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4. Ticks on the run: A mathematical model of Crimean-Congo Haemorrhagic Fever (CCHF)-key factors for transmission

Author

Bhowmick, Suman, Kasi, Khushal Khan, Gethmann, Jörn, Fischer, Susanne, Conraths, Franz J., Sokolov, Igor M., and Lentz, Hartmut H. K.

Subjects
Physics - Biological Physics, Quantitative Biology - Populations and Evolution
Abstract

Crimean-Congo haemorrhagic fever (CCHF) is a tick-borne zoonotic disease caused by the Crimean-Congo hemorrhagic fever virus (CCHFV). Ticks belonging to the genus \textit{Hyalomma} are the main vectors and reservoir for the virus. It is maintained in nature in an endemic vertebrate-tick-vertebrate cycle. CCHFV is prevalent in wide geographical areas including Asia, Africa, South-Eastern Europe and the Middle East. Over the last decade, several outbreaks of CCHFV have been observed in Europe, mainly in Mediterranean countries. Due to the high case/fatality ratio of CCHFV in human sometimes, it is of great importance for public health. Climate change and the invasion of CCHFV vectors in Central Europe suggest that the establishment of the transmission in Central Europe may be possible in future. We 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 $R_0$ shows that decreasing in the tick survival time is an efficient method to eradicate 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 trasstadial and transovarial stages are important factors to sustain the disease cycle. The proposed model dynamics are calibrated through an empirical multi-country analysis and multidimensional scaling reveals the disease-parameter sets of different countries burdened with CCHF are different. This necessary information may help us to select most efficient control strategies.

Published
2021

5. Can a patchy model describe the potential spread of West Nile virus in Germany?

Author

Bhowmick, Suman, Gethmann, Jörn, Sokolov, Igor M., Conraths, Franz J., and Lentz, Hartmut H. K.

Subjects
Physics - Biological Physics, Quantitative Biology - Populations and Evolution
Abstract

In 2018, West Nile Virus (WNV) was detected for the first time in Germany. Since the first detection, 36 human cases and 175 cases in horses and birds are detected. The transmission cycle of West Nile Virus includes birds and mosquitoes and -- as dead-end hosts -- people and horses. Spatial dissemination of the disease is caused by the movements of birds and mosquitoes. While the activity and movement of mosquitoes are depending mainly on temperature, in the birds there is a complex movement pattern caused by local birds and long range dispersal birds. To this end, we have developed a metapopulation network model framework to delineate the potential spatial distribution and spread of WNV across Germany as well as to evaluate the risk throughout our proposed network model. Our model facilitates the interconnection amongst the vector, local birds and long range dispersal birds contact networks. We have assumed different distance dispersal kernels models for the vector and avian populations with the intention to include short and long range dispersal. The model includes spatial variation of mosquito abundance and the movements to resemble the reality.

Published
2021

6. Dog Ownership and Risk for Alveolar Echinococcosis, Germany

Author

Schmidberger, Julian, Uhlenbruck, Anne, Schlingeloff, Patrycja, Maksimov, Pavlo, Conraths, Franz J., Mayer, Benjamin, and Kratzer, Wolfgang

Subjects
Dog owners -- Health aspects, Echinococcosis -- Risk factors -- Demographic aspects, Health
Abstract

Human alveolar echinococcosis is a rare disease that can be caused by the parasite Echinococcus multilocularis (1,2). The pathogen E. multilocularis and human cases of the disease are predominantly distributed [...]

Published
2022
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13. Disease spread through animal movements: a static and temporal network analysis of pig trade in Germany

Author

Lentz, Hartmut H. K., Koher, Andreas, Hövel, Philipp, Gethmann, Jörn, Sauter-Louis, Carola, Selhorst, Thomas, and Conraths, Franz J.

Subjects
Physics - Physics and Society, Quantitative Biology - Populations and Evolution
Abstract

Background: Animal trade plays an important role for the spread of infectious diseases in livestock populations. As a case study, we consider pig trade in Germany, where trade actors (agricultural premises) form a complex network. The central question is how infectious diseases can potentially spread within the system of trade contacts. We address this question by analyzing the underlying network of animal movements. Methodology/Findings: The considered pig trade dataset spans several years and is analyzed with respect to its potential to spread infectious diseases. Focusing on measurements of network-topological properties, we avoid the usage of external parameters, since these properties are independent of specific pathogens. They are on the contrary of great importance for understanding any general spreading process on this particular network. We analyze the system using different network models, which include varying amounts of information: (i) static network, (ii) network as a time series of uncorrelated snapshots, (iii) temporal network, where causality is explicitly taken into account. Findings: Our approach provides a general framework for a topological-temporal characterization of livestock trade networks. We find that a static network view captures many relevant aspects of the trade system, and premises can be classified into two clearly defined risk classes. Moreover, our results allow for an efficient allocation strategy for intervention measures using centrality measures. Data on trade volume does barely alter the results and is therefore of secondary importance. Although a static network description yields useful results, the temporal resolution of data plays an outstanding role for an in-depth understanding of spreading processes. This applies in particular for an accurate calculation of the maximum outbreak size., Comment: main text 33 pages, 17 figures, supporting information 7 pages, 7 figures

Published
2016
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15. Tenacity of Animal Disease Viruses on Wood Surfaces Relevant to Animal Husbandry.

