Research

16 pages, 2022 KiB

Open AccessArticle

Oral Fluids for the Early Detection of Classical Swine Fever in Commercial Level Pig Pens

by Erin Robert, Kalhari Goonewardene, Ian El Kanoa, Orie Hochman, Charles Nfon and Aruna Ambagala

Viruses 2024, 16(3), 318; https://doi.org/10.3390/v16030318 - 20 Feb 2024

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Abstract

The early detection of classical swine fever (CSF) remains a key challenge, especially when outbreaks are caused by moderate and low-virulent CSF virus (CSFV) strains. Oral fluid is a reliable and cost-effective sample type that is regularly surveilled for endemic diseases in commercial [...] Read more.

The early detection of classical swine fever (CSF) remains a key challenge, especially when outbreaks are caused by moderate and low-virulent CSF virus (CSFV) strains. Oral fluid is a reliable and cost-effective sample type that is regularly surveilled for endemic diseases in commercial pig herds in North America. Here, we explored the possibility of utilizing oral fluids for the early detection of CSFV incursions in commercial-size pig pens using two independent experiments. In the first experiment, a seeder pig infected with the moderately-virulent CSFV Pinillos strain was used, and in the second experiment, a seeder pig infected with the highly-virulent CSFV Koslov strain was used. Pen-based oral fluid samples were collected daily and individual samples (whole blood, swabs) every other day. All samples were tested by a CSFV-specific real-time RT-PCR assay. CSFV genomic material was detected in oral fluids on the seventh and fourth day post-introduction of the seeder pig into the pen, in the first and second experiments, respectively. In both experiments, oral fluids tested positive before the contact pigs developed viremia, and with no apparent sick pigs in the pen. These results indicate that pen-based oral fluids are a reliable and convenient sample type for the early detection of CSF, and therefore, can be used to supplement the ongoing CSF surveillance activities in North America. Full article

(This article belongs to the Special Issue Endemic and Emerging Swine Viruses 2023)

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18 pages, 7342 KiB

Open AccessArticle

Passive Surveillance as a Key Tool for African Swine Fever Eradication in Wild Boar: A Protocol to Find Carcasses Tested and Validated in the Mediterranean Island of Sardinia

by Elisabetta Coradduzza, Federica Loi, Francesca Porcu, Daniela Mandas, Fabio Secci, Marco Efisio Pisanu, Cinzia Pasini, Carlo Zuddas, Marcella Cherchi, Daniele Denurra, Ennio Bandino, Antonio Pintore, Vittorio Guberti and Stefano Cappai

Viruses 2024, 16(1), 136; https://doi.org/10.3390/v16010136 - 18 Jan 2024

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Abstract

African swine fever (ASF) is one of the most important and serious contagious hemorrhagic viral diseases affecting domestic pigs and wild boar and is associated with high mortality rates while also having an extensive sanitary and socioeconomic impact on the international trade of [...] Read more.

African swine fever (ASF) is one of the most important and serious contagious hemorrhagic viral diseases affecting domestic pigs and wild boar and is associated with high mortality rates while also having an extensive sanitary and socioeconomic impact on the international trade of animal and swine products. The early detection of the disease is often hampered by inadequate surveillance. Among the surveillance strategies used, passive surveillance of wild boars is considered the most effective method for controlling the African swine fever virus (ASFV). Otherwise, the design of a sufficiently sensitive ASF surveillance system requires a solid understanding of the epidemiology related to the local eco-social context, especially in the absence of virus detection. Even if the number of carcasses needed to demonstrate ASF eradication has been established, the scientific context lacks detail compared to protocols applied in the active search for wild boar carcasses. The aim of this study was to describe the protocol applied in the active search for carcasses, providing detailed information on the number of people and dogs as well as the amount of time and space used within the Mediterranean area. Using a specific tool developed to record, trace, and share field data (the GAIA observer app), a total of 33 active searches for wild boar carcasses were organized during 2021–2023. Most of these searches were planned to find carcasses that had previously been reported by hunters. A total of 24 carcasses were found, with only 2 carcasses not previously reported. The final protocol applied involved four people, with an average speed of 1.5 km/h. When a carcass had been previously reported, about 2 km of distance had to be covered in about 1.5 h to find the carcass, and even less time was spent when a dog (untrained) was present. In conclusion, it can be stated that, when searching for carcasses, solid collaboration with local hunters or other forest visitors is necessary to ensure carcasses are reported. The process involves small groups of experts actively searching for carcasses, possibly with the use of hunting dogs without special training. The data presented could be of valid support for those countries characterized by Mediterranean vegetation that are faced with the need to plan active carcass searches. Full article

