Porcine epidemic diarrhea virus: an update overview of virus epidemiology, vaccines, and control strategies in South Korea

Porcine epidemic diarrhea virus (PEDV) has posed significant financial threats to the domestic pig industry over the last three decades in South Korea. PEDV infection will mostly result in endemic persistence in the affected farrow-to-finish (FTF) herds, leading to endemic porcine epidemic diarrhea (PED) followed by year-round recurrent outbreaks. This review aims to encourage collaboration among swine producers, veterinarians, and researchers to offer answers that strengthen our understanding of PEDV in efforts to prevent and control endemic PED and to prepare for the next epidemics or pandemics. We found that collaboratively implementing a PED risk assessment and customized four-pillar-based control measures is vital to interrupt the chain of endemic PED in affected herds: the former can identify on-farm risk factors while the latter aims to compensate for or improve weaknesses via herd immunity stabilization and virus elimination. Under endemic PED, long-term virus survival in slurry and asymptomatically infected gilts (“Trojan Pigs”) that can transmit the virus to farrowing houses are key challenges for PEDV eradication in FTF farms and highlight the necessity for active monitoring and surveillance of the virus in herds and their environments. This paper underlines the current knowledge of molecular epidemiology and commercially available vaccines, as well as the risk assessment and customized strategies to control PEDV. The intervention measures for stabilizing herd immunity and eliminating virus circulation may be the cornerstone of establishing regional or national PED eradication programs.

Two Cases of Herpes Virus Infection of Nose Mimicking Acute Invasive Fungal Infection in Immunocompromised Hosts

Various invasive fungal infections can occur in immunocompromised hosts, and an acute invasive fungal infection (AIFI) can be fatal. Because of its high mortality rate, AIFI must be quickly diagnosed and treated, such as anti-fungal agents or surgical debridement. In an immunocompromised host, nasal herpes simplex infection, usually caused by herpes simplex virus (HSV) type-1, can have various clinical manifestations, some of which can mimic AIFI. However, the management of acute viral infection differs significantly from invasive fungal infections of the nose. A fast and accurate differential diagnosis is mandatory because a delay in the disease-specific treatment of acute invasive infections can lead to mortality. This report describes two immunocompromised patients with mucosal and skin lesions around the nose. We provide clinical clues when mucosal lesions of the nasal cavity and skin lesions around the nose develop in immunocompromised hosts.

Generation of Hepatic Progenitor Cells from the Primary Hepatocytes of Nonhuman Primates Using Small Molecules

BACKGROUND@#Since primates have more biological similarities to humans than do other animals, they are a valuable resource in various field of research, including biomedicine, regenerative medicine, and drug discovery. However, there remain limitations to maintenance and expansion of primary hepatocytes derived from nonhuman primates. To overcome these limitations, we developed a novel culture system for primate cells. @*METHODS@#Primary hepatocytes from Macaca fascicularis (mf-PHs) were isolated from hepatectomized liver. To generate chemically derived hepatic progenitor cells (mf-CdHs), mf-PHs were cultured with reprogramming medium containing A83-01, CHIR99021, and hepatocyte growth factor (HGF). The bi-potent differentiation capacity of mf-CdHs into hepatocytes and biliary epithelial cells was confirmed by treatment with hepatic differentiation medium (HDM) and cholangiocytic differentiation medium (CDM), respectively. @*RESULTS@#mf-PHs cultured with reprogramming medium showed rapid proliferation capacity in vitro and expressed progenitor-specific markers. Moreover, when cultured in HDM, these progenitor cells stably differentiated into hepatocytelike cells expressing the mature hepatic markers. On the other hand, when cultured in CDM, the differentiated biliary epithelial cells expressed mature cholangiocyte characteristics. @*CONCLUSION@#The results of the present study demonstrate that we successfully induced the formation of hepatic progenitor cells from mf-PHs by culturing them with a combination of small molecules, including growth factors. These results offer a means of expanding nonhuman primate hepatocytes without genetic manipulation for cellular resource, preclinical applications and regenerative medicine for the liver.