Author

Oettler, Martin J., Conraths, Franz J., Roesler, Uwe, Reiche, Sven, Homeier-Bachmann, Timo, and Denzin, Nicolai

Subjects
*VETERINARY virology, *WOOD, *NORWAY spruce, *NEWCASTLE disease virus, *POPLARS, *EUROPEAN beech, *VIRUS inactivation, *ANIMAL culture
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 log10) 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. [ABSTRACT FROM AUTHOR]

Published
2024
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16. Efficiency of Virucidal Disinfectants on Wood Surfaces in Animal Husbandry.

Author

Oettler, Martin J., Conraths, Franz J., Roesler, Uwe, Reiche, Sven, Homeier-Bachmann, Timo, and Denzin, Nicolai

Subjects
WOOD, POPLARS, DISINFECTION & disinfectants, ANIMAL culture, NORWAY spruce, EUROPEAN beech, VIRUS inactivation
Abstract

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. [ABSTRACT FROM AUTHOR]

Published
2024
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30. Geographic Distribution of Raccoon Roundworm, Baylisascaris procyonis, Germany and Luxembourg

Author

Heddergott, Mike, Steinbach, Peter, Schwarz, Sabine, Anheyer-Behmenburg, Helena E., Sutor, Astrid, Schliephake, Annette, Jeschke, Diana, Striese, Michael, Muller, Franz, MeyerKayser, Elisabeth, Stubbe, Michael, Osten-Sacken, Natalia, Kruger, Susann, Gaede, Wolfgang, Runge, Martin, Hoffmann, Lothar, Ansorge, Hermann, Conraths, Franz J., and Frantz, Alain C.

Subjects
Roundworms, Roundworm infections, Public health, Diseases, Public health movements, Health
Abstract

The raccoon roundworm (Baylisascaris procyonis) is a gastrointestinal parasitic nematode of the raccoon (Procyon lotor). It is common in its native range in North America, where its prevalence in raccoons [...]

Published
2020
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33. Modelling the monthly abundance of Culicoides biting midges in nine European countries using Random Forests machine learning

Author

Cuéllar, Ana Carolina, Kjær, Lene Jung, Baum, Andreas, Stockmarr, Anders, Skovgard, Henrik, Nielsen, Søren Achim, Andersson, Mats Gunnar, Lindström, Anders, Chirico, Jan, Lühken, Renke, Steinke, Sonja, Kiel, Ellen, Gethmann, Jörn, Conraths, Franz J., Larska, Magdalena, Smreczak, Marcin, Orłowska, Anna, Hamnes, Inger, Sviland, Ståle, Hopp, Petter, Brugger, Katharina, Rubel, Franz, Balenghien, Thomas, Garros, Claire, Rakotoarivony, Ignace, Allène, Xavier, Lhoir, Jonathan, Chavernac, David, Delécolle, Jean-Claude, Mathieu, Bruno, Delécolle, Delphine, Setier-Rio, Marie-Laure, Scheid, Bethsabée, Chueca, Miguel Ángel Miranda, Barceló, Carlos, Lucientes, Javier, Estrada, Rosa, Mathis, Alexander, Venail, Roger, Tack, Wesley, and Bødker, Rene

Published
2020
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45. First-Passage Time Analysis Based on GPS Data Offers a New Approach to Estimate Restricted Zones for the Management of Infectious Diseases in Wildlife: A Case Study Using the Example of African Swine Fever.

