• Korean Journal of Veterinary Service
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• v.46 no.3
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• pp.193-202
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• 2023

Porcine epidemic diarrhea is an infectious intestinal disease caused by the porcine epidemic diarrhea virus (PEDV). Especially, when suckling piglets are infected, the mortality rate is close to 100%. PEDV is classified into G1 and G2 types based on genetic differences. The G2 type PEDV outbreak in the United States in 2013 was highly pathogenic and contagious, and it has spread worldwide and caused continuous economic losses. Most commercial vaccines used are G1 type vaccines, and existing vaccines do not fully protect piglets due to genetic differences. In this study, we evaluated the safety of the newly developed G2 type attenuated HSGP vaccine strain by inoculating it into piglets and testing whether the vaccine virus spreads to the non-vaccinated, negative pigs and whether the vaccine reverts to its virulence during serial passage experiments. Each experiment lasted for 7 days for each passage, and fecal viral titers, clinical symptoms, and weight gain were measured daily. After the experiment, necropsy was performed to measure intestinal virus titer and pathological evaluation. As a result of the first passage, no transmission of the vaccine virus to negative pigs co-housed with vaccinated pigs was observed. In addition, after four consecutive passage experiments, the clinical symptoms and small intestine lesions were gradually alleviated, and no virus was detected in the feces in the fourth passage experiment. Therefore, it was concluded that the vaccine was safe without virulence reversion in accordance with the guidelines of the current licensing authority. However, further studies are needed on the genetic changes and biological characteristics of the mutant virus that occur during successive passages of the attenuated vaccine since the replication and clinical symptoms of the virus increased until the third passage during successive passages of the vaccine virus. Based on this study, it was concluded that virulence reversion and safety evaluation of attenuated vaccines through serial passage in target animals can be useful to evaluate the safety of attenuated viruses.

• Journal of Preventive Medicine and Public Health
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• v.38 no.2
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• pp.182-188
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• 2005

Objectives: This study was undertaken to investigate the source of infection and mode of transmission of shigellosis, which occurred sporadically among residents and students in a subcounty of Cheongwon county, Chungbuk province, Korea, from June 4 to July 3 2003. Methods: 692 subjects completed a questionnaire and provided a swab for microbiological examinations,and 7 environmental specimens were examined for bacterial organisms. PFGE (pulsed-field gel electrophoresis) and fingerprinting were performed to find the genetic relationship among the temporally associated sporadic isolates. Results: A total of 29 patients had symptoms consistent with the case definition, with 13 confirmed and 16 suspected cases. The frequency of diarrhea was 6 times or more a day (80.8%), with a duration of 1 to 4 days (88.5%) in most cases. The most common symptoms accompanying the diarrhea were fever (80.9%) followed by abdominal pain (76.9%), headache (65.4%), chill (61.5%), vomiting (46.2%) and tenesmus (15.4%). The epidemic curve was characteristic of a person-to-person transmission. The PFGE and fingerprinting demonstrated identical or similar DNA patterns among the 3 Shigella sonnei isolates (A51, A53 and A61 types) found in this outbreak. Conclusion: A genetically identical strain of S. sonnei was estimated to be the cause of this outbreak, and the mode of transmission was most likely person-to-person.

• Journal of Veterinary Clinics
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• v.26 no.5
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• pp.463-466
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• 2009

A swine farm located in the Kyungpook province (designated as farm D that have been suffering from PED for several years was selected to study the etiology and the outbreak pattern of PED by clinical and laboratory examinations. Clinical examination indicated that sows exhibited signs of mastitis resulting in an inadequate transfer of lactogenic immunity against PEDV to newborn piglets. Furthermore, serological tests revealed that all sow groups and their piglets had low levels of anti-PEDV antibody. These data suggest that improper vaccination program has been indeed performed in this farm. Remarkably, despite no symptoms of PED in weaners, the presence of PEDV was identified by RT-PCR from fecal samples of weaning piglets, indicating persistent PEDV circulation in the herd. Based on these results, the following basic control schemes were executed for the control of PEDV circulation in the farm; a) A quick removal of affected pigs and disinfection of affected sheds. b) restructuring of vaccination program and employment of consultant. c) prompt treatment of mastitis and removal of poor lactogenic sows, and d) enhancement of biosecurity of farrowing house by acquisition of additional space. We evaluated risk factors and implementation of control measures in two months and were unable to found any case related to PEDV infection. Taken together, our data indicate that the method described above is effective for the control of PED outbreak in farm persistently suffering from PEDV infection.

