The Experts below are selected from a list of 13245 Experts worldwide ranked by ideXlab platform
Didier Raoult - One of the best experts on this subject based on the ideXlab platform.
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Monitoring human Tick-Borne Disease risk and Tick bite exposure in Europe: available tools and promising future methods.
Ticks and tick-borne diseases, 2014Co-Authors: Vinh Vu Hai, Didier Raoult, Lionel Almeras, Cristina Socolovschi, Philippe Parola, Frédéric PagèsAbstract:Ticks are the main vector for infectious Disease pathogens in both humans and animals, and Tick-Borne Diseases are currently spreading throughout Europe. Various surveillance methods have been developed to estimate the burden and risk of Tick-Borne Diseases and host exposure to Tick bites. The ultimate aims of these approaches are to determine the risk level of a Tick-Borne Disease in a given area, determine its health priority, identify the at-risk population and propose specific countermeasures or complementary studies as needed. The purpose of this review is to present the current methods for monitoring the circulation of Tick-Borne Diseases and to highlight the use of salivary antigens as original and recently developed serological tools that could be useful for Tick bite risk assessment and could improve the current surveillance methods.
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mediterranean spotted fever
Infectious Disease Clinics of North America, 2008Co-Authors: Clarisse Rovery, Didier RaoultAbstract:Rickettsial Disease has recently undergone an important evolution, particularly in the field of molecular genetics. This development includes Mediterranean spotted fever (MSF), a Tick-Borne Disease caused by Rickettsia conorii . Important changes have occurred in ecologic and epidemiologic comprehension of the Disease, and in the occurrence of severe forms. However, many questions still remain, including the identity of the real vector and reservoir of R conorii , and whether other risk factors exist for a severe form of MSF.
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dermacentor Borne necrosis erythema and lymphadenopathy clinical and epidemiological features of a new Tick Borne Disease
Clinical Microbiology and Infection, 2004Co-Authors: José A Oteo, Didier Raoult, Aránzazu Portillo, Valvanera Ibarra, José Ramón Blanco, Martinez V De Artola, F J Marquez, Pedro AndaAbstract:This paper describes the epidemiological and clinical features of a Tick-Borne Disease differing somewhat from other Tick-Borne Diseases found previously in Spain. All patients were bitten by Dermacentor marginatus or a large Tick. The clinical features include a crustaceous or necrotic lesion at the site of the Tick's attachment, surrounded by an erythema (erythema migrans-like) and painful regional lymphadenopathies. The probable aetiological agent is Rickettsia slovaca. Similar cases have been reported in other European countries.
G. Ralph Corey - One of the best experts on this subject based on the ideXlab platform.
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Tick-Borne Disease.
American family physician, 2005Co-Authors: Robert L. Bratton, G. Ralph CoreyAbstract:Tick-Borne Diseases in the United States include Rocky Mountain spotted fever, Lyme Disease, ehrlichiosis, tularemia, babesiosis, Colorado Tick fever, and relapsing fever. It is important for family physicians to consider these illnesses when patients present with influenza-like symptoms. A petechial rash initially affecting the palms and soles of the feet is associated with Rocky Mountain spotted fever, whereas erythema migrans (annular macule with central clearing) is associated with Lyme Disease. Various other rashes or skin lesions accompanied by fever and influenza-like illness also may signal the presence of a Tick-Borne Disease. Early, accurate diagnosis allows treatment that may help prevent significant morbidity and possible mortality. Because 24 to 48 hours of attachment to the host are required for infection to occur, early removal can help prevent Disease. Treatment with doxycycline or tetracycline is indicated for Rocky Mountain spotted fever, Lyme Disease, ehrlichiosis, and relapsing fever. In patients with clinical findings suggestive of Tick-Borne Disease, treatment should not be delayed for laboratory confirmation. If no symptoms follow exposure to Tick bites, empiric treatment is not indicated. The same Tick may harbor different infectious pathogens and transmit several with one bite. Advising patients about prevention of Tick bites, especially in the summer months, may help prevent exposure to dangerous vector-Borne Diseases.
S. E. Randolph - One of the best experts on this subject based on the ideXlab platform.
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Dynamics of Tick-Borne Disease systems: minor role of recent climate change.
Revue scientifique et technique (International Office of Epizootics), 2008Co-Authors: S. E. RandolphAbstract:Tick-Borne Disease systems are very sensitive to climate through the impact of temperature and moisture stress on rates of the demographic processes of Ticks. There is no a priori reason, however, to expect Tick abundance or seasonal activity patterns to respond to climate change in ways that inevitably increase the risk of infection by the transmitted pathogens. Changing host availability may be more important than climate in determining Tick abundance. The credibility of any (inherently untestable) predictions of future system-specific changes will be strengthened if based on satisfactory explanations of the past. Tick-Borne encephalitis (TBE) in Europe is presented as a case study: observed patterns of climate change are too similar within and between countries to provide the sole explanation for the extreme spatio-temporal heterogeneity of the marked upsurges in TBE incidence over the past two decades. Instead, a nexus of interacting factors affecting both the risk of infection and exposure of humans to that risk, and each differing in force in space and time, is a more powerful model. Many of these factors are driven by socio-economic changes, and include climate, land cover, wildlife, agricultural practices, industrial activities, (un)employment and income. The same principle may apply to the periodic epidemics of Crimean-Congo haemorrhagic fever.
