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Management of a Focal Introduction of ASF Virus in Wild Boar: The Belgian Experience. Pathogens 2023; 12:pathogens12020152. [PMID: 36839424 PMCID: PMC9961158 DOI: 10.3390/pathogens12020152] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/13/2023] [Accepted: 01/14/2023] [Indexed: 01/18/2023] Open
Abstract
African swine fever (ASF) is a fatal disease of suids that was detected in wild boar in Belgium in September 2018. The measures implemented to stop the spread and eliminate the African swine fever virus consisted of creating restriction zones, organising efficient search and removal of carcasses, constructing wire fences, and depopulating wild boar in the area surrounding the infected zone. The ASF management zone included the infected and the white zones and covered 1106 km² from which 7077 wild boar have been removed. A total of 5338 wild boars have been qPCR-tested and 833 have been detected ASF-positive. The search effort amounted to 60,631 h with a main focus on the infected zone (88%). A total of 277 km of fences have been set up. The main cause of mortality in the infected zone was the virus itself, while hunting, trapping, and night shooting were used together to reduce the wild boar density in the surrounding white zones. After continuous dispersion of the virus until March 2019, the epidemic wave stopped, and the last fresh positive case was discovered in August 2019. Hence, Belgium was declared free of the disease in November 2020.
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Abstract
Introduction African swine fever (ASF) is a lethal haemorrhagic disease of Suidae, present in Poland since 2014. The natural reservoir of ASF in Europe is the wild boar (Sus scrofa); however, human activity facilitates long-distance introductions of the disease. In ASF control it is important to identify areas at increased risk of infection. Such identification and estimation of the disease's progress and subsequent spread will help to identify the specific preventive action needs in given zones. Serving this purpose, this study is a spatial and statistical analysis of ASF spread through noted outbreak data. Material and Methods The spatial-temporal analysis was conducted on the basis of data including the time and location of all ASF outbreaks both in wild boars and domestic pigs in Poland in 2014-2021. Results The analysis indicates possible routes and directions for further ASF spread in Poland, estimates the annual increase of the affected area (approx. 25,000 km2 every year since 2017) and marks trends. The strong method-independent correlation between the year and the surface area affected by African swine fever indicated a near-linear generalised trend. Conclusion Given the growth trend, we can expect ASF to expand further into new territories of the country; however, it is important to realise that there is still a significant area to protect, because 60% of Poland remains ASF-free.
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Shotin AR, Mazloum A, Igolkin AS, Shevchenko IV, Elsukova AA, Aronova EV, Vlasova NN. [Alternative approaches to the diagnosis of African swine fever in the Russian Federation in 2017-2021]. Vopr Virusol 2022; 67:290-303. [PMID: 36097710 DOI: 10.36233/0507-4088-112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 09/11/2022] [Indexed: 06/15/2023]
Abstract
INTRODUCTION Prevention and control of African swine fever (ASF) transmission on the territory of the Russian Federation requires monitoring based on testing of samples from pigs and wild boars. Specific anti-ASFV antibodies are rarely detected in samples during routine serological diagnostics. Although, ASF isolates with weakened virulence were confirmed in Russia and neighboring countries.The aim of this work was to determine the possibility of using alternative samples for ASF diagnosis and evaluate the effectiveness of the diagnostic methods used on the territory of Russia. MATERIALS AND METHODS Biological materials obtained from experimentally infected animals and samples collected in the "field" conditions were used in this study. RESULTS Complex testing (RT-PCR and ELISA) is a more effective approach to diagnose chronic and asymptomatic forms of ASF compared to the separate use of these techniques. The possibility and efficiency of using alternative samples in diagnostics are demonstrated. It was confirmed that IPT method overcomes ELISA by high diagnostic sensitivity and detection of antibodies on earlier stages in extended range of samples. Anti-ASFV antibodies were detected in domestic and wild pigs in five regions of Russia. Samples from infected pigs that are negative in RT-PCR can be positive for anti-ASFV antibodies. The detection of antibodies in samples from shot wild boars (negative or uncertain in RT-PCR test) suggests the existence of animals surviving ASF infection. CONCLUSION The data obtained suggest a revision of the ASF surveillance strategy, by introducing complex diagnostic methods aimed at detection of both the virus genome and anti-ASFV antibodies simultaneously.
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Affiliation(s)
| | - A Mazloum
- FGBI "Federal Centre for Animal Health"
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Schulz K, Oļševskis E, Viltrop A, Masiulis M, Staubach C, Nurmoja I, Lamberga K, Seržants M, Malakauskas A, Conraths FJ, Sauter-Louis C. Eight Years of African Swine Fever in the Baltic States: Epidemiological Reflections. Pathogens 2022; 11:pathogens11060711. [PMID: 35745565 PMCID: PMC9230151 DOI: 10.3390/pathogens11060711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/13/2022] [Accepted: 06/16/2022] [Indexed: 02/04/2023] Open
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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Affiliation(s)
- Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, 17493 Greifswald-Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
- Correspondence: ; Tel.: +49-3835-171-803
| | - Edvīns Oļševskis
- Food and Veterinary Service, 1050 Riga, Latvia; (E.O.); (K.L.); (M.S.)
- Institute of Food Safety, Animal Health and Environment-“BIOR”, 1076 Riga, Latvia
| | - Arvo Viltrop
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Science, 51006 Tartu, Estonia;
| | - Marius Masiulis
- State Food and Veterinary Service, LT07170 Vilnius, Lithuania; (M.M.); (A.M.)
- Dr. L Kriauceliunas Small Animal Clinic, Veterinary Academy, Lithuanian University of Health Sciences, LT47181 Kaunas, Lithuania
| | - Christoph Staubach
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, 17493 Greifswald-Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Imbi Nurmoja
- Estonian Veterinary and Food Laboratory (VFL), 51006 Tartu, Estonia;
| | - Kristīne Lamberga
- Food and Veterinary Service, 1050 Riga, Latvia; (E.O.); (K.L.); (M.S.)
- Faculty of Veterinary Medicine, Latvia University of Life Sciences and Technologies, 3001 Jelgava, Latvia
| | - Mārtiņš Seržants
- Food and Veterinary Service, 1050 Riga, Latvia; (E.O.); (K.L.); (M.S.)
| | - Alvydas Malakauskas
- State Food and Veterinary Service, LT07170 Vilnius, Lithuania; (M.M.); (A.M.)
