307 results on '"Conraths FJ"'
Search Results
2. Evaluation of a commercial ELISA for the specific detection of antibodies against Besnoitia besnoiti
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Schares, G, Basso, W, Majzoub, M, Rostaher, A, Scharr, JC, Langenmayer, MC, Selmair, J, Dubey, JP, Cortes, HC, Conraths, FJ, Haupt, T, Pürro, M, Raeber, A, Buholzer, P, and Gollnick, NS
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Besnoitia ,ELISA - Abstract
Vet Parasitol. 2011 Jan 10;175(1-2):52-9. Epub 2010 Oct 28. Evaluation of a commercial ELISA for the specific detection of antibodies against Besnoitia besnoiti. Schares G, Basso W, Majzoub M, Rostaher A, Scharr JC, Langenmayer MC, Selmair J, Dubey JP, Cortes HC, Conraths FJ, Haupt T, Pürro M, Raeber A, Buholzer P, Gollnick NS. Source Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Wusterhausen, Germany. gereon.schares@fli.bund.de Abstract Bovine besnoitiosis is an economically important disease in cattle caused by the protozoan parasite Besnoitia besnoiti, which occurs endemically in many countries of Africa and Asia and is spreading in Europe. Serological identification of subclinically infected cattle is important to avoid the introduction of infected animals into naive herds. Here we determine the sensitivity and specificity of the PrioCHECK(®) Besnoitia Ab, a serological test recently introduced into the European market. Analytical specificity was examined using sera from animals experimentally infected with parasites related to B. besnoiti (n=27). Three animals experimentally infected with Neospora caninum or Toxoplasma gondii showed inconclusive reactions in the ELISA (percent positivity relative to the positive control [PP] 10% ≤ 20%) while all other sera reacted negative (PP
- Published
- 2011
3. Schmallenberg virus, a novel orthobunyavirus infection in ruminants in Europe: Potential global impact and preventive measures
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Conraths, FJ, primary, Peters, M, additional, and Beer, M, additional
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- 2013
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4. Control of coccidiosis into the next millennium
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Smith, NC, Lunden, A, Conraths, FJ, Chapman, HD, Smith, NC, Lunden, A, Conraths, FJ, and Chapman, HD
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- 1998
5. 'Schmallenberg virus'--a novel orthobunyavirus emerging in Europe.
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Beer M, Conraths FJ, VAN DER Poel WH, Beer, M, Conraths, F J, and van der Poel, W H M
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In 2011, a novel orthobunyavirus of the Simbu serogroup, the Schmallenberg virus (SBV), was discovered using a metagenomic approach. SBV caused a large epidemic in Europe in ruminants. As with related viruses such as Akabane virus, it appears to be transmitted by biting midges. Transplacental infection often results in the birth of malformed calves, lambs and goat kids. In more than 5000 farms in Germany, The Netherlands, Belgium, France, UK, Italy, Spain, Luxembourg, Denmark and Switzerland acute infections of adult ruminants or malformed SBV-positive offspring were detected, and high seroprevalences were seen in adult ruminants in the core regions in The Netherlands, Germany and Belgium. The discovery of SBV, the spread of the epidemic, the role of vectors, the impact on livestock, public health issues, SBV diagnosis and measures taken are described in this review. Lessons to be learned from the Schmallenberg virus epidemic and the consequences for future outbreaks are discussed. [ABSTRACT FROM AUTHOR]
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- 2013
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6. A long-term serological survey on Aujeszky's disease virus infections in wild boar in East Germany.
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Pannwitz G, Freuling C, Denzin N, Schaarschmidt U, Nieper H, Hlinak A, Burkhardt S, Klopries M, Dedek J, Hoffmann L, Kramer M, Selhorst T, Conraths FJ, Mettenleiter T, and Müller T
- Abstract
SUMMARYBetween 1985 and 2008, a total of 102 387 wild boar sera originating from Eastern Germany covering an area of 108 589 km2 were tested for the presence of Aujeszky's disease virus (ADV)-specific antibodies. From 1985 until 1991 and from 1992 until 2008, wild boar sera were exclusively investigated using either conventional seroneutralization assays (n=39 621) or commercial gB and full antigen ELISAs (n=62 766), respectively. Spatial-temporal analysis revealed an increasing ADV seroprevalence from 0·4% to 15·9%, on average, during the 24-year observation period that went along with a continuous spread of the infection in a western direction. During 2006 and 2008, 18% of the 66 affected districts had ADV seroprevalences >30%. There was a significant correlation between ADV seroprevalence and the hunting index of population density (HIPD) of wild boar in the entire study area, although this did not hold true for some regions. Seroprevalences did not differ between sexes but were age-dependent. East Germany has been officially free of Aujeszky's disease (pseudorabies) in domestic pigs since 1985. Although a risk for domestic pigs cannot be completely ruled out, experience has shown that ADV in domestic pigs could be eliminated although the virus was present in the wild boar population. Despite increasing ADV seroprevalence in the East German wild boar population no spillover infections from wild boar to domestic pigs have been reported. To further trace ADV infections in the wild boar population in Germany, a nationwide serological monitoring programme should be implemented. [ABSTRACT FROM AUTHOR]
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- 2012
7. Novel lyssavirus in Natterer's bat, Germany.
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Freuling CM, Beer M, Conraths FJ, Finke S, Hoffmann B, Keller B, Kliemt J, Mettenleiter TC, Mühlbach E, Teifke JP, Wohlsein P, Müller T, Freuling, Conrad M, Beer, Martin, Conraths, Franz J, Finke, Stefan, Hoffmann, Bernd, Keller, Barbara, Kliemt, Jeannette, and Mettenleiter, Thomas C
- Abstract
A virus isolated from a Natterer's bat (Myotis nattererii) in Germany was differentiated from other lyssaviruses on the basis of the reaction pattern of a panel of monoclonal antibodies. Phylogenetic analysis supported the assumption that the isolated virus, Bokeloh bat lyssavirus, may represent a new member of the genus Lyssavirus. [ABSTRACT FROM AUTHOR]
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- 2011
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8. Ducks as sentinels for avian influenza in wild birds.
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Globig A, Baumer A, Revilla-Fernández S, Beer M, Wodak E, Fink M, Greber N, Harder TC, Wilking H, Brunhart I, Matthes D, Kraatz U, Strunk P, Fiedler W, Fereidouni SR, Staubach C, Conraths FJ, Griot C, Mettenleiter TC, and Stärk KD
- Abstract
To determine the effectiveness of ducks as sentinels for avian influenza virus (AIV) infection, we placed mallards in contact with wild birds at resting sites in Germany, Austria, and Switzerland. Infections of sentinel birds with different AIV subtypes confirmed the value of such surveillance for AIV monitoring. [ABSTRACT FROM AUTHOR]
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- 2009
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9. Monitoring of putative vectors of bluetongue virus serotype 8, Germany.
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Hoffmann B, Bauer B, Bauer C, Bätza HJ, Beer M, Clausen PH, Geier M, Gethmann JM, Kiel E, Liebisch G, Liebisch A, Mehlhorn H, Schaub GA, Werner D, Conraths FJ, Hoffmann, Bernd, Bauer, Burkhard, Bauer, Christian, Bätza, Hans Joachim, and Beer, Martin
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To identify the vectors of bluetongue virus (BTV) in Germany, we monitored Culicoides spp. biting midges during April 2007-May 2008. Molecular characterization of batches of midges that tested positive for BTV suggests C. obsoletus sensu stricto as a relevant vector of bluetongue disease in central Europe. [ABSTRACT FROM AUTHOR]
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- 2009
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10. A new Puumala hantavirus subtype in rodents associated with an outbreak of Nephropathia epidemica in South-East Germany in 2004.
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Essbauer S, Schmidt J, Conraths FJ, Friedrich R, Koch J, Hautmann W, Pfeffer M, Wölfel R, Finke J, Dobler G, Ulrich R, Essbauer, S, Schmidt, J, Conraths, F J, Friedrich, R, Koch, J, Hautmann, W, Pfeffer, M, Wölfel, R, and Finke, J
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- 2006
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11. Epidemiology of bluetongue virus serotype 8, Germany.
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Conraths FJ, Gethmann JM, Staubach C, Mettenleiter TC, Beer M, Hoffmann B, Conraths, Franz J, Gethmann, Jörn M, Staubach, Christoph, Mettenleiter, Thomas C, Beer, Martin, and Hoffmann, Bernd
- Abstract
In Germany, bluetongue disease had not been reported before 2006. During August 2006-August 2008, >24,000 bluetongue virus serotype 8 infections were reported, most (20,635) in 2007. In 2006 and 2007, respectively, case-fatality rates were 6.4% and 13.1% for cattle and 37.5% and 41.5% for sheep. Vaccination in 2008 decreased cases. [ABSTRACT FROM AUTHOR]
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- 2009
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12. Comparison of different diagnostic protocols for the detection of Toxocara spp. in faecal samples of cats and dogs.
