Vertebrate Reservoirs of Arboviruses : Myth, Synonym of Amplifier, or Reality?

The rapid succession of the pandemic of arbovirus diseases, such as dengue, West Nile fever, chikungunya, and Zika fever, has intensified research on these and other arbovirus diseases worldwide. Investigating the unique mode of vector-borne transmission requires a clear understanding of the roles of vertebrates. One major obstacle to this understanding is the ambiguity of the arbovirus definition originally established by the World Health Organization. The paucity of pertinent information on arbovirus transmission at the time contributed to the notion that vertebrates played the role of reservoir in the arbovirus transmission cycle. Because this notion is a salient feature of the arbovirus definition, it is important to reexamine its validity. This review addresses controversial issues concerning vertebrate reservoirs and their role in arbovirus persistence in nature, examines the genesis of the problem from a historical perspective, discusses various unresolved issues from multiple points of view, assesses the present status of the notion in light of current knowledge, and provides options for a solution to resolve the issue.Peer reviewe

Epidemiology of West Nile in Europe and in the Mediterranean Basin

In the last 30 years several cases of West Nile (WN) virus infection were reported in horses and humans in Europe and in the Mediterranean Basin. Most of them were determined by strains of the Lineage 1 included in the European Mediterranean/Kenyan cluster. Strains of this cluster are characterised by a moderate pathogenicity for horses and humans and limited or no pathogenicity for birds. In recent years, however, WN cases determined by strains grouped in the Israeli/American cluster of Lineage 1 or in the lineage 2 have been reported in Hungary and Austria. The role of migrating birds in introducing new viruses to Europe has been often demonstrated. The migratory birds, which may be infected in their African wintering places, carry the virus northward to European sites during spring migrations. In the past, the virus introduction determined occasional cases of WN. In the recent years, new epidemiological scenarios are developing. In few occasions it has been evidenced the capability of WNV strains of overwintering by using local birds and mosquitoes. Species of Culex amongst mosquitoes and magpies (Pica pica), carrion crows (Corvus corone) and rock pigeons (Columba livia) amongst resident birds are the most probable species involved in this hypothetical WND endemic cycle

Characterization of Rabensburg Virus, a Flavivirus Closely Related to West Nile Virus of the Japanese Encephalitis Antigenic Group

Rabensburg virus (RABV), a Flavivirus with ∼76% nucleotide and 90% amino acid identity with representative members of lineage one and two West Nile virus (WNV), previously was isolated from Culex pipiens and Aedes rossicus mosquitoes in the Czech Republic, and phylogenetic and serologic analyses demonstrated that it was likely a new lineage of WNV. However, no direct link between RABV and human disease has been definitively established and the extent to which RABV utilizes the typical WNV transmission cycle is unknown. Herein, we evaluated vector competence and capacity for vertical transmission (VT) in Cx. pipiens; in vitro growth on avian, mammalian, and mosquito cells; and infectivity and viremia production in birds. RABV infection and replication only were detected on mosquito cells. Experimentally inoculated birds did not become infected. Cx. pipiens had poor peroral vector competence and a higher VT rate as compared to US-WNV in Cx. pipiens. As a result, we postulate that RABV is an intermediate between the mosquito-specific and horizontally transmitted flaviviruses

Vector-borne disease intelligence: strategies to deal with disease burden and threats

Owing to the complex nature of vector-borne diseases (VBDs), whereby monitoring of human case patients does not suffice, public health authorities experience challenges in surveillance and control of VBDs. Knowledge on the presence and distribution of vectors and the pathogens that they transmit is vital to the risk assessment process to permit effective early warning, surveillance, and control of VBDs. Upon accepting this reality, public health authorities face an ever-increasing range of possible surveillance targets and an associated prioritization process. Here, we propose a comprehensive approach that integrates three surveillance strategies: population-based surveillance, disease-based surveillance, and context-based surveillance for EU member states to tailor the best surveil-lance strategy for control ofVBDs in their geographic region. By classifying the surveillance structure into five different contexts, we hope to provide guidance in optimizing surveil-lance efforts. Contextual surveillance strategies for VBDs entail combining organization and data collection approaches that result in disease intelligence rather than a preset static structure. (Résumé d'auteur

Натечные карбонатные новообразования набережной реки Туры: особенности строения и процессы формирования

International audienc

Emerging horizons for tick-borne pathogens: from the ‘one pathogen–one disease’ vision to the pathobiome paradigm

Ticks as vectors of several notorious zoonotic pathogens, represent an important and increasing threat for human, animal health in Europe. Recent application of new technology revealed the complexity of the tick microbiome that might impact upon its vectorial capacity. Appreciation of these complex systems is expanding our vision of tick-borne pathogens leading us to evolve a more integrated view that embraces the “pathobiome” representing the pathogenic agent integrated within its abiotic and biotic environments. In this review, we will explore how this new vision will revolutionize our understanding of tick-borne diseases. We will discuss the implications in terms of research approach for the future in order to efficiently prevent and control the threat posed by ticks