- Department of Veterinary Pathobiology, Veterinary Academy, Lithuanian University of Health Sciences, LT44307 Kaunas, Lithuania
| | - Franz Josef Conraths
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, 17493 Greifswald-Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, 17493 Greifswald-Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
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African Swine Fever (ASF) Trend Analysis in Wild Boar in Poland (2014–2020). Animals (Basel) 2022; 12:ani12091170. [PMID: 35565596 PMCID: PMC9105269 DOI: 10.3390/ani12091170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 12/10/2022] Open
Abstract
Simple Summary African swine fever (ASF) has been present in Poland since 2014. The article describes and explains the changes in the ASF epidemic in the wild boar population in the period 2014–2020. In that relatively short time, the disease has spread to about half of the territory of Poland, affecting eastern and western provinces. Most ASF-positive animals were molecular/virus-positive, however, the observation of the increase of serologically positive animals (potential survivors) in successive years of the epidemic, especially in areas where the virus has been present for a longer time, may indicate the potential beginning of ASF endemicity in Poland. Abstract African swine fever (ASF) is a lethal hemorrhagic disease of Suidae, i.e., domestic pigs and wild boars. The disease was introduced to Poland in 2014 and is now present in the wild boar population. Appropriate ASF prevention requires further research for answers to fundamental questions about the importance of vectors in virus transmission, the impact of environmental factors on the presence of ASFV in wild boar habitats, and the role of survivors as potential virus carriers and their part in the potential endemicity of ASF. In order to analyze the changes in the molecular and serological prevalence of ASFV in wild boar population in Poland, real-time PCR and ELISA/IPT tests were conducted. In the analyzed period (2014–2020), most of the ASF-positive wild boars were molecular/virus-positive, however, over the years the percentage and the number of seropositive animals has increased. At the beginning of the epidemic, the disease was limited to a small area of the country. Since then, it has spread to new provinces of Poland. From the beginning and until today, most notifications of ASF-positive wild boars were for carcasses (passive surveillance), however, the number of serologically positive animals is still increasing. Despite the fact that notifications of ASF outbreaks are still being received near the eastern border of Poland, the old ASF area seems to be limited mainly to ASF serologically positive animals, which may indicate the beginning of ASF endemicity in Poland.
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Schulz K, Schulz J, Staubach C, Blome S, Nurmoja I, Conraths FJ, Sauter-Louis C, Viltrop A. African Swine Fever Re-Emerging in Estonia: The Role of Seropositive Wild Boar from an Epidemiological Perspective. Viruses 2021; 13:2121. [PMID: 34834928 PMCID: PMC8625046 DOI: 10.3390/v13112121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 02/07/2023] Open
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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Affiliation(s)
- Katja Schulz
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17498 Greifswald-Insel Riems, Germany; (J.S.); (C.S.); (F.J.C.); (C.S.-L.)
| | - Jana Schulz
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17498 Greifswald-Insel Riems, Germany; (J.S.); (C.S.); (F.J.C.); (C.S.-L.)
| | - Christoph Staubach
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17498 Greifswald-Insel Riems, Germany; (J.S.); (C.S.); (F.J.C.); (C.S.-L.)
| | - Sandra Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17498 Greifswald-Insel Riems, Germany;
| | - Imbi Nurmoja
- Estonian Veterinary and Food Laboratory (VFL), Kreutzwaldi 30, 51006 Tartu, Estonia;
| | - Franz J. Conraths
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17498 Greifswald-Insel Riems, Germany; (J.S.); (C.S.); (F.J.C.); (C.S.-L.)
| | - Carola Sauter-Louis
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17498 Greifswald-Insel Riems, Germany; (J.S.); (C.S.); (F.J.C.); (C.S.-L.)
| | - Arvo Viltrop
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Science, Kreutzwaldi 62, 51014 Tartu, Estonia;
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Lim JS, Kim E, Ryu PD, Pak SI. Basic reproduction number of African swine fever in wild boars ( Sus scrofa) and its spatiotemporal heterogeneity in South Korea. J Vet Sci 2021; 22:e71. [PMID: 34553516 PMCID: PMC8460458 DOI: 10.4142/jvs.2021.22.e71] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 07/29/2021] [Accepted: 08/05/2021] [Indexed: 11/21/2022] Open
Abstract
Background African swine fever (ASF) is a hemorrhagic fever occurring in wild boars (Sus scrofa) and domestic pigs. The epidemic situation of ASF in South Korean wild boars has increased the risk of ASF in domestic pig farms. Although basic reproduction number (R0) can be applied for control policies, it is challenging to estimate the R0 for ASF in wild boars due to surveillance bias, lack of wild boar population data, and the effect of ASF-positive wild boar carcass on disease dynamics. Objectives This study was undertaken to estimate the R0 of ASF in wild boars in South Korea, and subsequently analyze the spatiotemporal heterogeneity. Methods We detected the local transmission clusters using the spatiotemporal clustering algorithm, which was modified to incorporate the effect of ASF-positive wild boar carcass. With the assumption of exponential growth, R0 was estimated for each cluster. The temporal change of the estimates and its association with the habitat suitability of wild boar were analyzed. Results Totally, 22 local transmission clusters were detected, showing seasonal patterns occurring in winter and spring. Mean value of R0 of each cluster was 1.54. The estimates showed a temporal increasing trend and positive association with habitat suitability of wild boar. Conclusions The disease dynamics among wild boars seems to have worsened over time. Thus, in areas with a high elevation and suitable for wild boars, practical methods need to be contrived to ratify the control policies for wild boars.
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Affiliation(s)
- Jun-Sik Lim
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea
| | - Eutteum Kim
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea
| | - Pan-Dong Ryu
- College of Veterinary Medicine, Seoul National University, Seoul 08732, Korea
| | - Son-Il Pak
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea.
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Bergmann H, Schulz K, Conraths FJ, Sauter-Louis C. A Review of Environmental Risk Factors for African Swine Fever in European Wild Boar. Animals (Basel) 2021; 11:ani11092692. [PMID: 34573659 PMCID: PMC8465043 DOI: 10.3390/ani11092692] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 12/20/2022] Open
Abstract
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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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, Blome S. African Swine Fever in Wild Boar in Europe-A Review. Viruses 2021; 13:1717. [PMID: 34578300 PMCID: PMC8472013 DOI: 10.3390/v13091717] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 12/20/2022] Open
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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Affiliation(s)
- Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (F.J.C.); (C.P.); (K.S.)
| | - Franz J. Conraths
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (F.J.C.); (C.P.); (K.S.)
| | - Carolina Probst
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (F.J.C.); (C.P.); (K.S.)
| | - Ulrike Blohm
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Immunology, Südufer 10, 17493 Greifswald-Insel Riems, Germany;
| | - Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (F.J.C.); (C.P.); (K.S.)
| | - Julia Sehl
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany;
| | - Melina Fischer
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Diagnostic Virology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (M.F.); (J.H.F.); (M.B.); (S.B.)
| | - Jan Hendrik Forth
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Diagnostic Virology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (M.F.); (J.H.F.); (M.B.); (S.B.)
| | - Laura Zani
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of International Animal Health/One Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (L.Z.); (K.D.)
| | - Klaus Depner
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of International Animal Health/One Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (L.Z.); (K.D.)
| | - Thomas C. Mettenleiter
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany;
| | - Martin Beer
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Diagnostic Virology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (M.F.); (J.H.F.); (M.B.); (S.B.)
| | - Sandra Blome
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Diagnostic Virology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (M.F.); (J.H.F.); (M.B.); (S.B.)
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Schulz K, Masiulis M, Staubach C, Malakauskas A, Pridotkas G, Conraths FJ, Sauter-Louis C. African Swine Fever and Its Epidemiological Course in Lithuanian Wild Boar. Viruses 2021; 13:1276. [PMID: 34208894 PMCID: PMC8310040 DOI: 10.3390/v13071276] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/27/2021] [Accepted: 06/28/2021] [Indexed: 12/31/2022] Open
Abstract
African swine fever (ASF) has been present in Lithuania since 2014. It is mainly the wild boar population that is affected. Currently, little is known about the epidemiological course of ASF in Lithuania. In the present study, ASF surveillance data from 2016-2021 were analyzed. The numbers of samples taken from hunted wild boar and wild boar found dead per year and month were recorded and the prevalence was estimated for each study month and administrative unit. A Bayesian space-time model was used to calculate the temporal trend of the prevalence estimates. In addition, population data were analyzed on a yearly basis. Most samples were investigated in 2016 and 2017 and originated from hunted animals. Prevalence estimates of ASF virus-positive wild boar decreased from May 2019 onwards. Seroprevalence estimates showed a slight decrease at the same time, but they increased again at the end of the study period. A significant decrease in the population density was observed over time. The results of the study show that ASF is still present in the Lithuanian wild boar population. A joint interdisciplinary effort is needed to identify weaknesses in the control of ASF in Lithuania and to combat the disease more successfully.
