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Determination of the ratios of natural stable isotopes (C-13/C-12 and N-15/N-14) in unfed Ixodes ricinus nymphs and adults, which, in their previous stage, fed on captive wild rodents (Apodemus sylvaticus and Myodes glareolus), wild birds (Parus major and Cyanistes caeruleus) or domestic ruminants (Ovis aries and Bos taurus), demonstrated that it is possible to identify each host category with confidence. First, the tick-blood spacing, which is the difference between values obtained from ticks and the blood of hosts that they had fed on in the previous stage, was consistent (152 spacings investigated from 15 host individuals in total). Second, potential confounding factors (tick age and sex) did not affect the discriminatory power of the isotope patterns, nor did different rearing conditions (room temperature vs. 4 degrees C) or the duration of development (maximum of 430 days). The findings that the tick-blood isotope spacings, across a diverse range of hosts, were similar and predictable, and that confounders had little or no effect on this, strongly support the usage of the isotope approach. Because each of the host categories has a different role in the population dynamics of I. ricinus and in tick-borne pathogen ecology, the method described here has great potential for the clarification of tick and tick-borne pathogen ecology in the field. Dieter Heylen is funded by the Marie Sklodowska-Curie Actions (EU-Horizon 2020, Individual Global Fellowship, project no. 799609) and the Fund for Scientific Research - Flanders (FWO). The research was partly funded by the Bill & Melinda Gates Foundation. The feeding of ticks on hosts was performed in accordance with ethical committee-approved animal use protocols (birds - University of Antwerp: 2009-32; rodents-IS Insect Services GmbH: Landesamt fur Gesundheit und Soziales H 0222/01 and Department of Economy of Canton Neuchatel: authorization 2/2009; ruminants - Friedrich-Loeffler-Institut: permission ref. no. LALLF M-V/TSD/7221.3-2.1-010/07). All authors contributed critically to the draft manuscript and approved the final version submitted for publication. The authors declare that have no conflicts of interest.

Tick-borne encephalitis virus (TBEV) is the causative agent of tick-borne encephalitis (TBE) and causes neurological disease in humans in Eurasia. TBEV is transmitted by ticks of the genus Ixodes. Currently 10,000-12,000 clinical cases are reported annually in ≈30 TBE endemic countries. Since 1990 the epidemiology of TBE is characterized by a global increase of clinical cases and an expansion of risk areas. Similar trends are also observed in Switzerland but few studies confirmed the emergence of new TBE foci by detecting viral RNA in field-collected ticks. In this study, free-living Ixodes ricinus (L.) ticks from one nonendemic and three new TBE endemic regions located in the Western part of Switzerland were screened during four consecutive years (2007-2010) for the presence of TBEV. A total of 9,868 I. ricinus ticks (6,665 nymphs and 3,203 adults) were examined in pools for TBEV by real-time reverse transcription polymerase chain reaction. Our results confirmed the presence of viral RNA in 0.1% (6/6120) of questing ticks collected in one new endemic region. Among TBE endemic sites, the minimal infection rate per 100 ticks tested ranged from 0.21 (1/477) to 0.95 (1/105). Four positive samples were sequenced and phylogenetic analysis of the NS5 gene showed that all TBEV nucleotide sequences belonged to the European subtype and were split into two distinct lineages originating probably independently from two distinct foci located North-East and East of the study region

in: 20th European Society for Vector Ecology Conference 2016: book of abstracts, p. 157. doi:10.3920/978-90-8686-837-7 Lyme borreliosis, is a tick-borne disease caused by Borrelia burgdorferi sensu lato, that is considered an emerging disease in some regions of the world, namely in Portugal. The aims of this study is the key role of birds and lizards as reservoirs for the etiologic agent of Lyme borreliosis in Portugal. FCT, UN, NIH info:eu-repo/semantics/publishedVersion