Assessing the risk of recurrence of porcine epidemic diarrhea virus in affected farms on Jeju Island, South Korea

Background@#Porcine epidemic diarrhea virus (PEDV) is a swine enteropathogenic coronavirus that has devastated the swine industry in South Korea over the last 30 years. The lack of an effective method to control the endemics has led to a surge in PEDV recurrences in affected farms throughout the country. @*Objectives@#In the first step toward establishing systematic monitoring of and active control measures over the swine populations, we constructed an assessment model that evaluates the status of (1) biosecurity, (2) herd immunity, and (3) virus circulation in each of the PEDVinfected farms. @*Methods@#A total of 13 farrow-to-finish pig farms with a history of acute PEDV infection on Jeju Island were chosen for this study. The potential risk of the recurrence in these farms was estimated through on-site data collection and laboratory examination. @*Results@#Overall, the data indicated that a considerable number of the PEDV-infected farms had lax biosecurity, achieved incomplete protective immunity in the sows despite multi-dose vaccination, and served as incubators of the circulating virus; thus, they face an increased risk of recurrent outbreaks. Intriguingly, our results suggest that after an outbreak, a farm requires proactive tasks, including reinforcing biosecurity, conducting serological and virus monitoring to check the sows’ immunity and to identify the animals exposed to PEDV, and improving the vaccination scheme and disinfection practices if needed. @*Conclusions@#The present study highlights the significance of coordinated PEDV management in infected farms to reduce the risk of recurrence and further contribute towards the national eradication of PEDV.

Characteristics of HER2-Positive Breast Cancer according to HER2 2+/ Low or 3+/High Classification by Immunohistochemistry Assay: Study of 205 Cases Treated in a Single Center

Purpose@#To investigate the characteristics of HER2-positive breast cancer according to HER2 low (2+) or high (3+) classification using immunohistochemistry (IHC). @*Methods@#Data were collected from 205 HER2-positive breast cancer patients in the final assay, regardless of IHC or in situ hybridization (ISH). We thus classified patients into two groups: HER2 2+/low and HER2 3+/high based on the IHC assay. We subsequently compared the clinical and pathological characteristics between groups. @*Results@#The median patient age was 49 years in the HER2 2+/low group and 53 years in the HER2 3+/high group. We observed a significantly lower Allred score for estrogen receptor (ER) and progesterone receptor (PR) (0-6) (p<0.001), less lymphatic invasion (LI), (p=0.010), neural invasion (p=0.041), higher Ki-67 (p=0.001), and lower Bcl-2 (p<0.001) in the HER2 3+/high group than in the HER2 2+/low group. Lymph node recurrence was more frequently observed in the HER2 2+/low group than in HER2 3+/high group (p=0.005). Disease-free survival (DFS) was better in the HER2 3+/high group than in the HER2 2+/low group (p=0.028), but there were no significant differences in overall survival between the groups (p=0.233). @*Conclusion@#The HER2 3+/high group was associated with lower ER and PR expression, less LI, higher Ki-67, and lower Bcl-2 than that in HER2 2+/low group in HER2-positive breast cancer. Furthermore, compared to the HER2 2+/low group, the HER2 3+/high group had an improved DFS.

Generation of Hepatic Progenitor Cells from the Primary Hepatocytes of Nonhuman Primates Using Small Molecules

