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African swine fever (ASF) emerged in Germany in 2020. A few weeks after the initial occurrence, infected wild boar were detected in Saxony. In this study, data from wild boar surveillance in Saxony were analyzed. The analysis focused on the eastern districts of the state, where the disease likely spread through infected wild boar. Additionally, data from Meissen, located approximately 65 km further west, were examined. In Meissen, the disease emerged one year later, and a human-mediated introduction was suspected. To evaluate the progression of ASF in the two study areas over time, data from active and passive surveillance were analyzed both descriptively and using a Bayesian space–time model. Prevalence estimates were calculated for wild boar testing positive for the ASF virus and for ASF-specific antibodies. Higher prevalence estimates were observed in the eastern districts, indicating a stronger viral load, consistent with patterns seen in other European regions. Over time, seroprevalence increased, suggesting an accumulation of surviving wild boar. The findings provide important insights into the epidemiology of ASF in wild boar over time. They complement the existing knowledge and support targeted ASF control measures. This is particularly significant, as ASF continues to spread across Europe rather than being successfully eradicated. [ABSTRACT FROM AUTHOR]

Obtaining a complete good-quality sequence and annotation for the long double-stranded DNA genome of the African swine fever virus (ASFV) from next-generation sequencing (NGS) technology has proven difficult, despite the increasing availability of reference genome sequences and the increasing affordability of NGS. A gap analysis conducted by the global African swine fever research alliance (GARA) partners identified that a standardized, automatic pipeline for NGS analysis was urgently needed, particularly for new outbreak strains. Whilst there are several diagnostic and research labs worldwide that collect isolates of the ASFV from outbreaks, many do not have the capability to analyze, annotate, and format NGS data from outbreaks for submission to NCBI, and some publicly available ASFV genomes have missing or incorrect annotations. We developed an automated, standardized pipeline for the analysis of NGS reads that directly provides users with assemblies and annotations formatted for their submission to NCBI. This pipeline is freely available on GitHub and has been tested through the GARA partners by examining two previously sequenced ASFV genomes; this study also aimed to assess the accuracy and limitations of two strategies present within the pipeline: reference-based (Illumina reads) and de novo assembly (Illumina and Nanopore reads) strategies. [ABSTRACT FROM AUTHOR]

The rapid spread of African swine fever virus (ASFV), causing severe and often lethal disease in domestic pigs and Eurasian wild boar, continues to be a threat to pig populations and dependent industries. Despite scientific achievements that have deepened our understanding of ASFV pathogenesis, alternative transmission routes for ASFV remain to be elucidated. We previously demonstrated the efficient transmission of ASFV from infected boars to naïve recipient gilts via artificial insemination, thereby highlighting the importance of surveillance of boar semen prior to its shipment. Since the accurate and reliable detection of even low amounts of ASFV in boar semen is key to disease prevention and control, we established a suitable diagnostic workflow to efficiently detect the ASFV genome in boar semen. Here, we assessed the sensitivity of various routine nucleic acid extraction kits as well as qPCR protocols in detecting the ASFV genome in the blood and semen of infected boars. The feasibility of the respective kits and methods for future use in boar studs was also considered. Variability in sensitivity mostly concerned samples with low to very low amounts of the ASFV genome. Ultimately, we defined a well-suited workflow for precisely detecting the ASFV genome in boar semen as early as 2 days post ASFV infection. [ABSTRACT FROM AUTHOR]

African swine fever (ASF) is one of the most pathogenic viral diseases of swine leading to clinical and pathomorphological signs of a viral hemorrhagic fever (1). In 2007, ASF was [...]

Over the last years, African swine fever (ASF) has gone pandemic and within the European Union affected wild boar populations are main drivers. This brings new challenges, i.e. risk assessment needs for agricultural products and the role of mechanical arthropod vectors. Answering the call "Survival of African swine fever virus in feed, bedding materials and mechanical vectors and their potential role in virus transmission" (GP/EFSA/ALPHA/2021/09), relevant feed and bedding materials were chosen for stability experiments. All matrices were contaminated with ASFV and stored at five different ambient conditions (‐20°C, 4°C, 10°C, 20°C, and 37°C) over a period of up to nine months. Replicate samples were evaluated at different time‐points using real‐time PCRs and virus isolation. Additionally, the possible role of three types of blood‐sucking arthropods was assessed. In detail, studies were carried out on how long representative arthropods harbored viral genome and infectious virus upon feeding on infectious blood. In a last step, further proof‐of‐concept data were generated on the transmission of ASFV via ingestion of (small) arthropods after an infected blood meal. Concluding, detection of infectious virus was rather limited in most matrices while detection of viral genome was possible over the entire study period. At lower temperatures, however, the virus was stable on feed matrices over several days or even weeks, especially on beet and potatoes. Grass, grass silage and corn silage did not allow re‐isolation of virus at any time‐point. The studies on the detectability of the virus in arthropods showed that the virus is generally detectable for a certain period of time depending on temperature and ingested volume. The detectability of virus in stable flies exceeded the expectations with over 168 hours at cool temperatures. The feeding experiment did not lead to infection of pigs. However, the power of this proof‐of‐concept study is limited. [ABSTRACT FROM AUTHOR]

Porcine epidemic diarrhea (PED) is an acute and highly contagious enteric disease of swine that results in severe enteritis, diarrhea, vomiting, and dehydration (1). Porcine epidemic diarrhea virus (PEDV), the [...]