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Winterfeld DT, Schauer B, Globokar M, Pantchev N, Mouchantat S, Conraths FJ, Kampen H, Dups-Bergmann J, Schares G, and Maksimov P
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- Animals, Cats, Dogs, DNA, Helminth genetics, DNA, Helminth isolation & purification, Multiplex Polymerase Chain Reaction methods, Parasite Egg Count methods, Toxocara canis isolation & purification, Toxocara canis genetics, Toxocara isolation & purification, Toxocara genetics, Feces parasitology, Toxocariasis diagnosis, Toxocariasis parasitology, Cat Diseases diagnosis, Cat Diseases parasitology, Dog Diseases diagnosis, Dog Diseases parasitology, Sensitivity and Specificity
- Abstract
Background: Toxocara canis and Toxocara cati are parasitic nematodes that occur worldwide. As embryonated Toxocara spp. eggs in the environment pose a zoonotic risk, especially for children, optimal diagnostic approaches are necessary for effective disease response and management, including surveillance. However, little is known about the performance of different diagnostic protocols for detecting Toxocara spp. in the faeces of cats and dogs, hampering movement towards an optimal diagnostic process. This study aimed to compare detection methods, including a newly developed sequential sieving protocol (SF-SSV) and a high-throughput multiplex qPCR-based method to facilitate epidemiological studies., Methods: Species-specific Toxocara spp. egg suspensions and canine and feline faecal samples from the field were used to estimate analytical and diagnostic sensitivity of the protocols. The performance of two automated DNA extraction protocols using enzymatic and mechanical lysis were compared by multiplex qPCR, targeting both T. canis and T. cati-specific genomic sequences. All samples were examined by microscopy-based techniques, the sedimentation flotation technique (SF) and a newly developed SF-SSV for the detection, enrichment and purification of parasite eggs. The costs and processing times necessary for all protocols were estimated and compared for both single samples and sets of 100 samples., Results: To detect Toxocara spp. eggs, SF-SSV showed the highest analytical sensitivity and a significantly higher diagnostic sensitivity than the DNA detection methods. Mechanical lysis performed better than enzymatic lysis for automated DNA extraction. In automated DNA extraction, 96-well plates performed better than 24-well plates. DNA detection and microscopy-based parasitological methods showed substantial agreement between the results generated by each method. Microscopy-based techniques required the lowest costs and least hands-on time for a single sample. However, when costs and labour were estimated for a set of 100 samples, the DNA detection protocol using 96-well plates for extraction revealed costs similar to SF-SSV and the fastest processing times., Conclusions: SF-SSV was superior in terms of analytical and diagnostic sensitivity for the detection of Toxocara spp. eggs. For larger sets of samples, multiplex qPCR-based DNA detection represents an alternative to microscopy-based methods, based on the possibility of faster sample processing at similar costs to SF-SSV, and the ability to provide species-specific diagnoses., (© 2024. The Author(s).)
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- 2024
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13. Impact of Farm Management Practices on Tick Infestation in Punjab's Livestock: A Comprehensive Epidemiological Study.
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Alvi MHA, Rehman A, Jamil T, Iqbal MZ, Durrani AZ, Khan AU, Usman M, Sauter-Louis C, and Conraths FJ
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Tick infestation poses an important challenge to livestock in Pakistan. Farm management practices and environmental variables can influence tick infestation prevalence in animals. To this end, a cross-sectional survey of 96 farms in four different geographical districts (24 farms from each district) was conducted in Punjab, Pakistan, between October 2021 and January 2022. An epidemiological questionnaire was designed focusing on farm management practices and their impact on tick infestations at these farms. Data were collected via in-person interviews. Regional and farm-specific variables' associations were evaluated using Pearson's chi-square test and Fischer's exact test, respectively. A multivariable logistic regression model was used to identify significant risk factors. This study identified that using soft bedding materials, e.g., wheat straw, leaf litter or plain soil posed a significant risk of tick infestation. Additionally, the absence of quarantine measures, open sheds and inadequate drainage were found as contributing factors in univariable analysis. Higher tick prevalence in the hotter seasons highlighted the influence of Punjab's extreme weather on tick infestation. Despite regular veterinary visits and the use of acaricidal drugs, the prevalence of tick infestation at these farms suggested potential drug resistance in the ticks. The study recommended establishing quarantine practices, improving farms' drainage systems and bedding and using a combination of chemical and traditional remedies to tackle drug resistance in ticks. Education and awareness programs on tick-borne diseases and control measures are advocated to reduce the tick infestation burden on animals. Further research on longitudinal studies to better understand tick population dynamics and develop effective acaricides is encouraged. This called for collaborative control efforts among farmers, veterinarians and research institutions.
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- 2024
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14. Scavenger-induced scattering of wild boar carcasses over large distances and its implications for disease management.
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Rietz J, Ischebeck S, Conraths FJ, Probst C, Zedrosser A, Fiderer C, Reckel F, von Hoermann C, Müller J, and Heurich M
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- Animals, Swine, Ecosystem, African Swine Fever, Germany, Foxes, Sus scrofa
- Abstract
Vertebrate scavengers provide essential ecosystem services such as accelerating carrion decomposition by consuming carcasses, exposing tissues to microbial and invertebrate decomposers, and recycling nutrients back into the ecosystem. Some scavengers do not consume carcasses on site but rather scatter their remains in the surroundings, which might have important implications for nutrient transport, forensic investigations and the spread of diseases such as African Swine Fever. However, only a few studies have investigated and measured the scatter distances. Using wild boar (Sus scrofa) carcasses and limbs, we monitored scavenging behavior and measured scatter distances of mammals. We placed 20 carcasses (up to 25 kg) and 21 separate limbs equipped with very high frequency (VHF) transmitters and monitored scavenger activity using camera traps in a mountainous region in southeast Germany. Except for one carcass, all other carcasses and limbs were scattered. We measured 72 scatter distances (of 89 scattering events; mean = 232 m, maximum = 1250 m), of which 75% were dispersed up to 407 m. Scavengers moved scattered pieces into denser vegetation compared to the half-open vegetation at provisioning sites. Red foxes (Vulpes vulpes) were the most common scavenger species, contributing to 72 scattering events (58 measured scatter distances). Our results provide evidence of scatter distances farther than previously assumed and have far-reaching implications for disease management or forensic investigations, as the broader surroundings of carcasses must be included in search efforts to remove infectious material or relevant body parts for forensic analysis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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15. Efficiency of Virucidal Disinfectants on Wood Surfaces in Animal Husbandry.
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Oettler MJ, Conraths FJ, Roesler U, Reiche S, Homeier-Bachmann T, and Denzin N
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The aim of this study was to test the inactivation of viruses on germ carriers of different types of wood using a disinfectant in order to assess the biosafety of wood as a building material in animal husbandry. The laboratory disinfectant efficacy tests were based on German testing guidelines and current European standards. Five different types of wood germ carriers, i.e., spruce ( Picea abies ), pine ( Pinus sylvestris ), poplar ( Populus sp.), beech ( Fagus sylvatica ) and Douglas fir ( Pseudotsuga menziesii ), were inoculated with enveloped or non-enveloped viruses and then treated with one of three different disinfectants. The results revealed that intact, fine-sawn timber with a low roughness depth can be effectively inactivated. Peracetic acid proved to be the most effective disinfectant across all tests. Regardless of the pathogen and the type of wood, a concentration of 0.1% of the pure substance at a temperature of 10 °C and an exposure time of one hour can be recommended. At a temperature of -10 °C, a concentration of 0.75% is recommended. The basic chemicals formic acid and glutaraldehyde demonstrated only limited effectiveness overall. The synergistic effects of various wood components on the inactivation of viruses offer potential for further investigation. Disinfectant tests should also be conclusively verified in field trials to ensure that the results from standardised laboratory tests can be transferred to real stable conditions.
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- 2024
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16. Tenacity of Animal Disease Viruses on Wood Surfaces Relevant to Animal Husbandry.
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Oettler MJ, Conraths FJ, Roesler U, Reiche S, Homeier-Bachmann T, and Denzin N
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- Animals, Virus Inactivation, Wood virology, Animal Husbandry methods
- Abstract
The aim of this study was to analyse the hygienic suitability of wood often used in animal husbandry. To this end, the inactivation of viruses (Enterovirus E as a surrogate for non-enveloped viruses and Newcastle disease virus as a surrogate for enveloped viruses) on germ carriers consisting of various types of wood was studied over an extended period to assess the biosafety of wood as an agricultural building material. The study was designed to assess the intrinsic biocidal activity of the wood itself, without the use of a disinfectant. The laboratory tests were based on German test guidelines and current European standards. Five different types of wood germ carriers, i.e., spruce ( Picea abies ), pine ( Pinus sylvestris ), poplar ( Populus sp.), beech ( Fagus sylvatica ) and Douglas fir ( Pseudotsuga menziesii ), as well as stainless-steel carriers, were inoculated with enveloped and non-enveloped viruses and stored for up to four months, and the remaining infectivity of the viruses was continuously assessed. The results showed that intact, finely sawn timber with a low depth of roughness had an inactivating effect on the viruses up to 7.5 decadal logarithmic levels. For the non-enveloped virus, inactivation was fastest on Douglas fir wood, with the target reduction for effective inactivation (reduction by factor 4.0 log
10 ) being achieved after two weeks, and for the enveloped virus on pine wood, it was already achieved from the day of drying. The hygienic effects of the wood carriers may be due to their hygroscopic properties and wood constituents. These effects offer potential for further investigation, including tests with other wood species rich in extractives.- Published
- 2024
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17. Automated Detection and Counting of Wild Boar in Camera Trap Images.
