Background: Bats have been considered natural reservoirs for several pathogenic human coronaviruses (CoVs) in the last two decades. Recently, a bat CoV was detected in the Republic of Korea; its entire genome was sequenced and reported to be genetically similar to that of the severe acute respiratory syndrome CoV (SARS-CoV). Objectives: The objective of this study was to compare the genetic sequences of SARSCoV, SARS-CoV-2, and the two Korean bat CoV strains 16BO133 and B15-21, to estimate the likelihood of an interaction between the Korean bat CoVs and the human angiotensinconverting enzyme 2 (ACE2) receptor. Methods: The phylogenetic analysis was conducted with the maximum-likelihood (ML) method using MEGA 7 software. The Korean bat CoVs receptor binding domain (RBD) of the spike protein was analyzed by comparative homology modeling using the SWISS-MODEL server. The binding energies of the complexes were calculated using PRODIGY and MM/GBGA. Results: Phylogenetic analyses of the entire RNA-dependent RNA polymerase, spike regions, and the complete genome revealed that the Korean CoVs, along with SARS-CoV and SARSCoV-2, belong to the subgenus Sarbecovirus, within BetaCoVs. However, the two Korean CoVs were distinct from SARS-CoV-2. Specifically, the spike gene of the Korean CoVs, which is involved in host infection, differed from that of SARS-CoV-2, showing only 66.8%–67.0% nucleotide homology and presented deletions within the RBD, particularly within regions critical for cross-species transmission and that mediate interaction with ACE2. Binding free energy calculation revealed that the binding affinity of Korean bat CoV RBD to hACE2 was drastically lower than that of SARS-CoV and SARS-CoV-2. Conclusions These results suggest that Korean bat CoVs are unlikely to bind to the human ACE2 receptor.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging zoonotic disease, which causes high fever, thrombocytopenia, and death in humans and animals in East Asian countries. The pathogenicity of SFTS virus (SFTSV) remains unclear. We intraperitoneally infected three groups of mice: wild-type (WT), mice treated with blocking anti-type I interferon (IFN)-α receptor antibody (IFNAR Ab), and IFNAR knockout (IFNAR−/−) mice, with four doses of SFTSV (KH1, 5 × 105 to 5 × 102 FAID50). The WT mice survived all SFTSV infective doses. The IFNAR Ab mice died within 7 days post-infection (dpi) with all doses of SFTSV except that the mice were infected with 5 × 102 FAID50 SFTSV. The IFNAR−/− mice died after infection with all doses of SFTSV within four dpi. No SFTSV infection caused hyperthermia in any mice, whereas all the dead mice showed hypothermia and weight loss. In the WT mice, SFTSV RNA was detected in the eyes, oral swabs, urine, and feces at 5 dpi. Similar patterns were observed in the IFNAR Ab and IFNAR−/− mice after 3 dpi, but not in feces. The IFNAR Ab mice showed viral shedding until 7 dpi. The SFTSV RNA loads were higher in organs of the IFNAR−/− mice compared to the other groups. Histopathologically,coagulation necrosis and mononuclear inflammatory cell infiltration in the liver and white pulp atrophy in the spleen were seen as the main lesions in the IFN signaling lacking mice. Immunohistochemically, SFTSV antigens were mainly detected in the marginal zone of the white pulp of the spleen in all groups of mice, but more viral antigens were observed in the spleen of the IFNAR−/− mice. Collectively, the IFN signaling-deficient mice were highly susceptible to SFTSV and more viral burden could be demonstrated in various excreta and organs of the mice when IFN signaling was inhibited.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging zoonotic disease, which causes high fever, thrombocytopenia, and death in humans and animals in East Asian countries. The pathogenicity of SFTS virus (SFTSV) remains unclear. We intraperitoneally infected three groups of mice: wild-type (WT), mice treated with blocking anti-type I interferon (IFN)-α receptor antibody (IFNAR Ab), and IFNAR knockout (IFNAR−/−) mice, with four doses of SFTSV (KH1, 5 × 105 to 5 × 102 FAID50). The WT mice survived all SFTSV infective doses. The IFNAR Ab mice died within 7 days post-infection (dpi) with all doses of SFTSV except that the mice were infected with 5 × 102 FAID50 SFTSV. The IFNAR−/− mice died after infection with all doses of SFTSV within four dpi. No SFTSV infection caused hyperthermia in any mice, whereas all the dead mice showed hypothermia and weight loss. In the WT mice, SFTSV RNA was detected in the eyes, oral swabs, urine, and feces at 5 dpi. Similar patterns were observed in the IFNAR Ab and IFNAR−/− mice after 3 dpi, but not in feces. The IFNAR Ab mice showed viral shedding until 7 dpi. The SFTSV RNA loads were higher in organs of the IFNAR−/− mice compared to the other groups. Histopathologically,coagulation necrosis and mononuclear inflammatory cell infiltration in the liver and white pulp atrophy in the spleen were seen as the main lesions in the IFN signaling lacking mice. Immunohistochemically, SFTSV antigens were mainly detected in the marginal zone of the white pulp of the spleen in all groups of mice, but more viral antigens were observed in the spleen of the IFNAR−/− mice. Collectively, the IFN signaling-deficient mice were highly susceptible to SFTSV and more viral burden could be demonstrated in various excreta and organs of the mice when IFN signaling was inhibited.

