The Experts below are selected from a list of 10422 Experts worldwide ranked by ideXlab platform
Lise Gern - One of the best experts on this subject based on the ideXlab platform.
-
Search for blood or water is influenced by Borrelia burgdorferi in Ixodes ricinus
Parasites & Vectors, 2015Co-Authors: Coralie Herrmann, Lise GernAbstract:An increasing number of studies suggest that vector-borne parasites are able to alter phenotypic traits in their arthropod vectors so that microorganism transmission is enhanced. This review documents this phenomenon, which occurs between Borrelia burgdorferi bacteria, the causative agents of Lyme borreliosis, and their tick vectors belonging to the Ixodes ricinus complex. It also reviews the influence of other tick-borne pathogens on these ticks. Ticks belonging to the Ixodes ricinus complex benefit from Borrelia Infection by an increased lifespan (more fat and more resistance to desiccation) and by an increased questing period (less need to move to the litter zone to rehydrate), which enhances tick chances to find a host and to subsequently transmit the pathogens.
-
Do the level of energy reserves, hydration status and Borrelia Infection influence walking by Ixodes ricinus (Acari: Ixodidae) ticks?
Parasitology, 2012Co-Authors: Coralie Herrmann, Lise GernAbstract:Ixodes ricinus horizontal movement within a humidity gradient and the influence of Infection by Borrelia burgdorferi sensu lato (s.l.) on tick walking were investigated. Nymphs were placed within an arena containing a humidity gradient ranging from 45 to 95% relative humidity (RH). After 1 h of acclimation at 70% RH ticks were released so that they could either stay, or walk towards either the wet or the dry end. Their position was recorded 2 h post-release. Fat content was quantified and Borrelia Infection was detected using real-time PCR and PCR followed by Reverse Line Blotting. Among the 1500 ticks tested, 29·85% were infected. More low-fat nymphs walked inside the arena than high-fat individuals. When nymphs walked, more low-fat ticks walked towards wetter than drier air, whereas more high-fat individuals walked towards drier than wetter air. Among high-fat nymphs, a lower proportion of Borrelia-infected ticks walked inside the arena compared to uninfected individuals, as though spirochetes manipulated their arthropod vector to stay. However, Borrelia Infection had no effect on walking direction towards the dry or the wet end. Hence, it appears that I. ricinus nymphs walk horizontally over short distances within a humidity gradient depending on both energy resources and Borrelia Infection.
-
survival of ixodes ricinus acari ixodidae under challenging conditions of temperature and humidity is influenced by Borrelia burgdorferi sensu lato Infection
Journal of Medical Entomology, 2010Co-Authors: Coralie Herrmann, Lise GernAbstract:ABSTRACT To determine whether Borrelia burgdorferi sensu lato (s.l.) influences tick survival under thermohygrometric stress, Ixodes ricinus (L.) (Acari: Ixodidae) questing ticks were tested under various relative humidities (13, 32, 51.5, 61, and 89% RH) at two different temperatures (12.5 and 25°C) and investigated for Borrelia Infection. Survival rate of females was highest (77.6%), followed by males (51.6%), and nymphs (43.2%). The thermohygrometric factor that most importantly determined survival was saturation deficit (SD). As SD increased, tick survival rate decreased in all stages. Among the 1,500 ticks tested for B. burgdorferi s.l., 34.8% (n = 522) were infected. Adult Infection rate (39.6%) was higher than that of nymphs (25.5%). Infection load in real-time polymerase chain reaction ranged from 1 to 1.2 million spirochetes per tick. B. afzelii (39.7%), B. burgdorferi sensu stricto (12.1%), B. garinii (37.9%), B. myamotoi (3.6%), and B. valaisiana (23.8%) were recorded. B. garinii infected signi...
-
Early detection of Borrelia burgdorferi sensu lato Infection in Balb/c mice by co-feeding Ixodes ricinus ticks.
International journal of medical microbiology : IJMM, 2003Co-Authors: Yves Cheminade, Jean-luc Perret, Vincent Weynants, Yves Lobet, Lise GernAbstract:In Europe, Borrelia burgdorferi is transmitted by Ixodes ricinus to animals and human. When infected and uninfected ticks co-feed on a host, spirochetes are transmitted from ticks to animal and also to uninfected ticks. Here, we used uninfected ticks to co-feed with infected ticks on mice to evaluate this method to detect early Infection in mice. A total of 128 mice were challenged by infected nymphs placed in capsules glued on the back of the mice. Three days later uninfected larvae were added in the capsule to co-feed with infected nymphs and were examined for Borrelia Infection after natural detachment. Infection in mice was also determined by xenodiagnosis and by spirochete isolation from ear skin biopsy and back skin biopsy taken at the tick attachment site one month after Infection. A total of 111 mice were found to be infected by at least one of these four methods. Borrelia Infection was observed in 95% of mice by the co-feeding method, in 92% of mice by xenodiagnosis, in 69% and in 68% of mice by cultivation of ear and back skin biopsies, respectively. Our results demonstrate that the co-feeding method is a very sensitive method which can be used to detect very early Infection in mice infected by tick bites.