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Schütz AK, Louton H, Fischer M, Probst C, Gethmann JM, Conraths FJ, and Homeier-Bachmann T
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Camera traps are becoming widely used for wildlife monitoring and management. However, manual analysis of the resulting image sets is labor-intensive, time-consuming and costly. This study shows that automated computer vision techniques can be extremely helpful in this regard, as they can rapidly and automatically extract valuable information from the images. Specific training with a set of 1600 images obtained from a study where wild animals approaching wild boar carcasses were monitored enabled the model to detect five different classes of animals automatically in their natural environment with a mean average precision of 98.11%, namely 'wild boar', 'fox', 'raccoon dog', 'deer' and 'bird'. In addition, sequences of images were automatically analyzed and the number of wild boar visits and respective group sizes were determined. This study may help to improve and speed up the monitoring of the potential spread of African swine fever virus in areas where wild boar are affected.
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- 2024
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18. Genotyping of European Toxoplasma gondii strains by a new high-resolution next-generation sequencing-based method.
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Joeres M, Maksimov P, Höper D, Calvelage S, Calero-Bernal R, Fernández-Escobar M, Koudela B, Blaga R, Vrhovec MG, Stollberg K, Bier N, Sotiraki S, Sroka J, Piotrowska W, Kodym P, Basso W, Conraths FJ, Mercier A, Galal L, Dardé ML, Balea A, Spano F, Schulze C, Peters M, Scuda N, Lundén A, Davidson RK, Terland R, Waap H, de Bruin E, Vatta P, Caccio S, Ortega-Mora LM, Jokelainen P, and Schares G
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- Pregnancy, Female, Humans, Genotype, Multiplex Polymerase Chain Reaction, High-Throughput Nucleotide Sequencing, DNA, Protozoan genetics, Genetic Variation, Polymorphism, Restriction Fragment Length, Toxoplasma genetics
- Abstract
Purpose: A new high-resolution next-generation sequencing (NGS)-based method was established to type closely related European type II Toxoplasma gondii strains., Methods: T. gondii field isolates were collected from different parts of Europe and assessed by whole genome sequencing (WGS). In comparison to ME49 (a type II reference strain), highly polymorphic regions (HPRs) were identified, showing a considerable number of single nucleotide polymorphisms (SNPs). After confirmation by Sanger sequencing, 18 HPRs were used to design a primer panel for multiplex PCR to establish a multilocus Ion AmpliSeq typing method. Toxoplasma gondii isolates and T. gondii present in clinical samples were typed with the new method. The sensitivity of the method was tested with serially diluted reference DNA samples., Results: Among type II specimens, the method could differentiate the same number of haplotypes as the reference standard, microsatellite (MS) typing. Passages of the same isolates and specimens originating from abortion outbreaks were identified as identical. In addition, seven different genotypes, two atypical and two recombinant specimens were clearly distinguished from each other by the method. Furthermore, almost all SNPs detected by the Ion AmpliSeq method corresponded to those expected based on WGS. By testing serially diluted DNA samples, the method exhibited a similar analytical sensitivity as MS typing., Conclusion: The new method can distinguish different T. gondii genotypes and detect intra-genotype variability among European type II T. gondii strains. Furthermore, with WGS data additional target regions can be added to the method to potentially increase typing resolution., (© 2023. The Author(s).)
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- 2024
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19. Identification of predilection sites for wild boar carcass search based on spatial analysis of Latvian ASF surveillance data.
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Rogoll L, Schulz K, Staubach C, Oļševskis E, Seržants M, Lamberga K, Conraths FJ, and Sauter-Louis C
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- Animals, Latvia epidemiology, Spatial Analysis, Sus scrofa, Swine, African Swine Fever epidemiology, African Swine Fever Virus
- Abstract
Targeted search for wild boar carcasses is essential for successful control of African swine fever (ASF) in wild boar populations. To examine whether landscape conditions influence the probability of finding ASF-positive carcasses, this study analyzed Global Positioning System (GPS) coordinates of Latvian wild boar carcasses and hunted wild boar, extracted from the CSF/ASF wild boar surveillance database of the European Union, and random coordinates in Latvia. Geographic information system (GIS) software was used to determine the landscape type and landscape composition of carcass detection sites and to measure distances from the carcasses to nearest waterbodies, forest edges, roads and settlements. The results of the automated measurements were validated by manually analyzing a smaller sample. Wild boar carcasses were found predominantly in forested areas and closer to waterbodies and forest edges than random GPS coordinates in Latvia. Carcasses of ASF-infected wild boar were found more frequently in transitional zones between forest and woodland shrub, and at greater distances from roads and settlements compared to ASF-negative carcasses and random points. This leads to the hypothesis, that ASF-infected animals seek shelter in quiet areas further away from human disturbance. A detailed collection of information on the environment surrounding carcass detection sites is needed to characterize predilection sites more accurately., (© 2024. The Author(s).)
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- 2024
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20. Seasonal Occurrence of African Swine Fever in Wild Boar and Domestic Pigs in EU Member States.
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Rogoll L, Güttner AK, Schulz K, Bergmann H, Staubach C, Conraths FJ, and Sauter-Louis C
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- Humans, Swine, Animals, Seasons, Agriculture, Disease Outbreaks veterinary, Sus scrofa, African Swine Fever epidemiology
- Abstract
Since 2007, African swine fever (ASF) has spread widely within Europe and beyond. Most affected countries recorded outbreaks in domestic pigs and cases in wild boar. Outbreak data from 2014 to 2021 were used to investigate the seasonal pattern of ASF in domestic pigs and wild boar across affected member states of the European Union, since knowledge of seasonal patterns may provide the potential to adapt prevention, surveillance and control during times of increased risk. In domestic pigs, a yearly peak was observed in many European countries in summer (predominantly in July and August). In wild boar, the patterns showed more variability. In many countries, there was a seasonal peak of ASF occurrence in winter (predominantly in January and December), with an additional summer peak in the Baltic States (predominantly in July) and a further spring peak in Poland (predominantly in March). The observed seasonal effects may be related to the abundance and population dynamics of wild boar and to seasonality in pig farming. Moreover, ASF occurrence may also be influenced by human activities in both domestic pigs and wild boar.
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- 2023
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21. The diffusion metrics of African swine fever in wild boar.
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Lentz HHK, Bergmann H, Conraths FJ, Schulz J, and Sauter-Louis C
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- Animals, Swine, Benchmarking, Diffusion, Disease Outbreaks veterinary, Sus scrofa, African Swine Fever epidemiology
- Abstract
To control African swine fever (ASF) efficiently, easily interpretable metrics of the outbreak dynamics are needed to plan and adapt the required measures. We found that the spread pattern of African Swine Fever cases in wild boar follows the mechanics of a diffusion process, at least in the early phase, for the cases that occurred in Germany. Following incursion into a previously unaffected area, infection disseminates locally within a naive and abundant wild boar population. Using real case data for Germany, we derive statistics about the time differences and distances between consecutive case reports. With the use of these statistics, we generate an ensemble of random walkers (continuous time random walks, CTRW) that resemble the properties of the observed outbreak pattern as one possible realization of all possible disease dissemination patterns. The trained random walker ensemble yields the diffusion constant, the affected area, and the outbreak velocity of early ASF spread in wild boar. These methods are easy to interpret, robust, and may be adapted for different regions. Therefore, diffusion metrics can be useful descriptors of early disease dynamics and help facilitate efficient control of African Swine Fever., (© 2023. Springer Nature Limited.)
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- 2023
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22. African Swine Fever in Wild Boar: German Hunters' Perception of Surveillance and Control-A Questionnaire Study.
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Rogoll L, Schulz K, Conraths FJ, and Sauter-Louis C
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Since the first occurrence of African swine fever (ASF) in wild boar in Germany in 2020, the disease has primarily affected the wild boar population in the eastern part of the country close to the border with Poland. Local hunters play a crucial role in implementing surveillance and control. To evaluate their perceptions of existing control measures and analyze regional differences between hunters from ASF-affected and non-affected regions, a questionnaire study was conducted among the German hunting community. Hunters from non-affected areas held a more optimistic view regarding the effectiveness of control measures compared to hunters from affected areas. However, control measures that hinder hunting were generally perceived as ineffective. Measures that collided with hunters' understanding of fair hunting practices were regarded as controversial. Financial incentives and reducing bureaucracy were the most favored approaches to increase hunters' participation. Moreover, the possibility of eating or selling the meat of hunted wild boar and the provision of infrastructure for implementing ASF control were considered motivating. Thus, this study highlights the importance of compensating hunters and addressing their concerns to maintain their engagement in ASF control. To enhance compliance with controversial measures, thoughtful communication and raising awareness are essential.
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- 2023
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23. A ring trial to harmonize Toxoplasma gondii microsatellite typing: comparative analysis of results and recommendations for optimization.
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Joeres M, Cardron G, Passebosc-Faure K, Plault N, Fernández-Escobar M, Hamilton CM, O'Brien-Anderson L, Calero-Bernal R, Galal L, Luttermann C, Maksimov P, Conraths FJ, Dardé ML, Ortega-Mora LM, Jokelainen P, Mercier A, and Schares G
- Subjects
- Humans, Animals, Genetic Variation, Polymorphism, Restriction Fragment Length, DNA, Protozoan genetics, Microsatellite Repeats, Genotype, Toxoplasma genetics, Toxoplasmosis, Animal
- Abstract
A ring trial among five European laboratories was organized to reach consistency in microsatellite (MS) typing of the zoonotic parasite Toxoplasma gondii. Three sample sets were circulated and analyzed by each laboratory following a previously published method that is based on fragment length polymorphism of 15 MS markers. The first sample set compared typing results in general and focused on effects of DNA concentration; the second sample set focused on the polymorphic fingerprinting markers that can differentiate T. gondii strains within the same archetypal lineage; and the third set focused on non-archetypal genotypes. Methodological variations between laboratories, including the software programs used to determine MS fragment length, were collated using a questionnaire. Overall, lineage-level typing results reached a high level of agreement, especially in samples with the highest DNA concentrations. However, laboratory-specific differences were observed for particular markers. Major median differences in fragment length, of up to 6 base pairs, were related to the fluorophore used to label fragment-specific primers. In addition, primer pairs with identical sequences obtained from different suppliers resulted in fragments of differing length. Furthermore, differences in the way the sequencing profiles were assessed and interpreted may have led to deviating results in fragment length determination. Harmonization of MS typing, for example, by using the same fluorophores or by numerical adjustments applied to the fragment-lengths determined, could improve the uniformity of the results across laboratories. This is the first interlaboratory comparison, providing guidelines (added as a supplement) for the optimization of this technique., (© 2023. The Author(s).)
