• Asian-Australasian Journal of Animal Sciences
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• 제6권3호
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• pp.331-337
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• 1993

In order to understand the effect of duck hepatitis B virus (DHBV) on the economic performance of ducks, Three groups (DHBV congenitally infected, experimentally infected and DHBV negative) Brown Tsaiya ducks (Anas platyrhyncha) were used for experimental animals. Artificial insemination and pedigree hatching were applied in the propagation of ducklings, and the efficiency of vertical transmission and experimental infection was analyzed through the detection of DHBV DNA in the sera of 8-week-old offspring. The observation of the records of the first year indicated that the persistent infection had no significant effects on the performance of ducks, except the egg number of survival ducks up to 40 week of age. Thus DHBV infection did not appear to give ill effects to the economic performance of ducks in first laying year. A higher infection rate (85.3%) was obtained in congenital transmission than that (75.5%) of experimental infection. Both modes of infection did not reach 100% infectious rate, although some ducks developed transient viraemia in a tracing of DHBV DNA for 24 weeks to 11 challenged ducklings.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제19권2호
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• pp.83-95
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• 2016

Hepatitis C virus (HCV) infection is a major medical challenge affecting around 200 million people worldwide. The main site of HCV replication is the hepatocytes of the liver. HCV is a positive enveloped RNA virus from the flaviviridae family. Six major HCV genotypes are implicated in the human infection. In developed countries the children are infected mainly through vertical transmission during deliveries, while in developing countries it is still due to horizontal transmission from adults. Minimal nonspecific and brief symptoms are initially found in approximately 15% of children. Acute and chronic HCV infection is diagnosed through the recognition of HCV RNA. The main objective for treatment of chronic HCV is to convert detected HCV viremia to below the detection limit. Children with chronic HCV infection are usually asymptomatic and rarely develop severe liver damage. Therefore, the benefits from current therapies, pegylated-Interferon plus ribavirin, must be weighed against their adverse effects. This combined treatment offers a 50-90% chance of clearing HCV infection according to several studies and on different HCV genotype. Recent direct acting antiviral (DAA) drugs which are well established for adults have not yet been approved for children and young adults below 18 years. The most important field for the prevention of HCV infection in children would be the prevention of perinatal and parenteral transmission. There are areas of focus for new lines of research in pediatric HCV-related disease that can be addressed in the near future.

• Journal of applied mathematics & informatics
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• 제27권3_4호
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• pp.779-793
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• 2009

This paper deals with a delayed SEIRS epidemic model with pulse vaccination and crowded incidence rate. Moreover, the case of vertical and horizontal transmission is considered. By using the discrete dynamical system determined by the stroboscopic map, the exact infection-free periodic solution of the SEIRS model is obtained. Further, by employing the comparison arguments, we prove that under the condition that $R_*$ < 1 the infection-free periodic solution is globally attractive, and that under the condition that $R^*$ > 1 the disease is uniformly persistent, which means that after some period of time the disease will become endemic.

• Journal of Preventive Medicine and Public Health
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• 제29권2호
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• pp.331-346
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• 1996

Exploring the epidemiological trend of HIV/AIDS is required for making the national AIDS policy. In this study, the trend of HIV/AIDS incidence, rout of transmission and some characteristics of AIDS for the past 11 years in Korea using the reported cases from the national STD screening scheme were reviewed. Based on the results, the trend of main route of transmission according to the year was established by stage and the HIV/AIDS cases in this year was estimated and that to the year 2000 was projected by 'Epimodel' programme. The results were as follows : 1. Of the total infected persons, 76% were in their twenties and thirties, socioeconomically and sexually active age groups. While the transmission by sexual contact overseas was decreasing, the infection through domestic heterosexual and homosexual contact was increasing. 2. In the middle of the 1980's, the infected persons were mainly prostitutes infected through heterosexual contact with the HIV positive foreigner in this county(stage 1). And in the late of the 1980's the main source of infection was the sexual contact overseas and the domestic heterosexual contact(stage 2). Since the early of the 1990's, the infection through the heterosexual contact with non-regular sexual partner in this country has increased rapidly(stage 3), which was the evidence of the possibility of HIV epidemics. After that, it was expected that the infection through the homosexual contacts, the heterosexual contacts with commercial sex workers outside and the non-regular sexual contact inside of this country would increase continuously. In the result, the occurrence of neonatal infection by vertical transmission was expected(stage4). 3. The number of HIV/AIDS was estimated at 572 to 2,313 and the projected number of HIV/AIDS to the you 2000 was around 5,800 including 627 AIDS patients. For the further study on the estimation and projection of HIV/AIDS, it was suggested that the sampling survey on the HIV infection rate in the high risk groups and the sentinel hospital surveillance system should be conducted.

