Canine parvovirus type-2 (CPV-2) is a major etiological agent causing gastrointestinal enteritis in domestic and wild carnivores. Since the emergence of CPV-2 in the late 1970s, subtypes CPV-2a, CPV-2b, and CPV-2c have spread worldwide. CPV-2 prevalence differed according to region and season. This study aims to investigate the prevalence of CPV-2 infection in Korea. Samples were collected from 536 dog feces in animal shelters and 225 necropsied intestinal tissues of dog carcasses submitted in the Animal and Plant Quarantine Agency (APQA) for diagnostic purposes from 2016 to 2020 in Korea. Among the 761 samples, 181 (23.8%) were positive for the following subtypes: CPV-2a (n=138), CPV-2c (n=16), CPV-2b (n=14), and CPV-2 (n=2). Feline parvovirus (n=2) and co-infection with CPV-2a and CPV-2c (n=1) were also detected. There was no significant difference in the regional distribution of CPV-2 in Korea, which is prevalent in winter. This result shows the prevalence of CPV-2 according to various environments in Korea and will be useful in establishing an effective prevention strategy against CPV-2 that reflects the situation in Korea with continuous monitoring.

A solid-phase competition enzyme-linked immunosorbent assay (ELISA), recombinant VP2 (rVP2) protein, and monoclonal antibody (mAb) were developed for the specific and sensitive detection of porcine parvovirus (PPV) antibodies in pig sera. A total of 1,544 sera samples were collected from breeding pig farms located in the Gyeongsangbuk-do Province in the Republic of Korea. The optimal operating conditions of SC-ELISA were as follows. The concentration of rVP2 proteins coated on the wells was 4 μg/mL, the swine sera were diluted 1:2, and the HRP-conjugated PPV VP2 mAb (9A8 clone) was used at 500 ng/mL. These results suggest that the SC-rVP-ELISA assay may be a valuable alternative to the current diagnostic tools used to detect PPV-specific monoclonal antibodies and broadly monitor PPV infections in domestic pigs at different breeding stages.

In this study, the near-complete genome sequence of the novel reassortant H1N2 influenza A virus strain A/swine/Korea/KS60/2016 is reported. Sequences of the hemagglutinin (HA), neuraminidase (NA), and polymerase basic 2 (PB2) genes were analyzed, revealing that the isolates contain segments from previous Korean swine H1N2 strains. Additionally, the remaining genes of this strain originated from human H1N1 strains in 2009.

Porcine parvovirus 2 (PPV2) was recently detected in the Republic of Korea. This paper reports two near-complete genome sequences of PPV2 identified for the first time in the lung tissue of aborted pig fetuses.

Influenza A virus (IAV) causes respiratory disease in birds and mammals, including pigs and humans. Infection by IAV in pigs increases not only economic losses in the swine industry but also the emergence of novel IAV variants via gene reassortment, which is important due to the susceptibility of both birds and humans to IAV. This study provides serological data obtained during a study to detect IAV infections in pigs in the Republic of Korea during 2018 and 2019. A total of 1,559 samples were collected from 74 domestic pig farms. Hemagglutination inhibition (HI) assays were performed using the A/Swine/Korea/25-13(H1N1), A/Swine/Korea/E102 (H1N2), and A/Swine/Korea/Cy10/2007 (H3N2) viruses as antigens. The HI assay results showed that 266 of the 1,559 samples were seropositive (17.0%). Among these, H1N1, H1N2, and H3N2 comprised 7.3% (114), 6.0% (93), and 8.8% (137) of the 1,559 samples, respectively. Co-infections of H1N1/H1N2, H1N1/H3N2, H1N2/H3N2 and H1N1/H1N2/H3N2 were observed in 2.1% (31), 1.5% (23), 1.5% (24), and 0.8% (13) of the 1,559 samples, respectively. Interestingly, IAV infections were detected in all nine provinces of the country.

In this study, antibody responses after vaccination against equine influenza were investigated among 1,591 horses in the Republic of Korea using the hemagglutination inhibition (HI) test. Equine influenza has not occurred since 2011 and a commercial vaccine against H3N8 has been used. The equine influenza virus, A/equine/South Africa/4/03 (H3N8), was used as the antigen in the HI assay. The mean seropositive rate was 90.5% in 2019. Except for stallion whose seropositive rate was 78.5%, all seropositive rates of other horse types were over 90%. Regionally, except for Gangwon-do and Jeju-do whose seropositive rates were 89.0% and 87.1%, all seropositive rates in other provinces were over 90%. In the future, more through vaccination against equine influenza needs to be done based on this investigation result.