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Affiliation(s)
- Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Marius Masiulis
- Emergency Response Division, State Food and Veterinary Service, Siesiku 19, LT-07170 Vilnius, Lithuania; (M.M.); (A.M.)
- Dr. L. Kriauceliunas Small Animal Clinic, Veterinary Academy, Lithuanian University of Health Sciences, Tilzes Street 18, LT-47181 Kaunas, Lithuania
- National Food and Veterinary Risk Assessment Institute, J. Kairiūkščio Street 10, LT-08409 Vilnius, Lithuania;
| | - Christoph Staubach
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Alvydas Malakauskas
- Emergency Response Division, State Food and Veterinary Service, Siesiku 19, LT-07170 Vilnius, Lithuania; (M.M.); (A.M.)
- Department of Veterinary Pathobiology, Veterinary Academy, Lithuanian University of Health Sciences, Tilzes Street 18, LT-47181 Kaunas, Lithuania
| | - Gediminas Pridotkas
- National Food and Veterinary Risk Assessment Institute, J. Kairiūkščio Street 10, LT-08409 Vilnius, Lithuania;
| | - Franz J. Conraths
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
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Desmecht D, Gerbier G, Gortázar Schmidt C, Grigaliuniene V, Helyes G, Kantere M, Korytarova D, Linden A, Miteva A, Neghirla I, Olsevskis E, Ostojic S, Petit T, Staubach C, Thulke H, Viltrop A, Richard W, Wozniakowski G, Cortiñas JA, Broglia A, Dhollander S, Lima E, Papanikolaou A, Van der Stede Y, Ståhl K. Epidemiological analysis of African swine fever in the European Union (September 2019 to August 2020). EFSA J 2021; 19:e06572. [PMID: 33976715 PMCID: PMC8100952 DOI: 10.2903/j.efsa.2021.6572] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
An update on the African swine fever (ASF) situation in the 10 affected Member States (MS) in the EU and in two neighbouring countries from the 1 September 2019 until the 31 August 2020 is provided. The dynamics of the proportions of PCR- and ELISA-positive samples since the first ASF detection in the country were provided and seasonal patterns were investigated. The impact of the ASF epidemic on the annual numbers of hunted wild boar in each affected MS was investigated. To evaluate differences in the extent of spread of ASF in the wild boar populations, the number of notifications that could be classified as secondary cases to a single source was calculated for each affected MS and compared for the earliest and latest year of the epidemic in the country. To evaluate possible risk factors for the occurrence of ASFV in wild boar or domestic pigs, a literature review was performed. Risk factors for the occurrence of ASF in wild boar in Romanian hunting grounds in 2019 were identified with a generalised linear model. The probability to find at least one PCR-confirmed ASF case in wild boar in a hunting ground in Romania was driven by environmental factors, wild boar abundance and the density of backyard pigs in the hunting ground area, while hunting-related variables were not retained in the final model. Finally, measures implemented in white zones (ASF-free zones that are geographically adjacent to an area where ASF is present in wild boar) to prevent further spread of ASF were analysed with a spatially, explicit stochastic individual-based model. To be effective, the wild boar population in the white zone would need to be drastically reduced before ASF arrives at the zone and it must be wide enough. To achieve the necessary pre-emptive culling targets of wild boar in the white zone, at the start of the establishment, the white zone should be placed sufficiently far from the affected area, considering the speed of the natural spread of the disease. This spread is faster in denser wild boar populations. After a focal ASF introduction, the white zone is always close to the infection hence pre-emptive culling measures in the white zone must be completed in short term, i.e. in a few months.
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Comparative Analysis of Full Genome Sequences of African Swine Fever Virus Isolates Taken from Wild Boars in Russia in 2019. Pathogens 2021; 10:pathogens10050521. [PMID: 33925986 PMCID: PMC8146468 DOI: 10.3390/pathogens10050521] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/16/2021] [Accepted: 04/21/2021] [Indexed: 11/17/2022] Open
Abstract
In this study, we report on the full genome phylogenetic analysis of four ASFV isolates obtained from wild boars in Russia. These samples originated from two eastern and two western regions of Russia in 2019. Phylogenetic analysis indicated that the isolates were assigned to genotype II and grouped according to their geographical origins. The two eastern isolates shared 99.99% sequence identity with isolates from China, Poland, Belgium, and Moldova, whereas the western isolates had 99.98% sequence identity with isolates from Lithuania and the original Georgia 2007 isolate. Based on the full genome phylogenies, we identified three single locus targets, MGF-360-10L, MGF-505-9R, and I267L, that yielded the same resolving power as the full genomes. The ease of alignment and a high level of variation make these targets a suitable selection as additional molecular markers in future ASFV phylogenetic practices.
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Lim JS, Vergne T, Pak SI, Kim E. Modelling the Spatial Distribution of ASF-Positive Wild Boar Carcasses in South Korea Using 2019-2020 National Surveillance Data. Animals (Basel) 2021; 11:ani11051208. [PMID: 33922261 PMCID: PMC8145688 DOI: 10.3390/ani11051208] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/19/2021] [Accepted: 04/19/2021] [Indexed: 11/18/2022] Open
Abstract
Simple Summary Since African swine fever (ASF) virus in wild boar populations can spill over to domestic pigs, it is crucial to understand the disease determinants in the wild compartment. However, the imperfect detection sensitivity of wild boar surveillance jeopardizes our ability to understand ASF spatial distribution. In this study, we used national surveillance data of ASF in wild boars collected in the Republic of Korea from 2019–2020 to model the spatial distribution of ASF-positive carcasses for two successive study periods associated with different surveillance intensity. The model allowed us to identify disease risk factors in the Republic of Korea, determine the spatial distribution of the risk of ASF, and estimate the sensitivity of surveillance. The outputs of this study are relevant to policy makers for developing and improving risk-based surveillance programs for ASF in wild boars. Abstract In September 2019, African swine fever (ASF) was reported in South Korea for the first time. Since then, more than 651 ASF cases in wild boars and 14 farm outbreaks have been notified in the country. Despite the efforts to eradicate ASF among wild boar populations, the number of reported ASF-positive wild boar carcasses have increased recently. The purpose of this study was to characterize the spatial distribution of ASF-positive wild boar carcasses to identify the risk factors associated with the presence and number of ASF-positive wild boar carcasses in the affected areas. Because surveillance efforts have substantially increased in early 2020, we divided the study into two periods (2 October 2019 to 19 January 2020, and 19 January to 28 April 2020) based on the number of reported cases and aggregated the number of reported ASF-positive carcasses into a regular grid of hexagons of 3-km diameter. To account for imperfect detection of positive carcasses, we adjusted spatial zero-inflated Poisson regression models to the number of ASF-positive wild boar carcasses per hexagon. During the first study period, proximity to North Korea was identified as the major risk factor for the presence of African swine fever virus. In addition, there were more positive carcasses reported in affected hexagons with high habitat suitability for wild boars, low heat load index (HLI), and high human density. During the second study period, proximity to an ASF-positive carcass reported during the first period was the only significant risk factor for the presence of ASF-positive carcasses. Additionally, low HLI and elevation were associated with an increased number of ASF-positive carcasses reported in the affected hexagons. Although the proportion of ASF-affected hexagons increased from 0.06 (95% credible interval (CrI): 0.05–0.07) to 0.09 (95% CrI: 0.08–0.10), the probability of reporting at least one positive carcass in ASF-affected hexagons increased from 0.49 (95% CrI: 0.41–0.57) to 0.73 (95% CrI: 0.66–0.81) between the two study periods. These results can be used to further advance risk-based surveillance strategies in the Republic of Korea.