Arthropod-borne viruses (Arboviruses) are transmitted by arthropods such as Culicoides biting midges and cause abortion, stillbirth, and congenital malformation in ruminants, apparently leading to economic losses to farmers. To monitor the distribution of Culicoides and to determine their relationship with different environmental conditions (temperature, humidity, wind speed, and altitude of the farms) on 5 cattle farms, Culicoides were collected during summer season (May-September) in 2016 and 2017, and analyzed for identification of species and detection of arboviruses. About 35% of the Culicoides were collected in July and the collection rate increased with increase in temperature and humidity. The higher altitude where the farms were located, the more Culicoides were collected on inside than outside. In antigen test of Culicoides against 5 arboviruses, only Chuzan virus (CHUV) (2.63%) was detected in 2016. The Akabane virus (AKAV), CHUV, Ibaraki virus and Bovine ephemeral fever virus (BEFV) had a positive rate of less than 1.8% in 2017. In antigen test of bovine whole blood, AKAV (12.96%) and BEFV (0.96%) were positive in only one of the farms. As a result of serum neutralization test, antibodies against AKAV were generally measured in all the farms. These results suggest that vaccination before the season in which the Culicoides are active is probably best to prevent arbovirus infections.
Agriculture ; Altitude ; Animals ; Antibodies ; Arbovirus Infections ; Arboviruses ; Arthropods ; Cattle ; Ceratopogonidae ; Ephemeral Fever Virus, Bovine ; Farmers ; Humidity ; Jeollabuk-do ; Korea ; Neutralization Tests ; Palyam Virus ; Ruminants ; Seasons ; Stillbirth ; Vaccination ; Wind

On December 3, 2014, a type O foot-and-mouth disease (FMD) outbreak began in Korea. Although vaccinations were administered, FMD cases increased steadily for five months, and reached 185 cases by April 2015. Most of the affected animals were pigs, which are vulnerable to vaccination. The FMD virus belonged to the South-East Asia (SEA) topotype that had been observed three times in Korea between April 2010 and July 2014. However, the FMD virus isolated in December 2014 had a unique feature; that is, partial deletion of the 5′ non-coding region, a deletion not seen in previous SEA topotype isolates identified in Korea. We conclude that this outbreak included the introduction of a new FMD strain to Korea, and that Korea was now affected by genetically similar FMD virus strains that are related to those from neighboring countries.
Animals ; Asia ; Foot-and-Mouth Disease ; Korea ; Swine ; Vaccination

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis. This study was conducted to clarify the molecular characteristics of BLVs obtained from a specific region in Korea. Proviral BLVs were detected in anti-BLV antibody-positive blood samples by PCR. Env and gag fragments were sequenced and compared to previously published reference sequences. Analysis of the env gene sequence revealed that the YI strain was highly similar to genotype 1, including United States and Japanese strains. The gag gene sequence had the highest degree of similarity with a Japanese strain.
Animals ; Asian Continental Ancestry Group ; Cattle* ; Enzootic Bovine Leukosis ; Genes, env ; Genes, gag* ; Genotype ; Humans ; Korea ; Leukemia Virus, Bovine* ; Polymerase Chain Reaction ; United States

Five cases of orf virus infection in Korean black goats were diagnosed in our laboratory between 2010 and 2011. One orf virus (ORF/2011) was isolated from an ovine testis cell line (OA3.Ts) for use as a vaccine candidate. Sequences of the major envelope protein and orf virus interferon resistance genes were determined and compared with published reference sequences. Phylogenetic analyses revealed that orf viruses from Korean black goats were most closely related to an isolate (ORF/09/Korea) from dairy goats in Korea. This result indicates that the orf viruses might have been introduced from dairy goats into the Korean black goat population.
Animals ; Ecthyma, Contagious/epidemiology/*virology ; Goat Diseases/*epidemiology/virology ; Goats ; Molecular Sequence Data ; Orf virus/*genetics/isolation & purification/metabolism ; Phylogeny ; Polymerase Chain Reaction/veterinary ; Republic of Korea/epidemiology ; Sequence Analysis, DNA/veterinary ; Sequence Homology

