• Korean Journal of Veterinary Service
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• v.45 no.2
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• pp.125-131
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• 2022

The purpose of this study was to examine antibody titers to structural protein (SP) of the foot-and-mouth disease (FMD) virus after vaccination in animals of the Seoul zoo. After the initial inoculation of FMD vaccine to the susceptible animals of the zoo, a total of 235 blood samples were collected from 42 species of zoo animals during treatment or necropsy. All samples were tested by using enzyme-linked immunosorbent assay (ELISA). The overall positive rate of SP antibodies against FMD virus was 94.0% (221/235). However, the positive rates varied according to animal species. The results of positive rates in 30 species were 100% but in 12 species were 50-94.7%. We showed that most animals that have received FMD vaccine in Seoul zoo have been reached to the level of herd immunity against FMD virus after the vaccination. To the best of our knowledge, this study would be the first report for monitoring the vaccine-induced SP antibody titers against FMD virus after vaccination in various zoo animal species in Korea.

• Korean Journal of Veterinary Service
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• v.17 no.1
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• pp.9-18
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• 1994

Neutralized antibody titer of Akabane disease virus were performed from 810 dairy cows in 45 farming households from May 1992 to December 1993 in Incheon area. The 503 dairy cows at the 21 farming household were conducted from May to December 1992, 307 cows were from January to December 1993 The results obtained are summarized as follows 1. Evaluation of neutralized antibody titer of 810 dairy cows tested during two yews revealed that 68.1% (552 hearts) , during the four year revealed that 69.6% (350 heads), the later year was 65.8%(202 heads ) was more than antibody titer 16. 2. Antibody investigation according to area and years, showed no significant difference in the whole area and both years as 65-73% from 1992, and as 65-70% from 1993 had an antibody titer of above 16 or more. 3. Antibody investigation according to age, showed that 34.4% of cows aged below 2 had a titer of above 16, compared with 80.8% for cows aged above 5. It demonstrated that the younger cows had the lower titer level, and the older the higher. 4. Monthly variation of antibody titer showed that the highest level of antibody titer was observed in September, the lowest was in June. It meant that the best periods of vaccination were April, May, June. 5. The result of epidemidogical study to 40 farming households showed that 35 farms (87.5%) had abortions of which were 14 stillbirths, 5 abnormal births, and 13 farms (32.5%) had vaccination.

• Korean Journal of Veterinary Service
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• v.14 no.1
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• pp.19-26
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• 1991

A considerably high rate of abnormal deliveries of unknown etiology was observed among dairy cattles from November 1988 to February 1989 and Korean native tattles from January to April 1990. The abnormal deliveries consisted of abortions, stillbirths and calf deformities refers to as congenital arthrogryposis hydranencephaly (AH )syndrome. In order to know the level of Akabane antibody of dairy cattle raised in Kyungbuk province, serum neutralization test was conducted with Akabane virus(OBE-1 strain) and HmLu(Hamster lung) cell line. The results were summarized as follows. 1. During 4 months(Nov. 1988-Feb. 1989), abortion (3 heads), stillbirth(1 head) and congenital abnormalities(13 heads) of newborn were occurred in 17 dairy cattles raised in Kyungbuk province. 2. During 4 months(Jan.-Apr.1990), stillbirth(2 heads) and congenital deformities (13 heads) of newborn were occurred in 15 Korean native tattles raised in Kyungbuk province. 3. In Fev, and Apr. 1990, 1,005 dairy cattles at 99 farms were investigated on the actual condition of possessing Akabane antibody. The result was that 1,000 heads (99.9%) in 1,005 dairy cattles reacted as positive condition in Akahane antibody. The antibody titer was from 4 to over 256. 4. 189 heads (18.8%) of 1,005 dairy cattles werw below antibody titer 8 and 816 heads (81.2%) were over 16. 5. Akabane antibody titer of east coast legions(Pohang Yeongil etc) was all over 16, that of internal legions (Yeongiu, Andong. etc) was relatively low, The result suggest that the vaccination for Akabane disease will be unnecessary for the time being because of possessing higher antibody titer reaction except the newly introduced cattle and Akabane virus was widely disseminated in kyungbuk province during the summer months in 1987 or 1988.

• Korean Journal of Veterinary Research
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• v.42 no.2
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• pp.241-251
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• 2002

Modified-live (ML) infectious laryngotracheitis (ILT) vaccines have been widely used as a preventive measure in Korea since the first outbreak of ITL. Recently, it has been observed that chickens vaccinated with the commercially available ML ILT vaccine have sometimes exhibited adverse clinical signs. In this study, we evaluated the quality of the vaccines by comparing titer of each vaccine batch and testing the stability of ILT virus (ILTV) in vaccine diluents and compared the safety and efficacy of vaccines in specific pathogen free (SPF) chickens. The ratio of maximum titer to minimum titer of vaccine produced by most manufacturers was 2 to 15. However, 2 out of 11 manufacturers produced vaccines of which the ratio was 74 to 478. Most vaccines examined were maintained vaccine titers suitable for national regulations within expiry date. However, some vaccines did not keep the titer required for the national regulations. In the test for stability of ILTV in various diluents, ILTV was highly stable in lactose-phosphate-glutamine-gelatin solution, sucrose-phophate-glutamine-albumin solution and some vaccine diluents produced by manufacturers. The safety of ML ILT vaccines was assessed in 10-day-old SPF chicks. Mortality in SPF chicks inoculated intratracheally with one dose of vaccine varied depending on vaccines and some vaccines produced 50-85% mortality. Seven-week-old SPF chickens were vaccinated intraocularly with ML ILT vaccines and then challenged intratracheally with ILT challenge virus 14 days after vaccination. The protection rate was assessed by clinical signs and reisolation of the ILT challenge virus from tracheas taken at day 4 after challenge. There were slight respiratory reactions in some vaccinated chickens after vaccination but these reactions disappeared within 5 days after vaccination. No further clinical signs and death were observed. Protection rate determined by clinical signs and mortality was 100% in all vaccinated groups. However, the challenge virus was isolated from all tracheas of chickens vaccinated with vaccine B or control groups. The challenge virus was also isolated in the trachea of one in five chickens vaccinated with either vaccine F or K, but not in tracheas of chickens vaccinated with other vaccines. In the present study, the stability of vaccine diluents, pathogenicity and protection rate based on reisolation test of the challenge virus were different depending on vaccines produced by eleven manufacturers.