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Affiliation(s)
- Jun-Sik Lim
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea; (J.-S.L.); (S.-I.P.)
| | - Timothée Vergne
- UMR ENVT-INRAE 1225, Ecole Nationale Vétérinaire de Toulouse, 31300 Toulouse, France;
| | - Son-Il Pak
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea; (J.-S.L.); (S.-I.P.)
| | - Eutteum Kim
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea; (J.-S.L.); (S.-I.P.)
- Correspondence:
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14
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Wang F, Zhang H, Hou L, Yang C, Wen Y. Advance of African swine fever virus in recent years. Res Vet Sci 2021; 136:535-539. [PMID: 33882382 DOI: 10.1016/j.rvsc.2021.04.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 04/09/2021] [Accepted: 04/12/2021] [Indexed: 12/14/2022]
Abstract
African swine fever (ASF) is one of the most devastating hemorrhagic infectious diseases that affect pigs and wild suids due to the lack of a vaccine or an effective treatment. The large dsDNA genome of African swine fever virus (ASFV) contains up to 167 ORFs that are predicted to encode proteins. Since its introduction to China in 2018, this genome has aroused the enthusiasm of researchers throughout the world. Here, we review the research progress on ASFV in recent years. Given the importance of this disease, this review will highlight recent discoveries in basic virology, focusing mainly on epidemiology, virulence, pathogenic mechanisms, diagnosis, vaccine development, and treatment; this will help in understanding virus-host interactions and disease prevention regarding ASFV.
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Affiliation(s)
- Fengxue Wang
- College of Veterinary Medicine, Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases at the Ministry of Agriculture, Inner Mongolia Agricultural University, Inner Mongolia Autonomous Region, Huhhot 010018, People's Republic of China.
| | - He Zhang
- College of Veterinary Medicine, Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases at the Ministry of Agriculture, Inner Mongolia Agricultural University, Inner Mongolia Autonomous Region, Huhhot 010018, People's Republic of China
| | - Lina Hou
- College of Veterinary Medicine, Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases at the Ministry of Agriculture, Inner Mongolia Agricultural University, Inner Mongolia Autonomous Region, Huhhot 010018, People's Republic of China
| | - Chao Yang
- College of Veterinary Medicine, Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases at the Ministry of Agriculture, Inner Mongolia Agricultural University, Inner Mongolia Autonomous Region, Huhhot 010018, People's Republic of China
| | - Yongjun Wen
- College of Veterinary Medicine, Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases at the Ministry of Agriculture, Inner Mongolia Agricultural University, Inner Mongolia Autonomous Region, Huhhot 010018, People's Republic of China
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15
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Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Depner K, Drewe JA, Garin‐Bastuji B, Gonzales Rojas JL, Gortazar Schmidt C, Herskin M, Michel V, Miranda Chueca MÁ, Pasquali P, Roberts HC, Sihvonen LH, Spoolder H, Stahl K, Velarde A, Winckler C, Abrahantes JC, Dhollander S, Ivanciu C, Papanikolaou A, Van der Stede Y, Blome S, Guberti V, Loi F, More S, Olsevskis E, Thulke HH, Viltrop A. ASF Exit Strategy: Providing cumulative evidence of the absence of African swine fever virus circulation in wild boar populations using standard surveillance measures. EFSA J 2021; 19:e06419. [PMID: 33717352 PMCID: PMC7926520 DOI: 10.2903/j.efsa.2021.6419] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
EFSA assessed the role of seropositive wild boar in African swine fever (ASF) persistence. Surveillance data from Estonia and Latvia investigated with a generalised equation method demonstrated a significantly slower decline in seroprevalence in adult animals compared with subadults. The seroprevalence in adults, taking more than 24 months to approach zero after the last detection of ASFV circulation, would be a poor indicator to demonstrate the absence of virus circulation. A narrative literature review updated the knowledge on the mortality rate, the duration of protective immunity and maternal antibodies and transmission parameters. In addition, parameters potentially leading to prolonged virus circulation (persistence) in wild boar populations were reviewed. A stochastic explicit model was used to evaluate the dynamics of virus prevalence, seroprevalence and the number of carcasses attributed to ASF. Secondly, the impact of four scenarios on the duration of ASF virus (ASFV) persistence was evaluated with the model, namely a: (1) prolonged, lifelong infectious period, (2) reduction in the case-fatality rate and prolonged transient infectiousness; (3) change in duration of protective immunity and (4) change in the duration of protection from maternal antibodies. Only the lifelong infectious period scenario had an important prolonging effect on the persistence of ASF. Finally, the model tested the performance of different proposed surveillance strategies to provide evidence of the absence of virus circulation (Exit Strategy). A two-phase approach (Screening Phase, Confirmation Phase) was suggested for the Exit Strategy. The accuracy of the Exit Strategy increases with increasing numbers of carcasses collected and tested. The inclusion of active surveillance based on hunting has limited impact on the performance of the Exit Strategy compared with lengthening of the monitoring period. This performance improvement should be reasonably balanced against an unnecessary prolonged 'time free' with only a marginal gain in performance. Recommendations are provided for minimum monitoring periods leading to minimal failure rates of the Exit Strategy. The proposed Exit Strategy would fail with the presence of lifelong infectious wild boar. That said, it should be emphasised that the existence of such animals is speculative, based on current knowledge.
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Cappai S, Rolesu S, Feliziani F, Desini P, Guberti V, Loi F. Standardized Methodology for Target Surveillance against African Swine Fever. Vaccines (Basel) 2020; 8:vaccines8040723. [PMID: 33276509 PMCID: PMC7761549 DOI: 10.3390/vaccines8040723] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 11/26/2020] [Accepted: 11/30/2020] [Indexed: 12/15/2022] Open
Abstract
African swine fever (ASF) remains the most serious pig infectious disease, and its persistence in domestic pigs and wild boar (WB) is a threat for the global industry. The surveillance of WB plays a central role in controlling the disease and rapidly detecting new cases. As we are close to eradicating ASF, the need to find any possible pockets of infection is even more important. In this context, passive surveillance is the method of choice for effective surveillance in WB. Considering the time and economic resources related to passive surveillance, to prioritize these activities, we developed a standardized methodology able to identify areas where WB surveillance should be focused on. Using GIS-technology, we divided a specific Sardinian infected area into 1 km2 grids (a total of 3953 grids). Variables related to WB density, ASF cases during the last three years, sex and age of animals, and the type of land were associated with each grid. Epidemiological models were used to identify the areas with both a lack of information and an high risk of hidden ASFV persistence. The results led to the creation of a graphic tool providing specific indications about areas where surveillance should be a priority.
