Migratory birds as disseminators of ticks and the tick-borne pathogens Borrelia bacteria and tick-borne encephalitis (TBE) virus: a seasonal study at Ottenby Bird Observatory in South-eastern Sweden

Background Birds can act as reservoirs of tick-borne pathogens and can also disperse pathogen-containing ticks to both nearby and remote localities. The aims of this study were to estimate tick infestation patterns on migratory birds and the prevalence of different Borrelia species and tick-borne encephalitis virus (TBEV) in ticks removed from birds in south-eastern Sweden. Methods Ticks were collected from resident and migratory birds captured at the Ottenby Bird Observatory, Öland, Sweden, from March to November 2009. Ticks were molecularly identified to species, and morphologically to developmental stage, and the presence of Borrelia bacteria and TBEV was determined by quantitative real-time PCR. Results A total of 1339 ticks in the genera Haemaphysalis, Hyalomma, and Ixodes was recorded of which I. ricinus was the most abundant species. Important tick hosts were the European robin (Erithacus rubecula), Blackbird (Turdus merula), Tree pipit (Anthus trivialis), Eurasian wren (Troglodytes troglodytes), Common redstart (Phoenicurus phoenicurus), Willow warbler (Phylloscopus trochilus), and Common whitethroat (Sylvia communis). Borrelia bacteria were detected in 25% (285/1,124) of the detached ticks available for analysis. Seven Borrelia species (B. afzelii, B. burgdorferi (s.s.), B. garinii, B. lusitaniae, B. turdi, B. valaisiana, and B. miyamotoi) were identified. B. turdi was recorded for the first time in ticks in Sweden. The number of Borrelia cells per tick ranged from 2.0 × 100 to 7.0 × 105. B. miyamotoi-containing ticks contained a significantly higher median number of Borrelia cells than B. burgdorferi (s.l.)-containing ticks. B. garinii and B. miyamotoi were the most prevalent Borrelia species in tick larvae. Larvae of I. ricinus with B. garinii were removed from seven bird species, particularly S. communis and A. trivialis, which may suggest that the larvae had contracted the Borrelia bacteria from or via these birds. Also, a high percentage of tick larvae containing B. miyamotoi was removed from E. rubecula. All ticks were negative for TBEV. Conclusions The results corroborate the view that the contributions of birds to human disease are substantial, particularly as blood hosts for ticks and for their short-, medium-, and long-distance dispersal. Moreover, several ground-foraging bird species appear to be important for the maintenance and dispersal of Borrelia species. The absence of TBEV in the ticks conforms to other similar studies.

Migratory birds as disseminators of ticks and the tick-borne pathogens Borrelia bacteria and tick-borne encephalitis (TBE) virus – a seasonal study at Ottenby Bird Observatory in South-eastern Sweden

Background:Birds can act as reservoirs of tick-borne pathogens and can also disperse pathogen-containing ticks to both nearby and remote localities. The aims of this study were to estimate tick infestation patterns on migratory birds and the prevalence of different Borrelia species and tick-borne encephalitis virus (TBEV) in ticks removed from birds in south-eastern Sweden.Methods:Ticks were collected from resident and migratory birds captured at the Ottenby Bird Observatory, Öland, Sweden, from March to November 2009. Ticks were molecularly identified to species, and morphologically to developmental stage, and the presence of Borrelia bacteria and TBEV was determined by quantitative real-time PCR.Results:A total of 1,339 ticks in the genera Haemaphysalis, Hyalomma and Ixodes was recorded of which I. ricinus was the most abundant species. Important tick hosts were the European robin (Erithacus rubecula), Blackbird (Turdus merula), Tree pipit (Anthus trivialis), Eurasian wren (Troglodytes troglodytes), Common redstart (Phoenicurus phoenicurus), Willow warbler (Phylloscopus trochilus), and Common whitethroat (Sylvia communis). Borrelia bacteria were detected in 25 % (285/1,124) of the detached ticks available for analysis. Seven Borrelia species (B. afzelii, B. burgdorferi sensu stricto, B. garinii, B. lusitaniae, B. turdi, B. valaisiana and B. miyamotoi) were identified. B. turdi was recorded for the first time in ticks in Sweden. The number of Borrelia cells per tick ranged from 2.0 × 100 to 7.0 × 105. B. miyamotoi-containing ticks contained a significantly higher median number of Borrelia cells than B. burgdorferi sensu lato-containing ticks. B. garinii and B. miyamotoi were the most prevalent Borrelia species in tick larvae. Larvae of I. ricinus with B. garinii were removed from seven bird species, particularly S. communis and A. trivialis, which may suggest that the larvae had contracted the Borrelia bacteria from or via these birds. Also, a high percentage of tick larvae containing B. miyamotoi was removed from E. rubecula. All ticks were negative for TBEV.Conclusions:The results corroborate the view that the contributions of birds to human disease are substantial, particularly as blood hosts for ticks and for their short-, medium- and long-distance dispersal. Moreover, several ground-foraging bird species appear to be important for the maintenance and dispersal of Borrelia species. The absence of TBEV in the ticks conforms to other similar studies.