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Ticks and Tick Borne Disease systems in space and from space
Advances in Parasitology, 2000Co-Authors: S. E. RandolphAbstract:Analyses within geographical information systems (GISs) indicate that small- and large-scale ranges of hard Tick species (Ixodidae) are determined more by climate and vegetation than by host-related factors. Spatial distributions of Ticks may therefore be analysed by statistical methods that seek correlations between known Tick presence/absence and ground- or remotely-sensed (RS) environmental factors. In this way, local habitats of Amblyomma variegatum in the Caribbean and Ixodes ricinus in Europe have been mapped using Landsat RS imagery, while regional and continental distributions of African and temperate Tick species have been predicted using multi-temporal information from the National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer (NOAA-AVHRR) imagery. These studies illustrate ways of maximizing statistical accuracy, whose interpretation is then discussed in a biological framework. Methods such as discriminant analysis are biologically transparent and interpretable, while others, such as logistic regression and tree-based classifications, are less so. Furthermore, the most consistently significant variable for predicting Tick distributions, the RS Normalized Difference Vegetation Index (NDVI), has a sound biological basis in that it is related to moisture availability to free-living Ticks and correlated with Tick mortality rates. The development of biological process-based models for predicting the spatial dynamics of Ticks is a top priority, especially as the risk of Tick-Borne infections is commonly related not simply to the vector's density, but to its seasonal population dynamics. Nevertheless, using statistical pattern-matching, the combination of RS temperature indices and NDVI successfully predicts certain temporal features essential for the transmission of Tick-Borne encephalitis virus, which translate into a spatial pattern of Disease foci on a continental scale.
Brian F Allan - One of the best experts on this subject based on the ideXlab platform.
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interacting effects of wildlife loss and climate on Ticks and Tick Borne Disease
Proceedings of The Royal Society B: Biological Sciences, 2017Co-Authors: Georgia Titcomb, Brian F Allan, Tyler Ainsworth, Lauren H Henson, Tyler Hedlund, Robert M Pringle, Todd M Palmer, Laban Njoroge, Michael G Campana, Robert C FleischerAbstract:Both large-wildlife loss and climatic changes can independently influence the prevalence and distribution of zoonotic Disease. Given growing evidence that wildlife loss often has stronger community-level effects in low-productivity areas, we hypothesized that these perturbations would have interactive effects on Disease risk. We experimentally tested this hypothesis by measuring Tick abundance and the prevalence of Tick-Borne pathogens (Coxiella burnetii and Rickettsia spp.) within long-term, size-selective, large-herbivore exclosures replicated across a precipitation gradient in East Africa. Total wildlife exclusion increased total Tick abundance by 130% (mesic sites) to 225% (dry, low-productivity sites), demonstrating a significant interaction of defaunation and aridity on Tick abundance. When differing degrees of exclusion were tested for a subset of months, total Tick abundance increased from 170% (only mega-herbivores excluded) to 360% (all large wildlife excluded). Wildlife exclusion differentially affected the abundance of the three dominant Tick species, and this effect varied strongly over time, likely due to differences among species in their host associations, seasonality, and other ecological characteristics. Pathogen prevalence did not differ across wildlife exclusion treatments, rainfall levels, or Tick species, suggesting that exposure risk will respond to defaunation and climate change in proportion to total Tick abundance. These findings demonstrate interacting effects of defaunation and aridity that increase Disease risk, and they highlight the need to incorporate ecological context when predicting effects of wildlife loss on zoonotic Disease dynamics.