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Affiliation(s)
- Stefano Cappai
- OEVR—Sardinian Regional Veterinary Epidemiological Observatory, Istituto Zooprofilattico Sperimentale della Sardegna “G. Pegreffi”, 09125 Cagliari, Italy; (S.C.); (S.R.)
| | - Sandro Rolesu
- OEVR—Sardinian Regional Veterinary Epidemiological Observatory, Istituto Zooprofilattico Sperimentale della Sardegna “G. Pegreffi”, 09125 Cagliari, Italy; (S.C.); (S.R.)
| | - Francesco Feliziani
- Italian Reference Laboratory for Pestivirus and Asfivirus, Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati”, 06126 Perugia, Italy;
| | - Pietro Desini
- ATS Sardegna, ASSL Sassari, Servizio di Sanità Animale, 07100 Sassari, Italy;
| | - Vittorio Guberti
- ISPRA—Institute for Environmental Protection and Research, 00144 Roma, Italy;
| | - Federica Loi
- OEVR—Sardinian Regional Veterinary Epidemiological Observatory, Istituto Zooprofilattico Sperimentale della Sardegna “G. Pegreffi”, 09125 Cagliari, Italy; (S.C.); (S.R.)
- Correspondence: ; Tel.: +39-327-6925-232
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Schulz K, Boklund A. The Epidemiology of African Swine Fever, Its Complexity and the Requirement for Multiple Solution Approaches. Animals (Basel) 2020; 10:ani10101900. [PMID: 33081270 PMCID: PMC7603031 DOI: 10.3390/ani10101900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 11/16/2022] Open
Affiliation(s)
- Katja Schulz
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Insel Riems, Germany
- Correspondence:
| | - Anette Boklund
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark;
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Pautienius A, Schulz K, Staubach C, Grigas J, Zagrabskaite R, Buitkuviene J, Stankevicius R, Streimikyte Z, Oberauskas V, Zienius D, Salomskas A, Sauter-Louis C, Stankevicius A. African swine fever in the Lithuanian wild boar population in 2018: a snapshot. Virol J 2020; 17:148. [PMID: 33028388 PMCID: PMC7542886 DOI: 10.1186/s12985-020-01422-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/28/2020] [Indexed: 01/19/2023] Open
Abstract
The first cases of African swine fever (ASF) were detected in the Lithuanian wild boar population in 2014. Since then, the disease spread slowly through the whole country, affecting both, wild boar and domestic pigs. In the other Baltic states, which both are also affected by ASF since 2014, the recent course of ASF prevalence suggests that the countries might be well under way of disease elimination. In contrast, in Lithuania the epidemic seems to be still in full progress. In the present study, we aimed to extend a previous prevalence study in Lithuania. Looking at ASF virus (ASFV) and seroprevalence estimates of wild boar in all months of 2018 and in all affected municipalities in Lithuania, the course of ASF was evaluated on a temporal and spatial scale. A non-spatial beta-binomial model was used to correct for under- or overestimation of the average prevalence estimates. Within 2018 no big differences between the prevalence estimates were seen over time. Despite of the lower sample size, highest ASFV prevalence estimates were found in dead wild boar, suggesting higher detection rates through passive surveillance than through active surveillance. Accordingly, with the maximum prevalence of 87.5% in May 2018, the ASFV prevalence estimates were very high in wild boar found dead. The number of samples originating from hunted animals (active surveillance) predominated clearly. However, the ASFV prevalence in those animals was lower with a maximum value of 2.1%, emphasizing the high value of passive surveillance. A slight increase of the seroprevalence in hunted wild boar could be seen over time. In the center of Lithuania, a cluster of municipalities with high ASFV and seroprevalence estimates was found. The results of the study indicate that ASFV is still circulating within the Lithuanian wild boar population, constituting a permanent risk of disease transmission into domestic pig holdings. However, additional, more recent data analyses are necessary to re-evaluate the course of ASF in Lithuania and thus, to be able to make a statement about the stage of the ASF epidemic in the country. This is of huge importance for Lithuania for evaluating control measures and their efficacy, but also for neighbouring countries to assess the risk of disease spread from Lithuania.
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Affiliation(s)
- Arnoldas Pautienius
- Immunology Laboratory, Department of Anatomy and Physiology, Faculty of Veterinary Medicine, Lithuanian University of Health Sciences, Tilzes Str. 18, Kaunas, Lithuania
- Faculty of Veterinary Medicine, Institute of Microbiology and Virology, Lithuanian University of Health Sciences, Tilzes Str. 18, Kaunas, Lithuania
| | - Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
| | - Christoph Staubach
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Juozas Grigas
- Immunology Laboratory, Department of Anatomy and Physiology, Faculty of Veterinary Medicine, Lithuanian University of Health Sciences, Tilzes Str. 18, Kaunas, Lithuania
- Faculty of Veterinary Medicine, Institute of Microbiology and Virology, Lithuanian University of Health Sciences, Tilzes Str. 18, Kaunas, Lithuania
| | - Ruta Zagrabskaite
- National Food and Veterinary Risk Assessment Institute, J. Kairiukscio Str. 10, Vilnius, Lithuania
| | - Jurate Buitkuviene
- National Food and Veterinary Risk Assessment Institute, J. Kairiukscio Str. 10, Vilnius, Lithuania
| | - Rolandas Stankevicius
- Department of Animal Breeding and Nutrition, Faculty of Animal Husbandry Technology, Lithuanian University of Health Sciences, Tilzes Str. 18, Kaunas, Lithuania
| | - Zaneta Streimikyte
- Faculty of Veterinary Medicine, Institute of Microbiology and Virology, Lithuanian University of Health Sciences, Tilzes Str. 18, Kaunas, Lithuania
| | - Vaidas Oberauskas
- Immunology Laboratory, Department of Anatomy and Physiology, Faculty of Veterinary Medicine, Lithuanian University of Health Sciences, Tilzes Str. 18, Kaunas, Lithuania
| | - Dainius Zienius
- Faculty of Veterinary Medicine, Institute of Microbiology and Virology, Lithuanian University of Health Sciences, Tilzes Str. 18, Kaunas, Lithuania
| | - Algirdas Salomskas
- Department of Pathobiology, Faculty of Veterinary Medicine, Lithuanian University of Health Sciences, Tilzes Str. 18, Kaunas, Lithuania
| | - Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Arunas Stankevicius
- Immunology Laboratory, Department of Anatomy and Physiology, Faculty of Veterinary Medicine, Lithuanian University of Health Sciences, Tilzes Str. 18, Kaunas, Lithuania
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Mathematical Approach to Estimating the Main Epidemiological Parameters of African Swine Fever in Wild Boar. Vaccines (Basel) 2020; 8:vaccines8030521. [PMID: 32932614 PMCID: PMC7563513 DOI: 10.3390/vaccines8030521] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/09/2020] [Accepted: 09/10/2020] [Indexed: 12/15/2022] Open
Abstract
African swine fever (ASF) severely threatens the swine industry worldwide, given its spread and the absence of an available licensed vaccine, and has caused severe economic losses. Its persistence in wild boar (WB), longer than in domestic pig farms, and the knowledge gaps in ASF epidemiology hinder ASF virus (ASFV) eradication. Even in areas where disease is effectively controlled and ASFV is no longer detected, declaring eradication is difficult as seropositive WBs may still be detected. The aim of this work was to estimate the main ASF epidemiological parameters specific for the north of Sardinia, Italy. The estimated basic (R0) and effective (Re) reproduction numbers demonstrate that the ASF epidemic is declining and under control with an R0 of 1.139 (95% confidence interval (CI) = 1.123-1.153) and Re of 0.802 (95% CI = 0.612-0.992). In the last phases of an epidemic, these estimates are crucial tools for identifying the intensity of interventions required to definitively eradicate the disease. This approach is useful to understand if and when the detection of residual seropositive WB is no longer associated with any further ASFV circulation.