Coralie Herrmann - One of the best experts on this subject based on the ideXlab platform.
-
Search for blood or water is influenced by Borrelia burgdorferi in Ixodes ricinus
Parasites & Vectors, 2015Co-Authors: Coralie Herrmann, Lise GernAbstract:An increasing number of studies suggest that vector-borne parasites are able to alter phenotypic traits in their arthropod vectors so that microorganism transmission is enhanced. This review documents this phenomenon, which occurs between Borrelia burgdorferi bacteria, the causative agents of Lyme borreliosis, and their tick vectors belonging to the Ixodes ricinus complex. It also reviews the influence of other tick-borne pathogens on these ticks. Ticks belonging to the Ixodes ricinus complex benefit from Borrelia Infection by an increased lifespan (more fat and more resistance to desiccation) and by an increased questing period (less need to move to the litter zone to rehydrate), which enhances tick chances to find a host and to subsequently transmit the pathogens.
-
Do the level of energy reserves, hydration status and Borrelia Infection influence walking by Ixodes ricinus (Acari: Ixodidae) ticks?
Parasitology, 2012Co-Authors: Coralie Herrmann, Lise GernAbstract:Ixodes ricinus horizontal movement within a humidity gradient and the influence of Infection by Borrelia burgdorferi sensu lato (s.l.) on tick walking were investigated. Nymphs were placed within an arena containing a humidity gradient ranging from 45 to 95% relative humidity (RH). After 1 h of acclimation at 70% RH ticks were released so that they could either stay, or walk towards either the wet or the dry end. Their position was recorded 2 h post-release. Fat content was quantified and Borrelia Infection was detected using real-time PCR and PCR followed by Reverse Line Blotting. Among the 1500 ticks tested, 29·85% were infected. More low-fat nymphs walked inside the arena than high-fat individuals. When nymphs walked, more low-fat ticks walked towards wetter than drier air, whereas more high-fat individuals walked towards drier than wetter air. Among high-fat nymphs, a lower proportion of Borrelia-infected ticks walked inside the arena compared to uninfected individuals, as though spirochetes manipulated their arthropod vector to stay. However, Borrelia Infection had no effect on walking direction towards the dry or the wet end. Hence, it appears that I. ricinus nymphs walk horizontally over short distances within a humidity gradient depending on both energy resources and Borrelia Infection.
-
survival of ixodes ricinus acari ixodidae under challenging conditions of temperature and humidity is influenced by Borrelia burgdorferi sensu lato Infection
Journal of Medical Entomology, 2010Co-Authors: Coralie Herrmann, Lise GernAbstract:ABSTRACT To determine whether Borrelia burgdorferi sensu lato (s.l.) influences tick survival under thermohygrometric stress, Ixodes ricinus (L.) (Acari: Ixodidae) questing ticks were tested under various relative humidities (13, 32, 51.5, 61, and 89% RH) at two different temperatures (12.5 and 25°C) and investigated for Borrelia Infection. Survival rate of females was highest (77.6%), followed by males (51.6%), and nymphs (43.2%). The thermohygrometric factor that most importantly determined survival was saturation deficit (SD). As SD increased, tick survival rate decreased in all stages. Among the 1,500 ticks tested for B. burgdorferi s.l., 34.8% (n = 522) were infected. Adult Infection rate (39.6%) was higher than that of nymphs (25.5%). Infection load in real-time polymerase chain reaction ranged from 1 to 1.2 million spirochetes per tick. B. afzelii (39.7%), B. burgdorferi sensu stricto (12.1%), B. garinii (37.9%), B. myamotoi (3.6%), and B. valaisiana (23.8%) were recorded. B. garinii infected signi...
Barbara Tschirren - One of the best experts on this subject based on the ideXlab platform.