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- 2023
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24. SARS-CoV-2 Infection and Clinical Signs in Cats and Dogs from Confirmed Positive Households in Germany.
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Michelitsch A, Allendorf V, Conraths FJ, Gethmann J, Schulz J, Wernike K, and Denzin N
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- Animals, Cats, Dogs, Humans, SARS-CoV-2, Antibodies, Viral, Risk Factors, Germany epidemiology, COVID-19 diagnosis, COVID-19 epidemiology, COVID-19 veterinary, Cat Diseases diagnosis, Cat Diseases epidemiology
- Abstract
On a global scale, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a serious threat to the health of the human population. Not only humans can be infected, but also their companion animals. The antibody status of 115 cats and 170 dogs, originating from 177 German households known to have been SARS-CoV-2 positive, was determined by enzyme-linked immunosorbent assay (ELISA), and the results were combined with information gathered from a questionnaire that was completed by the owner(s) of the animals. The true seroprevalences of SARS-CoV-2 among cats and dogs were 42.5% (95% CI 33.5-51.9) and 56.8% (95% CI 49.1-64.4), respectively. In a multivariable logistic regression accounting for data clustered in households, for cats, the number of infected humans in the household and an above-average contact intensity turned out to be significant risk factors; contact with humans outside the household was a protective factor. For dogs, on the contrary, contact outside the household was a risk factor, and reduced contact, once the human infection was known, was a significant protective factor. No significant association was found between reported clinical signs in animals and their antibody status, and no spatial clustering of positive test results was identified.
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- 2023
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25. The First Eighteen Months of African Swine Fever in Wild Boar in Saxony, Germany and Latvia-A Comparison.
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Richter M, Schulz K, Elflein T, Achterberg J, Oļševskis E, Seržants M, Lamberga K, Conraths FJ, and Sauter-Louis C
- Abstract
African swine fever (ASF) emerged in Latvia in 2014. In 2020, the virus has been detected in the German federal state, Saxony. In both regions, the virus was probably introduced by infected wild boar coming from affected neighboring countries. As the current ASF control strategy at EU level had not yet been developed at the time of ASF introduction into Latvia, disease control measures in both study areas differed over time. Assessing the course of ASF in Saxony and the implemented control strategies, the first 18 months of the ASF epidemic were epidemiologically compared between Saxony and Latvia. ASF wild boar surveillance data were analyzed and the prevalence of ASF virus-positive wild boar was estimated. For estimating the wild boar density, the numbers of wild boar per km² were calculated for the respective geographical areas. The number of samples collected from hunted wild boar and wild boar found dead was higher in Saxony. The ASF virus prevalence in Latvia was significantly higher than in Saxony, indicating that Saxony has had more time for getting prepared for dealing with an ASF incursion. Experience from other countries and the rapid implementation of new control strategies may have helped Saxony deal with ASF.
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- 2023
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26. The perceptions of Lithuanian hunters towards African swine fever using a participatory approach.
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Stončiūtė E, Malakauskas A, Conraths FJ, Masiulis M, Sauter-Louis C, and Schulz K
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- Female, Swine, Animals, Lithuania epidemiology, Pandemics, Sus scrofa, African Swine Fever epidemiology, African Swine Fever prevention & control, African Swine Fever Virus, COVID-19 veterinary, Swine Diseases epidemiology
- Abstract
Background: African swine fever (ASF) has been present in Lithuania since 2014. The disease affects mainly the wild boar population. Thus, hunters play a key role in the performance of disease surveillance and control measures. We used participatory methods to gain insight into the knowledge of hunters and to include their perceptions in the design and the implementation of surveillance and control measures to increase their effectiveness., Results: The willingness and the interest of hunters to participate was high, but only eight focus group meetings with 33 hunters could be held due to the COVID-19 pandemic. The overall knowledge of Lithuanian hunters regarding ASF, investigated by semi-structured interviews, was sufficient to understand their part in ASF control and surveillance. However, their knowledge did not necessarily lead to an increased acceptance of some ASF control measures, like the targeted hunting of female wild boar. Participating hunters showed a good understanding of the processes of the surveillance system. Their trust in the performance within this system was highest towards the hunters themselves, thus emphasizing the importance of acknowledging their role in the system. Hunters refused measures including the reduction of hunting activities. They feared a complete elimination of the wild boar population, which in turn demonstrates the necessity to increase professional information exchange., Conclusions: The perceptions of Lithuanian hunters regarding ASF surveillance and control in wild boar resembled those obtained in neighboring countries. It is imperative to communicate the results with decision-makers, to consider the views of hunters, when designing or adapting measures to control ASF in wild boar and to communicate with hunters on these measures and their justification., (© 2022. The Author(s).)
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- 2022
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27. Identification of Risk Factors for African Swine Fever: A Systematic Review.
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Bergmann H, Dups-Bergmann J, Schulz K, Probst C, Zani L, Fischer M, Gethmann J, Denzin N, Blome S, Conraths FJ, and Sauter-Louis C
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- Swine, Animals, Disease Outbreaks prevention & control, Risk Factors, Sus scrofa, African Swine Fever epidemiology, African Swine Fever prevention & control, African Swine Fever Virus, Swine Diseases epidemiology
- Abstract
African swine fever (ASF) is an internationally-spreading viral pig disease that severely damages agricultural pork production and trade economy as well as social welfare in disease-affected regions. A comprehensive understanding of ASF risk factors is imperative for efficient disease control. As the absence of effective ASF vaccines limits disease management options, the identification and minimisation of ASF-associated risk factors is critical to preventing ASF outbreaks. Here, we compile currently known potential ASF risk factors identified through a systematic literature review. We found 154 observation-based and 1239 potential ASF risk factors, which we were able to group into the following defined risk categories: 'ASF-virus', 'Biosecurity', 'Disease control', 'Environment', 'Husbandry', 'Movement', 'Network', 'Pig', 'Society' and 'Surveillance'. Throughout the epidemiological history of ASF there have been similar risk categories, such as 'Environment'-related risk factors, predominantly reported in the literature irrespective of the ASF situation at the time. While ASF risk factor reporting has markedly increased since 2010, the majority of identified risk factors overall have referred to domestic pigs. The reporting of risk factors for ASF in wild boar mostly commenced from 2016 onwards. The compendium of ASF risk factors presented herein defines our current knowledge of ASF risk factors, and critically informs ASF-related problem solving.
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- 2022
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28. Clustering of Cryptosporidium species infections among sheep and cattle but not children in remote highland communities of Madagascar.
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Krumkamp R, Conraths FJ, Caccio S, Schares G, Hogan B, Winter D, Jaeger A, Melhem S, Rakotozandrindrainy N, May J, Rakotozandrindrainy R, and Eibach D
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- Animals, Cattle, Child, Preschool, Cluster Analysis, Cross-Sectional Studies, Feces, Genotype, Humans, Infant, Livestock, Madagascar, Prevalence, Sheep, Cattle Diseases, Cryptosporidiosis, Cryptosporidium
- Abstract
Background: The aim of this study was to identify local transmission patterns of Cryptosporidium spp. infections among livestock and humans in four extremely rural and remote highland communities in Madagascar., Methods: In this cross-sectional study, households were randomly sampled throughout a 1-year study period, with one feces sample collected from each child (≤ 5 years old), sheep and cattle. Cryptosporidium spp. were identified using a nested PCR assay targeting the 18S ribosomal RNA gene. All samples positive for Cryptosporidium hominis were further subtyped by sequencing the 60-kDa glycoprotein gene (gp60). Spatial clustering methods were applied to analyze potential transmission patterns., Results: In total, 252 households participated in the study, and samples from 197 children, 862 cattle and 334 sheep were collected and included in the study. Of the samples collected, 11 (5.6%) from children, 30 (3.5%) from cattle and 42 (12.6%) from sheep tested positive for Cryptosporidium spp. Very little overlap in the species distribution between human and animal infections was found. Global (overall) and local (spatially defined) clustering was observed for Cryptosporidium spp. infections in sheep and for Cryptosporidium xiaoi/bovis infections among sheep and cattle., Discussion: The results of this analysis do not support the occurrence of defined disease outbreaks, rather they point to a continuous series of transmission events that are spatially aggregated. Despite the close coexistence between humans, sheep and cattle in the study area, mutual transmission was not observed. Hence, the study underlines the importance of sustained sanitation and hygiene measures to prevent cryptosporidiosis transmission among infants, since asymptomatic children serve as an infection reservoir. Similarly, the study highlights the importance of improving hygiene to reduce the transmission of Cryptosporidium spp. in livestock, an infection with serious consequences, especially in newborn calves., (© 2022. The Author(s).)
