Agathe Auer

This review explores the biological basis and epidemiological implications of natural resistance to ASFV. It dispels the misconception that African wild su

African Swine Fever Virus (ASFV) genotype II dominates outbreaks in Tanzania’s Southern Highlands, continuing to persist as the dominant strain over a decade after its first incursion in 2010. A total of 205 samples from 120 holdings were collected, with 21 confirmed ASFV-positive animals from 14 holdings. Molecular analysis revealed genetic uniformity among isolates, all clustering within ASFV genotype II. Poor biosecurity measures, such as feeding of untreated swill (80% of holdings) and lack of restrictions on visitors (90% of holdings), were identified as risk factors. Additionally, co-infection with porcine circovirus-2 (PCV-2) further complicates disease management. This study underscores the urgent need for enhanced biosecurity and farmer education to mitigate ASFV outbreaks in endemic regions.

This paper explores the significance of quality vaccines in managing ASF in Asia, where it poses a substantial threat to the pork industry. It emphasizes the risks associated with substandard vaccines, including the emergence of new virus strains that complicate disease control. Highlighting recent advancements in vaccine deployment in Vietnam, the paper calls for rigorous testing and regulations to guarantee vaccine effectiveness and safety. The authors advocate for the implementation of vaccines with the inclusion of differentiating infected from vaccinated animals (DIVA), which enhances disease management strategies in both endemic and non-endemic regions. The conclusion underscores the necessity of stringent standards in vaccine development and strict adherence to regulatory guidelines to ensure successful ASF management and maintain public trust in the vaccines.

Selective culling, also known as the “tooth extraction approach”, is a strategy for controlling African swine fever (ASF) by removing only sick and suspect animals instead of the entire herd in Vietnam. This method prioritizes preserving healthy animals, particularly valuable breeding pigs. Despite its implementation in various forms, no standardized protocol based on scientific principles has been established. Farms typically adapt this strategy based on their understanding, which can vary significantly. In implementing of selective culling that is not based on scientific principles, there is a significant risk of spreading the disease. The aim of this study is to evaluate the consequences of selective culling as currently implemented in Vietnam. Our analysis on a large sow farm revealed that current practices rely heavily on clinical observations without laboratory confirmations. This approach allows ASF-infected animals to remain on the farm longer, potentially exacerbating the spread of the virus. Thus, selective culling poses a substantial risk by potentially exacerbating the spread of disease. Our findings emphasize that early diagnosis of ASF and systematic removal of infected pigs are critical components for the effective implementation of selective culling strategies and that a high level of fragmentation to minimize contact between animals plays a key role. The optimal approach is to test conspicuous animals and separate them. Under no circumstances should suspect animals be left in the herd for several days before they become severely ill and succumb to the disease.

African swine fever (ASF) is a highly contagious and severe viral hemorrhagic disease in domestic and wild pigs. ASF seriously affects the global swine industry as the mortality rate can reach 100% with highly virulent strains. In 2007, ASF was introduced into the Caucasus and spread to Russia and later into other European and Asian countries. This study reported the first whole-genome sequence (WGS) of the ASF virus (ASFV) that was detected in a Mongolian wild boar. This sequence was then compared to other WGS samples from Asia and Europe. Results show that the ASFV Genotype II from Mongolia is similar to the Asian Genotype II WGS. However, there were three nucleotide differences found between the Asian and European genome sequences, two of which were non-synonymous. It was also observed that the European Genotype II ASFV WGS was more diverse than that of the Asian counterparts. The study demonstrates that the ASFV Genotype II variants found in wild boars and domestic pigs are highly similar, suggesting these animals might have had direct or indirect contact, potentially through outdoor animal breeding. In conclusion, this study provides a WGS and mutation spectrum of the ASFV Genotype II WGS in Asia and Europe and thus provides important insights into the origin and spread of ASFV in Mongolia.