BACKGROUND@#Since primates have more biological similarities to humans than do other animals, they are a valuable resource in various field of research, including biomedicine, regenerative medicine, and drug discovery. However, there remain limitations to maintenance and expansion of primary hepatocytes derived from nonhuman primates. To overcome these limitations, we developed a novel culture system for primate cells. @*METHODS@#Primary hepatocytes from Macaca fascicularis (mf-PHs) were isolated from hepatectomized liver. To generate chemically derived hepatic progenitor cells (mf-CdHs), mf-PHs were cultured with reprogramming medium containing A83-01, CHIR99021, and hepatocyte growth factor (HGF). The bi-potent differentiation capacity of mf-CdHs into hepatocytes and biliary epithelial cells was confirmed by treatment with hepatic differentiation medium (HDM) and cholangiocytic differentiation medium (CDM), respectively. @*RESULTS@#mf-PHs cultured with reprogramming medium showed rapid proliferation capacity in vitro and expressed progenitor-specific markers. Moreover, when cultured in HDM, these progenitor cells stably differentiated into hepatocytelike cells expressing the mature hepatic markers. On the other hand, when cultured in CDM, the differentiated biliary epithelial cells expressed mature cholangiocyte characteristics. @*CONCLUSION@#The results of the present study demonstrate that we successfully induced the formation of hepatic progenitor cells from mf-PHs by culturing them with a combination of small molecules, including growth factors. These results offer a means of expanding nonhuman primate hepatocytes without genetic manipulation for cellular resource, preclinical applications and regenerative medicine for the liver.

Assessing the risk of recurrence of porcine epidemic diarrhea virus in affected farms on Jeju Island, South Korea

Background@#Porcine epidemic diarrhea virus (PEDV) is a swine enteropathogenic coronavirus that has devastated the swine industry in South Korea over the last 30 years. The lack of an effective method to control the endemics has led to a surge in PEDV recurrences in affected farms throughout the country. @*Objectives@#In the first step toward establishing systematic monitoring of and active control measures over the swine populations, we constructed an assessment model that evaluates the status of (1) biosecurity, (2) herd immunity, and (3) virus circulation in each of the PEDVinfected farms. @*Methods@#A total of 13 farrow-to-finish pig farms with a history of acute PEDV infection on Jeju Island were chosen for this study. The potential risk of the recurrence in these farms was estimated through on-site data collection and laboratory examination. @*Results@#Overall, the data indicated that a considerable number of the PEDV-infected farms had lax biosecurity, achieved incomplete protective immunity in the sows despite multi-dose vaccination, and served as incubators of the circulating virus; thus, they face an increased risk of recurrent outbreaks. Intriguingly, our results suggest that after an outbreak, a farm requires proactive tasks, including reinforcing biosecurity, conducting serological and virus monitoring to check the sows’ immunity and to identify the animals exposed to PEDV, and improving the vaccination scheme and disinfection practices if needed. @*Conclusions@#The present study highlights the significance of coordinated PEDV management in infected farms to reduce the risk of recurrence and further contribute towards the national eradication of PEDV.

Characteristics of HER2-Positive Breast Cancer according to HER2 2+/ Low or 3+/High Classification by Immunohistochemistry Assay: Study of 205 Cases Treated in a Single Center

Purpose@#To investigate the characteristics of HER2-positive breast cancer according to HER2 low (2+) or high (3+) classification using immunohistochemistry (IHC). @*Methods@#Data were collected from 205 HER2-positive breast cancer patients in the final assay, regardless of IHC or in situ hybridization (ISH). We thus classified patients into two groups: HER2 2+/low and HER2 3+/high based on the IHC assay. We subsequently compared the clinical and pathological characteristics between groups. @*Results@#The median patient age was 49 years in the HER2 2+/low group and 53 years in the HER2 3+/high group. We observed a significantly lower Allred score for estrogen receptor (ER) and progesterone receptor (PR) (0-6) (p<0.001), less lymphatic invasion (LI), (p=0.010), neural invasion (p=0.041), higher Ki-67 (p=0.001), and lower Bcl-2 (p<0.001) in the HER2 3+/high group than in the HER2 2+/low group. Lymph node recurrence was more frequently observed in the HER2 2+/low group than in HER2 3+/high group (p=0.005). Disease-free survival (DFS) was better in the HER2 3+/high group than in the HER2 2+/low group (p=0.028), but there were no significant differences in overall survival between the groups (p=0.233). @*Conclusion@#The HER2 3+/high group was associated with lower ER and PR expression, less LI, higher Ki-67, and lower Bcl-2 than that in HER2 2+/low group in HER2-positive breast cancer. Furthermore, compared to the HER2 2+/low group, the HER2 3+/high group had an improved DFS.