• Tuberculosis and Respiratory Diseases
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• v.41 no.3
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• pp.289-298
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• 1994

Background: Most studies of Mycoplasma pneumonia involve a group of admitted patients in hospital, usually with major medical illness. So we investigated the epidemiologic and radiologic features during the course of outbreak of pneumonia in Chunnam coastal area. Methods: We retrospectively studied the epidemiologic and clinical feature of 105 patients with serologically proven Mycoplasma pneumonia treated at Kwang-Yang Hospital during a epidemic period of Jun.1993 to Dec.1993. All cases of pneumonia developed in this period were also reviewed and compared with serologically proven group. Results: 1) There were 63 males and 42 females. 2) More than half(57%) of cases belonged to 5-9 years of age group, and mean age was 6.5 years old. Mean age was steadily decreased as prevalence of Mycoplasma pneumonia had been subsided. 3) A major determinant of the outbreak seemed to be the population density rather than the population size. 4) The common radiologic features were interstitial in type, and 67 cases was restricted to one lobe. Lobar types are more common in late childhood, and interstitial or diffuse types in early childhood. Conclusion: These epidemiologic and radiographic characteristics would contribute to the diagnosis of Mycoplasma pneumonia.

• Journal of Medicine and Life Science
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• v.18 no.2
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• pp.25-30
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• 2021

Many people reported suspected food poisoning after consuming food at the same snack bar on June 18, 2020. Thus, an in-depth epidemiological investigation was conducted to identify the infectious agent and establish additional food poisoning prevention measures. The study included people who reported to the local public health center after June 18 with acute gastroenteritis symptoms within 4 days of consuming food from the snack bar. The onset of symptoms and food items consumed by individuals were then investigated via phone calls and on-site visits. Afterward, the infectious agent was identified from human samples (stool or rectal swab) of four restaurant employees and 89 people and from environmental samples (materials, cooking utensils, and water). The analysis revealed that the incubation period ranged from 2 hours to 92 hours, with a median and mode of 16 hours and 12 hours, respectively. Moreover, the epidemic curve had a unimodal shape because of common exposure, which reached its peak on June 18. After monitoring for 8 days, which is more than twice the maximum incubation period of 92 hours, the end of the epidemic was declared on June 28 as no additional cases were reported. Analysis of human and environmental samples revealed Salmonella bareilly of the pulsed-field gel electrophoresis pulsotype SAPX01.017 as the causative agent. Therefore, it was concluded that the food poisoning outbreak was caused by S. bareilly.

• Neonatal Medicine
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• v.15 no.1
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• pp.44-53
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• 2008

Purpose : Epidemic keratoconjunctivitis (EKC) caused by adenovirus is a highly contagious disease, which has been reported as outbreaks involving adults in the community. However, there has been no report on EKC outbreak by adenovirus in a neonatal intensive care unit (NICU) in Korea. Aims of this study were to investigate the EKC outbreak by adenovirus type 8 in NICU and to confirm an effectiveness of polymerase chain reaction (PCR) for diagnosis. Methods : Conjunctival swab or nasopharyngeal aspirate specimens were taken from all patients and tested by viral culture and PCR. Adenovirus serotype was determined by sequencing of PCR product of selected region of hexon gene using the virus isolates or specimens. Results : An outbreak of EKC occurred which was involving 12 preterm infants in the NICU of the Seoul National University Children's Hospital between July 12th and August 1st, 2005. Three hospital staffs and one family member of the neonate were also affected. Adenovirus was detected in 12/12 (100%), 6/11 (54.5%) by PCR and virus culture, respectively. Eleven PCR-positive neonates were identified as serotype 8 by sequencing. The first affected 4 babies have had routine ROP (retinopathy of prematurity) examinations one week ago. While previous outbreaks were sustained for a few months, the event in our unit was controlled without complications in 3 weeks. Conclusion : We analyzed the EKC outbreak by adenovirus type 8 in NICU. Adenovirus serotype was identified by PCR and sequencing with high sensitivity for the first time in Korea, so we suggest this method can be very useful for rapid diagnosis and infection control.

