Ixodes ricinus; climate change; phenology; Borrelia burgdorferi; TBE virus; tick-borne pathogens; population genetic
Lommano Elena, Burri Caroline, Maeder Gilles, Guerne Maude, Bastic Viktoria, Patalas Eva, Gern Lise (2012), Prevalence and genotyping of tick-borne encephalitis virus in questing Ixodes ricinus ticks in a new endemic area in Western Switzerland, in Journal of medical Entomology
, 49, 156-164.
Pérez David, Kneubühler Yvan, Rais Olivier, Gern Lise (2012), Seasonality of Ixodes ricinus ticks on vegetation and on rodents and Borrelia burgdorferi sensu lato genospecies diversity in two lyme borreliosis-endemic areas in Switzerland., in Vector borne and zoonotic diseases (Larchmont, N.Y.)
, 12(8), 633-44.
Lommano Elena, Bertaiola Luce, Dupasquier Christèle, Gern Lise (2012), Infections and coinfections of questing Ixodes ricinus ticks by emerging zoonotic pathogens in Western Switzerland., in Applied and environmental microbiology
, 78(13), 4606-12.
Herrmann C, Gern L (2012), Do the level of energy reserves, hydration status and Borrelia infection influence walking by Ixodes ricinus (Acari: Ixodidae) ticks?, in Parasitology
, 139(3), 330-7.
Burri Caroline, Korva Misa, Bastic Viktoria, Knap Natasa, Avsic-Zupanc Tatjana, Gern Lise (2012), Serological evidence of tick-borne encephalitis virus infection in rodents captured at four sites in Switzerland., in Journal of medical entomology
, 49(2), 436-9.
Burri Caroline, Dupasquier Christèle, Bastic Viktoria, Gern Lise (2011), Pathogens of emerging tick-borne diseases, anaplasma phagocytophilum, rickettsia spp., and babesia spp., in ixodes ticks collected from rodents at four sites in Switzerland (Canton of Bern), in Vector-Borne and Zoonotic Diseases
, 11(7), 939-944.
Pérez David, Kneubühler Yvan, Rais Olivier, Jouda Fatima, Gern Lise (2011), Borrelia afzelii ospC genotype diversity in Ixodes ricinus questing ticks and ticks from rodents in two Lyme borreliosis endemic areas: contribution of co-feeding ticks., in Ticks and tick-borne diseases
, 2(3), 137-42.
Huegli Delphine, Moret Jacqueline, Rais Olivier, Moosmann Yves, Erard Philippe, Malinverni Raffaele, Gern Lise (2011), Prospective study on the incidence of infection by Borrelia burgdorferi sensu lato after a tick bite in a highly endemic area of Switzerland., in Ticks and tick-borne diseases
, 2(3), 129-36.
Burri C, Bastic V, Maeder G, Patalas E, Gern L (2011), Microclimate and the zoonotic cycle of tick-borne encephalitis virus in Switzerland., in Journal of medical entomology
, 48(3), 615-27.
Gigandet Luca, Stauffer Emilie, Douet Véronique, Rais Olivier, Moret Jacqueline, Gern Lise (2011), Prevalence of three zoonotic Babesia species in Ixodes ricinus (Linné, 1758) nymphs in a suburban forest in Switzerland., in Vector borne and zoonotic diseases (Larchmont, N.Y.)
, 11(4), 363-6.
Herrmann Coralie, Gern Lise (2010), Survival of Ixodes ricinus (Acari: Ixodidae) under challenging conditions of temperature and humidity is influenced by Borrelia burgdorferi sensu lato infection., in Journal of medical entomology
, 47(6), 1196-204.
Gern L, Lienhard R, Péter O (2010), [Diseases and pathogenic agents transmitted by ticks in Switzerland]., in Revue médicale suisse
, 6(266), 1906-9.
Gern Lise, Douet Véronique, López Zully, Rais Olivier, Cadenas Francisca Morán (2010), Diversity of Borrelia genospecies in Ixodes ricinus ticks in a Lyme borreliosis endemic area in Switzerland identified by using new probes for reverse line blotting., in Ticks and tick-borne diseases
, 1(1), 23-9.
Gern Lise, Sell Katy (2009), Isolation of Borrelia burgdorferi sensu lato from the skin of the European badger (Meles meles) in Switzerland., in Vector borne and zoonotic diseases (Larchmont, N.Y.)
, 9(2), 207-8.
Lyme borreliosis (LB) and Tick-borne encephalitis (TBE), both due to the bites of the tick Ixodes ricinus, are significant vector-borne diseases in humans in Switzerland. Risk of acquiring these diseases is primarily related to the frequency of contacts with infected ticks. Human activity is one of the factors influencing these contacts. In addition, spatial and temporal variations of tick density are also important. Global climate change is suspected in having potential effects on distributions of tick-borne diseases. Increase in temperature may result in the extension of suitable habitats into higher altitudes. However assessing the relative importance of climate changes needs solid long-term data on ticks, which can then be statistically analysed and tested on biological models. Therefore, we will continue our long-term study (1996-today) on the seasonal tick activity in relation with climatic data and on infection with Borrelia. We intend to statistically analyse these long-term datasets. This should help to disentangle short-term fluctua-tions from long-term trends. These data will also be used to test and perfect an I. ricinus tick population model. TBE is a severe neurological disease caused by a flavivirus. Recently, an increase of TBE clinical cases (spike in 2006) and an emergence of new TBE foci were observed in Switzerland. Here, we will study the role of migratory and local birds in the transport and the maintenance of TBE virus and identify new TBE foci in the western part of Switzerland by detection of the virus in ticks by Real-Time PCR. We also intend to analyse ticks for other tick-borne pathogens using the Reverse Line Blot (RLB) technique.LB is a systemic disease due to Borrelia burgdorferi sensu lato (sl). Up to now, 15 Borrelia spe-cies have been described. In endemic areas in Switzerland, up to six Borrelia species may circulate bet-ween hosts and ticks. The ospC gene of B. burgdorferi sl is highly variable within each species and can be used to define groups. A few ospC groups cause invasive forms of the disease, other groups are not invasive or non pathogenic to humans. Intra-species differences also play roles in the development of the infection in the tick and in the transmission cycle. We are interested in studying these last points in relati-on with ospC groups. Recent studies suggested that Borrelia infection in I. ricinus ticks might also play a role in ge-ographical dispersal of ticks. In fact, studying population genetic of I. ricinus, it was observed that female ticks were more related to each other than males, meaning that males seemed more prone to dispersal than females. One explanation being that immature males would feed preferentially on hosts that move for long distance, like birds, whereas immature females would attach to rodents, which are less vagil. Since B. garinii and B. valaisiana are associated with birds, and B. afzelii and B. burgdorferi ss with ro-dents, it was hypothetised that male and female ticks may be differentially infected. It was shown that Borrelia species seems to play a role in local adaptation of I. ricinus. Since we have samples from ticks and Borrelia species collected on a long-term basis at high altitudes where they had not been observed before, we will study population genetic in the context of tick dispersion in relation with their infection by Borrelia species.The projects should contribute to a better understanding of the eco-epidemiology of I. ricinus and tick-borne pathogens in relation with human risk to acquire the diseases. Our long-term dataset on ticks in relation with climatic data and on their infection by Borrelia allow a statistical analysis and modelling of the situations, which are relevant to local human risk. This may also help to understand the exponential inc-rease of TBE incidence and appearance of new foci in parts of Switzerland.