As aves selvagens são frequentemente infestadas por carraças e são consideradas reservatório da Borrelia burgdorferi s.l. (sensu lato), um complexo de bactérias transmitidas por carraças, que causam a borreliose de Lyme. De 2010 a 2014 recolhemos 2820 carraças de 690 aves infestadas pertencentes a 40 espécies, e avaliámos a infecção por B. burgdorferi s.l. por nested PCR nestas carraças. Oito espécies de carraças foram identificadas, sendo, Ixodes frontalis (37%) e I. ricinus (34%) as espécies mais comuns. O Melro (Turdus merula) e o Pisco-de-peito-ruivo (Erithacus rubecula) foram as espécies mais infestadas, possivelmente devido aos seus hábitos de pesquisa de alimento a níveis mais baixos. Carraças do género Ixodes sp. infectadas com Borrelia burgdorferi s.l. foram recolhidas de Tentilhões (Fringilla coelebs), Chapins-reais (Parus major), Toutinegras-dosvalados (Sylvia melanocephala), Carriças (Troglodytes troglodytes), Tordos-ruivos (Turdus iliacus), Melros (T. merula) e Tordos-pintos (Turdus philomelos), com maior prevalência em carraças provenientes de T. philomelos (26%). Detectámos B. turdi (4,4%), B. valaisiana (3,7%), B. garinii (3,3%), B. miyamotoi (0,06%) e B. bissettii (0,06%) em Ixodes sp. recolhidas das aves. A caracterização genética das linhagens de B. turdi sugere divergência filogenética da linhagem originalmente detectada no Japão. Uma experiência de xenodiagnóstico provou a capacidade reservatório de T. merula para B. valaisiana e B. turdi. Estes resultados reforçam o papel das aves como agentes chave na manutenção de diferentes genoespécies do complexo B. burgdorferi s.l. Wild birds are often infested by ticks and considered reservoirs of the tick-transmitted bacteria Borrelia burgdorferi s.l. (sensu lato), the etiologic agent of Lyme borreliosis. In 2010-2014 we collected 2820 ticks from 690 infested birds of 40 species in Portugal, and assessed their B. burgdorferi s.l. infection by nested PCR. Eight tick species were identified, and, Ixodes frontalis (37%) and I. ricinus (34%) were the most common. Blackbird (Turdus merula) and Robin (Erithacus rubecula) were the most infested species, possibly due to their ground foraging behaviour. Infected Ixodes sp. were collected from Chaffinch (Fringilla coelebs), Great Tit (Parus major) Sardinian Wabler (Sylvia melanocephala), Wren (Troglodytes troglodytes), Redwing (Turdus iliacus), T. merula and Song Thrush (Turdus philomelos), with higher prevalence in ticks from T. philomelos (26%). We detected B. turdi (4.4%), B. valaisiana (3.7%), B. garinii (3.3%), B. miyamotoi (0.06%) and B. bissettii (0.06%) in Ixodes sp. collected from birds. The genetic characterization of B. turdi strains suggests their phylogenetic divergence from the strain originally detected in Japan. A xenodiagnostic experiment proved the reservoir competency of T. merula for B. valaisiana and B. turdi. These results strengthen the role of birds as key agents for the maintenance of different genospecies of the B. burgdorferi complex. Este trabalho foi financiado pela Fundação para a Ciência e a Tecnologia (UID/MULTI/04046/2013 e SFRH/BPD/62898/2009). N/A

Zecken gehören zur Klasse der Arachnida oder Spinnentiere. Weltweit existieren mehr als 800 verschiedene Arten von Zecken. Nur etwa 30 dieser Zecken stechen den Menschen regelmäßig. Etwa 90% der Zecken gehören zur Familie der Schildzecken oder Ixodidae. Die etwa 100 verschiedenen Lederzecken (Argasidae) haben in Europa keine große medizinische Bedeutung. In Europa ist es die Zecke Ixodes ricinus, die den Menschen am häufigsten sticht. Diese Zecke überträgt Borrelia burgdorferi, den Erreger der Lyme-Borreliose sowie das Frühsommer-Meningoenzephalitis (FSME)-Virus. Der Lebenszyklus von I. ricinus läuft in drei sich folgenden Stadien ab: Larve, Nymphe und adulte Zecken (männlich oder weiblich). Alle drei Stadien benötigen Blut für ihre Entwicklung. Die Zecke ernährt sich an einem großen Spektrum von Wirtstieren, etwa 50 davon dienen als Reservoir für B. burgdorferi. In einzelnen Regionen wird eine sehr hohe Dichte von Zecken (bis zu 300 Tiere/100 m2) beobachtet. Bei einem Zeckenstich soll die Zecke so rasch wie möglich entfernt werden.

