weapon. These bacteria were detected by nearly 110 mammarial species, 25 bird species, some amphibians and fishes. In Germany the occurrence of tularemia was reported to 1961 and than this disease was not observed over 40 years. Since 2004 the number of infections caused by F. tularensis are increasing. The aim of this investigation is to discover the widespread of F. tularensis in the wildlife and in arthropods. This needs the improvement of diagnostic methods which allow to identify and differentiate the bacteria F. tularensis and their subspecies tularensis, holarctica, mediaasiatica and novicida. Furthermore the isolates will be genotyped using different molecular methods.
The importance of established and emerging tick-borne pathogens in Central and Northern Europe is steadily increasing. In 2007 we collected Ixodes ricinus ticks feeding on birds (N=211) and rodents (N=273), but also host-seeking stages (N=196) in a habitat in Central Germany. In order to find out more about their natural transmission cycles, the ticks were tested for the presence of Lyme disease borreliae, Anaplasma phagocytophilum, spotted fever group (SFG) rickettsiae, Francisella tularensis, and babesiae. Altogether, 20.1% of 680 examinded ticks carried at least one pathogen. Bird-feeding ticks were more frequently infected with Borrelia spp. (15.2%) and A. phagocytophilum (3.2%) than rodent-feeding (2.6%; 1.1%) or questing ticks (5.1%; 0%). Babesia spp. showed higher prevalences in ticks parasitizing on birds (13.2%) and host-seeking ticks (10.7%) whereas ticks from small mammals were less frequently infected (6.6%). SFG rickettsiae and F. tularensis were also found in ticks collected off birds (2.1%; 1.2%), rodents (1.8%; 1.5%) and vegetation (4.1%; 1.6%). Various combinations of co-infections occurred in 10.9% of all positive ticks, indicating interaction of transmission cycles. Our results suggest that birds are not only important reservoirs for several pathogens but also act as vehicles for infected ticks and might therefore play a key role in the dispersal of tick-borne diseases.
Section overview
Subjects
- Animal health
- Biotechnology
Framework programme
Funding programme
Excutive institution
FLI - Institute for Bacterial Infections and Zoonoses (FLI-IBIZ)