Histological and lectin histochemical studies in the vomeronasal organ of the Korean black goat, Capra hircus coreanae.

We examined the localization of olfactory marker protein (OMP), protein gene product9.5 (PGP9.5), and glycan diversity in the vomeronasal organ (VNO) of the Korean black goat (Capra hircus coreanae) during the prenatal and postnatal periods using immunohistochemistry and lectin histochemistry. In fetal and 1-day-old goats, OMP was occasionally identified in receptor cells of the VNO sensory epithelium, and PGP9.5 was localized in both the sensory and non-sensory epithelia. In VNO from adult goats, OMP was abundant in the sensory epithelium and scarce in single cells of the non-sensory epithelium. These results suggest that OMP production is initiated in the VNO sensory epithelium (VNE) during the fetal stage, and that its activity is increased in adult VNO receptor cells and solitary cells in the non-sensory epithelium (VNSE). Furthermore, the free borders of the sensory epithelia were positive for 7 lectins, and 6 lectins were moderately and/or highly abundant in receptor cells. Supporting and basal cells, and nerve bundles had similar expression patterns. In VNE, 7 lectins were observed in the free border, and 6 in ciliated, goblet, and basal cells, and in gland acini. The intensities of WGA, LCA, and PNA were high in VSE receptor cells, and the intensity of PNA was high in ciliated cells of the VNSE. The other 3 lectins showed similar patterns throughout development. Collectively, these results confirm that the Korean black goat VNO starts developing during the late fetal stages and differentiates further after birth.

Adverse Effects of Classical Swine Fever Virus LOM Vaccine and Jeju LOM Strains in Pregnant Sows and Specific Pathogen-Free Pigs.

In Jeju island of South Korea, a classical swine fever (CSF) non-vaccinated region, many pig farmers insisted on abortion and stillbirth in pregnant sows and high mortality of suckling/weaning piglets by circulating CSF virus from 2014 to 2018. We investigated whether CSF viruses isolated from pigs in Jeju Island (Jeju LOM) have recovered their pathogenicity by conducting experiments using pregnant sows and specific pathogen-free (SPF) pigs. The CSF modified live LOM vaccine (MLV-LOM) and Jeju LOM strains induced abortion and stillbirth in pregnant sows. Viral antigens were detected in the organs of fetuses and stillborn piglets in the absence of specific pathological lesions associated with the virulent CSF virus in both groups (MLV-LOM and Jeju LOM strain). However, antigen was detected in one newborn piglet from a sow inoculated with a Jeju LOM strain, suggesting that it may cause persistent infections in pigs. SPF pigs inoculated with the MLV-LOM or Jeju LOM strains were asymptomatic, but virus antigen was detected in several organ and blood samples. Virus shedding in both groups of animals was not detected in the feces or saliva until 21 days post inoculation. The serum concentration of the three major cytokines, IFN-α, TNF-α, and IL-10, known to be related to lymphocytopenia, were similar in both groups when the MLV-LOM or Jeju LOM strains were inoculated into SPF pigs. In conclusion, Jeju LOM strains exhibited most of the characteristics of the MLV-LOM in pigs and resulted in the same adverse effects as the MLV-LOM strain.

Impact of a Live Attenuated Classical Swine Fever Virus Introduced to Jeju Island, a CSF-Free Area.

Here, we examine the effects of LOM(Low virulence of Miyagi) strains isolated from pigs (Jeju LOM strains) of Jeju Island, where vaccination with a live attenuated classical swine fever (CSF) LOM vaccine strain was stopped. The circulation of the Jeju LOM strains was mainly caused by a commercial swine erysipelas (Erysipelothrix rhusiopathiae) vaccine mixed with a LOM vaccine strain, which was inoculated into pregnant sows of 20 pig farms in 2014. The Jeju LOM strain was transmitted to 91 pig farms from 2015 to 2018. A histopathogenic investigation was performed for 25 farms among 111 farms affected by the Jeju LOM strain and revealed pigs infected with the Jeju LOM strain in combination with other pathogens, which resulted in the abortion of fetuses and mortality in suckling piglets. Histopathologic examination and immunohistochemical staining identified CSF-like lesions. Our results also confirm that the main transmission factor for the Jeju LOM strain circulation is the vehicles entering/exiting farms and slaughterhouses. Probability estimates of transmission between cohabiting pigs and pigs harboring the Jeju LOM strain JJ16LOM-YJK08 revealed that immunocompromised pigs showed horizontal transmission (r = 1.22). In a full genome analysis, we did not find genetic mutation on the site that is known to relate to pathogenicity between Jeju LOM strains (2014-2018) and the commercial LOM vaccine strain. However, we were not able to determine whether the Jeju LOM strain (2014-2018) is genetically the same virus as those of the commercial LOM vaccine due to several genetic variations in structure and non-structure proteins. Therefore, further studies are needed to evaluate the pathogenicity of the Jeju LOM strain in pregnant sow and SPF pigs and to clarify the characteristics of Jeju LOM and commercial LOM vaccine strains.