Simulation study about cardiac arrest recognition of emergency medical dispatcher using video call

Objective@#Bystander cardiopulmonary resuscitation is important for the survival of cardiac arrest patients. The rapid recognition of cardiac arrest by dispatchers leads to quicker initiation of bystander cardiopulmonary resuscitation. This study examines the use of video phone by dispatchers in recognizing cardiac arrest. @*Methods@#Between June to October 2018, 227 participants were recruited (114 lay people and 113 dispatchers) for this study. Lay people participants answered prepared questionnaires after watching 6 scenario video clips of a collapsed virtual patient with unresponsiveness. Dispatchers were divided into two groups: audio call group and video call group. The audio call group judged for occurrence of a cardiac arrest in the 6 scenarios, referring only to questionnaires of the lay people. The video call group judged the same scenarios referring to questionnaires and scenario video clips. The score of correct answers of each scenario was subsequently analyzed. @*Results@#Significant difference was obtained for the total score among the audio call group and the video call group (3.67 ±1.3 vs. 4.66±1.11, respectively; P<0.001). In 2 scenarios concerning cardiac arrest with gasping, the correct answer rate was higher in the video call group (63.9% vs. 85.2%, P<0.001; 59.5% vs. 74.8%, P=0.014). In 2 other scenarios showing non-cardiac arrest with normal breathing, the correct answer rate was also higher in the video call group (52.7% vs. 71.4, P=0.010; 38.2% vs. 63.6%, P<0.001). @*Conclusion@#This study determined that compared to the audio call group, dispatchers of the video call group were more accurate in recognizing cardiac arrest. This indicates that video phones are more helpful in determining gasping and in discerning cardiac arrest with syncope or seizure.

Generation and protective efficacy of a cold-adapted attenuated genotype 2b porcine epidemic diarrhea virus

The recent emergence and re-emergence of porcine epidemic diarrhea virus (PEDV) underscore the urgent need for the development of novel, safe, and effective vaccines against the prevailing strain. In this study, we generated a cold-adapted live attenuated vaccine candidate (Aram-P29-CA) by short-term passage of a virulent PEDV isolate at successively lower temperatures in Vero cells. Whole genome sequencing identified 12 amino acid changes in the cold-adapted strain with no insertions and deletions throughout the genome. Animal inoculation experiments confirmed the attenuated phenotype of Aram-P29-CA virus in the natural host. Pregnant sows were orally administered P29-CA live vaccines two doses at 2-week intervals prior to parturition, and the newborn piglets were challenged with the parental virus. The oral homologous prime-boost vaccination of P29-CA significantly improved the survival rate of the piglets and notably mitigated the severity of diarrhea and PEDV fecal shedding after the challenge. Furthermore, strong antibody responses to PEDV were detected in the sera and colostrum of immunized sows and in the sera of their offspring. These results demonstrated that the cold-adapted attenuated virus can be used as a live vaccine in maternal vaccination strategies to provide durable lactogenic immunity and confer passive protection to litters against PEDV.

Prevalence and molecular characterization of novel recombinant enterovirus G isolates in Jeju Province of South Korea / 대한수의학회지

Enterovirus species G (EV-G) is highly diverse, and is ubiquitous in pig populations, usually without diarrhea. The present study aimed to investigate the presence of novel EV-G recombinants with the torovirus papain-like cysteine protease (PLCP) in Jeju pig herds. EV-G1-PLCP mono-infections were most prevalent in diarrheic weaned piglets. The PLCP genes of the Jeju isolates varied in size and junction sequences, and were greatly heterogeneous, with 77.0–90.7% homology amongst all recombinants. Our results suggest that the exogenous PLCP gene has undergone continuous rapid mutation in the individual EV-G genomes following cross-order recombination, thereby causing clinical disease in swine.

