Diagnostic sensitivity of porcine biological samples for detecting African swine fever virus infection after natural consumption in feed and liquid

Abstract

African swine fever virus (ASFV) is a global threat to swine production and sustainable pork supply. Without a commercially available vaccine, prevention of ASFV entry and spread is reliant on biosecurity and early detection of infection. Although ASFV ingestion in swill or feed by naïve pigs is a likely route of initial introduction, controlled experimental studies rarely utilize natural consumption as the infection route. In the current study, we utilized biological samples collected from pigs 5 days after natural consumption of ASFV in feed and liquid to assess diagnostic sensitivity for early detection of virus infection. Biological samples (serum, spleen, lymph nodes, tonsils, and faeces) were assessed for the presence of ASFV using quantitative PCR and virus isolation. Statistical methods modelled the detection sensitivity of each sample type with each diagnostic assay in individual samples. Our results provide important information that can be incorporated into ASFV surveillance programs.

Generation of High-Quality African Swine Fever Virus Complete Genome from Field Samples by Next-Generation Sequencing

“…It was revealed that the ASFV detection rates by real-time PCR in the spleen (70.6%) were slightly higher than that in the lymph node (58.8%). However, the ASFV detection rates by virus isolation in the spleens (94.1%) were much higher than those in the lymph nodes (29.4%) [ 42 ]. Our study provides solid evidence for addressing the spleen as the sample of choice to obtain a high-quality ASFV genome sequence.…”

“…A high load of ASFV DNA was detected in blood in the early, clinical and later phases of ASFV experimental infection [ 43 ]. At 5~8 days post-infection, the ASFV DNA detected in the blood increased dramatically from 10 2 copies/μL to 10 7 copies/μL [ 42 ]. Whole blood samples are suitable for high-throughput ASFV genome sequencing, considering there is no need for homogenization.…”

A suitable sampling strategy for the detection of African swine fever virus in living and deceased pigs in the field: a retrospective study

“…Subsequently, 5 μL of the extracted DNA was utilized for qPCR detection, which was performed on a Step One Plus instrument (ABI) using the PerfectStart ® II Probe qPCR SuperMix (TransGen Biotech, China) according to the manufacturer’s instructions. Specific primers for the ASFV B646L gene were designed based on the ASFV isolate Pig/HLJ/18 (GenBank: MK333180.1) ( 18 ) and used for qPCR: 5’-AAAATGATACGCAGCGAAC-3’(forward), 5’-TTGTTTACCAGCTGTTTGGAT-3’ (reverse), and 5’-FAM-TTCACAGCATTTTCCCGAGAACT-BHQ1-3’ (probe) ( 17 ). The results of qPCR were recorded as quantification cycle values (Cq values), and a Cq value of <40 was considered as a positive result.…”

“…Additionally, ASFV has been reported to be able to spread through multiple routes, including contact and aerosol transmission (11,13,14). And also, ASFV-positive pigs have been found to harbor a significant quantity of virus particles in their blood and deep tissues (10,11,(15)(16)(17), which indicates that the process of blood sampling and necropsy procedures may lead to extensive contamination of the virus within the facility in the event of ASFV outbreaks in large-scale farms. Consequently, the accurate evaluation of ASFV presence in appropriate clinical samples is crucial for mitigating ASFV transmission in extensive commercial pig operations (18).…”

Cell Lines for the Development of African Swine Fever Virus Vaccine Candidates: An Update

“…Overall, MA-104 discovery could be an opportunity to improve diagnostic capacity and avoid the requirement of donor swine, the latter being time-consuming and unavailable in some laboratories [ 101 ]. Nevertheless, more studies are still required to verify whether MA-104 can be considered the best substrate to grow ASFV strains for large-scale vaccine production.…”