West Nile Virus: Basic Principles, Replication Mechanism, Immune Response and Important Genetic Determinants of Virulence

Medical genetic

Use of wild bird surveillance, human case data and GIS spatial analysis for predicting spatial distributions of West Nile Virus in Greece

West Nile Virus (WNV) is the causative agent of a vector-borne, zoonotic disease with a worldwide distribution. Recent expansion and introduction of WNV into new areas, including southern Europe, has been associated with severe disease in humans and equids, and has increased concerns regarding the need to prevent and control future WNV outbreaks. Since 2010, 524 confirmed human cases of the disease have been reported in Greece with greater than 10% mortality. Infected mosquitoes, wild birds, equids, and chickens have been detected and associated with human disease. The aim of our study was to establish a monitoring system with wild birds and reported human cases data using Geographical Information System (GIS). Potential distribution of WNV was modelled by combining wild bird serological surveillance data with environmental factors (e.g. elevation, slope, land use, vegetation density, temperature, precipitation indices, and population density). Local factors including areas of low altitude and proximity to water were important predictors of appearance of both human and wild bird cases (Odds Ratio = 1,001 95%CI = 0,723–1,386). Using GIS analysis, the identified risk factors were applied across Greece identifying the northern part of Greece (Macedonia, Thrace) western Greece and a number of Greek islands as being at highest risk of future outbreaks. The results of the analysis were evaluated and confirmed using the 161 reported human cases of the 2012 outbreak predicting correctly (Odds = 130/31 = 4,194 95%CI = 2,841–6,189) and more areas were identified for potential dispersion in the following years. Our approach verified that WNV risk can be modelled in a fast cost-effective way indicating high risk areas where prevention measures should be implemented in order to reduce the disease incidence

Polarisation of Major Histocompatibility Complex II Host Genotype with Pathogenesis of European Brown Hare Syndrome Virus.

A study was conducted in order to determine the occurrence of European Brown Hare Syndrome virus (EBHSV) in Denmark and possible relation between disease pathogenesis and Major Histocompatibility Complex (MHC) host genotype. Liver samples were examined from 170 brown hares (hunted, found sick or dead), collected between 2004 and 2009. Macroscopical and histopathological findings consistent with EBHS were detected in 24 (14.1%) hares; 35 (20.6%) had liver lesions not typical of the syndrome, 50 (29.4%) had lesions in other tissues and 61 (35.9%) had no lesions. Sixty five (38.2%) of 170 samples were found to be EBHSV-positive (RT-PCR, VP60 gene). In order to investigate associations between viral pathogenesis and host genotype, variation within the exon 2 DQA gene of MHC was assessed. DQA exon 2 analysis revealed the occurrence of seven different alleles in Denmark. Consistent with other populations examined so far in Europe, observed heterozygosity of DQA (H o = 0.1180) was lower than expected (H e = 0.5835). The overall variation for both nucleotide and amino acid differences (2.9% and 14.9%, respectively) were lower in Denmark than those assessed in other European countries (8.3% and 16.9%, respectively). Within the peptide binding region codons the number of nonsynonymous substitutions (dN) was much higher than synonymous substitutions (dS), which would be expected for MHC alleles under balancing selection. Allele frequencies did not significantly differ between EBHSV-positive and -negative hares. However, allele Leeu-DQA*30 was detected in significantly higher (P = 0.000006) frequency among the positive hares found dead with severe histopathological lesions than among those found sick or apparently healthy. In contrast, the latter group was characterized by a higher frequency of the allele Leeu-DQA*14 as well as the proportion of heterozygous individuals (P = 0.000006 and P = 0.027). These data reveal a polarisation between EBHSV pathogenesis and MHC class II genotype within the European brown hare in Denmark

Development of a multiplex bead assay to detect serological responses to Brucella species in domestic pigs and wild boar with the potential to overcome cross-reactivity with Yersinia enterocolitica O:9

This article belongs to the Special Issue Emerging Themes in Brucella and Brucellosis.The aim of this study was to develop a multiplex bead assay using a Brucella rLPS antigen, a Brucella suis smooth antigen, and a Yersinia enterocolitica O:9 antigen that not only discriminates Brucella-infected from Brucella-uninfected pigs and wild boar, but also overcomes the cross reactivity with Y. enterocolitica O:9. Sera from 126 domestic pigs were tested: 29 pigs were Brucella infected, 80 were non-infected and 17 were confirmed to be false positive serological reactors (FPSR). Sera from 49 wild boar were tested: 18 were positive and 31 were negative. Using the rLPS antigen, 26/29 Brucella-infected domestic pigs and 15/18 seropositive wild boar were positive, while 75/80 non-Brucella infected domestic pigs, all FPSR, and all seronegative wild boar were negative. Using the smooth B. suis 1330 antigen, all Brucella-infected domestic pigs, 9/17 FPSR and all seropositive wild boar were positive, while all non-infected pigs and 30/31 seronegative wild boar were negative. The ratio of the readouts from the smooth B. suis antigen and Y. enterocolitica O:9 antigen enabled discriminating all Brucella infected individuals from the FPSR domestic pigs. These results demonstrate the potential of this assay for use in the surveillance of brucellosis, overcoming the cross-reactivity with Y. enterocolitica.We thankfully acknowledge the financial support of the European Union Seventh Framework Programme (2007–2013) under grant agreement no. 222633 (WildTech) entitled “Novel Technologies for Surveillance of Emerging and Re-emerging Infections of Wildlife”.Peer reviewe

