African swine fever virus (ASFV) causes highly lethal hemorrhagic disease among pigs, and ASFV’s extreme antigenic diversity hinders vaccine development. We show that p72 ASFV phylogenetic analysis does not accurately define ASFV hemadsorption inhibition assay serogroups. Thus, conventional ASFV genotyping cannot discriminate between viruses of different virulence or predict efficacy of a specific ASFV vaccine.

African Swine Fever Virus, Russia, 2012

The first notifications of the unknown disease of cattle appeared in September–October 2015 in North Caucasus region of Russia (Republic of North Ossetia-Alania). The clinical signs included watery discharge from eyes, apathy, loss of appetite, salivation, lameness and nodular skin lesions. Capripoxvirus genome was detected by real-time PCR in the tissue samples of sick animals. The aetiological agent was isolated in the primary cell cultures of lamb testis and goat testis, as well as in the continuous MDBK cell culture. Further sequencing of the GPCR gene and phylogenetic analysis showed the close genetic relationship of isolated capripoxvirus with a group of lumpy skin disease virus. Koch's postulates were fulfilled by the experimental infection of four calves with a suspension of tissue samples from sick animals.

African swine fever (ASF) is a contagious viral disease in pigs and wild boars which poses a major threat to the pig industry. Rapid and accurate diagnosis is necessary to control ASF. Hence, we developed a rapid diagnostic method using a recombinase polymerase amplification (RPA) assay targeting the conserved sequences of CP204L (p30) thatcan rapidly detect ASF virus (ASFV) genotype strains I and II. The lower detection limit of the real-time RPA assay was 5 × 10¹ copies per reaction. The real-time RPA assay effectively detected ASFV isolates and clinical specimens belonging to ASFV genotypes I and II. The sensitivity and specificity of the assay were 96.8% (95% confidence interval (CI): 83.3–99.9) and 100% (95% CI: 88.4–100.0), respectively. The agreement between the real-time RPA assay and a reference commercial real-time quantitative polymerase chain reaction (qPCR) was 100%. The real-time RPA assay had a detection time of 6.0 min (95% CI: 5.7–6.2), which was significantly shorter than that of qPCR (49 min; 95% CI: 47.4–50.6; p < 0.001). Thus, the developed real-time RPA assay is a rapid and accurate diagnostic tool for detecting ASFV genotypes I and II.

Porcine epidemic diarrhea (PED) is a contagious viral disease in pigs, caused by the coronavirus porcine epidemic diarrhea virus (PEDV). PEDV infection results in significant mortality in piglets in unvaccinated herds. Like many others RNA viruses, PEDV has high evolutionary rate and is prone to genetic mutations. In this study, we analyzed the complete genome sequence of the recently sequenced isolate PEDV/Belgorod/dom/2008. A recombination event in S gene of PEDV/Belgorod/dom/2008 was detected. Pairwise identity analysis of the whole genome sequences revealed that PEDV/Belgorod/dom/2008 is an intermediate between PEDV and transmissible gastroenteritis virus (TGEV) strains. These results can be used for further analysis of the evolutionary variability, prevalence, and epidemiology of the porcine epidemic diarrhea virus.

African swine fever virus causes hemorrhagic disease in swine. Attenuated strains are reported in Africa, Europe, and Asia. Few studies on the diagnostic detection of attenuated ASF viruses are available. Two groups of pigs were inoculated with an attenuated ASFV. Group 2 was also vaccinated with an attenuated porcine reproductive and respiratory syndrome virus vaccine. Commercially available ELISA, as well as extraction and qPCR assays, were used to detect antibodies in serum and oral fluids (OF) and nucleic acid in buccal swabs, tonsillar scrapings, OF, and blood samples collected over 93 days, respectively. After 12 dpi, serum (88.9% to 90.9%) in Group 1 was significantly better for antibody detection than OF (0.7% to 68.4%). Group 1′s overall qPCR detection was highest in blood (48.7%) and OF (44.2%), with the highest detection in blood (85.2%) from 8 to 21 days post inoculation (dpi) and in OF (83.3%) from 1 to 7 dpi. Group 2′s results were not significantly different from Group 1, but detection rates were lower overall. Early detection of attenuated ASFV variants requires active surveillance in apparently healthy animals and is only reliable at the herd level. Likewise, antibody testing will be needed to prove freedom from disease.