Author

Wielgus, Elodie, Klamm, Alisa, Conraths, Franz J., Dormann, Carsten F., Henrich, Maik, Kronthaler, Franz, and Heurich, Marco

Subjects
WILDLIFE diseases, DISEASE management, COMMUNICABLE diseases, AFRICAN swine fever, WILD boar, LOCATION data, SWINE breeding
Abstract

An essential part of any disease containment and eradication policy is the implementation of restricted zones, but determining the appropriate size of these zones can be challenging for managers. We designed a new method, based on animal movement, to help assess how large restricted zones should be after a spontaneous outbreak to successfully control infectious diseases in wildlife. Our approach uses first-passage time (FPT) analysis and Cox proportional hazard (CPH) models to calculate and compare the risk of an animal leaving different-sized areas. We illustrate our approach using the example of the African swine fever (ASF) virus and its wild pig reservoir host species, the wild boar (Sus scrofa), and we investigate the feasibility of applying this method to other systems. Using GPS data from 57 wild boar living in the Hainich National Park, Germany, we calculate the time spent by each individual in areas of different sizes using FPT analysis. We apply CPH models on the derived data to compare the risk of leaving areas of different sizes and to assess the effects of season and the sex of the wild boar on the risk of leaving. We conduct survival analyses to estimate the risk of leaving an area over time. Our results indicate that the risk of leaving an area decreases exponentially by 10% for each 100 m increase in radius size so that the differences were more pronounced for small sizes. Furthermore, the probability of leaving increases exponentially with time. Wild boar had a similar risk of leaving an area of a given size throughout the year, except in spring and winter, when females had a much lower risk of leaving. Our findings are in agreement with the literature on wild boar movement, further validating our method, and repeated analyses with location data resampled at different rates gave similar results. Our results may be applicable only to our study area, but they demonstrate the applicability of the proposed method to any ecosystem where wild boar populations are likely to be infected with ASF and where restricted zones should be established accordingly. The outlined approach relies solely on the analysis of movement data and provides a useful tool to determine the optimal size of restricted zones. It can also be applied to future outbreaks of other diseases. [ABSTRACT FROM AUTHOR]

Published
2023
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46. Monthly variation in the probability of presence of adult Culicoides populations in nine European countries and the implications for targeted surveillance

Author

Cuéllar, Ana Carolina, Jung Kjær, Lene, Baum, Andreas, Stockmarr, Anders, Skovgard, Henrik, Nielsen, Søren Achim, Andersson, Mats Gunnar, Lindström, Anders, Chirico, Jan, Lühken, Renke, Steinke, Sonja, Kiel, Ellen, Gethmann, Jörn, Conraths, Franz J., Larska, Magdalena, Smreczak, Marcin, Orłowska, Anna, Hamnes, Inger, Sviland, Ståle, Hopp, Petter, Brugger, Katharina, Rubel, Franz, Balenghien, Thomas, Garros, Claire, Rakotoarivony, Ignace, Allène, Xavier, Lhoir, Jonathan, Chavernac, David, Delécolle, Jean-Claude, Mathieu, Bruno, Delécolle, Delphine, Setier-Rio, Marie-Laure, Venail, Roger, Scheid, Bethsabée, Chueca, Miguel Ángel Miranda, Barceló, Carlos, Lucientes, Javier, Estrada, Rosa, Mathis, Alexander, Tack, Wesley, and Bødker, René

Published
2018
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49. Outbreaks among wild birds and domestic poultry caused by reassorted influenza A(H5N8) clade 2.3.4.4 viruses, Germany, 2016

Author

Pohlmann, Anne, Starick, Elke, Harder, Timm, Grund, Christian, Hoper, Dirk, Globig, Anja, Staubach, Christoph, Dietze, Klaas, Strebelow, Gunter, Ulrich, Reiner G., Schinkothe, Jan, Teifke, Jens P., Conraths, Franz J., Mettenleiter, Thomas C., and Beer, Martin

Subjects
Veterinary epidemiology -- Analysis, Poultry (Animals) -- Health aspects -- Research, Avian influenza -- Genetic aspects -- Research, Health
Abstract

During 2014-2015, after massive outbreaks of highly pathogenic avian influenza (HPAI) on the Korean Peninsula, subtype H5N8 viruses (group A clade 2.3.4.4) caused outbreaks among wild birds and domestic poultry [...]

Published
2017
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50. Evaluation of different magnetic capture protocols for the detection of Echinococcus multilocularis DNA in red foxes

Author

Davidson, Rebecca K., Dam-Deisz, Cecile, Skarsfjord Edgar, Kristin, Berg, Rebecca, Winterfeld, Deliah, Van der Giessen, Joke, Conraths, Franz J., Nørgaard, Dan, Øines, Øivind, and Maksimov, Pavlo

Subjects
magnetic capture, protocol comparison, Echinococcus multilocularis
Abstract

This work forms part of JRP-WP4-T3 Organisation of selected PTs from WP2 and WP3 of the One Health EJP project Multi-centre study on Echinococcus multilocularis and Echinococcus granulosus s.l. in Europe: development and harmonization of diagnostic methods in the food chain (MEmE). Four laboratories tested and evaluated different magnetic capture protocols for the detection of E. multilocularis DNA in red fox faeces.

Published
2022
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