Since anthropo-zoonotic outbreaks of SARS-CoV-2 have been reported in mink farms, it is important to monitor the seroprevalence within this population. To investigate the accuracy of nucleo (N) or spike (S) protein-based assays to detect anti-SARS-CoV-2 antibodies in animal serum, we compared four assays, two commercial N-based enzyme-linked immunosorbent assays (ELISA) validated for animal sera and two luciferase immunoprecipitation systems (LIPS-N and LIPS-S), to the reference standard plaque reduction neutralisation test (PRNT). Samples included in this study were derived from a naturally infected mink population. For the first time in this study, serum samples of mink were collected over a 307-day period, at different time points, thus providing an overview of performances of four different rapid serological tests over time. The assays were compared by performing a correlation analysis using R2, Spearmans rank-order correlation coefficient, and Fleiss and Cohens kappa for analysis of agreement to PRNT, and an UpSet chart was created to visualize the number of shared positive samples between assays. Cohens kappa test on categorical data showed an excellent agreement between PRNT and LIPS-S, while agreements between PRNT and N-based methods decreased from fair for LIPS-N to poor agreements for the ELISA kits. In addition, LIPS-S revealed the highest number of true-positive SARS-CoV-2 samples compared to N-based methods. Despite an excellent agreement between LIPS-S and PRNT, a weak correlation was detectable between PRNT titres and relative light units. This study shows that the LIPS-S assay can be used for serological surveillance within a naturally exposed mink population, while N-based serological assays are less accurate providing a higher number of false-negative results, especially at a later stage of infection, thus indicating that N antibodies are less persistent in naturally exposed mink. Our findings provide crucial information for veterinarians and competent authorities involved in surveillance and outbreak investigation in wild and farmed minks.

With the recent spread of African swine fever (ASF) in Europe, Asia, and the Caribbean region, after being endemic for decades in Africa, PCR-based commercial kits and various master mixes are increasingly being used in addition to the OIE recommended protocol from King et al., 2003 (World Organisation for animal Health, 2021). Often, the availability and cost of commercial kits or master mixes can be a limiting factor for diagnostic laboratories, in addition to the requirements for transportation and storage of temperature-sensitive reagents in remote areas. In such cases, alternatives should be ready to maximize surveillance and mining of ASF. To evaluate alternatives, we tested five commercial quantitative real-time PCR (qPCR) master mixes from Applied Biosystems, Bio-Rad, Biotechrabbit, Promega and Qiagen using the same primers and probe mix derived from the King et al., 2003 protocol for the sensitivity, specificity, correlation and inter-assay agreement. We further included three ad hoc molecular diagnostic kits [VetMax ^TM African Swine Fever Virus Detection Kit (Applied Biosystems), ID Gene African Swine Fever Duplex (ID-Vet) and Virotype ASF PCR Kit (Qiagen/Indical)]. The limit of detection (LOD) was assessed for each assay. The comparative study panel comprised 83 archived DNA samples from ASFV clinical samples, belonging to five different genotypes from outbreaks in 16 countries in Asia and Africa. The analytical specificity was assessed against a panel of swine pathogens. The LOD ranged from 13 to 41 gene copies per reaction; VetMax ^TM African Swine Fever Virus Detection Kit from Applied Biosystems exhibited the lowest detection limit (13 gene copies per reaction) and iQ Supermix from Bio-Rad the highest detection limit (41 gene copies per reaction). Cq values obtained from the lowest dilution, in which all replicates (n = 25) could still be amplified (50 gene copies per reaction), were not significantly different between kits using Kruskal-Wallis test. Inter assay agreement was assessed using statistical test Fleiss-Kappa and was shown to be excellent in all cases. Agreement using statistical test Bland-Altman was good for samples with Cq values < 25 and moderate for Cq values > 25. We conclude that all the assays evaluated in this study can be used for the routine detection of ASFV. This article is protected by copyright. All rights reserved

The process of anaerobic digestion (AD) is valued as a carbon‐neutral energy source, while simultaneously treating organic waste, making it safer for disposal or use as a fertilizer on agricultural land. The AD process in many European nations, such as Germany, has grown from use of small, localized digesters to the operation of large‐scale treatment facilities, which contribute significantly to national renewable energy quotas. However, these large AD plants are costly to run and demand intensive farming of energy crops for feedstock. Current policy in Germany has transitioned to support funding for smaller digesters, while also limiting the use of energy crops. AD within Ireland, as a new technology, is affected by ambiguous governmental policies concerning waste and energy. A clear governmental strategy supporting on‐site AD processing of agricultural waste will significantly reduce Ireland's carbon footprint, improve the safety and bioavailability of agricultural waste, and provide an indigenous renewable energy source. © 2016 Society of Chemical Industry