-
Small‐scale spatial variation in Infection risk shapes the evolution of a Borrelia resistance gene in wild rodents
Molecular ecology, 2018Co-Authors: Luca Cornetti, Daniela Hilfiker, Mélissa Lemoine, Barbara TschirrenAbstract:Spatial variation in pathogen-mediated selection is predicted to influence the evolutionary trajectory of host populations and lead to spatial variation in their immunogenetic composition. However, to date few studies have been able to directly link small-scale spatial variation in Infection risk to host immune gene evolution in natural, nonhuman populations. Here, we use a natural rodent-Borrelia system to test for associations between landscape-level spatial variation in Borrelia Infection risk along replicated elevational gradients in the Swiss Alps and Toll-like receptor 2 (TLR2) evolution, a candidate gene for Borrelia resistance, across bank vole (Myodes glareolus) populations. We found that Borrelia Infection risk (i.e., the product of Borrelia prevalence in questing ticks and the average tick load of voles at a sampling site) was spatially variable and significantly negatively associated with elevation. Across sampling sites, Borrelia prevalence in bank voles was significantly positively associated with Borrelia Infection risk along the elevational clines. We observed a significant association between naturally occurring TLR2 polymorphisms in hosts and their Borrelia Infection status. The TLR2 variant associated with a reduced likelihood of Borrelia Infection was most common in rodent populations at lower elevations that face a high Borrelia Infection risk, and its frequency changed in accordance with the change in Borrelia Infection risk along the elevational clines. These results suggest that small-scale spatial variation in parasite-mediated selection affects the immunogenetic composition of natural host populations, providing a striking example that the microbial environment shapes the evolution of the host's immune system in the wild.
-
polymorphisms at the innate immune receptor tlr2 are associated with Borrelia Infection in a wild rodent population
Proceedings of The Royal Society B: Biological Sciences, 2013Co-Authors: Barbara Tschirren, Martin Andersson, Kristin Scherman, Helena Westerdahl, Peer R E Mittl, Lars RabergAbstract:The discovery of the key role of Toll-like receptors (TLRs) in initiating innate immune responses and modulating adaptive immunity has revolutionized our understanding of vertebrate defence against pathogens. Yet, despite their central role in pathogen recognition and defence initiation, there is little information on how variation in TLRs influences disease susceptibility in natural populations. Here, we assessed the extent of naturally occurring polymorphisms at TLR2 in wild bank voles (Myodes glareolus) and tested for associations between TLR2 variants and Infection with Borrelia afzelii, a common tick-transmitted pathogen in rodents and one of the causative agents of human Lyme disease. Bank voles in our population had 15 different TLR2 haplotypes (10 different haplotypes at the amino acid level), which grouped in three well-separated clusters. In a large-scale capture–mark–recapture study, we show that voles carrying TLR2 haplotypes of one particular cluster (TLR2c2) were almost three times less likely to be Borrelia infected than animals carrying other haplotypes. Moreover, neutrality tests suggested that TLR2 has been under positive selection. This is, to our knowledge, the first demonstration of an association between TLR polymorphism and parasitism in wildlife, and a striking example that genetic variation at innate immune receptors can have a large impact on host resistance.
José M. Venzal - One of the best experts on this subject based on the ideXlab platform.
-
Borrelia Infection in Ixodes pararicinus ticks (Acari: Ixodidae) from northwestern Argentina.
Acta tropica, 2014Co-Authors: Santiago Nava, Amalia R.m. Barbieri, Leticia Maya, Rodney Colina, Atilio J. Mangold, Marcelo B. Labruna, José M. VenzalAbstract:The aim of this work was to describe for the first time the presence of Borrelia burgdorferi sensu lato infecting ticks in Argentina. Unfed specimens of Ixodes pararicinus collected from vegetation in Jujuy Province were tested for Borrelia Infection by PCR targeting the gene flagellin (fla), the rrfA-rrlB intergenic spacer region (IGS) and the 16S rDNA (rrs) gene. One male and one female of I. pararicinus collected in Jujuy were found to be positive to Borrelia Infection with the three molecular markers tested. Phylogenetically, the Borrelia found in I. pararicinus from Jujuy belongs to the B. burgdorferi s.l complex, and it was similar to one of the genospecies detected in I. aragaoi from Uruguay. Also, this genospecies is closely related to two genospecies known from USA, Borrelia americana and the Borrelia sp. genospecies 1. The epidemiological risk that implies the Infection with Borrelia in I. paracinus ticks from Argentina appears to be low because the genospecies detected is not suspected of having clinical relevance and there are no records of Ixodes ticks biting humans in the southern cone of South America. Further studies are needed to assess accurately if there is risk of borreliosis transmitted by ticks in South America.
Marika Nordberg - One of the best experts on this subject based on the ideXlab platform.
-
A prospective study on the incidence of Borrelia burgdorferi sensu lato Infection after a tick bite in Sweden and On the Aland Islands, Finland (2008-2009)
Ticks and tick-borne diseases, 2015Co-Authors: Peter Wilhelmsson, Linda Fryland, Pontus Lindblom, Johanna Sjöwall, Clas Ahlm, Johan Berglund, Mats Haglund, Anna J. Henningsson, Peter Nolskog, Marika NordbergAbstract:Lyme borreliosis (LB) is a common and increasing tick-borne disease in Europe. The risk of acquiring a Borrelia Infection after a tick bite is not fully known. Therefore, we investigated the incide ...