African Swine Fever Re-Emerging in Estonia: The Role of Seropositive Wild Boar from an Epidemiological Perspective
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...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-10-01
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| Series: | Viruses |
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| Online Access: | https://www.mdpi.com/1999-4915/13/11/2121 |
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| author | Katja Schulz Jana Schulz Christoph Staubach Sandra Blome Imbi Nurmoja Franz J. Conraths Carola Sauter-Louis Arvo Viltrop |
| author_facet | Katja Schulz Jana Schulz Christoph Staubach Sandra Blome Imbi Nurmoja Franz J. Conraths Carola Sauter-Louis Arvo Viltrop |
| author_sort | Katja Schulz |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-03-10T04:59:05Z |
| format | Article |
| id | doaj.art-548dc080e2e74eb5ad614a7876df4f50 |
| institution | Directory Open Access Journal |
| issn | 1999-4915 |
| language | English |
| last_indexed | 2024-03-10T04:59:05Z |
| publishDate | 2021-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Viruses |
| spelling | doaj.art-548dc080e2e74eb5ad614a7876df4f502023-11-23T01:55:10ZengMDPI AGViruses1999-49152021-10-011311212110.3390/v13112121African Swine Fever Re-Emerging in Estonia: The Role of Seropositive Wild Boar from an Epidemiological PerspectiveKatja Schulz0Jana Schulz1Christoph Staubach2Sandra Blome3Imbi Nurmoja4Franz J. Conraths5Carola Sauter-Louis6Arvo Viltrop7Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17498 Greifswald-Insel Riems, GermanyInstitute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17498 Greifswald-Insel Riems, GermanyInstitute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17498 Greifswald-Insel Riems, GermanyInstitute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17498 Greifswald-Insel Riems, GermanyEstonian Veterinary and Food Laboratory (VFL), Kreutzwaldi 30, 51006 Tartu, EstoniaInstitute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17498 Greifswald-Insel Riems, GermanyInstitute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17498 Greifswald-Insel Riems, GermanyInstitute of Veterinary Medicine and Animal Sciences, Estonian University of Life Science, Kreutzwaldi 62, 51014 Tartu, EstoniaAfrican 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.https://www.mdpi.com/1999-4915/13/11/2121African swine feverEstoniaASFV-carrierconfidence in freedomdetection probabilitysensitivity of surveillance |
| spellingShingle | Katja Schulz Jana Schulz Christoph Staubach Sandra Blome Imbi Nurmoja Franz J. Conraths Carola Sauter-Louis Arvo Viltrop African Swine Fever Re-Emerging in Estonia: The Role of Seropositive Wild Boar from an Epidemiological Perspective Viruses African swine fever Estonia ASFV-carrier confidence in freedom detection probability sensitivity of surveillance |
| title | African Swine Fever Re-Emerging in Estonia: The Role of Seropositive Wild Boar from an Epidemiological Perspective |
| title_full | African Swine Fever Re-Emerging in Estonia: The Role of Seropositive Wild Boar from an Epidemiological Perspective |
| title_fullStr | African Swine Fever Re-Emerging in Estonia: The Role of Seropositive Wild Boar from an Epidemiological Perspective |
| title_full_unstemmed | African Swine Fever Re-Emerging in Estonia: The Role of Seropositive Wild Boar from an Epidemiological Perspective |
| title_short | African Swine Fever Re-Emerging in Estonia: The Role of Seropositive Wild Boar from an Epidemiological Perspective |
| title_sort | african swine fever re emerging in estonia the role of seropositive wild boar from an epidemiological perspective |
| topic | African swine fever Estonia ASFV-carrier confidence in freedom detection probability sensitivity of surveillance |
| url | https://www.mdpi.com/1999-4915/13/11/2121 |
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