• 대한수학회논문집
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• 제17권1호
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• pp.175-187
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• 2002

The existence and uniqueness of steady states for the age structured S-I-R epidemic model is considered. Intercohort form with external force is considered for the force of infection. Existence is obtained for nonvanishing external force of infection. Uniqueness is shown for the case where there is no vertical transmission of the disease.

• Clinical and Experimental Pediatrics
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• 제64권5호
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• pp.239-246
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• 2021

Background: The consequences of severe acute respiratory syndrome corona virus 2 on mother and fetus remain unknown due to a lack of robust evidence from prospective studies. Purpose: This study evaluated the effect of coronavirus disease 2019 (COVID-19) on neonatal outcomes and the scope of vertical transmission. Methods: This ambispective observational study enrolled pregnant women with COVID-19 in North India from April 1 to August 31, 2020 to evaluate neonatal outcomes and the risk of vertical transmission. Results: A total of 44 neonates born to 41 COVID-19-positive mothers were evaluated. Among them, 28 patients (68.3%) (2 sets of twins) were delivered within 7 days of testing positive for COVID-19, 23 patients (56%) (2 sets of twins) were delivered by cesarean section; 13 newborns (29.5%) had low birth weight; 7 (15.9%) were preterm; and 6 (13.6%) required neonatal intensive care unit admission, reflecting an increased incidence of cesarean delivery and low birth weight but zero neonatal mortality. Samples of cord blood, placental membrane, vaginal fluid, amniotic fluid, peritoneal fluid (in case of cesarean section), and breast milk for COVID-19 reverse transcription-polymerase chain reaction tested negative in 22 prospective delivery cases. Nasopharyngeal swabs of 2 newborns tested positive for COVID-19: one at 24 hours and the other on day 4 of life. In the former case, biological samples were not collected as the mother was asymptomatic and her COVID-19 report was available postdelivery; hence, the source of infection remained inconclusive. In the latter case, all samples tested negative, ruling out the possibility of vertical transmission. All neonates remained asymptomatic on follow-up. Conclusion: COVID-19 does not have direct adverse effects on the fetus per se. The possibility of vertical transmission is almost negligible, although results from larger trials are required to confirm our findings.

• 한국균학회지
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• 제50권4호
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• pp.263-274
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• 2022

표고는 중요한 상업용 버섯이며, 표고에서의 바이러스 감염에 대한 여러 보고가 있었다. 톱밥 재배 품종인 산백향(NIFoS 2778)과 태향고(NIFoS 4317)에 대한 바이러스 검출 결과, 이들이 2개의 mycoviruses (LeV-HKB 및 LeNSRV1)에 감염되어 있음을 확인하였다. 각 품종의 자실체에서 분리된 담자포자에서 유래한 80개의 단핵균사에서 바이러스 감염을 조사한 결과, 대부분의 단 핵균사들이 바이러스에 감염되어 있었으며, LeV-HKB와 LeNSRV1의 수직감염률에 차이가 있었다. LeV-HKB가 LeNSRV1 보다 높은 수직감염률을 나타낸 것이다. 따라서 mycovirus의 수직 감염 기작이 바이러스 종에 따라 다른 것으로 보인다. 다음으로, 담자포자 유래 단핵균사들의 생장속도를 조사하여 바이러스 감염과 생장속도의 상관관계를 조사하였다. 바이러스 감염과 균사 생장속도 사이에 통계적으로 유의한 상관관계가 없었지만, 감염된 바이러스의 종류가 늘어날수록 생장속도가 감소하는 경향을 확인하였다. 본 연구는 mycovirus의 수직 감염 기작을 이해하는 데 기여하고, 바이러스에 감염되지 않은 단핵균사를 이용한 무바이러스 품종 개발을 촉진하는 데 기여할 수 있을 있을 것 기대된다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제2권1호
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• pp.109-115
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• 1999

