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Spotted fever Rickettsia species in Hyalomma and Ixodes ticks infesting migratory birds in the European Mediterranean area.

Wallménius K, Barboutis C, Fransson T, Jaenson TG, Lindgren PE, Nyström F, Olsen B, Salaneck E, Nilsson K - Parasit Vectors (2014)

Bottom Line: The majority (65%) of ticks was engorged and nearly all ticks contained visible blood.Migratory birds appear to have a great impact on the dissemination of Rickettsia-infected ticks, some of which may originate from distant locations.The potential ecological, medical and veterinary implications of such Rickettsia infections need further examination.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Medical Sciences, Section of Clinical Microbiology, Uppsala University, Uppsala, Sweden. kenneth.nilsson@medsci.uu.se.

ABSTRACT

Background: A few billion birds migrate annually between their breeding grounds in Europe and their wintering grounds in Africa. Many bird species are tick-infested, and as a result of their innate migratory behavior, they contribute significantly to the geographic distribution of pathogens, including spotted fever rickettsiae. The aim of the present study was to characterize, in samples from two consecutive years, the potential role of migrant birds captured in Europe as disseminators of Rickettsia-infected ticks.

Methods: Ticks were collected from a total of 14,789 birds during their seasonal migration northwards in spring 2009 and 2010 at bird observatories on two Mediterranean islands: Capri and Antikythira. All ticks were subjected to RNA extraction followed by cDNA synthesis and individually assayed with a real-time PCR targeting the citrate synthase (gltA) gene. For species identification of Rickettsia, multiple genes were sequenced.

Results: Three hundred and ninety-eight (2.7%) of all captured birds were tick-infested; some birds carried more than one tick. A total number of 734 ticks were analysed of which 353 ± 1 (48%) were Rickettsia-positive; 96% were infected with Rickettsia aeschlimannii and 4% with Rickettsia africae or unidentified Rickettsia species. The predominant tick taxon, Hyalomma marginatum sensu lato constituted 90% (n = 658) of the ticks collected. The remaining ticks were Ixodes frontalis, Amblyomma sp., Haemaphysalis sp., Rhipicephalus sp. and unidentified ixodids. Most ticks were nymphs (66%) followed by larvae (27%) and adult female ticks (0.5%). The majority (65%) of ticks was engorged and nearly all ticks contained visible blood.

Conclusions: Migratory birds appear to have a great impact on the dissemination of Rickettsia-infected ticks, some of which may originate from distant locations. The potential ecological, medical and veterinary implications of such Rickettsia infections need further examination.

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Related in: MedlinePlus

Illustration of the wintering and breeding areas and migration directions of five bird species. Breeding (green) and wintering (light brown) areas for some bird species included in the study, based on Cramp and Perrins [36-38]. Arrows show the main direction of movements from wintering areas towards breeding areas during spring migration.Sedge Warbler Acrocephalus schoenobaenus. The locations of Capri (C) and Antikythira (A) bird observatories in Italy and Greece, respectively, are shown by white squares.
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Figure 3: Illustration of the wintering and breeding areas and migration directions of five bird species. Breeding (green) and wintering (light brown) areas for some bird species included in the study, based on Cramp and Perrins [36-38]. Arrows show the main direction of movements from wintering areas towards breeding areas during spring migration.Sedge Warbler Acrocephalus schoenobaenus. The locations of Capri (C) and Antikythira (A) bird observatories in Italy and Greece, respectively, are shown by white squares.

Mentions: The European bird population includes a few billion birds that migrate annually during spring to their breeding grounds in Europe and return during autumn to their non-breeding grounds in Africa [32]. Species that spend most of their time on the ground in search of food usually have relatively high tick infestation rates [33]. The present study reflects how tick-infested birds may be an important factor for tick dispersal and enhance tick dispersal by carrying infected ticks over long distances to new locations. The geographic distribution of the dominant tick species of the H. marginatum complex and migratory routes of observed bird species are summarized in Figures 1, 2, 3, 4, 5 and 6 respectively.