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- 2022
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29. Connect to Protect: Dynamics and Genetic Connections of Highly Pathogenic Avian Influenza Outbreaks in Poultry from 2016 to 2021 in Germany.
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King J, Staubach C, Lüder C, Koethe S, Günther A, Stacker L, Rubbenstroth D, Dietze K, Grund C, Conraths FJ, Harder T, Beer M, and Pohlmann A
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- Animals, Animals, Wild, Birds, Disease Outbreaks veterinary, Germany epidemiology, Phylogeny, Poultry, Influenza A virus genetics, Influenza in Birds, Poultry Diseases epidemiology
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During autumn/winter in 2016-2017 and 2020-2021, highly pathogenic avian influenza viruses (HPAIV) caused severe outbreaks in Germany and Europe. Multiple clade 2.3.4.4b H5 HPAI subtypes were responsible for increased mortality in wild birds and high mortality and massive losses in the poultry sector. To clarify putative entry sources and delineate interconnections between outbreaks in poultry holdings and wild birds, we applied whole-genome sequencing and phylodynamic analyses combined with the results of epidemiological outbreak investigations. Varying outbreak dynamics of the distinct reassortants allowed for the identification of individual, putatively wild bird-mediated entries into backyard holdings, several clusters comprising poultry holdings, local virus circulation for several weeks, direct farm-to-farm transmission and potential reassortment within a turkey holding with subsequent spill-over of the novel reassorted virus into the wild bird population. Whole-genome sequencing allowed for a unique high-resolution molecular epidemiology analysis of HPAIV H5Nx outbreaks and is recommended to be used as a standard tool. The presented detailed account of the genetic, temporal, and geographical characteristics of the recent German HPAI H5Nx situation emphasizes the role of poultry holdings as an important source of novel genetic variants and reassortants.
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- 2022
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30. Dog Ownership and Risk for Alveolar Echinococcosis, Germany.
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Schmidberger J, Uhlenbruck J, Schlingeloff P, Maksimov P, Conraths FJ, Mayer B, and Kratzer W
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- Animals, Case-Control Studies, Dogs, Germany epidemiology, Humans, Ownership, Pets, Dog Diseases epidemiology, Dog Diseases parasitology, Dog Diseases prevention & control, Echinococcosis epidemiology, Echinococcosis parasitology, Echinococcosis transmission, Echinococcosis veterinary, Echinococcus multilocularis
- Abstract
Human alveolar echinococcosis is caused by the parasite Echinococcus multilocularis, and dog ownership has been identified as a risk factor. We sought to specify the factors of dog ownership underlying this risk by conducting a case-control study among dog owners in Germany. The analysis revealed an increased odds ratio of ≈7-fold for dog owners whose dogs roam unattended in fields, 13-fold for dog owners who feed their dogs organic waste daily, 4-fold for dog owners who take their dog to a veterinarian only in case of illness, and 10-fold for dog owners who have never been informed by a veterinarian about the risk for infection. The results highlight the risk for infection associated with various factors of dog ownership and the value of veterinarians informing owners about prevention.
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- 2022
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31. African swine fever: Why the situation in Germany is not comparable to that in the Czech Republic or Belgium.
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Sauter-Louis C, Schulz K, Richter M, Staubach C, Mettenleiter TC, and Conraths FJ
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- Animals, Belgium epidemiology, Czech Republic epidemiology, Germany epidemiology, Sus scrofa, Swine, African Swine Fever epidemiology, African Swine Fever Virus, Swine Diseases
- Abstract
After the first occurrence of African swine fever (ASF) in Germany in September 2020, control measures were implemented that resembled those taken in the Czech Republic and Belgium, the only two countries that succeeded in eliminating ASF from their territory so far in the current epidemic. In the present study, the epidemiological course of ASF in the first 6 months since introduction in these three countries is compared. Within 6 months, Germany experienced more cases than the Czech Republic and Belgium. The affected area in Germany, measured using minimal convex polygons, is much larger than the respective areas in the Czech Republic and in Belgium. All cases in the Czech Republic and in Belgium clustered in one single defined area, suggesting point-source introductions, whereas in Germany four distinct spatial clusters were observed, which indicates that multiple incursions had occurred along the border with Poland. While the overall course of the disease was comparable, when individual clusters were considered, the summarized data showed clear differences between the situation in Germany compared to that in the Czech Republic and Belgium. Germany experienced several independent introductions, caused by continuous infection pressure along the border to Poland, while the infection was only introduced on a single occasion each into the Czech Republic and Belgium. These differences may require appropriate adaptation of control measures, in particular concerning fencing along the border., (© 2021 The Authors. Transboundary and Emerging Diseases published by Wiley-VCH GmbH.)
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- 2022
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32. Eight Years of African Swine Fever in the Baltic States: Epidemiological Reflections.
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Schulz K, Oļševskis E, Viltrop A, Masiulis M, Staubach C, Nurmoja I, Lamberga K, Seržants M, Malakauskas A, Conraths FJ, and Sauter-Louis C
- Abstract
African swine fever (ASF) was first detected in Lithuania, Latvia, and Estonia in 2014 and has since been circulating in the Baltic States with a similar epidemiological course characterized by persistence of the disease in the wild boar population and occasional spill-over infections in domestic pigs. The aim of the present study was to evaluate surveillance data on ASF in wild boar from the three countries to improve our understanding of the course of the disease. ASF surveillance and wild boar population data of the countries were analyzed. In all three countries, a decrease in the prevalence of ASF virus-positive wild boar was observed over time. Although somewhat delayed, an increase in the seroprevalence was seen. At the same time, the wild boar population density decreased significantly. Towards the end of the study period, the wild boar population recovered, and the prevalence of ASF virus-positive wild boar increased again, whereas the seroprevalence decreased. The decreasing virus prevalence has obviously led to virus circulation at a very low level. Together with the decreasing wild boar population density, the detection of ASF-infected wild boar and thus ASF control has become increasingly difficult. The course of ASF and its continuous spread clearly demonstrate the necessity to scrutinize current ASF surveillance and control strategies fundamentally and to consider new transdisciplinary approaches.
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- 2022
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33. Does having a cat in your house increase your risk of catching COVID-19?
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Allendorf V, Denzin N, Conraths FJ, Boden LA, Elvinger F, Magouras I, Stegeman A, Wood JLN, Urueña AC, Grace KEF, and Stärk KDC
- Abstract
Due to the zoonotic origin of SARS-Coronavirus 2 (SARS-CoV-2), the potential for its transmission from humans back to animals and the possibility that it might establish ongoing infection pathways in other animal species has been discussed. Cats are highly susceptible to SARS-CoV-2 and were shown experimentally to transmit the virus to other cats. Infection of cats has been widely reported. Domestic cats in COVID-19-positive households could therefore be a part of a human to animal to human transmission pathway. Here, we report the results of a qualitative risk assessment focusing on the potential of cat to human transmission in such settings. The assessment was based on evidence available by October 2021. After the introduction of SARS-CoV-2 to a household by a human, cats may become infected and infected cats may pose an additional infection risk for other members of the household. In order to assess this additional risk qualitatively, expert opinion was elicited within the framework of a modified Delphi procedure. The conclusion was that the additional risk of infection of an additional person in a household associated with keeping a domestic cat is very low to negligible, depending on the intensity of cat-to-human interactions. The separation of cats from humans suffering from SARS-CoV-2 infection should contribute to preventing further transmission., Competing Interests: The authors declare no conflicts of interest., (© 2022 The Authors.)
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- 2022
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34. Outbreak investigation and identification of risk factors associated with the occurrence of foot and mouth disease in Punjab, Pakistan.
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Ali I, Rehman A, Mushtaq MH, Ijaz M, Khaliq MS, Khan MSU, Khalid S, Masud A, Abbas A, Parveen S, Saman A, Sauter-Louis C, and Conraths FJ
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- Animals, Case-Control Studies, Cattle, Disease Outbreaks veterinary, Livestock, Pakistan epidemiology, Risk Factors, Swine, Cattle Diseases epidemiology, Foot-and-Mouth Disease epidemiology, Foot-and-Mouth Disease Virus, Swine Diseases epidemiology
- Abstract
Foot-and-mouth disease (FMD) is a highly contagious viral disease of domesticated and wild ruminants and pigs that causes enormous economic losses through morbidity, mortality, and trade restrictions. Although the disease is endemic in Pakistan, seasonal outbreaks occur every year throughout the country. This study aimed to investigate FMD outbreaks and to identify the risk factors associated with FMD outbreaks between January and April 2019 in the Punjab province. We performed outbreak investigations (n = 64) for FMD in nine districts of the Punjab province through Divisional Disease Diagnostic Laboratories, Livestock and Dairy Development Department Punjab. Subsequently, we conducted a case-control study including 128 livestock farms (case to control ratio = 1). The data on various plausibly associated factors were collected using a structured questionnaire from each farm. The FMD outbreaks started during the month of January, culminated in February (n = 36, 56.25%) and stopped during the month of April 2019. The most common serotype was O (45.83%), followed by Asia1 (29.17%) and A (13.89%); however, some case farms had mixed infection with serotypes A and O (9.72%) and serotypes O and Asia1 (1.39%). Multivariable analysis revealed that the history of introducing a new animal with unknown FMD vaccination status in the herd (OR =11.51, 95% CI = 3.28 - 40.47), not practicing regular vaccination against FMD (OR = 20.81, 95% CI = 4.59 - 94.35), history of the visit of an animal broker (OR = 9.06, 95% CI = 2.31 - 35.61), distance of the farm to a nearby livestock farm (OR = 6.13, 95% CI = 1.39 - 27.01) and large herd size (OR = 20.79, 95% CI = 2.45 - 176.27) were significantly associated with the occurrence of FMD outbreaks in Punjab province during 2019. In conclusion, improving biosecurity measures, avoiding the introduction of animals without FMD vaccination history and regular vaccination against FMD can significantly reduce the occurrence of the disease on livestock farms in Pakistan., (Copyright © 2022 Elsevier B.V. All rights reserved.)