Hepatitis C virus (HCV) has been identified as an important cause of posttransfusion hepatitis, but vertical transmission of chronic infected HCV RNA positive mothers has been documented in some cases. The reports of the risk of perinatal infection have been widely varied in the literature. The authors experienced one case of vertical transmission of HCV in an infant of a mother who had hepatitis C during pregnancy. At admission, HCV RNA (+), Ig G anti HCV (+) and Ig M anti HCV (+) were found in the mother. Also at admission, HCV RNA (+), Ig G anti HCV (+), Ig M anti HCV (+), elevation of liver aminotransferase level and hepatosplenomegaly on ultrasonography were found in the baby on day 31. HCV RNA (-), Ig M anti HCV (-) and normal of liver aminotransferase level were noted on day 250 in the serum of the infant. We used reverse transcriptase polymerase chain reaction (RT-PCR) technique to find a very small amount of HCV RNA in the serum. All the findings suggest vertical transmission of HCV RNA from mother to infant during 3rd trimester of pregnancy.

• Journal of Yeungnam Medical Science
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• 제9권2호
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• pp.407-415
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• 1992

Anti-HCV 양성인 만성간질환 환자 80명의 가족중 3가족에 걸쳐 3명이 anti-HCV 양성이었고 양성율 3.5%로서 HBsAg 양성 만성간질환 환자 60명의 가족중 40가족에서 HBsAg 양성자가 나타난 결과가 양성을 66.7%보다 월등히 낮은 수치를 보였다. 이 결과를 볼때 HCV는 HBV와는 다른 정도의 감염력을 가지거나 또는 다른 형태의 개체면역반응을 유도하여 항체 형성이 낮은 것이 아닌지 고려해 보아야겠다. 가족중 배우자나 자녀에 있어서의 감염율은 HBV와 비교될 정도는 아니었으나 anti-HCV 양성인 사람이 배우자나 자녀였으므로 향후 성적접촉이나 수직감염에 의한 감염 가능성에 관해 더욱 조사가 필요할 것으로 사료된다. 그러나 아직 HCV RNA를 직접검사하는 PCR검사가 보편화되어 있지 못하며 HCV 감염의 진단을 위한 검사법이 여러가지 난무하는 이유로 이후 정밀도가 높으며 쉽게 이용될 수 있는 HCV 감염진단을 위한 검사법이 확립되어 정확한 HCV 환자의 파악이 먼저 되어야 HCV 감염의 역학적 조사가 정확히 이루어지며 HCV 감염관리에 도움이 될 것으로 생각된다.

• Pediatric Infection and Vaccine
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• 제26권1호
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• pp.66-70
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• 2019

신생아의 태반을 통한 사람면역결핍바이러스 감염은 아프리카에서 흔하지만, 대한민국에서는 아직 보고된 적이 없다. 대한민국에서 사람면역결핍바이러스 감염자의 수는 증가하는 추세이며, 특히 생식연령에서의 사람면역결핍바이러스 감염자의 수가 증가하고 있다. 이는 사람면역결핍바이러스 수직 감염의 위험성을 높인다. 저자들은 아직 국내에 보고되지 않은 자궁 내 전파를 통한 신생아의 사람면역결핍바이러스 감염을 경험하였기에 보고하는 바이다. 자궁 내 전파를 통한 사람면역결핍바이러스 감염의 예후는 좋지 않으나 본 증례의 남아는 생후 9개월 경까지 정상 성장과 발달을 보였으며 특별한 의학적 문제가 없었다.