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Schulz K, Conraths FJ, Staubach C, Viltrop A, Oļševskis E, Nurmoja I, Lamberga K, Sauter-Louis C. To sample or not to sample? Detection of African swine fever in wild boar killed in road traffic accidents. Transbound Emerg Dis 2020; 67:1816-1819. [PMID: 32249548 DOI: 10.1111/tbed.13560] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 02/25/2020] [Accepted: 03/25/2020] [Indexed: 11/28/2022]
Abstract
African swine fever (ASF) in wild boar remains a threat for the global pig industry. Therefore, surveillance is of utmost importance, not only to control the disease but also to detect new introductions as early as possible. Passive surveillance is regarded as the method of choice for an effective detection of ASF in wild boar populations. However, the relevance of wild boar killed through road traffic accidents (RTA) for passive surveillance seems to be unclear. Using comprehensive ASF wild boar surveillance data from Estonia and Latvia, the prevalence of ASF-infected wild boar was calculated and the probability of infection as measured by PCR compared for animals that were hunted, found dead, shot sick or killed in a RTA. The number of samples originating from wild boar killed in a RTA was low and so was the ASF prevalence in these animals. However, the reasons for this low number of RTA animals remain unknown. Therefore, we recommend to sample wild boar killed in a RTA to a greater extent, also to explore, if this approach can increase the detection probability, and to avoid missing disease introduction.
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Affiliation(s)
- Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany
| | - Franz Josef Conraths
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany
| | - Christoph Staubach
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany
| | - Arvo Viltrop
- Estonian University of Life Science, Institute of Veterinary Medicine and Animal Sciences, Tartu, Estonia
| | - Edvīns Oļševskis
- Food and Veterinary Service, Riga, Lativa
- Institute of Food Safety, Animal Health and Environment - "BIOR", Riga, Lativa
| | - Imbi Nurmoja
- Estonian University of Life Science, Institute of Veterinary Medicine and Animal Sciences, Tartu, Estonia
- Estonian Veterinary and Food Laboratory (VFL), Tartu, Estonia
| | - Kristīne Lamberga
- Food and Veterinary Service, Riga, Lativa
- Latvian University of Life Sciences and Technologies, Jelgava, Lativa
| | - Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany
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21
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Urner N, Mõtus K, Nurmoja I, Schulz J, Sauter-Louis C, Staubach C, Conraths FJ, Schulz K. Hunters' Acceptance of Measures against African Swine Fever in Wild Boar in Estonia. Prev Vet Med 2020; 182:105121. [PMID: 32818692 DOI: 10.1016/j.prevetmed.2020.105121] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 07/08/2020] [Accepted: 08/10/2020] [Indexed: 11/26/2022]
Abstract
African swine fever (ASF) was first identified in Estonia in 2014, initially detected in wild boar and spreading to affect almost the whole country from late 2016 onwards. Passive surveillance and the control measures applied in Estonia are the main actions in the attempt to control the wild boar population and therefore limit the spread of ASF. Implementation and success of both activities depend mainly on the involvement and commitment of the executing force: the Estonian hunters. Thus, their acceptance of the measures is of utmost importance and with the help of participatory methods, their acceptability can be assessed. Participatory epidemiology allows the involvement of key stakeholders in planning control measures and surveillance strategies and gathering information otherwise inaccessible. By conducting focus group discussions and utilizing participatory tools, this study aimed to assess the acceptance of ASF control measures by hunters in Estonia. Furthermore, the study aimed to detect means to improve the motivation of hunters to support passive surveillance. Among hunters, the results ranked the trust in lower authorities (e.g. local official veterinarians) towards implementing control measures as high (in contrast to higher officials e.g. 'Ministry of Rural Affairs'), while perceiving themselves as the most trustworthy group among those implementing ASF control measures. Hunting and every measure supporting increased hunting, for example selective hunting, bait feeding and incentives for hunting wild boar, were deemed favourable for hunters. These measures also received the highest trust for controlling ASF. All measures hindering hunting and the movement of wildlife, for example fencing or involvement of the army in ASF control, were described as unpleasant or even unethical and trust in these measures to control the disease successfully was lacking. When assessing the perceived consequences for hunters of finding a dead wild boar, arising financial costs, additional workload and time consumption were highlighted. In line with these results, the two tools with the strongest motivational effect for taking part in passive surveillance were: (1) higher monetary incentives as compensation for the hunters' work, and (2) the reduction of the negative consequences by limiting the hunters' duties to solely reporting found dead wild boar. In conclusion, participatory methods can be used as a highly suitable tool for the evaluation of acceptance of measures and surveillance systems. Potentially, the results can help to improve control and passive surveillance in Estonia, as well as functioning as an example for other countries battling or awaiting ASF.
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Affiliation(s)
- Nico Urner
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
| | - Kerli Mõtus
- Estonian University of Life Science, Institute of Veterinary Medicine and Animal Sciences, Kreutzwaldi 62, 51014, Tartu, Estonia.
| | - Imbi Nurmoja
- Estonian University of Life Science, Institute of Veterinary Medicine and Animal Sciences, Kreutzwaldi 62, 51014, Tartu, Estonia; Estonian Veterinary and Food Laboratory (VFL), Kreutzwaldi 30, 51006, Tartu, Estonia.
| | - Jana Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Novel and Emerging Infectious Diseases, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
| | - Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
| | - Christoph Staubach
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
| | - Franz J Conraths
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
| | - Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
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22
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Molecular Characterization of African Swine Fever Virus Isolates in Estonia in 2014-2019. Pathogens 2020; 9:pathogens9070582. [PMID: 32709020 PMCID: PMC7400522 DOI: 10.3390/pathogens9070582] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/28/2022] Open
Abstract
After the extensive spread of the African swine fever virus (ASFV) genotype II in Eastern Europe, the first case of African swine fever (ASF) in Estonia was diagnosed in September 2014. By the end of 2019, 3971 ASFV-positive wild boars were found, and 27 domestic pig outbreaks were reported. A selection of ASFV isolates from wild boar and domestic pigs (during the period of September 2014–2019) was molecularly characterized using standardized genotyping procedures. One of the proven markers to characterize this virus is the central variable region (CVR) within the B602L gene. In summer 2015, a new ASFV genotype II CVR variant 2 (GII-CVR2) was confirmed in Estonia. The results suggest that the GII-CVR2 variant was only confirmed in wild boar from a limited area in southern Estonia in 2015 and 2016. In addition to GII-CVR2, a single nucleotide polymorphism (SNP) that resulted in amino acid change was identified within the genotype II CVR variant 1 (GII-CVR1). The GII-CVR1/SNP1 strain was isolated in Estonia in November 2016. Additional GII-CVR1/SNP1 cases were confirmed in two neighbouring counties, as well as in one outbreak farm in June 2017. Based on the available data, no GII-CVR2 and GII-CVR1/SNP1 have been reported by other affected European countries. The spread of variant strains in Estonia has been limited over time, and restricted to a relatively small area.
