Development of a Novel Indirect ELISA for the Serological Diagnosis of African Swine Fever Using p11.5 Protein as a Target Antigen.

African swine fever is a hemorrhagic viral disease with a mortality rate of nearly 100% in pigs. Hence, it is classified as a notifiable disease by the World Organization for Animal Health. Because no field-available vaccine exists, African swine fever virus (ASFV) control and eradication solely depend on good farm biosecurity management and rapid and accurate diagnosis.

A Spontaneously Occurring African Swine Fever Virus with 11 Gene Deletions Partially Protects Pigs Challenged with the Parental Strain.

African swine fever (ASF) is an infectious Suidae disease caused by the ASF virus (ASFV). Adaptation to less susceptible, non-target host cells is one of the most common techniques used to attenuate virulent viruses. However, this may induce many mutations and large-scale rearrangements in the viral genome, resulting in immunostimulatory potential loss of the virus in vivo.

Novel bovine viral diarrhea virus (BVDV) virus-like particle vaccine candidates presenting the E2 protein using the SpyTag/SpyCatcher system induce a robust neutralizing antibody response in mice.

Bovine viral diarrhea virus (BVDV) is a pathogen of commercial consequence in cattle. Although many modified live and killed vaccines are commercially available, their drawbacks precipitate the need for new effective vaccines. Virus-like particles (VLPs) are a safe and powerful technology used in several human and veterinary vaccines; however, it is difficult to produce large amounts of BVDV VLPs.

Usability of Immortalized Porcine Kidney Macrophage Cultures for the Isolation of ASFV without Affecting Virulence.

Immortalized porcine kidney macrophage (IPKM) cells are highly susceptible to major African swine fever virus (ASFV) isolates. To clarify the compatibility of this cell line for ASFV isolation from biomaterials, animal experiments and isolation were performed. Pork products seized at international airports were subjected to virus inoculation in pigs () and IPKM cell cultures () to examine the viability and virulence of the contaminating viruses.

Mutations in the tumor suppressor gene p53 in cattle are associated with enzootic bovine leukosis.

Enzootic bovine leukosis (EBL) is a B-cell lymphoma caused by the bovine leukemia virus (BLV). Although an association between EBL and mutations in the bovine tumor suppressor gene TP53 (bTP53) has been suggested, the substantive incidence rate of bTP53 mutations in EBL cattle is still unclear. In this study, we investigated the complete sequence (exons 2-11) of bTP53 in tissue and peripheral blood leukocyte (PBL) samples obtained from 154 EBL cattle and 117 cattle without EBL (non-EBL cattle) to elucidate the correlation between bTP53 mutations and EBL.

An immortalized porcine macrophage cell line competent for the isolation of African swine fever virus.

African swine fever virus (ASFV) is the etiological agent of African swine fever (ASF), a fatal hemorrhagic disease of domestic pigs and wild boar. The virus primarily infects macrophage and monocyte host cells, these do not grow in vitro. Many attempts have been made to establish sustainable ASFV-sensitive cell lines, but which supported only low viral replication levels of limited, mostly artificially attenuated strains of ASFV.

Experimental infection of pigs with different doses of the African swine fever virus Armenia 07 strain by intramuscular injection and direct contact.

We experimentally infected pigs with the African swine fever virus (ASFV) Armenia 07 strain (genotype II) to analyze the effect of different dose injections on clinical manifestations, virus-shedding patterns, histopathology, and transmission dynamics by direct contact. Each three pigs and four pigs were injected intramuscularly with 0.1 fifty percent hemadsorbing doses (HAD)/ml, 10 HAD/ml and 10 HAD/ml of ASFV Armenia 07 strain, respectively.

A cloned classical swine fever virus derived from the vaccine strain GPE causes cytopathic effect in CPK-NS cells via type-I interferon-dependent necroptosis.