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Knowledge and prevention of Tick-Borne Diseases vary across an urban-to-rural human land-use gradient
Ticks and tick-borne diseases, 2013Co-Authors: Brett R. Bayles, Gregory Evans, Brian F AllanAbstract:Abstract We sought to determine the behavioral risk of exposure to Tick-Borne Diseases across a human land-use gradient in a region endemic for Diseases transmitted by the lone star Tick. We measured the knowledge, attitudes, and preventive behaviors of visitors to 14 suburban, exurban, and rural recreational parks. A structured interview was conducted to determine respondents’ (n = 238) knowledge of Tick-Borne Disease risk, perceived susceptibility to Tick-Borne Disease, and Tick bite prevention behaviors. We found significant differences across park types for most personal protective behaviors. Individuals in exurban parks were more likely to perform frequent Tick checks and use chemical insect repellents compared to other park types (p
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invasive honeysuckle eradication reduces Tick Borne Disease risk by altering host dynamics
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Brian F Allan, Humberto P Dutra, Lisa S Goessling, Kirk Barnett, Jonathan M Chase, Robert J Marquis, Genevieve Pang, Gregory A Storch, Robert E Thach, John L OrrockAbstract:Despite the ubiquity of invasive organisms and their often deleterious effects on native flora and fauna, the consequences of biological invasions for human health and the ecological mechanisms through which they occur are rarely considered. Here we demonstrate that a widespread invasive shrub in North America, Amur honeysuckle (Lonicera maackii), increases human risk of exposure to ehrlichiosis, an emerging infectious Disease caused by bacterial pathogens transmitted by the lone star Tick (Amblyomma americanum). Using large-scale observational surveys in natural areas across the St. Louis, Missouri region, we found that white-tailed deer (Odocoileus virginianus), a preeminent Tick host and pathogen reservoir, more frequently used areas invaded by honeysuckle. This habitat preference translated into considerably greater numbers of Ticks infected with pathogens in honeysuckle-invaded areas relative to adjacent honeysuckle-uninvaded areas. We confirmed this biotic mechanism using an experimental removal of honeysuckle, which caused a decrease in deer activity and infected Tick numbers, as well as a proportional shift in the blood meals of Ticks away from deer. We conclude that Disease risk is likely to be reduced when honeysuckle is eradicated, and suggest that management of biological invasions may help ameliorate the burden of vector-Borne Diseases on human health.
Sarah E Randolph - One of the best experts on this subject based on the ideXlab platform.
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economic downturn results in Tick Borne Disease upsurge
Parasites & Vectors, 2011Co-Authors: Elinor R Godfrey, Sarah E RandolphAbstract:Background The emergence of zoonoses is due both to changes in human activities and to changes in their natural wildlife cycles. One of the most significant vector-Borne zoonoses in Europe, Tick-Borne encephalitis (TBE), doubled in incidence in 1993, largely as a consequence of the socio-economic transition from communism to capitalism and associated environmental changes.
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Tick Borne Disease systems mapping geographic and phylogenetic space
Advances in Parasitology, 2006Co-Authors: Sarah E Randolph, David J RogersAbstract:Evidence is presented that the evolution of the Tick-Borne flaviviruses is driven by biotic factors, principally the exploitation of new hosts as transmission routes. Because vector-Borne Diseases are limited by climatic conditions, however, abiotic factors have the potential to direct and constrain the evolutionary pathways. This idea is explored by testing the hypothesis that closely related viruses occupy more similar eco-climatic spaces than do more distantly related viruses. A statistical comparison of the conventional phylogenetic tree derived from molecular distances and a novel phenetic tree derived from distances between the climatic spaces within which each virus circulates, indicates that these trees match each other more closely than would be expected at random. This suggests that these viruses are indeed limited in the degree to which they can evolve into new environmental conditions.
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Evidence that climate change has caused 'emergence' of Tick-Borne Diseases in Europe?
International Journal of Medical Microbiology Supplements, 2004Co-Authors: Sarah E RandolphAbstract:Abstract Even though Tick-Borne Disease systems are highly susceptible to climatic influences, climate change to date is not necessarily the cause of the marked increased incidence of a variety of Tick-Borne Diseases in many parts of Europe over the past two decades. To test for causality, rather than coincidence, we need to examine whether the right sorts of climate change have occurred at the right time and in the right places to account for the observed heterogeneous temporal and spatial patterns of Tick-Borne Disease ‘emergence’. Tick-Borne encephalitis (TBE) incidence, for example, showed a 3-fold step increase from 1983 to 1986 in Sweden, doubled in 1993 in the Czech Republic, increased even more dramatically in the same year in Lithuania and Poland, but declined markedly in 1997 in Hungary, Croatia and Slovenia. Within each country, TBE incidence has changed to different degrees in different regions. Because other Tick-Borne Diseases, notably Lyme borreliosis, has commonly ‘emerged’ in parallel with TBE, we should first examine climate variables predicted to have a general effect on Tick abundance, which has indeed increased in the past decade. These include temperature and moisture stress, which have seasonally differential impacts. Monthly mean records for 1960–2000 from the UK Climate Research Unit's interpolated global climate surface reveal that mean spring, spring-autumn and winter temperatures have all increased gradually over the past 40 years, but apparently most sharply in the late 1980s, when moisture stress also increased. These climate data do not reveal any obvious differences between sites where TBE did or did not ‘emerge’, and in Sweden increases in TBE pre-dated the onset of warmer springs and winters. If recorded climate changes cannot yet satisfactorily explain the temporal and spatial patterns of Tick-Borne Disease change in Europe, the impact of biotic factors, such as increases in deer abundance and changing habitat structure, and of socio-political changes following the end of communist rule, demand more detailed quantitative analyses.