Spotted fever Rickettsia species in Hyalomma and Ixodes ticks infesting migratory birds in the European Mediterranean area.

Wallménius K, Barboutis C, Fransson T, Jaenson TG, Lindgren PE, Nyström F, Olsen B, Salaneck E, Nilsson K - Parasit Vectors (2014)

Illustration of the wintering and breeding areas and migration directions of five bird species. Breeding (green) and wintering (light brown) areas for some bird species included in the study, based on Cramp and Perrins [36-38]. Arrows show the main direction of movements from wintering areas towards breeding areas during spring migration.Sedge Warbler Acrocephalus schoenobaenus. The locations of Capri (C) and Antikythira (A) bird observatories in Italy and Greece, respectively, are shown by white squares.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4230250&req=5

Figure 3: Illustration of the wintering and breeding areas and migration directions of five bird species. Breeding (green) and wintering (light brown) areas for some bird species included in the study, based on Cramp and Perrins [36-38]. Arrows show the main direction of movements from wintering areas towards breeding areas during spring migration.Sedge Warbler Acrocephalus schoenobaenus. The locations of Capri (C) and Antikythira (A) bird observatories in Italy and Greece, respectively, are shown by white squares.
Mentions: The European bird population includes a few billion birds that migrate annually during spring to their breeding grounds in Europe and return during autumn to their non-breeding grounds in Africa [32]. Species that spend most of their time on the ground in search of food usually have relatively high tick infestation rates [33]. The present study reflects how tick-infested birds may be an important factor for tick dispersal and enhance tick dispersal by carrying infected ticks over long distances to new locations. The geographic distribution of the dominant tick species of the H. marginatum complex and migratory routes of observed bird species are summarized in Figures 1, 2, 3, 4, 5 and 6 respectively.

Bottom Line: The majority (65%) of ticks was engorged and nearly all ticks contained visible blood.Migratory birds appear to have a great impact on the dissemination of Rickettsia-infected ticks, some of which may originate from distant locations.The potential ecological, medical and veterinary implications of such Rickettsia infections need further examination.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Medical Sciences, Section of Clinical Microbiology, Uppsala University, Uppsala, Sweden. kenneth.nilsson@medsci.uu.se.

ABSTRACT

Background: A few billion birds migrate annually between their breeding grounds in Europe and their wintering grounds in Africa. Many bird species are tick-infested, and as a result of their innate migratory behavior, they contribute significantly to the geographic distribution of pathogens, including spotted fever rickettsiae. The aim of the present study was to characterize, in samples from two consecutive years, the potential role of migrant birds captured in Europe as disseminators of Rickettsia-infected ticks.

Methods: Ticks were collected from a total of 14,789 birds during their seasonal migration northwards in spring 2009 and 2010 at bird observatories on two Mediterranean islands: Capri and Antikythira. All ticks were subjected to RNA extraction followed by cDNA synthesis and individually assayed with a real-time PCR targeting the citrate synthase (gltA) gene. For species identification of Rickettsia, multiple genes were sequenced.

Results: Three hundred and ninety-eight (2.7%) of all captured birds were tick-infested; some birds carried more than one tick. A total number of 734 ticks were analysed of which 353 ± 1 (48%) were Rickettsia-positive; 96% were infected with Rickettsia aeschlimannii and 4% with Rickettsia africae or unidentified Rickettsia species. The predominant tick taxon, Hyalomma marginatum sensu lato constituted 90% (n = 658) of the ticks collected. The remaining ticks were Ixodes frontalis, Amblyomma sp., Haemaphysalis sp., Rhipicephalus sp. and unidentified ixodids. Most ticks were nymphs (66%) followed by larvae (27%) and adult female ticks (0.5%). The majority (65%) of ticks was engorged and nearly all ticks contained visible blood.

Conclusions: Migratory birds appear to have a great impact on the dissemination of Rickettsia-infected ticks, some of which may originate from distant locations. The potential ecological, medical and veterinary implications of such Rickettsia infections need further examination.

Show MeSH
Related in: MedlinePlus