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23
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Schulz K, Staubach C, Blome S, Nurmoja I, Viltrop A, Conraths FJ, Kristian M, Sauter-Louis C. How to Demonstrate Freedom from African Swine Fever in Wild Boar-Estonia as an Example. Vaccines (Basel) 2020; 8:E336. [PMID: 32630595 PMCID: PMC7350251 DOI: 10.3390/vaccines8020336] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 11/24/2022] Open
Abstract
Estonia has been combatting African swine fever (ASF) for six years now. Since October 2017, the disease has only been detected in the wild boar population, but trade restrictions had to remain in place due to international regulations. Yet, the epidemiological course of the disease has changed within the last few years. The prevalence of ASF virus (ASFV)-positive wild boar decreased steadily towards 0%. In February 2019, the last ASFV-positive wild boar was detected. Since then, positive wild boar samples have exclusively been positive for ASFV-specific antibodies, suggesting the possible absence of circulating ASFV in the Estonian wild boar population. However, as the role of seropositive animals is controversially discussed and the presence of antibody-carriers is regarded as an indication of virus circulation at EU and OIE level, Estonia remains under trade restrictions. To make the disease status of a country reliable for trading partners and to facilitate the process of declaration of disease freedom, we suggest to monitor the prevalence of seropositive wild boar in absence of ASFV-positive animals. The possibility to include ASF in the list of diseases, for which an official pathway for recognition of disease status is defined by the OIE should be evaluated.
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Affiliation(s)
- Katja Schulz
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Christoph Staubach
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Sandra Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Insel Riems, Germany;
| | - Imbi Nurmoja
- Estonian Veterinary and Food Laboratory (VFL), Kreutzwaldi 30, 51006 Tartu, Estonia;
- Estonian University of Life Science, Institute of Veterinary Medicine and Animal Sciences, Kreutzwaldi 62, 51014 Tartu, Estonia;
| | - Arvo Viltrop
- Estonian University of Life Science, Institute of Veterinary Medicine and Animal Sciences, Kreutzwaldi 62, 51014 Tartu, Estonia;
| | - Franz J. Conraths
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Maarja Kristian
- Veterinary and Food Board, Väike-Paala 3, 11415 Tallinn, Estonia;
| | - Carola Sauter-Louis
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
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24
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Oļševskis E, Schulz K, Staubach C, Seržants M, Lamberga K, Pūle D, Ozoliņš J, Conraths FJ, Sauter-Louis C. African swine fever in Latvian wild boar-A step closer to elimination. Transbound Emerg Dis 2020; 67:2615-2629. [PMID: 32372476 DOI: 10.1111/tbed.13611] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 11/29/2022]
Abstract
In 2014, African swine fever (ASF) emerged in Latvia for the first time. The majority of cases appeared in wild boar, but the presence of ASF in these animals constitutes a permanent threat to domestic pig holdings. Recent studies have shown an increase in serologically positive and a decrease in PCR-positive ASF cases in wild boar, possibly indicating a decline of ASF incidence. We aimed to investigate the course of the ASF epidemic in wild boar in Latvia, thus attaining further insights into the ASF epidemiology in this country with the goal of assessing the stage of the epidemic. Latvian ASF surveillance data of wild boar were utilized to estimate the seroprevalence and ASF virus (ASFV) prevalence in the wild boar population. Prevalence estimates were obtained for both the eastern and western part of the country and in addition for the 2014/2015 to 2018/2019 hunting seasons. Moreover, prevalence estimates for three different age classes were calculated. An increase in serologically positive yet PCR-negative wild boar samples from active surveillance was identified over time. When comparing the age groups, wild boar younger than one year displayed the ASFV prevalence to be higher than the seroprevalence, whereas older animals shared higher seroprevalence estimates. These findings support the assumption that only a small proportion of affected animals survive an infection, leading to an accumulation of their numbers over time. As a result, ASF elimination in a country with an infected wild boar population could possibly be achieved, if effective wild boar population management and surveillance is maintained and combined with the detection and removal of wild boar carcasses to reduce the viral load in the environment. In addition, the wild boar population should be kept as small as possible to break the ASFV infection cycle.
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Affiliation(s)
- Edvīns Oļševskis
- Food and Veterinary Service, Riga, Latvia.,Institute of Food Safety, Animal Health and Environment-'BIOR', Riga, Latvia
| | - Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany
| | - Christoph Staubach
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany
| | | | - Kristīne Lamberga
- Food and Veterinary Service, Riga, Latvia.,Latvia University of Life Sciences and Technologies, Jelgava, Latvia
| | - Daina Pūle
- Institute of Food Safety, Animal Health and Environment-'BIOR', Riga, Latvia
| | - Jānis Ozoliņš
- Latvian State Forest Research Institute 'Silava', Salaspils, Latvia
| | - Franz Josef Conraths
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany
| | - Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany
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25
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Martínez-Avilés M, Iglesias I, De La Torre A. Evolution of the ASF Infection Stage in Wild Boar Within the EU (2014-2018). Front Vet Sci 2020; 7:155. [PMID: 32296720 PMCID: PMC7141172 DOI: 10.3389/fvets.2020.00155] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 03/03/2020] [Indexed: 11/18/2022] Open
Abstract
African swine fever (ASF) is one of the most important emerging transboundary diseases of pigs, causing trade restrictions, and a health impact on susceptible pigs. Nine countries in the continental European Union (Estonia, Lithuania, Latvia, Poland, Czech Republic, Bulgaria, Belgium, Romania, and Hungary) have been affected by ASF from 2014 to 2018 and it keeps spreading despite the efforts to control it. For a number of years, we have witnessed high case-fatality rates in wild boar found dead particularly in new infected areas, which is typical of the peracute and acute forms of the infection at the beginning of an ASF epidemic. Experimental evidence with currently circulating strains indicates that some infected animals can remain asymptomatic and might even survive the infection. An increased presence of virus of moderate virulence can complicate ASF diagnosis as well as the mitigation and control of the disease. We analyze the ASF surveillance data in wild boar in the four EU countries where ASF has been present for longer, comparing the spatial density of antibody positive notifications with the time ASF has been present per region. Results indicate an increasing annual distribution of notifications based on antibodies over nucleic acid detection in hunted wild boar in Estonia, Latvia and Poland. Potentially, Lithuania, and Poland seem to have experienced more acute forms in 2017 and 2018 than Latvia and Estonia. Overall there was a positive statistical correlation between time with infection (TWI) and antibody positive density, with some variations in certain regions, particularly of Lithuania and Estonia. The increasing trend in potential survivors (hunted wild boar with confirmed PCR negative and antibody positive results) enhances the importance of surveillance design to sample and test shot wild boar. In conclusion, surveillance data based on ASFV detection by PCR and serology can be used to assess the status of the epidemic in wild boar.