• Journal of agricultural medicine and community health
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• v.21 no.1
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• pp.13-20
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• 1996

Paederus dermatitis caused by the contact of staphylinid beetles(Paederus fuscipes) body fluid(pederin) is characterized by linear erythematous vesicopustular lesions. An outbreak of dermatitis occurred at apartments located at the river side after rainy season in summer 1994. Authors surveyed 189 cases(94 males and 95 females) from 103 households reported at the apartment office in Kimcheon on September 1994. The results are as follows; 1. The causative agent of skin diseases was identified as Paederus fuscipes. 2. The attack rate of paederus dermatitis was 52.6% by households, and the residents in the middle floors of the apartments were attacked more frequently than those in other floors. All ages were affected. 3. The skin lesions developed by paederus were distributed on face(38.2%), neck(18.5%), shoulder and trunk(11.0%), arm and leg(10.3%), and back(6.6%). In 21 cases(15.4%), skin lesions were developed in multiple sites. 4. The apartments attacked by paederus was located near the sand and damp soil along the bank of the river. The fodder cultivating farm was located near the upper reaches of river, and a rice field and grape garden in the backyard of the apartment.

• Korean Journal of Veterinary Research
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• v.22 no.2
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• pp.171-174
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• 1982

The disease syndrome characterized by the acute vomiting and diarrhea with high mortality had been greatly epidemic in Korea since June, 1931 and it was followed serologically and electron microscopically for the clarification of the agent. The agent present in feces of dogs associated with this syndrome had characteristic feature in agglutinating pig red blood cells that was specifically inhibited by anti-CPV reference dog serum. This also showed the serological identity with the reference CPV antigen in immuno-diffusion. Electron micrograph of the material revealed parvovirus particles with size of 20nm and icosahedral structure. These results clearly indicated that CPV was the primary cause of canine epidemic prevailing in 1981 in Korea.

• Journal of Contemporary Eastern Asia
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• v.21 no.1
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• pp.33-42
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• 2022

The world has witnessed the outbreak of the Covid-19 epidemic. Mainstream and social media are playing an important role in Covid-19 pandemic prevention. This research explores awareness, communication channels and effectiveness of communication in the Covid-19 pandemic in rural areas of Thua Thien Hue province, Central Vietnam. Primary information was collected from 181 respondents, who are farmers, non-farmers and students. Secondary information was collected from reports and statistical data. Television, word of mouth and local loudspeakers are the main channels of mainstream media while social media mentions the role of Facebook and Zalo to transfer Covid-19 pandemic information. Mainstream media is still the main channel of farmers and old people while non-farmers and young people tend to access information through social media. Communication has significantly contributed to improving awareness and action of rural people in the Covid-19 epidemic prevention.

• Korean Journal of Veterinary Research
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• v.46 no.2
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• pp.107-117
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• 2006

This paper described the epidemiological characteristics of 2002 outbreak of classical swine fever (CSF) in Korea. A total of thirteen CSF-infected farms could be classified into two clusters according to the location and time of outbreak. Two farms located in the same county of Gangwon province and 11 farms located in several different districts of Incheon metropolitan/Gyeonggi province were identified as CSF-infected from April 16 to 30 and from October 7 to December 21 in 2002, respectively. As the result of epidemiological analysis, the two clusters of outbreaks were turned out to be independent epidemics which had different sources of virus introduction. Three farms were found to have been infected primarily; one located in Cheolwon county of Gangwon province and two located in Kangwha county of Incheon metropolitan area. The most likely factors of virus introduction into these primary infected farms were considered to be direct or indirect contact by foreign workers and/or owners of the infected farms who had come back from traveling in China before outbreaks. This was supported by the genetic typing of CSF viruses isolated from the pigs of infected farms. All the virus isolates of 2002 outbreak were found to be genetic type 2, whereas the viruses isolated before 2000 were type 3 and the reference strains, such as attenuated live vaccine virus (LOM strain) and high virulent challenge virus (ALD strain), were type 1. Accordingly, we concluded that the 2002 CSF outbreak must have been caused by a newly introduced virus from overseas and the type 3 virus must have been eradicated after the last outbreak of 1999 by the national CSF eradication campaign which were implemented since 1996. Based on the combined analysis of epidemiological data and genetic typing, the transmission routes of classical swine fever virus were found to be the movement of vehicles (60%) and persons (10%), neighbourhood spread (20%) and unknown (10%). It is expected that the analyzed data and findings of classical swine fever outbreak epidemic could be very useful to establish the disease control and eradication program for the country in the future.