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- 2022
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35. Spread of West Nile Virus and Usutu Virus in the German Bird Population, 2019-2020.
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Ziegler U, Bergmann F, Fischer D, Müller K, Holicki CM, Sadeghi B, Sieg M, Keller M, Schwehn R, Reuschel M, Fischer L, Krone O, Rinder M, Schütte K, Schmidt V, Eiden M, Fast C, Günther A, Globig A, Conraths FJ, Staubach C, Brandes F, Lierz M, Korbel R, Vahlenkamp TW, and Groschup MH
- Abstract
West Nile virus (WNV) and Usutu virus (USUV) are important flaviviruses circulating in Germany. While USUV was first reported more than 10 years ago, WNV has only reached the country in 2018. Wild birds are important amplifying hosts for both viruses. Therefore, we have been monitoring the bird population in different regions of Germany by a previously established network for many years. This report summarizes the results of molecular and/or serological methods of 2345 blood samples from birds of 22 different orders and over 2900 bird carcasses from 2019 and 2020. USUV RNA circulation was found in different regions of Germany, with emphasis on USUV lineages Europe 3 and Africa 3. Increased evidence of USUV lineage Europe 2 was detected in eastern Germany. WNV RNA was found only in birds from the eastern part of the country. The seroprevalence for USUV was between 3.11% and 7.20% in all three regions investigated, whereas the WNV seroprevalence spanned from 14.77% to 16.15% in eastern Germany, with a noticeable tendency for a westward and southward expansion in both years. Thus, wild bird monitoring for WNV and USUV can serve as an early warning system for a human exposure risk.
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- 2022
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36. Ticks on the Run: A Mathematical Model of Crimean-Congo Haemorrhagic Fever (CCHF)-Key Factors for Transmission.
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Bhowmick S, Kasi KK, Gethmann J, Fischer S, Conraths FJ, Sokolov IM, and Lentz HHK
- Abstract
Crimean-Congo haemorrhagic fever (CCHF) is a zoonotic disease caused by the Crimean-Congo hemorrhagic fever virus (CCHFV). Ticks of the genus Hyalomma are the main vectors and represent a reservoir for the virus. CCHF is maintained in nature in an endemic vertebrate-tick-vertebrate cycle. The disease is prevalent in wide geographical areas including Asia, Africa, South-Eastern Europe and the Middle East. It is of great importance for the public health given its occasionally high case/fatality ratio of CCHFV in humans. Climate change and the detection of possible CCHFV vectors in Central Europe suggest that the establishment of the transmission in Central Europe may be possible in future. We have developed a compartment-based nonlinear Ordinary Differential Equation (ODE) system to model the disease transmission cycle including blood sucking ticks, livestock and human. Sensitivity analysis of the basic reproduction number R0 shows that decreasing the tick survival time is an efficient method to control the disease. The model supports us in understanding the influence of different model parameters on the spread of CCHFV. Tick-to-tick transmission through co-feeding and the CCHFV circulation through transstadial and transovarial transmission are important factors to sustain the disease cycle. The proposed model dynamics are calibrated through an empirical multi-country analysis and multidimensional plot reveals that the disease-parameter sets of different countries burdened with CCHF are different. This information may help decision makers to select efficient control strategies.
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- 2022
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37. Extended-Spectrum ß-Lactamase-Producing Escherichia coli in Conventional and Organic Pig Fattening Farms.
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Meissner K, Sauter-Louis C, Heiden SE, Schaufler K, Tomaso H, Conraths FJ, and Homeier-Bachmann T
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Antimicrobial resistance is an increasing global problem and complicates successful treatments of bacterial infections in animals and humans. We conducted a longitudinal study in Mecklenburg-Western Pomerania to compare the occurrence of ESBL-producing Escherichia ( E.) coli in three conventional and four organic pig farms. ESBL-positive E. coli , especially of the CTX-M type, were found in all fattening farms, confirming that antimicrobial resistance is widespread in pig fattening and affects both conventional and organic farms. The percentage of ESBL-positive pens was significantly higher on conventional (55.2%) than on organic farms (44.8%) with similar proportions of ESBL-positive pens on conventional farms (54.3-61.9%) and a wide variation (7.7-84.2%) on organic farms. Metadata suggest that the farms of origin, from which weaner pigs were purchased, had a major influence on the occurrence of ESBL-producing E. coli in the fattening farms. Resistance screening showed that the proportion of pens with multidrug-resistant E. coli was similar on conventional (28.6%) and organic (31.5%) farms. The study shows that ESBL-positive E. coli play a major role in pig production and that urgent action is needed to prevent their spread.
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- 2022
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38. Investigation into a Superspreading Event of the German 2020-2021 Avian Influenza Epidemic.
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Denzin N, Bölling M, Pohlmann A, King J, Globig A, and Conraths FJ
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Between November 2020 and May 2021, Germany faced the largest highly pathogenic avian influenza (HPAI) epidemic recorded so far with 245 outbreaks in poultry and captive birds and more than 1000 diagnosed cases in wild birds. In March 2021, an HPAI outbreak of subtype H5N8 was confirmed in a holding rearing laying hens for sales. Disease introduction probably occurred via indirect contact with infected wild birds. Since the index farm sold chicken to customers including many smallholders, partly in travel trade, the primary outbreak triggered 105 known secondary outbreaks in five German federal states. An outbreak investigation was carried out with links between the involved farms retrieved from the German Animal Disease Notification System used for network analysis. In some cases, links were confirmed through sequence-based molecular analysis. Special emphasis was put on the estimation of the flock incubation period as a prerequisite of sound contact tracing. The unique circumstances of an outbreak farm with frequent direct trade contacts prior to disease suspicion enabled an assessment of the flock incubation period based on the consequences of contacts, further supported by molecular analysis and modeling of disease spread. In this case, the flock incubation period was at least 14 days.
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- 2022
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39. Computer Vision for Detection of Body Posture and Behavior of Red Foxes.
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Schütz AK, Krause ET, Fischer M, Müller T, Freuling CM, Conraths FJ, Homeier-Bachmann T, and Lentz HHK
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The behavior of animals is related to their health and welfare status. The latter plays a particular role in animal experiments, where continuous monitoring is essential for animal welfare. In this study, we focus on red foxes in an experimental setting and study their behavior. Although animal behavior is a complex concept, it can be described as a combination of body posture and activity. To measure body posture and activity, video monitoring can be used as a non-invasive and cost-efficient tool. While it is possible to analyze the video data resulting from the experiment manually, this method is time consuming and costly. We therefore use computer vision to detect and track the animals over several days. The detector is based on a neural network architecture. It is trained to detect red foxes and their body postures, i.e., 'lying', 'sitting', and 'standing'. The trained algorithm has a mean average precision of 99.91%. The combination of activity and posture results in nearly continuous monitoring of animal behavior. Furthermore, the detector is suitable for real-time evaluation. In conclusion, evaluating the behavior of foxes in an experimental setting using computer vision is a powerful tool for cost-efficient real-time monitoring.
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- 2022
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40. Genomic Analysis of ESBL-Producing E. coli in Wildlife from North-Eastern Germany.
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Homeier-Bachmann T, Schütz AK, Dreyer S, Glanz J, Schaufler K, and Conraths FJ
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Antimicrobial resistance (AMR) is a serious global health threat and extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales are a major contributor. This study aimed to gain a deeper insight into the AMR burden of wild animals. In total, 1595 fecal samples were collected by two systematic searches in Mecklenburg-Western Pomerania, north-east Germany. Samples were screened for ESBL-carrying Escherichia (E.) coli and isolates found were further analyzed using antimicrobial susceptibility testing and whole-genome sequencing. We found an estimated prevalence of 1.2% ESBL-producing E. coli in wild boar and 1.1% in wild ruminants. CTX-M-1 was the most abundant CTX-M type. We also examined fecal samples from wild boar and wild ruminants using shotgun metagenomics to gain insight into the resistome in wild animals. The latter revealed significantly lower normalized counts for AMR genes in wildlife samples compared to farm animals. The AMR gene levels were lower in wild ruminants than in wild boar. In conclusion, our study revealed a low prevalence of ESBL-producing E. coli and a low overall AMR gene burden in wild boar and wild ruminants, probably due to the secluded location of the search area.
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- 2022
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41. African Swine Fever Outbreaks in Lithuanian Domestic Pigs in 2019.