(This article belongs to the Special Issue Endemic and Emerging Swine Viruses 2023)

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17 pages, 1476 KiB

Open AccessArticle

Glycoprotein 5-Derived Peptides Induce a Protective T-Cell Response in Swine against the Porcine Reproductive and Respiratory Syndrome Virus

by Fernando Calderon-Rico, Alejandro Bravo-Patiño, Irasema Mendieta, Francisco Perez-Duran, Alicia Gabriela Zamora-Aviles, Luis Enrique Franco-Correa, Roberto Ortega-Flores, Ilane Hernandez-Morales and Rosa Elvira Nuñez-Anita

Viruses 2024, 16(1), 14; https://doi.org/10.3390/v16010014 - 21 Dec 2023

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Abstract

We analyzed the T-cell responses induced by lineal epitopes of glycoprotein 5 (GP5) from PRRSV to explore the role of this protein in the immunological protection mediated by T-cells. The GP5 peptides were conjugated with a carrier protein for primary immunization and booster [...] Read more.

We analyzed the T-cell responses induced by lineal epitopes of glycoprotein 5 (GP5) from PRRSV to explore the role of this protein in the immunological protection mediated by T-cells. The GP5 peptides were conjugated with a carrier protein for primary immunization and booster doses. Twenty-one-day-old pigs were allocated into four groups (seven pigs per group): control (PBS), vehicle (carrier), PTC1, and PTC2. Cytokine levels were measured at 2 days post-immunization (DPI) from serum samples. Cytotoxic T-lymphocytes (CTLs, CD8+) from peripheral blood were quantified via flow cytometry at 42 DPI. The cytotoxicity was evaluated by co-culturing primed lymphocytes with PRRSV derived from an infectious clone. The PTC2 peptide increased the serum concentrations of pro-inflammatory cytokines (i.e., TNF-α, IL-1β, IL-8) and cytokines that activate the adaptive cellular immunity associated with T-lymphocytes (i.e., IL-4, IL-6, IL-10, and IL-12). The concentration of CTLs (CD8+) was significantly higher in groups immunized with the peptides, which suggests a proliferative response in this cell population. Primed CTLs from immunized pigs showed cytolytic activity in PRRSV-infected cells in vitro. PTC1 and PTC2 peptides induced a protective T-cell-mediated response in pigs immunized against PRRSV, due to the presence of T epitopes in their sequences. Full article

(This article belongs to the Special Issue Endemic and Emerging Swine Viruses 2023)

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19 pages, 5579 KiB

Open AccessArticle

Molecular and Pathological Characterization of Classical Swine Fever Virus Genotype 2 Strains Responsible for the 2013–2018 Outbreak in Colombia

by Erin Robert, Kalhari Goonewardene, Lindsey Lamboo, Orlando Perez, Melissa Goolia, Charles Lewis, Cassidy N. G. Erdelyan, Oliver Lung, Katherine Handel, Estella Moffat, Carissa Embury-Hyatt, Nancy Naranjo Amaya, Claudia Patricia Calderón Parra, Diana Cristina Gómez Rueda, Maria Antonia Rincón Monroy, Alfonso Clavijo and Aruna Ambagala

Viruses 2023, 15(12), 2308; https://doi.org/10.3390/v15122308 - 24 Nov 2023

Cited by 2 | Viewed by 1237

Abstract

Classical swine fever (CSF) is a highly contagious transboundary viral disease of domestic and wild pigs. Despite mass vaccination and continuous eradication programs, CSF remains endemic in Asia, some countries in Europe, the Caribbean and South America. Since June 2013, Northern Colombia has [...] Read more.

Classical swine fever (CSF) is a highly contagious transboundary viral disease of domestic and wild pigs. Despite mass vaccination and continuous eradication programs, CSF remains endemic in Asia, some countries in Europe, the Caribbean and South America. Since June 2013, Northern Colombia has reported 137 CSF outbreaks, mostly in backyard production systems with low vaccination coverage. The purpose of this study was to characterize the virus responsible for the outbreak. Phylogenetic analysis based on the full-length E2 sequence shows that the virus is closely related to CSF virus (CSFV) genotype 2.6 strains circulating in Southeast Asia. The pathotyping experiment suggests that the virus responsible is a moderately virulent strain. The 190 nucleotide stretch of the E2 hypervariable region of these isolates also shows high similarity to the CSFV isolates from Colombia in 2005 and 2006, suggesting a common origin for the CSF outbreaks caused by genotype 2.6 strains. The emergence of genotype 2.6 in Colombia suggests a potential transboundary spread of CSFV from Asia to the Americas, complicating the ongoing CSF eradication efforts in the Americas, and emphasizes the need for continuous surveillance in the region. Full article