Prevalence and molecular characterization of novel recombinant enterovirus G isolates in Jeju Province of South Korea

Enterovirus species G (EV-G) is highly diverse, and is ubiquitous in pig populations, usually without diarrhea. The present study aimed to investigate the presence of novel EV-G recombinants with the torovirus papain-like cysteine protease (PLCP) in Jeju pig herds. EV-G1-PLCP mono-infections were most prevalent in diarrheic weaned piglets. The PLCP genes of the Jeju isolates varied in size and junction sequences, and were greatly heterogeneous, with 77.0–90.7% homology amongst all recombinants. Our results suggest that the exogenous PLCP gene has undergone continuous rapid mutation in the individual EV-G genomes following cross-order recombination, thereby causing clinical disease in swine.

Isolation and characterization of Korean porcine deltacoronavirus strain KNU16-07

Porcine deltacoronavirus (PDCoV) has emerged in several pig-raising countries and has been a causative pathogen associated with diarrheal diseases in South Korea since 2014. In the present study, we were able to isolate and cultivate a Korean PDCoV strain (KNU16-07) in cell culture and investigate its pathogenicity. PDCoV-inoculated piglets showed watery diarrhea accompanied by acute enteritis in the natural host. Sequencing analysis demonstrated the genetic stability of KNU16-07 for at least thirty serial passages.

Phenotypic and genotypic analyses of an attenuated porcine reproductive and respiratory syndrome virus strain after serial passages in cultured porcine alveolar macrophages

The porcine reproductive and respiratory syndrome virus (PRRSV) is a globally ubiquitous swine viral pathogen that causes major economic losses worldwide. We previously reported an over-attenuated phenotype of cell-adapted PRRSV strain CA-2-P100 in vivo. In the present study, CA-2-P100 was serially propagated in cultured porcine alveolar macrophage (PAM) cells for up to 20 passages to obtain the derivative strain CA-2-MP120. Animal inoculation studies revealed that both CA-2-P100 and CA-2-MP120 had decreased virulence, eliciting weight gains, body temperatures, and histopathologic lesions similar to those in the negative control group. However, compared to CA-2-P100 infection, CA-2-MP120 yielded consistently higher viremia kinetics and enhanced antibody responses in pigs. All pigs inoculated with CA-2-MP120 developed viremia and seroconverted to PRRSV. During 20 passages in PAM cells, CA-2-MP120 acquired 15 amino acid changes that were mostly distributed in nsp2 and minor structural protein-coding regions. Among these changes, 6 mutations represented reversions to the sequences of the reference CA-2 and parental CA-2-P20 strains. These genetic drifts may be hypothetical molecular markers associated with PRRSV macrophage tropism and virulence. Our results indicate that the PAM-passaged CA-2-MP120 strain is a potential candidate for developing a live, attenuated PRRSV vaccine.

Evaluation of the efficacy of an attenuated live vaccine based on virulent porcine reproductive and respiratory syndrome virus 2 in young pigs / 대한수의학회지

The efficacy of the CA-2-MP120 vaccine, a cell culture-attenuated strain of virulent porcine reproductive and respiratory syndrome virus (PRRSV), was assessed in pigs. Despite the persistence of viremia in all vaccinated animals during the immunization period, the virus was not detected in vaccinated pigs following challenge. Furthermore, no pigs in the vaccinated group shed PRRSV nasally, orally or rectally throughout the experiment. Moreover, histopathological lung and lymph node lesions in the immunized group were much milder than those in the unimmunized and challenged group. These results indicated that CA-2-MP120 can provide effective protection against virulent wildtype PRRSV-2.

Evaluation of the efficacy of an attenuated live vaccine based on virulent porcine reproductive and respiratory syndrome virus 2 in young pigs

The efficacy of the CA-2-MP120 vaccine, a cell culture-attenuated strain of virulent porcine reproductive and respiratory syndrome virus (PRRSV), was assessed in pigs. Despite the persistence of viremia in all vaccinated animals during the immunization period, the virus was not detected in vaccinated pigs following challenge. Furthermore, no pigs in the vaccinated group shed PRRSV nasally, orally or rectally throughout the experiment. Moreover, histopathological lung and lymph node lesions in the immunized group were much milder than those in the unimmunized and challenged group. These results indicated that CA-2-MP120 can provide effective protection against virulent wildtype PRRSV-2.