Classical swine fever viruses (CSFVs) do typically not show cytopathic effect (CPE) in cell culture, while some strains such as vaccine strain the GPE induce CPE in the swine kidney-derived CPK-NS cell line cultured in serum-free medium. These latter strains commonly lack N-mediated inhibition of type-I interferon (IFN) induction. In order to explore the molecular mechanisms of GPE-induced CPE, we analyzed the cellular pathways involved.

Simultaneous evaluation of diagnostic marker utility for enzootic bovine leukosis.

Background: Enzootic bovine leukosis (EBL) is a disease of cattle caused by bovine leukemia virus (BLV). More than 60% of BLV-infected cattle remain subclinical and are thus referred to as aleukemic (AL) cattle. Approximately 30% of infected cattle show a relatively stable increase in the number of B lymphocytes; these cattle are termed persistent lymphocytosis (PL) cattle.

END-phenomenon negative bovine viral diarrhea virus that induces the host's innate immune response supports propagation of BVDVs with different immunological properties.

Our previous study reported that persistently infected (PI) cattle of bovine viral diarrhea virus (BVDV) have co-infected with BVDV/END and /END that promote and inhibit host's type-I interferon (IFN) production, respectively. However, the relationship between co-infection of immunologically distinct BVDVs and persistent infection as well as the biological significance of END viruses remains unknown. Experiments using cultured cells revealed that END virus, which is unable to propagate in situations where the host's immune response is induced by IFN-α addition, is able to propagate under those conditions when co-infecting with END virus.

Experimental infection of pigs with a classical swine fever virus isolated in Japan for the first time in 26 years.

Following an outbreak of classical swine fever (CSF) in Japan, 2018, CSFV JPN/1/2018 was isolated from an infected pig sample. In this study, we carried out a comparative experimental infection in pigs using this strain and the highly virulent ALD strain and compared outcomes, including clinical manifestation, virus shedding patterns and antibody responses. Although pigs inoculated orally or intramuscularly with JPN/1/2018 developed hyperthermia and had decreased leucocyte numbers, they survived for the whole experimental period and showed less severe clinical signs than those infected with the ALD strain.

Reemergence of Classical Swine Fever, Japan, 2018.

In September 2018, classical swine fever reemerged in Japan after 26 years, affecting domestic pigs and wild boars. The causative virus belongs to the 2.1 subgenotype, which caused repeated outbreaks in eastern and Southeast Asia.

Genome Sequence of a Classical Swine Fever Virus of Subgenotype 2.1, Isolated from a Pig in Japan in 2018.

In 2018, classical swine fever virus (CSFV) was detected in Japan. Here, we report the whole-genome sequence of CSFV/JPN/1/2018. This virus is closely related to isolates in East Asia and is classified under subgenotype 2.

The effectiveness of colostral antibodies for preventing bovine leukemia virus (BLV) infection in vitro.

Background: Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). The incidence of EBL in Japan is increasing annually; and the cases of EBL in cattle younger than 2 years old has been reported. Therefore, it is vital to find a method to control BLV infection, especially in young calves.

Reciprocal complementation of bovine parainfluenza virus type 3 lacking either the membrane or fusion gene.

Two defective bovine parainfluenza virus type 3 (BPIV3) strains were generated, one lacking the membrane (M) protein gene and expressing EGFP (ΔM-EGFP) and the other lacking the fusion (F) protein gene and expressing mStrawberry (ΔF-mSB), by supplying deficient proteins in trans. When Madin-Darby bovine kidney (MDBK) cells were co-infected with ΔM-EGFP and ΔF-mSB at a multiplicity of infection (MOI) of 0.1, complemented viruses were easily obtained.

A single L288I substitution in the fusion protein of bovine parainfluenza virus type 3 enhances virus growth in semi-suitable cell lines.

The bovine parainfluenza virus type 3 BN-CE vaccine strain was obtained by serial passage of the BN-1 strain in chicken embryonic fibroblasts (CEF). We previously identified a substitution (L288I) in the fusion (F) protein between the two strains. To examine the effect of the substitution on CEF adaptation and attenuation, we generated a recombinant BN-1 strain with the L288I substitution in the F protein (F-EGFP).