(This article belongs to the Special Issue Endemic and Emerging Swine Viruses 2023)

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15 pages, 4304 KiB

Open AccessArticle

Seasonal Occurrence of African Swine Fever in Wild Boar and Domestic Pigs in EU Member States

by Lisa Rogoll, Ann-Kathrin Güttner, Katja Schulz, Hannes Bergmann, Christoph Staubach, Franz J. Conraths and Carola Sauter-Louis

Viruses 2023, 15(9), 1955; https://doi.org/10.3390/v15091955 - 20 Sep 2023

Cited by 2 | Viewed by 1203

Abstract

Since 2007, African swine fever (ASF) has spread widely within Europe and beyond. Most affected countries recorded outbreaks in domestic pigs and cases in wild boar. Outbreak data from 2014 to 2021 were used to investigate the seasonal pattern of ASF in domestic [...] Read more.

Since 2007, African swine fever (ASF) has spread widely within Europe and beyond. Most affected countries recorded outbreaks in domestic pigs and cases in wild boar. Outbreak data from 2014 to 2021 were used to investigate the seasonal pattern of ASF in domestic pigs and wild boar across affected member states of the European Union, since knowledge of seasonal patterns may provide the potential to adapt prevention, surveillance and control during times of increased risk. In domestic pigs, a yearly peak was observed in many European countries in summer (predominantly in July and August). In wild boar, the patterns showed more variability. In many countries, there was a seasonal peak of ASF occurrence in winter (predominantly in January and December), with an additional summer peak in the Baltic States (predominantly in July) and a further spring peak in Poland (predominantly in March). The observed seasonal effects may be related to the abundance and population dynamics of wild boar and to seasonality in pig farming. Moreover, ASF occurrence may also be influenced by human activities in both domestic pigs and wild boar. Full article

(This article belongs to the Special Issue Endemic and Emerging Swine Viruses 2023)

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12 pages, 958 KiB

Open AccessArticle

The 2022 Outbreaks of African Swine Fever Virus Demonstrate the First Report of Genotype II in Ghana

by Edward Spinard, Ayushi Rai, Jehadi Osei-Bonsu, Vivian O’Donnell, Patrick T. Ababio, Daniel Tawiah-Yingar, Daniel Arthur, Daniel Baah, Elizabeth Ramirez-Medina, Nallely Espinoza, Alyssa Valladares, Bonto Faburay, Aruna Ambagala, Theophlius Odoom, Manuel V. Borca and Douglas P. Gladue

Viruses 2023, 15(8), 1722; https://doi.org/10.3390/v15081722 - 11 Aug 2023

Cited by 4 | Viewed by 1373

Abstract

African swine fever (ASF) is a lethal disease of domestic pigs that has been causing outbreaks for over a century in Africa ever since its first discovery in 1921. Since 1957, there have been sporadic outbreaks outside of Africa; however, no outbreak has [...] Read more.

African swine fever (ASF) is a lethal disease of domestic pigs that has been causing outbreaks for over a century in Africa ever since its first discovery in 1921. Since 1957, there have been sporadic outbreaks outside of Africa; however, no outbreak has been as devastating and as far-reaching as the current pandemic that originated from a 2007 outbreak in the Republic of Georgia. Derivatives with a high degree of similarity to the progenitor strain, ASFV-Georgia/2007, have been sequenced from various countries in Europe and Asia. However, the current strains circulating in Africa are largely unknown, and 24 different genotypes have been implicated in different outbreaks. In this study, ASF isolates were collected from samples from swine suspected of dying from ASF on farms in Ghana in early 2022. While previous studies determined that the circulating strains in Ghana were p72 Genotype I, we demonstrate here that the strains circulating in 2022 were derivatives of the p72 Genotype II pandemic strain. Therefore, this study demonstrates for the first time the emergence of Genotype II ASFV in Ghana. Full article

(This article belongs to the Special Issue Endemic and Emerging Swine Viruses 2023)

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13 pages, 2235 KiB

Open AccessArticle

Classical Swine Fever Virus Structural Glycoprotein E2 Interacts with Host Protein ACADM during the Virus Infectious Cycle

by Elizabeth Vuono, Elizabeth Ramirez-Medina, Ediane Silva, Keith Berggren, Ayushi Rai, Nallely Espinoza, Douglas P. Gladue and Manuel V. Borca

Viruses 2023, 15(5), 1036; https://doi.org/10.3390/v15051036 - 23 Apr 2023

Cited by 1 | Viewed by 1442

Abstract

The E2 glycoprotein is one of the four structural proteins of the classical swine fever virus (CSFV) particle. E2 has been shown to be involved in many virus functions, including adsorption to host cells, virus virulence and interaction with several host proteins. Using [...] Read more.