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Affiliation(s)
| | - Irene Iglesias
- Centro de Investigación en Sanidad Animal (CISA), INIA, Valdeolmos, Spain
| | - Ana De La Torre
- Centro de Investigación en Sanidad Animal (CISA), INIA, Valdeolmos, Spain
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26
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Walczak M, Żmudzki J, Mazur-Panasiuk N, Juszkiewicz M, Woźniakowski G. Analysis of the Clinical Course of Experimental Infection with Highly Pathogenic African Swine Fever Strain, Isolated from an Outbreak in Poland. Aspects Related to the Disease Suspicion at the Farm Level. Pathogens 2020; 9:pathogens9030237. [PMID: 32235758 PMCID: PMC7157746 DOI: 10.3390/pathogens9030237] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 03/20/2020] [Accepted: 03/20/2020] [Indexed: 11/21/2022] Open
Abstract
This paper was aimed to characterize clinical signs and pathomorphological lesions in twenty-two pigs, infected intranasally by different doses of African swine fever virus (Pol18_28298_O111), isolated during the outbreak in a pig farm that occurred in Eastern Poland throughout 2018. This article also attempts to indicate risk, related to virus load and shedding, and present possible difficulties with proper disease recognition at the farm level. The results revealed that even a very low dose (5 HAU) may initiate the infection. Various forms of the disease (acute, subacute, and chronic), mainly with prodromal clinical signs like fever, apathy, and reduced feed intake were observed. The most frequently observed lesions (82%) were: hyperemia and enlargement of lymph nodes and splenomegaly. The minimal incubation period was estimated at five days post-infection (dpi). Mortality ranged from 80–100%. Two pigs survived the infection. Some viremic animals presented delayed fever. In some cases, the fever was not detectable. Shortly after viremia, the virus was secreted ion the urine, feces, and saliva. The highest levels of virus were found in the internal organs and blood; however in the case of one pig (chronic form), viral DNA was not detected in the spleen, liver, bone marrow, and brain. Veterinary diagnosis may be difficult, and the final results should always be based on laboratory investigations.
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27
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Mačiulskis P, Masiulis M, Pridotkas G, Buitkuvienė J, Jurgelevičius V, Jacevičienė I, Zagrabskaitė R, Zani L, Pilevičienė S. The African Swine Fever Epidemic in Wild Boar ( Sus scrofa) in Lithuania (2014-2018). Vet Sci 2020; 7:E15. [PMID: 32019088 PMCID: PMC7157679 DOI: 10.3390/vetsci7010015] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 01/21/2020] [Accepted: 01/24/2020] [Indexed: 11/16/2022] Open
Abstract
In January 2014 the first case of African swine fever (ASF) in wild boar of the Baltic States was reported from Lithuania. It has been the first occurrence of the disease in Eastern EU member states. Since then, the disease spread further affecting not only the Baltic States and Poland but also south-eastern Europe, the Czech Republic and Belgium. The spreading pattern of ASF with its long-distance spread of several hundreds of kilometers on the one hand and the endemic situation in wild boar on the other is far from being understood. By analyzing data of ASF cases in wild boar along with implemented control measures in Lithuania from 2014-2018 this study aims to contribute to a better understanding of the disease. In brief, despite huge efforts to eradicate ASF, the disease is now endemic in the Lithuanian wild boar population. About 86% of Lithuanian's territory is affected and over 3225 ASF cases in wild boar have been notified since 2014. The ASF epidemic led to a considerable decline in wild boar hunting bags. Intensified hunting might have reduced the wild boar population but this effect cannot be differentiated from the population decline caused by the disease itself. However, for ASF detection sampling of wild boar found dead supported by financial incentives turned out to be one of the most effective tools.
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Affiliation(s)
- Petras Mačiulskis
- Department of Veterinary Pathobiology, Lithuanian University of Health Sciences, LT-44307 Kaunas, Lithuania
- Management Department, National Food and Veterinary Risk Assessment Institute, 10 LT-08409 Vilnius, Lithuania;
| | - Marius Masiulis
- Department of Veterinary Pathobiology, Lithuanian University of Health Sciences, LT-44307 Kaunas, Lithuania
- Emergency Response Division, State Food and Veterinary Service, LT-07170 Vilnius, Lithuania
| | - Gediminas Pridotkas
- Management Department, National Food and Veterinary Risk Assessment Institute, 10 LT-08409 Vilnius, Lithuania;
| | - Jūratė Buitkuvienė
- Serology Department, National Food and Veterinary Risk Assessment Institute, 10 LT-08409 Vilnius, Lithuania; (J.B.); (R.Z.)
| | - Vaclovas Jurgelevičius
- Molecular Biology and GMO Department, National Food and Veterinary Risk Assessment Institute, 10 LT-08409 Vilnius, Lithuania; (V.J.); (S.P.)
- Biology Department, Vytautas Magnus University, LT-44248 Kaunas, Lithuania
| | - Ingrida Jacevičienė
- Virology Department, National Food and Veterinary Risk Assessment Institute, 10 LT-08409 Vilnius, Lithuania;
| | - Rūta Zagrabskaitė
- Serology Department, National Food and Veterinary Risk Assessment Institute, 10 LT-08409 Vilnius, Lithuania; (J.B.); (R.Z.)
| | - Laura Zani
- International Animal Health Team, Friedrich-Loeffler-Institut, 17493 Greifswald–Insel Riems, Germany;
| | - Simona Pilevičienė
- Molecular Biology and GMO Department, National Food and Veterinary Risk Assessment Institute, 10 LT-08409 Vilnius, Lithuania; (V.J.); (S.P.)
- Biology Department, Vytautas Magnus University, LT-44248 Kaunas, Lithuania
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28
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Anette B, Anette B, Theodora CV, Klaus D, Daniel D, Vittorio G, Georgina H, Daniela K, Annick L, Aleksandra M, Simon M, Edvins O, Sasa O, Helen R, Mihaela S, Karl S, Hans‐Hermann T, Grigaliuniene V, Arvo V, Richard W, Grzegorz W, José AC, Sofie D, Andrey G, Corina I, Alexandra P, González VLC, Christian GS. Epidemiological analyses of African swine fever in the European Union (November 2018 to October 2019). EFSA J 2020. [DOI: 10.2903/j.efsa.2020.5996] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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29
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Schulz K, Conraths FJ, Blome S, Staubach C, Sauter-Louis C. African Swine Fever: Fast and Furious or Slow and Steady? Viruses 2019; 11:E866. [PMID: 31533266 PMCID: PMC6783890 DOI: 10.3390/v11090866] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/13/2019] [Accepted: 09/14/2019] [Indexed: 11/16/2022] Open
Abstract
Since the introduction of African swine fever (ASF) into Georgia in 2007, the disease has been spreading in an unprecedented way. Many countries that are still free from the disease fear the emergence of ASF in their territory either in domestic pigs or in wild boar. In the past, ASF was often described as being a highly contagious disease with mortality often up to 100%. However, the belief that the disease might enter a naïve population and rapidly affect the entire susceptible population needs to be critically reviewed. The current ASF epidemic in wild boar, but also the course of ASF within outbreaks in domestic pig holdings, suggest a constant, but relatively slow spread. Moreover, the results of several experimental and field studies support the impression that the spread of ASF is not always fast. ASF spread and its speed depend on various factors concerning the host, the virus, and also the environment. Many of these factors and their effects are not fully understood. For this review, we collated published information regarding the spreading speed of ASF and the factors that are deemed to influence the speed of ASF spread and tried to clarify some issues and open questions in this respect.
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Affiliation(s)
- Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
| | - Franz Josef Conraths
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
| | - Sandra Blome
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
| | - Christoph Staubach
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
| | - Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
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