To confirm that thrushes, such as blackbirds Turdus merula, play a role as reservoir for some Borrelia genospecies, we performed a xenodiagnostic experiment with blackbirds captured in a mixed wood located in Western Portugal where Borrelia turdi, an uncommon genospecies in Europe, was the most prevalent genospecies associated with birds. Two out of five birds harboured B. turdi infected Ixodes frontalis at the time of capture. Four out of five birds transmitted spirochaetes to Ixodes ricinus xenodiagnostic ticks: two birds transmitted Borrelia valaisiana to 25.7% and 10.5% of ticks, and two transmitted B. turdi to 6.4% and 5.4% of ticks. Our results showed that blackbirds transmit B. valaisiana and B. turdi to I. ricinus feeding larvae, acting as reservoir hosts for these genospecies in nature.

Birds as reservoirs for Borrelia burgdorferi s.l. in Western Europe: circulation of B. turdi and other genospecies in bird-tick cycles in Portugal. Norte AC, Ramos JA, Gern L, Núncio MS, Lopes de Carvalho I. SourceInstitute of Marine Research IMAR/CMA, Department of Life Sciences, University of Coimbra, Apartado 3046, 3001-401 Coimbra, Portugal. Center for Vector and Infectious Diseases Research, National Health Institute Doutor Ricardo Jorge, Lisbon, Portugal. Laboratory of Eco-Epidemiology of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland. Abstract Birds are important in the ecology of Borrelia burgdorferi sensu lato (s.l.) because they are important hosts for vector tick immature stages and are known reservoirs for some Borrelia genospecies. The aim of our study was to assess the role of common passerine bird species as reservoirs for B. burgdorferi s.l. in Western Europe. We surveyed birds in enzootic areas in Portugal, where no information is available for birds as reservoirs for this aetiologic agent and where B. lusitaniae, for which few reservoirs have been identified, is the dominant genospecies. Twenty-three birds (2.9%), including Turdus merula, T. philomelos, Parus major and Fringilla coelebs harboured infected ticks, but only Turdus sp. harboured infected tick larvae. In one study area, although B. lusitaniae was dominant in questing Ixodes ricinus, no ticks feeding on birds were infected with this genospecies, and B. valaisiana was the dominant genospecies in I. ricinus larvae feeding on birds. In the other area ticks collected from birds were mainly I. frontalis which were infected with B. turdi. Two skin biopsies (4.2%) from two T. merula were positive, one for B. valaisiana and the other for B. turdi. This is the first report for B. turdi in Western Europe. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd. PMID:22882497[PubMed - as supplied by publisher]

In 1986, a 26% seroprevalence of IgG- anti-Borrelia burgdorferi antibodies was observed among 950 orienteers and the incidence of new clinical infections was 0.8%. In 1993, a total of 305 seropositive orienteers were reexamined. During that time, 15 cases (4.9%) of definite/probable Lyme disease occurred in this seropositive group (12 skin manifestations and 3 monoarticular joint manifestations). Among the 12 definite cases, 9 showed new clinical infections (7 EM, 1 acrodermatitis chronica atrophicans, 1 arthritis), and 3 were recurrent (2 EM, 1 arthritis). The annual incidence (0.8%) in this seropositive group was identical to the incidence observed among the whole population in 1986. The individual antibody titer decreased slightly but the seroreversion rate was low (7%). Serology was not very helpful in identifying clinical cases and evolutions, and it can be stated, that a positive serology is much more frequent in this risk group than clinical disease.