Survey for detecting persistently infected cattle with bovine viral diarrhea in Japan.

To establish effective and efficient control measures for bovine viral diarrhea (BVD) in Japan, a pilot survey on persistently infected (PI) animals in dairy farms was conducted. A total of 5,949 cattle from 79 farms in 11 prefectures were tested; seven cattle in six farms were identified as PI animals. The proportion of farms with PI animals in Japan was calculated as 7.

Serological survey of caprine arthritis-encephalitis virus infection in Japan.

A serological survey of caprine arthritis-encephalitis virus (CAEV) infection was conducted from September 2006 to February 2007 in Japan. A total of 857 serum samples were collected from 113 herds in 28 prefectures and were analyzed for the presence of CAEV antibodies using agar gel immunodiffusion test. The seroprevalence of CAEV infection at the herd and animal levels was 15.

The role of neighboring infected cattle in bovine leukemia virus transmission risk.

A cohort study was conducted to evaluate the risk of bovine leukemia virus (BLV) transmission to uninfected cattle by adjacent infected cattle in 6 dairy farms. Animals were initially tested in 2010-2011 using a commercial ELISA kit. Uninfected cattle were repeatedly tested every 4 to 6 months until fall of 2012.

Complete Genome Sequence of Bovine Viral Diarrhea Virus 2 Japanese Reference and Vaccine Strain KZ-91CP.

In this study, we report the complete genome sequence of the bovine viral diarrhea virus 2 Japanese reference strain KZ-91CP. The complete genome comprises 12,654 nucleotides and one open reading frame with 4,020 amino acids. A 369-nucleotide-long insertion encoding the chaperone protein DnaJ is found in the nonstructural 2 (NS2) coding region.

Infection of the upper respiratory tract of hamsters by the bovine parainfluenza virus type 3 BN-1 strain expressing enhanced green fluorescent protein.

Bovine parainfluenza virus type 3 (BPIV3) is an important pathogen associated with bovine respiratory disease complex (BRDC). We have generated a recombinant BPIV3 expressing enhanced green fluorescent protein (rBPIV3-EGFP) based on the BN-1 strain isolated in Japan. After intranasal infection of hamsters with rBPIV3-EGFP, EGFP fluorescence was detected in the upper respiratory tract including the nasal turbinates, pharynx, larynx, and trachea.

Complete genome sequence of the first isolate of genotype C bovine parainfluenza virus type 3 in Japan.

Bovine parainfluenza virus type 3 (BPIV3) isolates are classified into three genotypes (BPIV3a to -c). Here, we report the complete genome sequence of the BPIV3c isolate for the first time in Japan. Our results indicate that new primer sets will be required to detect all genotypes of BPIV3 strains.

First isolation of border disease virus in Japan is from a pig farm with no ruminants.

The first isolation of border disease virus (BDV) in Japan was from a pig farm of the farrow-to-finishing type that kept no small ruminants or cattle. The infection was detected in the course of sero-surveillance for classical swine fever virus (CSFV) in Japan. The infected pigs had no clinical symptoms of CSFV or other disease; nevertheless, a high sero-positive rate of 58.

Complete Genome Sequences of Bovine Parainfluenza Virus Type 3 Strain BN-1 and Vaccine Strain BN-CE.

Bovine parainfluenza virus type 3 (BPIV3) is associated with upper respiratory disease in cattle in many countries. Here, we report the complete genome sequences of the BPIV3 BN-1 strain, isolated from cattle in Japan, and the BN-CE vaccine strain, derived from the BN-1 strain by passages in chicken embryo fibroblasts.

Stability of recombinant bovine interferon-γ antiviral activity in the absence of stabilizing additives.

The stability of recombinant bovine interferon-γ (rbIFN-γ) produced by a baculovirus expression system was investigated under different storage conditions: freezing-thawing and storage for 30 days at temperatures of -80, 4, 25, and 37°C. Antiviral activity was not significantly decreased by freeze-thawing at least five times. Furthermore, although not statistically different, antiviral activity gradually decreased as temperature increased.