The E2 glycoprotein is one of the four structural proteins of the classical swine fever virus (CSFV) particle. E2 has been shown to be involved in many virus functions, including adsorption to host cells, virus virulence and interaction with several host proteins. Using a yeast two-hybrid screen, we have previously shown that the CSFV E2 specifically interacts with swine host protein medium-chain-specific acyl-Coenzyme A dehydrogenase (ACADM), an enzyme that catalyzes the initial step of the mitochondrial fatty acid beta-oxidation pathway. Here, we show that interaction between ACADM and E2 also happens in swine cells infected with CSFV using two different procedures: coimmunoprecipitation and a proximity ligation assay (PLA). In addition, the amino acid residues in E2 critically mediating the interaction with ACADM, M49 and P130 were identified via a reverse yeast two-hybrid screen using an expression library composed of randomly mutated versions of E2. A recombinant CSFV, E2ΔACADMv, harboring substitutions at residues M49I and P130Q in E2, was developed via reverse genomics from the highly virulent Brescia isolate. E2ΔACADMv was shown to have the same kinetics growth in swine primary macrophages and SK6 cell cultures as the parental Brescia strain. Similarly, E2ΔACADMv demonstrated a similar level of virulence when inoculated to domestic pigs as the parental Brescia. Animals intranasally inoculated with 10⁵ TCID₅₀ developed a lethal form of clinical disease with virological and hematological kinetics changes undistinguishable from those produced by the parental strain. Therefore, interaction between CSFV E2 and host ACADM is not critically involved in the processes of virus replication and disease production. Full article

(This article belongs to the Special Issue Endemic and Emerging Swine Viruses 2023)

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14 pages, 3287 KiB

Open AccessArticle

High-Risk Regions of African Swine Fever Infection in Mozambique

by Azido Ribeiro Mataca, Francisco Alyson Silva Oliveira, Ângelo André Lampeão, José Pereira Mendonça, Maria Aparecida Scatamburlo Moreira, Rinaldo Aparecido Mota, Wagnner José Nascimento Porto, David Germano Gonçalves Schwarz and Abelardo Silva-Júnior

Viruses 2023, 15(4), 1010; https://doi.org/10.3390/v15041010 - 20 Apr 2023

Cited by 1 | Viewed by 1615

Abstract

African swine fever (ASF) is a transboundary infectious disease that can infect wild and domestic swine and requires enhanced surveillance between countries. In Mozambique, ASF has been reported across the country, spreading between provinces, mainly through the movement of pigs and their by-products. [...] Read more.

African swine fever (ASF) is a transboundary infectious disease that can infect wild and domestic swine and requires enhanced surveillance between countries. In Mozambique, ASF has been reported across the country, spreading between provinces, mainly through the movement of pigs and their by-products. Subsequently, pigs from bordering countries were at risk of exposure. This study evaluated the spatiotemporal distribution and temporal trends of ASF in swine in Mozambique between 2000 and 2020. During this period, 28,624 cases of ASF were reported across three regions of the country. In total, the northern, central, and southern regions presented 64.9, 17.8, and 17.3% of the total cases, respectively. When analyzing the incidence risk (IR) of ASF per 100,000 pigs, the Cabo Delgado province had the highest IR (17,301.1), followed by the Maputo province (8868.6). In the space-time analysis, three clusters were formed in each region: (i) Cluster A involved the provinces of Cabo Delgado and Nampula (north), (ii) Cluster B involved the province of Maputo and the city of Maputo (south), and (iii) Cluster C consisted of the provinces of Manica and Sofala (central) in 2006. However, when analyzing the temporal trend in the provinces, most were found to be decreasing, except for Sofala, Inhambane, and Maputo, which had a stationary trend. To the best of our knowledge, this is the first study to evaluate the spatial distribution of ASF in Mozambique. These findings will contribute to increasing official ASF control programs by identifying high-risk areas and raising awareness of the importance of controlling the borders between provinces and countries to prevent their spread to other regions of the world. Full article

(This article belongs to the Special Issue Endemic and Emerging Swine Viruses 2023)

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