Migratory Birds as Disseminators of Ticks and the Tick-Borne Pathogens Borrelia Bacteria and Tick-Borne Encephalitis (TBE) Virus – A Seasonal Study at Ottenby Bird Observatory in South-Eastern Sweden

Introduction Birds can act as reservoirs of tick-borne pathogens and can also disperse pathogen-containing ticks to both nearby and remote localities. The aims of this study were to estimate tick infestation patterns on migratory birds and the prevalence of different Borrelia species and tick-borne encephalitis virus (TBEV) in ticks removed from birds in south-eastern Sweden.Materials and Methods Ticks were collected from resident and migratory birds captured at the Ottenby Bird Observatory, Öland, Sweden, from March to November 2009. Ticks were molecularly identified to species, and morphologically to developmental stage, and the presence of Borrelia bacteria and TBEV was determined by quantitative real-time PCR.Results A total of 1,339 ticks in the genera Haemaphysalis, Hyalomma and Ixodes was recorded of which I. ricinus was the most abundant species. Important tick hosts were the European robin (Erithacus rubecula), Blackbird (Turdus merula), Tree pipit (Anthus trivialis), Eurasian wren (Troglodytes troglodytes), Common redstart (Phoenicurus phoenicurus), Willow warbler (Phylloscopus trochilus), and Common whitethroat (Sylvia communis). Borrelia bacteria were detected in 25 % (285/1,124) of the detached ticks available for analysis. Seven Borrelia species (B. afzelii, B. burgdorferi sensu stricto, B. garinii, B. lusitaniae, B. turdi, B. valaisiana and B. miyamotoi) were identified. B. turdi was recorded for the first time in ticks in Sweden. The number of Borrelia cells per tick ranged from 2.0 × 100 to 7.0 × 105. B. miyamotoi-containing ticks contained a significantly higher median number of Borrelia cells than B. burgdorferi sensu lato-containing ticks. B. garinii and B. miyamotoi were the most prevalent Borrelia species in tick larvae. Larvae of I. ricinus with B. garinii were removed from seven bird species, particularly S. communis and A. trivialis, which may suggest that the larvae had contracted the Borrelia bacteria from or via these birds. Also, a high percentage of tick larvae containing B. miyamotoi was removed from E. rubecula. Of the 1,124 ticks analysed, all were negative for TBEV.Conclusions The results corroborate the view that the contributions of birds to human disease are substantial, particularly as blood hosts for ticks and for their short-, medium- and long-distance dispersal. Moreover, several ground-foraging bird species appear to be important for the maintenance and dispersal of Borrelia species. The absence of TBEV in all bird-derived ticks investigated conforms to other similar studies.

The effect of urbanization on population densities of forest passerine species in a Central European city

Typical, but less common, passerine forest species were selected for this study, such as Lullula arborea, Anthus trivialis, Troglodytes troglodytes, Prunella modularis, Turdus philomelos, Turdus viscivorus, Phylloscopus sibilatrix, Regulus regulus, Regulus ignicapillus, Muscicapa striata, Ficedula albicollis, Ficedula hypoleuca, Parus cristatus, Parus palustris, Parus ater, Certhia familiaris, Certhia brachydactyla, Oriolus oriolus, Garrulus glandarius, and Corvus corax. M. striata and T. philomelos were the most numerous among the 20 investigated species, the former one nested in a density of 6.7 pairs per 100 ha of wooded area, while the later one at 5.1 pairs per 100 ha. Density of most other species was below 3 pairs per 100 ha of wooded area. A. trivialis, P. cristatus and P. modularis were unexpectedly rare (< 1 pair per 100 ha). Otherwise, relatively numerous were T. troglodytes (1.8 p./100 ha), R. regulus (1.8 p./100 ha) and P. palustris (1.4 p./100 ha). P. cristatus, L. arborea, and T. viscivorus were the rarest species investigated (below 0.1 p./100 ha). Several bird species nested in wooded areas only in the outer zone of the city. This group included A. trivialis, R. regulus, P. ater, and C. corax. Population density of T. troglodytes, T. philomelos and O. oriolus were significantly higher in outer than in inner zone, while the reverse was true in the case of M. striata and F. hypoleuca.

Förändringar av häckfåglar på en sydsmåländsk gård från 1970- till 2010-talet

I compare the number of breeding birds of a 70 ha farm in a forest region of southern Sweden between the 1970s and the 2010s. The most important habitat change was replacement of 25 hectares 100 years old mixed forest by spruce plantation. Stands dominated by deciduous trees only grew older, and pastures were grazed by cattle both periods. More species decreased than increased, especially residents and tropical migrants decreased. For short distance migrants, the number of decreasing species were balanced by a similar number of increasing species. The density change of most species could be attributed to the replacement of the old mixed forest by the spruce plantation. Species preferring deciduous forest had much higher densities in the study plot than the regional averages. Two deciduous forest species, Pied Flycatcher Ficedula hypoleuca and Marsh Tit Poecile palustris declined strongly, the latter possibly due to competition from the increasing Blue Tit Cyanistes caeruleus. The Starling Sturnus vulgaris and the Tree Pipit Anthus trivialis stands out as drastically decreasing much more than local habitat changes can explain.