Fungi associated with free-living birds in Czechoslovakia and Yugoslavia

In 1080 samples (feathers, nesls, pellets, droppings, cloaca contents and visceral organs) collected from 92 species of free-living birds in many localities and habitats, a total of 6266 fungi was found; we identified 232 species and 112 genera of fungi (73.4 % Ascomycetes, 12.4 % Fungi imperfecti, 8.0 % Zygomycetes, 5.7 % Endomycetes, 0.3 % Oomycetes; and 0.2 % Basidiomycetes). The most common fungal genera were, in plumage, Alternaria. Cladosporium, Arthroderma, Chaetominum, Aspergillus, Penicillium and Chrllsosporium; in nests, Alternaria, Arthroderma, Penicillium, Aphanoascus and Scopulariopsis; on pellets, Penicillium, Mucor, Aspergillus, Chrysosporium and Rhizopus; in droppings, Scopulariopsis, Mucor, Aspergillus, Penicillium and Candida; from the cloaca contents, we isolated Penicillium, Candida, Aspergillus, Scopulariopsis, a. o., and from the visceral organs, Aspergillus, Penicillium, Rhodotorula, and some others. Of the fungi with a potential pathogenicity for homeotherms, we obtained, e. g., Absidia corymbifera, Aspergillus fumigatus, Candida albicans, Cryptococcus neoforrnans and Microsporum gypseum. We confirmed also the presence of several species of toxinogenic fungi (e. g., Aspergillus flavus), of the fungi with a potential pathogenicity for poikilotherms (e. g., Beauveria bassiana. Paecilomyces jarinosus, P. fumoso-roseus), and of plant parasites (Cylindrocarpon radicicola, Fusarium oxysponom and Verticillium albo-atrum). Aphanoascus reticulisporum has been described as comb. nov. (basionym: Anixiopsis: reticulispom ROUTIEN). 66 species of the fungi have not been recorded earlier in Czechoslovakia. Similarly, the occurrence of 111 species had, apparently, not been confirmed in free-living birds on a world-wide scale

The distribution patterns of fungi in free-living birds

Over 6260 fungi have been isolated from samples of feathers, nests, pellets, droppings, cloaca contents and visceral organs of 92 species of free-living birds in Czechoslovakia and Yugoslavia. Several species have been obtained of fungi pathogenic to homeotherms, poikilotherms and plants, and many fungi recorded belong to the toxinogenic species.Cellulolytic fungi have participated with 44.3 % in the total number of fungi, and keratinolytic fungi with 18.3 %. The thesis has been confirmed that habits (specific bionomics) of the birds influence,. to a certain degree, the distribution of the fungi among them. According to the results of this study, the fungi may conveniently be divided into three categories with respect to the character of their distribution and dispersal by free-living birds: (1) euryornithochous fungi , the occurrence of which in birds is undetermined by the birds' habits (ubiqitous species: Aspergillus flavus, Gliocladium roseum, Rhizopus. nigricans, Trichothecium roseum); (2) mesoornitohochorous fungi, the occurrence of which in birds is determined to a certain degree by the birds' habits (e. g., Aphanoascus fulvescens, Arthrodermcr curreyi, Chrysosporium keratinophilum, C. tropicum, Mucor hiemalis); (3) stenoornithochoruss fungi, which are associated with certain habit groups of the birds only (e. g., Aphanoascus terreus, Arthroderma ciferrii, A. tuberculatum,.Aspergillus fumigatus, Chrysosporium pannorum, Ctenomyces serratus). The importance of free-living birds in the spreading of pathogenic organisms has also been discussed from a more general point of view, particularly with regard to several epidemiologically important aspects of bird ecology such as synanthropism, migration (making possible a long-range carriage of pathogens or infected vectors), colonial breeding or mass roosting

First evidence of <i>Babesia venatorum</i> and <i>Babesia capreoli</i> in questing Ixodes ricinus ticks in the Czech Republic

Introduction and objective Ixodes ricinus is the most common tick species occurring in Central Europe and it serves as a principal vector of emerging human pathogens. The aim of this study was to determine the prevalence of Babesia spp. in host-seeking I. ricinus in urban and natural habitats. Material and Methods PCR was applied on samples to assess prevalence of Babesia spp. in questing ixodid ticks. Sequencing was used for Babesia species determination. Results 1,473 I. ricinus ticks (1,294 nymphs, 99 males and 80 females) were examined for the presence of Babesia spp. at the two study sites. Minimum infection rate for Babesia spp. was found to be 0.5% (infected I. ricinus nymphs were only detected in the natural ecosystem). Two Babesia species were identified by sequencing: B. venatorum (formerly called Babesia sp. EU1) and B. capreoli. Conclusions The results obtained represent the first evidence of the occurrence of B. venatorum and B. capreoli in host-seeking I. ricinus ticks in the Czech Republic