Clinical Nutrition Management Status in Convalescent Hospitals Before and After Healthcare Accreditation Process

The increasing elderly population has created an urgent need for well-managed convalescent hospitals, which should provide appropriate clinical nutrition services. The new accreditation policy requiring participation of all convalescent hospitals since 2013 may promote improvement of clinical nutrition services. This study examined whether or not the accreditation policy has increased practice level and dietitians' perception of the importance of clinical nutrition management. Of the 177 convalescent hospitals accredited by January 30, 2014, dietitians from 73 hospitals (41.2%) completed the survey questionnaire. The pre-tested questionnaire surveyed general characteristics of the hospital and dietitians, current status of clinical nutrition management, and changes in the perception and practice levels of various aspects of food and clinical nutrition management. In average, dietitians with more than 5 years of work experience (68.1%) provided food and clinical nutrition services (71.2%). After accreditation, dietitians' perception of the importance and practice level of clinical nutrition service increased (P<0.001). Level of perception, however, was significantly (P<0.001) higher than practice level before and after accreditation. During perception and practice level of initial nutrition assessment, a compulsory accreditation item, notably and significantly (P<0.001) improved after accreditation. The significant difference between perception and practice level disappeared after accreditation. In conclusion, the accreditation process had positive effects on clinical nutrition management in terms of dietitians' perception and practice levels. Making more accreditation items compulsory and providing motivation and professional education to dietitians in convalescent hospitals could lead to additional improvements.

Recurrent Upper Gastrointestinal Bleeding from Gastro-Cystic Fistula and Pancreatic Pseudocyst Bleeding / 대한췌담도학회지

Bleeding from pancreatic pseudocyst is a rare complication. Furthermore, massive upper gastrointestinal (GI) bleeding from gastro-cystic fistula formation and intracystic bleeding are both extremely rare and are also potentially fatal. A 53-year-old male was referred to the emergency room with melena and hematemesis. An urgent endoscopy revealed a massive gastric hematoma but showed no specific bleeding focus. Gastrocystic fistula formation and intracystic bleeding leakage to the stomach were suspicious in the follow-up endoscopy. A contrast-enhanced computed tomography scan demonstrated splenic artery pseudoaneurysm and extravasation of contrast media into the cyst that was abutted to the greater curvature side of the stomach. A splenic artery embolization was performed and no further bleeding occurred after embolization. Upper GI bleeding from gastro-cystic fistula and intracystic bleeding are rare but possible. Therefore, this possibility should be considered in the unknown cause of an upper GI bleeding in a patient with pancreatic pseudocyst.

Reemergence of porcine epidemic diarrhea virus on Jeju Island / 대한수의학회지

Porcine epidemic diarrhea virus (PEDV) strains responsible for recent outbreaks in the United States have been occurring in Mainland Korea since late 2013. Over the past 10 years, PEDV outbreaks have not been reported on Jeju Island. However, in late March of 2014, PEDV re-emerged on Jeju Island and was found to be genetically identical to PEDV strains currently circulating in Mainland Korea. The present study was conducted to provide a better understanding of the epidemiology of PEDV and more effective preventive measures against PED.

Reemergence of porcine epidemic diarrhea virus on Jeju Island / 대한수의학회지

Porcine epidemic diarrhea virus (PEDV) strains responsible for recent outbreaks in the United States have been occurring in Mainland Korea since late 2013. Over the past 10 years, PEDV outbreaks have not been reported on Jeju Island. However, in late March of 2014, PEDV re-emerged on Jeju Island and was found to be genetically identical to PEDV strains currently circulating in Mainland Korea. The present study was conducted to provide a better understanding of the epidemiology of PEDV and more effective preventive measures against PED.