Culicoides biting midges were collected on three cattle farms weekly using light traps overnight from May to October between 2010 and 2011 in the southern part of Korea. The seasonal and geographical abundance of Culicodes spp. were measured. A total of 16,538 biting midges were collected from 2010 to 2011, including seven species of Culicoides, four of which represented 98.42% of the collected specimens. These four species were Culicodes (C.) punctatus (n = 14,413), C. arakawae (n = 1,120), C. oxystoma (n = 427), and C. maculatus (n = 318). C. punctatus was the predominant species (87.15%).
Animals ; Arboviruses/isolation & purification ; Cattle ; Cattle Diseases/transmission/*virology ; Ceratopogonidae/*classification/*physiology ; Insect Vectors/physiology ; Population Density ; Republic of Korea/epidemiology ; Species Specificity ; Time Factors

Interferon is an important cytokine that plays a critical role in the initial host defense against viral infection. Recombinant human adenoviruses expressing human interferon-alpha (Ad-HIFNalpha) or pig interferon-beta fused with interleukin-18 (Ad-PIFNbeta-IL18) were constructed and used to induce an early protective response against foot and mouth disease (FMD). To analyze the antiviral effect, bovine thyroid and porcine kidney IBRS-2 cells and ICR mice were treated with Ad-HIFNalpha, Ad-PIFNbeta-IL18, and cocktail of Ad-HIFNalpha and Ad-PIFNbeta-IL18. The survival rate of suckling mice was monitored after foot and mouth disease virus (FMDV) challenge following intra-peritoneal (IP) administration of appropriate adenovirus. Indirect antigen ELISA was performed to evaluate inhibition of FMDV replication following challenge with the FMDV O, A, or Asia 1 serotypes in vitro. These recombinant adenoviruses reduced the replication of FMDV in susceptible cells, thereby decreasing the fatality in mice, suggesting that they can be a useful control method for the early protection against FMD infection in livestock after field trial.
Adenoviridae ; Adenoviruses, Human ; Animals ; Asia ; Enzyme-Linked Immunosorbent Assay ; Foot ; Foot-and-Mouth Disease ; Foot-and-Mouth Disease Virus ; Humans ; Interferon-alpha ; Interferon-beta ; Interferons ; Interleukin-18 ; Kidney ; Livestock ; Mice ; Mice, Inbred ICR ; Survival Rate ; Thyroid Gland

A survey was performed in Korea to monitor the prevalence of five bovine arboviruses [Akabane virus, Aino virus, Chuzan virus, bovine ephemeral fever (BEF) virus, and Ibaraki virus] in arthropod vectors, such as Culicoides species. To determine the possible applications of survey data in annual monitoring and warning systems in Korea, we examined the prevalence of bovine arboviruses in arthropod vectors using RT-PCR. To compare the sensitivity and specificity of virus detection, nested PCR was also performed in parallel for all five viruses. Using the RT-PCR, the detection limits were at least up to 10(1.5), 10(2.8), 10(2.0), 10(1.8), and 10(4.0) TCID50/ml for Akabane virus, Aino virus, Chuzan virus, BEF virus, and Ibaraki virus, respectively. When nested PCR was performed using 1 micronl of PCR product, the detection limits were increased, to 10(0.05), 10(1.8), 10(1.0), 10(0.008), and 10(2.0) TCID50/ml for Akabane virus, Aino virus, Chuzan virus, BEF virus, and Ibaraki virus, respectively. Thus, nested PCR increased the sensitivity of the virus detection limit by 1~2 log. We pooled 30~40 mosquitoes in one sample. We collected 113 samples in 2006, 135 samples in 2007, and 100 samples in 2008. Among these samples, Chuzan virus and BEF virus genes were detected at a range between 0.82% and 1.19%, and Akabane virus, Aino virus, and Ibaraki virus genes were detected at less than 0.20%. These data may provide some insight into future epidemiological studies of bovine arboviral diseases in Korea.
Animals ; Arboviruses ; Arthropod Vectors ; Arthropods ; Cattle ; Ceratopogonidae ; Culicidae ; Ephemeral Fever ; Epidemiologic Studies ; Korea ; Limit of Detection ; Organothiophosphorus Compounds ; Palyam Virus ; Polymerase Chain Reaction ; Prevalence ; Sensitivity and Specificity ; Viruses