| 11. |
- Mejlon, Hans, et al.
(författare)
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Questing behaviour of Ixodes ricinus ticks (Acari: Ixodidae)
- 1997
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Ingår i: Experimental & applied acarology. - 0168-8162 .- 1572-9702. ; 21:12, s. 747-754
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Tidskriftsartikel (refereegranskat)abstract
- The vertical distribution in the vegetation of questing Ixodes ricinus ticks was investigated in two different vegetation types ('high' and 'low' vegetation) at two localities in south-central Sweden during 1992-1993 (Torö) and 1995 (Bogesund). Significant correlations were found between the vertical distribution of immature ticks and the height of the vegetation. The greatest mean availabilities of the larvae and nymphs in low vegetation were in the intervals 0-9 and 30-39 cm, respectively. The larval numbers were greatest close to the ground (0-29) in both high and low vegetation. The larval : nymphal ratio, at ground level at localities free of ground vegetation, varied between 8:1 and 32:1. In high vegetation, the greatest mean numbers of nymphal and adult ticks were at height intervals of 50-59 and 60-79 cm, respectively. These ranges are within the estimated height interval (40-100 cm) of the main part of the body surface of their 'preferred' host, the roe deer (Capreolus capreolus). The presence of most questing I. ricinus larvae at ground level would favour the transmission of Borrelia burgdorferi s.l., since this is where the highly reservoir-competent rodents and shrews usually occur.
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| 12. |
- Mejlon, Hans, et al.
(författare)
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Seasonal prevalence of Borrelia burgdorferi in Ixodes ricinus in different vegetation types in Sweden
- 1993
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 25:4, s. 449-456
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this investigation was to estimate the seasonal risk of contracting human Lyme disease in different vegetation types in southern Sweden. Host-seeking Ixodes ricinus ticks (Acari: Ixodidae) were collected with standardized methods during May-September 1988 and March-October 1989 at 10 different sampling sites. Tick abundance was greatest during May-June and August-September. Prevalence of Borrelia burgdorferi infection of the ticks was assessed by phase-contrast microscopy complemented by immunology. Spirochetal infection of tick larvae was not detected. The prevalence of infection among nymphal ticks differed significantly between years and between sampling sites. Infection prevalence was greater in adult females than in nymphs, but was similar in female and male ticks. Among all vegetation types studied, the greatest Lyme disease risk was deemed to be from I. ricinus nymphs during May and September in mixed forest vegetation.
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| 13. |
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| 14. |
- Tälleklint, Lars, et al.
(författare)
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Transmission of the Lyme borreliosis spirochete at the mammal reservoir : tick vector interface in Sweden
- 1995
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Ingår i: Proceedings of the 2:nd International Conference on tick-borne pathogens at the host-vector interface.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- During 1988 to 1995 we examined the density of questing Ixodes ricinus nymphs infected with Borrelia burgdorferi s.l. at 12 areas in southern and southcentral Sweden. There were great differences in the density of questing Borrelia-infected I. ricinus nymphs between these areas, i.e., from <10 to >500 infected nymphs per hectare. The density of I. ricinus nymphs had a greater impact on this variation than the prevalence of Borrelia-infection in the nymphs, suggesting that reservoir incompetent cervids, which are important hosts for adult female I. ricinus, indirectly increase the risk of encountering Borrerlia-infected nymphal ticks despite the ability of cervids to divert larval ticks from reservoir competent mammals. There was a strong correlation between the mean number of Borrelia-infected nymphs per hectare and the mean number of nymphs per hectare, suggesting that it may be possible to assess the risk of encountering Borrelia-infected ticks in different areas without examining the prevalence of spirochetal infection.
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| 15. |
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| 16. |
- Waldenström, Jonas, et al.
(författare)
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Migrating birds and tickborne encephalitis virus
- 2007
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Ingår i: Emerging Infectious Diseases. - : Centers for Disease Control and Prevention (CDC). - 1080-6040 .- 1080-6059. ; 13:8, s. 1215-8
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Tidskriftsartikel (refereegranskat)abstract
- During spring and autumn 2001, we screened 13,260 migrating birds at Ottenby Bird Observatory, Sweden, and found 3.4% were infested with ticks. Four birds, each a different passerine species, carried tickborne encephalitis virus (TBEV)-infected ticks (Ixodes ricinus). Migrating birds may play a role in the geographic dispersal of TBEV-infected ticks.
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