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Malakauskas A, Schulz K, Kukanauskaitė I, Masiulis M, Conraths FJ, and Sauter-Louis C
- Abstract
While numerous risk factors of African swine fever (ASF) transmission to domestic pigs have been described, ASF virus introduction has often not been traced back to one single defined cause. The large number of ASF outbreaks that occurred in domestic pigs in Lithuania from 2014 through to 2018 raised the question regarding whether outbreak-specific risk factors and transmission routes could be identified. Therefore, a prospective matched case-control study was designed. Data from 18 outbreaks that occurred in Lithuanian in 2019 and 36 control farms were analyzed. Conditional multivariable logistic regression showed that two or more visits by veterinary inspection of a farm had a significant preventive effect on the occurrence of ASF on a farm (Odds ratio (OR) 14.21, confidence interval (CI) 1.09-185.60 for farms not inspected vs. farms inspected twice or more a year), while certain practices (e.g., mushroom picking, sharing equipment, etc.), which might facilitate the indirect introduction of ASF from fields and forests into piggeries, significantly increased the odds of an outbreak (OR 5.18, CI 1.10-24.44). The results of the study highlight the importance of veterinary inspections for increasing the biosecurity level on pig farms and the awareness of ASF. The knowledge on potential protective and risk factors may help to improve the prevention and control of ASF outbreaks in domestic pig farms in Lithuania and other affected countries.
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- 2022
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42. New Insights into Gastrointestinal and Pulmonary Parasitofauna of Wild Eurasian lynx ( Lynx lynx ) in the Harz Mountains of Germany.
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Segeritz L, Anders O, Middelhoff TL, Winterfeld DT, Maksimov P, Schares G, Conraths FJ, Taubert A, and Hermosilla C
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The Eurasian lynx ( Lynx lynx ) represents an endangered wild felid species. In Germany, it currently occurs in three isolated populations in and around the Harz Mountains, the Palatinate Forest and the Bavarian Forest. Lynx parasitic infections affect animal health and might have an influence on population performance. Therefore, we investigated the protozoan and helminth fauna of free-ranging Eurasian lynx of the Harz population with emphasis on zoonotic parasites. Individual scat samples ( n = 24) were collected from wild animals between 2019 and 2021 in the Harz National Park and surrounding areas. In total, 15 taxa of endoparasites were detected, including seven nematodes (i.e., Aelurostrongylus abstrusus , Angiostrongylus spp., Uncinaria stenocephala , Toxascaris leonina , Toxocara cati , Cylicospirura spp. and Capillaria spp.), one cestode (Diphyllobothriidae) and one trematode (Heterophylidae) as well as six protozoans (i.e., Cystoisospora rivolta , Cystoisospora felis , Toxoplasma gondii / Hammondia spp., Sarcocystis spp., Giardia intestinalis and Cryptosporidium spp.). Moreover, first-stage larvae (L1) of spurious lungworm, Protostrongylus pulmonalis , originating from lagomorph preys were identified. This work represents the first report on patent A. abstrusus and Angiostrongylus spp. infections in wild German Eurasian lynxes. Some of the identified parasites represent relevant pathogens for lynxes, circulating between these carnivorous definitive hosts and a variety of mammalian and invertebrate intermediate hosts, e.g., Sarcocystis spp., T. gondii/Hammondia spp., T. cati , T. leonina , A. abstrusus and Angiostrongylus spp., while others are considered exclusively pathogenic for wild felids (e.g., Cylicospirura spp., C. rivolta , C. felis ). This study provides insights in the occurrence of zooanthroponotically relevant metazoan (i.e., T. cati and U. stenocephala ) and protozoan (i.e., G. intestinalis ) species in free-ranging lynx. The present work should be considered as a baseline study for future monitoring surveys on endoparasites circulating in wild Eurasian lynx for appropriate management practices in lynx conservation strategies in Europe.
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- 2021
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43. Introduction and spread of variegated squirrel bornavirus 1 (VSBV-1) between exotic squirrels and spill-over infections to humans in Germany.
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Cadar D, Allendorf V, Schulze V, Ulrich RG, Schlottau K, Ebinger A, Hoffmann B, Hoffmann D, Rubbenstroth D, Ismer G, Kibbey C, Marthaler A, Rissland J, Leypoldt F, Stangel M, Schmidt-Chanasit J, Conraths FJ, Beer M, Homeier-Bachmann T, and Tappe D
- Subjects
- Animals, Bayes Theorem, Bornaviridae classification, Bornaviridae genetics, Encephalitis virology, Female, Genome, Viral, Germany epidemiology, Humans, Male, Mononegavirales Infections transmission, Phylogeny, Polymerase Chain Reaction, RNA, Viral, Seroepidemiologic Studies, Zoonoses transmission, Bornaviridae isolation & purification, Mononegavirales Infections epidemiology, Mononegavirales Infections virology, Sciuridae virology, Zoonoses epidemiology, Zoonoses virology
- Abstract
The variegated squirrel bornavirus 1 (VSBV-1) is a recently discovered emerging viral pathogen which causes severe and eventually fatal encephalitis in humans after contact to exotic squirrels in private holdings and zoological gardens. Understanding the VSBV-1 epidemiology is crucial to develop, implement, and maintain surveillance strategies for the detection and control of animal and human infections. Based on a newly detected human encephalitis case in a zoological garden, epidemiological squirrel trade investigations and molecular phylogeny analyses of VSBV-1 with temporal and spatial resolution were conducted. Phylogenetic analyses indicated a recent emergence of VSBV-1 in European squirrel holdings and several animal-animal and animal-human spill-over infections. Virus phylogeny linked to squirrel trade analysis showed the introduction of a common ancestor of the known current VSBV-1 isolates into captive exotic squirrels in Germany, most likely by Prevost's squirrels ( Callosciurus prevostii ). The links of the animal trade between private breeders and zoos, the likely introduction pathway of VSBV-1 into Germany, and the role of a primary animal distributor were elucidated. In addition, a seroprevalence study was performed among zoo animal caretakers from VSBV-1 affected zoos. No seropositive healthy zoo animal caretakers were found, underlining a probable high-case fatality rate of human VSBV-1 infections. This study illustrates the network and health consequences of uncontrolled wild pet trading as well as the benefits of molecular epidemiology for elucidation and future prevention of infection chains by zoonotic viruses. To respond to emerging zoonotic diseases rapidly, improved regulation and control strategies are urgently needed.
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- 2021
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44. African Swine Fever Re-Emerging in Estonia: The Role of Seropositive Wild Boar from an Epidemiological Perspective.
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Schulz K, Schulz J, Staubach C, Blome S, Nurmoja I, Conraths FJ, Sauter-Louis C, and Viltrop A
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- African Swine Fever blood, African Swine Fever virology, African Swine Fever Virus genetics, African Swine Fever Virus isolation & purification, African Swine Fever Virus physiology, Animals, Antibodies, Viral blood, Communicable Diseases, Emerging blood, Communicable Diseases, Emerging epidemiology, Communicable Diseases, Emerging virology, Epidemics, Estonia epidemiology, Seroepidemiologic Studies, Sus scrofa blood, Swine, African Swine Fever epidemiology, African Swine Fever Virus immunology, Communicable Diseases, Emerging veterinary, Sus scrofa virology
- Abstract
African swine fever (ASF) emerged in Estonia in 2014. From February 2019 to August 2020, no pigs or wild boar tested positive for ASF virus (ASFV), only ASFV-specific antibodies could be detected in shot wild boar. However, ASF recently re-emerged in wild boar. We tested three hypotheses that might explain the current situation: (i) ASFV may have been present throughout, but at a prevalence below the detection limit; (ii) seropositive wild boar may have remained infectious (i.e., virus-carriers) and kept the epidemic going; or (iii) ASF was gone for 1.5 years, but was recently re-introduced. Using Estonian surveillance data, the sensitivity of the surveillance system and the confidence in freedom from ASF were estimated. Furthermore, the detection probability was determined and cluster analyses were performed to investigate the role of serological positive wild boar. The results suggest that the surveillance system was not able to detect virus circulation at a design prevalence below 1%. With respect to the confidence in freedom from ASF, the results indicate that circulating virus should have been detected over time, if the prevalence was ≥2%. However, the decreasing wild boar population density and ongoing surveillance activities made ASFV circulation at a low prevalence unlikely. Cluster analyses provided no evidence for a significant accumulation of serologically positive wild boar in temporal connection to the re-emergence of ASFV. Further targeted research, such as long-term experimental studies and molecular epidemiology, is necessary to improve our knowledge on the epidemiology of ASF and to control the disease more effectively.
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- 2021
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45. Individual-based model for the control of Bovine Viral Diarrhea spread in livestock trade networks.
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Bassett J, Gethmann J, Blunk P, Conraths FJ, and Hövel P
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- Animals, Cattle, Dairying, Diarrhea prevention & control, Diarrhea veterinary, Livestock, Swine, Bovine Virus Diarrhea-Mucosal Disease epidemiology, Bovine Virus Diarrhea-Mucosal Disease prevention & control, Diarrhea Viruses, Bovine Viral
- Abstract
Bovine Viral Diarrhea (BVD) is a cattle disease that causes substantial financial losses, in particular to the dairy industry. Hence, several countries including Germany introduced compulsory disease control programs. For the case of Germany in particular, all animals had to be tested and persistently infected animals (PI animals) were removed from the population. The program was successful in reducing the number of PI animals, but was overtly expensive. Alternative approaches were therefore discussed to eliminate the remaining PI animals and alter the testing system in order to reduce costs. Contributing to these efforts, we developed an agent-based model that aimed to cover all relevant aspects of the disease biology and would allow to evaluate different control strategies. For the biological part of the infection spread, the model includes horizontal and vertical transmission, transient and persistent infections. Moreover, several control strategies including import of animals, trade restrictions, vaccination, as well as various testing schemes were included. The model was furthermore defined to be stochastic, event-driven and hierarchical, with cattle movements as the main route of spreading between farms. For the spread within farms, we included susceptible-infected-recovered (SIR) dynamics with an additional permanently infectious class. The interaction between the farms was described by a supply and demand farm manager mechanism governing the network structure and dynamics. Additionally, we carried out a sensitivity analysis of the input parameters to study the impact of extreme values on the model. Since the population size in the model is limited, we tested the influence of the initial population size on the model results. Our results showed that the model could accurately describe the dynamics of the disease in the presence and absence of disease control. Although we developed the model for the spread of BVD, it may be adapted to similar diseases of cattle and swine., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)
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- 2021
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46. Red foxes harbor two genetically distinct, spatially separated Echinococcus multilocularis clusters in Brandenburg, Germany.