Human hepatitis B virus (HBV) infection remains a serious public health problem worldwide, as it is one of the main risk factors for hepatocellular carcinoma (HCC). Cross-species transmission of HBV has been reported in non-human primates, and pigs may also be infected with HBV or an HBV-like agent. The purpose of this study was to demonstrate the presence of HBV antigens and anti-HBV antibodies in pig sera, providing further support for the existence of HBV or an HBV-like agent in pig populations. The HBV surface antigen (HBsAg) and HBV e antigen (HBeAg) in pig serum samples were detected using HBsAg and HBeAg ELISA Kits, respectively. Antibodies to HBsAg and the Hepatitis B core antigen (HBcAg) in serum samples were also detected using anti-HBsAg and anti-HBcAg antibody ELISA Kits, respectively. HBsAg and HBeAg were detected in 7 of 442 (1.6%) and 7 of 184 (3.8%) pig serum samples, respectively. Furthermore, antibodies specific to HBsAg and HBcAg were identified in 45 of 442 (10.2%) and 39 of 434 (9.0%) pig serum samples, respectively. However, neither HBV DNA nor antibodies to HBeAg were detected in 409 and 298 pig serum samples, respectively. HBV antigens and anti-HBV antibodies were both present in a considerable number of pig serum samples, suggesting that pigs could be infected with a variant HBV or an HBV-like agent. Further studies will be necessary to confirm cross-species infection of pigs with HBV.

One hundred one enterococcal isolates from feces of livestock animals in Korea were screened for the presence of bacteriocins. Sixteen of 41 (39%) E. faecalis and 4 of 56 (7.1%) E. faecium isolates showed antimicrobial activity against at least one indicator strain. Only 4 of 20 the enterococcal isolates showing antimicrobial activity possessed at least one bacteriocin gene. While entA and entB were detected in three isolates as a pair of genotype, entQ, bac31, and AS-48 were not found in the enterococcal isolates. In almost all isolates, a correlation between genotype and phenotype of these determinants was not always observed.

Aflatoxins produced by Aspergillus spp. are recognized as a major concern in animal and human health. In pigs, ingestion of aflatoxin-contaminated feeds causes immunosuppression, hepatotoxicosis and poor feed efficiency. In this study, we screened the contaminated level of aflatoxins in 449 pig feeds from 12 swine farms in Korea. For rapid and efficient screening of aflatoxins in pig feeds we evaluated the feasibility of three commercial ELISA kits for the screening of aflatoxins in pig feeds. Twenty-nine pig feed samples were examined for total aflatoxins using three ELISA kits, simultaneously. From three repetitions of each assay, the average intra-assay precisions and the average inter-assay precisions expressed as coefficient of variation (CV, %) for VeratoxⓇ Quantitative Aflatoxin test were 6.90 and 12.29, respectively. A statistical comparison of the results between HPLC and ELISAs showed that the correlation coefficient values for VeratoxⓇ was 0.96. The results demonstrated that we can apply the VeratoxⓇ Quantitative Aflatoxin test for the detection of aflatoxins in pig feed from the field. The screening of field samples with this ELISA kit showed that 11 out of 265 pig feeds for growers and weaners were contaminated with total aflatoxin levels exceeding 10 ppb, maximum tolerable limits for their compound feeds and the aflatoxins levels of remaining 184 pig feeds for other age groups of pigs were confirmed as below 20 ppb. The results from the screening indicated overall low levels of aflatoxins contamination in pig feeds.

Since there had been the first human outbreak of novel influenza A/H1N1 in Mexico, it has become pandemic throughout the world. In the Republic of Korea, the first human case was on May, 2009 and National Veterinary Research and Quarantine Service (NVRQS) has started monitoring novel influenza A/H1N1 on domestic swine farms. The first positive case was detected on 14, Dec, 2009 and until now, we have had total 17 positive cases. From the first case, we did epidemiological investigation on introduction and transmission of virus to pigs. We have concluded that virus had been introduced from humans to pigs, possibly from October to November, 2009 in our country. There were direct and indirect factors including the vehicles transporting veterinary medicine, feed, etc. related to transmission of virus from farm to farm. However, breeding pigs seem to be extrinsic to transmitting factors. Upon the epidemiological investigation, the off-limits of visitors to farms and the disinfection is thought to be critical for blocking the introduction and transmission of novel influenza A/H1N1. In addition, collecting and analyzing the genetic informations of influenza virus is important for predicting and handling the new pandemic influenza in the future.