Development of a multiplex bead assay for simultaneous serodiagnosis of antibodies against Mycobacterium bovis, Brucella suis, and Trichinella spiralis in wild boar

This article belongs to the Special Issue Farm Animal and Wildlife Zoonotic Microorganisms.The aim of this study was to evaluate the diagnostic performance of a multiplex bead assay for the simultaneous detection of antibodies against Mycobacterium bovis, Brucella suis, and Trichinella spiralis. Sera from Eurasian wild boar of known serological status for TB (64 seropositive, 106 seronegative), Brucella (30 seropositive, 39 seronegative), and Trichinella (21 seropositive, 97 seronegative) were used for the development and evaluation of the assay. Magnetic beads coated with recombinant MPB83 antigen (TB), a whole-cell B. suis 1330 antigen, and an E/S T. spiralis antigen were used for the detection of specific antibodies using Bio-Rad Bio-Plex technology. The sensitivities (Se) and specificities (Sp) of the multiplex assay were, for M. bovis, 0.98 and 0.86; for B. suis, 1.00 and 0.97; and for T. spiralis, 0.90 and 0.99 (Se and Sp, respectively). The results show the diagnostic potential of this assay for the simultaneous detection of antibodies against M. bovis, B. suis, and T. spiralis in wild boar.We thankfully acknowledge the financial support of the European Union Seventh Framework Programme (2007–2013) under grant agreement no. 222633 (WildTech) titled “Novel Technologies for Surveillance of Emerging and Re-emerging Infections of Wildlife”.Peer reviewe

Bacterial canine vector-borne zoonotic diseases in “One Health” concept

Canine vector-borne diseases constitute a large group of diseases transmitted by arthropods with worldwide distribution. A wide range of bacterial, viral, and parasitic agents that are transmitted by vectors cause disease to dogs, many of which can also affect humans and thus have an important zoonotic potential. Bacterial agents that are transmitted by vectors have been considered less important than viral or parasitic agents and are not commonly discussed in companion animal practice. However, close contact between pet animals and people offers favorable conditions for transmission of these bacteria. Many of these diseases have become a focus of interest for scientists in recent years. Increase in reservoir abundance, climate change, changing habitat structure, socio-political changes, and imports of dogs for welfare reasons and trade as well as traveling are considered to be potential factors for the pathogens and vectors introduction into new areas. Apart from, the veterinary aspect of these diseases, domestic dogs could play a central epidemiological role in the transmission of bacterial agents to humans, acting as reservoirs and sentinels, a circumstance that requires a One Health approach. This review highlights the most important of these bacterial agents, presenting updated current knowledge with special reference to treatment approach and One Health aspect

Colistin Resistant <i>mcr</i> Genes Prevalence in Livestock Animals (Swine, Bovine, Poultry) from a Multinational Perspective. A Systematic Review

The objective of this review is to collect and present the results of relevant studies on an international level, on the subject of colistin resistance due to mcr genes prevalence in livestock animals. After a literature search, and using PRISMA guidelines principles, a total of 40 swine, 16 bovine and 31 poultry studies were collected concerning mcr-1 gene; five swine, three bovine and three poultry studies referred to mcr-2 gene; eight swine, one bovine, two poultry studies were about mcr-3 gene; six swine, one bovine and one poultry manuscript studied mcr-4 gene; five swine manuscripts studied mcr-5 gene; one swine manuscript was about mcr-6, mcr-7, mcr-8, mcr-9 genes and one poultry study about mcr-10 gene was found. Information about colistin resistance in bacteria derived from animals and animal product foods is still considered limited and that should be continually enhanced; most of the information about clinical isolates are relative to enteropathogens Escherichia coli and Salmonella spp. This review demonstrates the widespread dispersion of mcr genes to livestock animals, indicating the need to further increase measures to control this important threat for public health issue

Current Data on Rickettsia felis Occurrence in Vectors, Human and Animal Hosts in Europe: A Scoping Review

Rickettsia&nbsp;felis is an emerging pathogen with increasing reports of human cases and detection in arthropod and animal host species worldwide. In this scoping review we record the newest data reported for R. felis in Europe: the vector and host species found to be infected, and the geographical distribution and prevalence of R. felis infection in vectors and hosts. A total of 15 European countries reported the occurrence of R. felis in hosts and vectors during 2017&ndash;2022. The vectors found to be infected by R. felis were flea, tick and mite species; Ctenocephalides felis and Ixodes ricinus were the dominant ones. The hosts found to be infected and/or exposed to R. felis were humans, cats and small mammals. Physicians should be aware of the epidemiology and include illness caused by R. felis in the differential diagnosis of febrile disease. Veterinarians should keep training pet owners on the need for effective year-round arthropod control on their pets, especially for fleas

Current Data on <i>Rickettsia felis</i> Occurrence in Vectors, Human and Animal Hosts in Europe: A Scoping Review

Rickettsia felis is an emerging pathogen with increasing reports of human cases and detection in arthropod and animal host species worldwide. In this scoping review we record the newest data reported for R. felis in Europe: the vector and host species found to be infected, and the geographical distribution and prevalence of R. felis infection in vectors and hosts. A total of 15 European countries reported the occurrence of R. felis in hosts and vectors during 2017–2022. The vectors found to be infected by R. felis were flea, tick and mite species; Ctenocephalides felis and Ixodes ricinus were the dominant ones. The hosts found to be infected and/or exposed to R. felis were humans, cats and small mammals. Physicians should be aware of the epidemiology and include illness caused by R. felis in the differential diagnosis of febrile disease. Veterinarians should keep training pet owners on the need for effective year-round arthropod control on their pets, especially for fleas