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Herzig M, Maksimov P, Staubach C, Romig T, Knapp J, Gottstein B, and Conraths FJ
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- Animals, Animals, Wild parasitology, DNA, Helminth genetics, Echinococcosis epidemiology, Echinococcus multilocularis pathogenicity, Female, Germany epidemiology, Male, Phylogeny, Zoonoses epidemiology, Zoonoses parasitology, Zoonoses transmission, Echinococcosis veterinary, Echinococcus multilocularis classification, Echinococcus multilocularis genetics, Foxes parasitology, Genetic Variation, Genotype
- Abstract
Background: Alveolar echinococcosis (AE) is a clinically serious zoonosis caused by the fox tapeworm Echinococcus multilocularis. We studied the diversity and the distribution of genotypes of E. multilocularis isolated from foxes in Brandenburg, Germany, and in comparison to a hunting ground in North Rhine-Westphalia., Methods: Echinococcus multilocularis specimens from 101 foxes, 91 derived from Brandenburg and 10 derived from North Rhine-Westphalia, were examined. To detect potential mixed infections with different genotypes of E. multilocularis, five worms per fox were analyzed. For genotyping, three mitochondrial markers, namely cytochrome c oxidase subunit 1 (Cox1), NADH dehydrogenase subunit 1 (Nad1), and ATP synthase subunit 6 (ATP6), and the nuclear microsatellite marker EmsB were used. To identify nucleotide polymorphisms, the mitochondrial markers were sequenced and the data were compared, including with published sequences from other regions. EmsB fragment length profiles were determined and confirmed by Kohonen network analysis and grouping of Sammon's nonlinear mapping with k-means clustering. The spatial distribution of genotypes was analyzed by SaTScan for the EmsB profiles found in Brandenburg., Results: With both the mitochondrial makers and the EmsB microsatellite fragment length profile analyses, mixed infections with different E. multilocularis genotypes were detected in foxes from Brandenburg and North Rhine-Westphalia. Genotyping using the mitochondrial markers showed that the examined parasite specimens belong to the European haplotype of E. multilocularis, but a detailed spatial analysis was not possible due to the limited heterogeneity of these markers in the parasite population. Four (D, E, G, and H) out of the five EmsB profiles described in Europe so far were detected in the samples from Brandenburg and North Rhine-Westphalia. The EmsB profile G was the most common. A spatial cluster of the E. multilocularis genotype with the EmsB profile G was found in northeastern Brandenburg, and a cluster of profile D was found in southern parts of this state., Conclusions: Genotyping of E. multilocularis showed that individual foxes may harbor different genotypes of the parasite. EmsB profiles allowed the identification of spatial clusters, which may help in understanding the distribution and spread of the infection in wildlife, and in relatively small endemic areas., (© 2021. The Author(s).)
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- 2021
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47. Review: Vaccines and Vaccination against Lumpy Skin Disease.
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Tuppurainen E, Dietze K, Wolff J, Bergmann H, Beltran-Alcrudo D, Fahrion A, Lamien CE, Busch F, Sauter-Louis C, Conraths FJ, De Clercq K, Hoffmann B, and Knauf S
- Abstract
The geographical distribution of lumpy skin disease (LSD), an economically important cattle disease caused by a capripoxvirus, has reached an unprecedented extent. Vaccination is the only way to prevent the spread of the infection in endemic and newly affected regions. Yet, in the event of an outbreak, selection of the best vaccine is a major challenge for veterinary authorities and farmers. Decision makers need sound scientific information to support their decisions and subsequent actions. The available vaccine products vary in terms of quality, efficacy, safety, side effects, and price. The pros and cons of different types of live attenuated and inactivated vaccines, vaccination strategies, and associated risks are discussed. Seroconversion, which typically follows vaccination, places specific demands on the tools and methods used to evaluate the effectiveness of the LSD vaccination campaigns in the field. We aimed to give a comprehensive update on available vaccines and vaccination against LSD, to better prepare affected and at-risk countries to control LSD and ensure the safe trade of cattle.
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- 2021
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48. Analysis of German BSE Surveillance Data: Estimation of the Prevalence of Confirmed Cases versus the Number of Infected, but Non-Detected, Cattle to Assess Confidence in Freedom from Infection.
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Greiner M, Selhorst T, Balkema-Buschmann A, Johnson WO, Müller-Graf C, and Conraths FJ
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- Animals, Bayes Theorem, Cattle, Freedom, Prevalence, Risk Assessment, Encephalopathy, Bovine Spongiform diagnosis, Encephalopathy, Bovine Spongiform epidemiology
- Abstract
Quantitative risk assessments for Bovine spongiform encephalopathy (BSE) necessitate estimates for key parameters such as the prevalence of infection, the probability of absence of infection in defined birth cohorts, and the numbers of BSE-infected, but non-detected cattle entering the food chain. We estimated three key parameters with adjustment for misclassification using the German BSE surveillance data using a Gompertz model for latent (i.e., unobserved) age-dependent detection probabilities and a Poisson response model for the number of BSE cases for birth cohorts 1999 to 2015. The models were combined in a Bayesian framework. We estimated the median true BSE prevalence between 3.74 and 0.216 cases per 100,000 animals for the birth cohorts 1990 to 2001 and observed a peak for the 1996 birth cohort with a point estimate of 16.41 cases per 100,000 cattle. For birth cohorts ranging from 2002 to 2013, the estimated median prevalence was below one case per 100,000 heads. The calculated confidence in freedom from disease (design prevalence 1 in 100,000) was above 99.5% for the birth cohorts 2002 to 2006. In conclusion, BSE surveillance in the healthy slaughtered cattle chain was extremely sensitive at the time, when BSE repeatedly occurred in Germany (2000-2009), because the entry of BSE-infected cattle into the food chain could virtually be prevented by the extensive surveillance program during these years and until 2015 (estimated non-detected cases/100.000 [95% credible interval] in 2000, 2009, and 2015 are 0.64 [0.5,0.8], 0.05 [0.01,0.14], and 0.19 [0.05,0.61], respectively).
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- 2021
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49. A Review of Environmental Risk Factors for African Swine Fever in European Wild Boar.
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Bergmann H, Schulz K, Conraths FJ, and Sauter-Louis C
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A detailed understanding of environmental risk factors for African swine fever (ASF) in wild boar will be not only essential for risk assessments but also for timely and spatially informed allocation of resources in order to manage wild boar-targeted ASF control measures efficiently. Here, we review currently known environmental risk factors that can influence the occurrence of ASF virus infection in wild boar when compared to disease occurrence in wild boar of a non-exposed reference scenario. Accordingly, the exposure of wild boar to environmental risk factors related to (1) climate, (2) land cover, (3) human activity, (4) wild boar and (5) ASF were evaluated. As key environmental risk factors in this review, increased ASF occurrence in wild boar was associated with seasonal patterns, forest coverage, presence of water, human presence, farming activities, wild boar density and ASF nearness. The review highlights inconsistencies in some of these risk factor associations with disease detection in space and time and may provide valuable insights for the investigation of ASF transmission dynamics. The examined risk information was applied to consider potential improvements of the ASF control strategy in wild boar regarding disease surveillance, hunting, wild boar carcass searches and ASF barrier implementation.
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- 2021
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50. African Swine Fever in Wild Boar in Europe-A Review.
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Sauter-Louis C, Conraths FJ, Probst C, Blohm U, Schulz K, Sehl J, Fischer M, Forth JH, Zani L, Depner K, Mettenleiter TC, Beer M, and Blome S
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- African Swine Fever Virus genetics, Animals, Disease Outbreaks, Europe epidemiology, Swine, African Swine Fever epidemiology, African Swine Fever Virus pathogenicity, Sus scrofa virology
- Abstract
The introduction of genotype II African swine fever (ASF) virus, presumably from Africa into Georgia in 2007, and its continuous spread through Europe and Asia as a panzootic disease of suids, continues to have a huge socio-economic impact. ASF is characterized by hemorrhagic fever leading to a high case/fatality ratio in pigs. In Europe, wild boar are especially affected. This review summarizes the currently available knowledge on ASF in wild boar in Europe. The current ASF panzootic is characterized by self-sustaining cycles of infection in the wild boar population. Spill-over and spill-back events occur from wild boar to domestic pigs and vice versa. The social structure of wild boar populations and the spatial behavior of the animals, a variety of ASF virus (ASFV) transmission mechanisms and persistence in the environment complicate the modeling of the disease. Control measures focus on the detection and removal of wild boar carcasses, in which ASFV can remain infectious for months. Further measures include the reduction in wild boar density and the limitation of wild boar movements through fences. Using these measures, the Czech Republic and Belgium succeeded in eliminating ASF in their territories, while the disease spread in others. So far, no vaccine is available to protect wild boar or domestic pigs reliably against ASF.
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- 2021
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