• Korean Journal of Veterinary Research
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• v.34 no.3
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• pp.529-536
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• 1994

To establish more specific and simple diagnostic methods for detection of the antibodies and antigens of Aujeszky's disease virus(ADV), we designed indirect dot-immunoassay(IDI) and double sandwich dotimmunoassay(DSDI) using the solid phases of nitrocellolose paper and polystyrene plate. The diagnostic efficacy of these methods was investigated. As the sensitivity of IDI was tested by various virus concentration, the specimens with the virus titer above $10^{4.0}TCID_{50}/0.2ml$ showed positive reaction, but that below $10^{1.0}TCID_{50}/ml$ revealed negative. Tonsil emulsion at the virus titer of $10^{4.5}TCID_{50}/0.2ml$ showed the highest sensitivity as diluted by 1/100. In detection of ADV antigens from the various tissues of the rats and pigs infected with ADV, IDI using monoclonal antibody showed the higher specificity as compared with IDI using polyclonal antibody and virus isolation method. The efficacy of the DSDI for detection of ADV antibody was compared with other tests. The sensitivity of DSDI was higher than virus neutralization(VN) and agar gel immunodiffusion test(AGID). Meanwhile, specificity of DSDI was lower than AGID, but similar to IDEA. In comparison with VN test, DSDI showed 96.9% agreement to VN test that is the highest of three tests. In general, application of polyclonal antibody in both tests caused the higher sensitivity but the lower specificty.

• Journal of Veterinary Clinics
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• v.17 no.1
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• pp.45-51
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• 2000

Sera from 425 Korean native and 203 Holstein cattle were collected from October 1994 to September 1995 from dairy farms and slaughterhouses in Chonnam province to study the exposure rate to bovine respiratory syncytial virus(BRSV). Serum antibody titers against BRSV were measured by neutralization test, and results were as follows: Overall prevalence of seropositive cattle to BRSV were 74.5%, and the exposure rate to BRSV was higher among the Holstein (77.3%) than among the Korean native cattle(73.2%). The serum antibody titers against BRSV ranged from 1:2~$\geq$1:256 in both species. Among Korean native cattle, the most frequent serum antibody titer was 1:4 against BRSV(19.3%), while only 1.4% of seropositive cattle had serum titer of $\geq$1: 256. Among Holstein cattle, 22.7% of examined cattle contained serum titer of 1:8, while 1.5% of seropositive cattle showed $\geq$ 1:256. Antibody titers against BRSV were higher among males than females in both Holstein (82.1% vs. 73.1%) and Korean native (74.5% vs. 69.2%) cattle. Prevalence of seropositive cattle by age in both species were evenly distributed, although the highest number (76.9%) of seropositive were at the age of 3 in Korean native cattle, while 83.5% of seropositive Holstein cattle were of 2 years old. The lowest seropositive rate was observed in cattle of less than 1 year old(25.0%). Seasonal occurrunce of BRSV was the highest in spring season in both Holstein (86.6%) and Korean native (81.0%) cattle (P<0.05).

• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.738-742
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• 1999

The objective of this experiment was to investigate the effect of Newcastle disease virus (NDV) and infectious bursal disease virus (IBDV) vaccination on performance of broiler chicks for five weeks. Two types of poultry houses and three patterns of vaccination ($NDV^-/IBDV^-$, $NDV^+/IBDV^-$ and $NDV^+/IBDV^+$) were factorially assigned to six treatments. NDV, B1 strain and IBDV, Bursin-2 vaccine were orally administered at 5, 14 and 7, 18 days, respectively. Forty eight hundred chicks were grouped into four replications with two hundnyd hybro $\times$ hybro chicks per each treatment. Weight gain, feed conversion ratio (FCR), mortality and product index were surveyed at the end of experiment. Bursa index and IBDV antibody titer of chicks were weekly measured. Weight gain of chicks vaccinated with $NDV^+/IBDV^+$ was significantly increased compared to that of other treatments at both window and windowless poultry houses (p<0.05). Chicks vaccinated with $NDV^+/IBDV^+$ also showed significantly improving the FCR and mortality compared to those of other treatments at both poultry houses (p<0.05). The bursa indecies of both poultry houses were high from one-day- to three-weeks-old, but were low for the rest of two weeks. IBDV antibody of all chicks was detected 100% by agar gel precipitation (AGP) test at one day old, but was not detected in $NDV^-/IBDV^-$ and $NDV^+/IBDV^-$ treatments at four weeks old. However, it showed 100% in $NDV^+/IBDV^+$ treatment. Antibody titer using ELISA showed similar trend to that of AGP test. The results of this experiment confirmed that IBDV and NDV combined vaccine significantly improved the performance of broiler chicks.

• Korean Journal of Veterinary Research
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• v.33 no.2
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• pp.227-234
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• 1993

A serological survey for antibody to chicken anemia agent(CAA) was carried out by virus neutralization test. Antibody to CAA was detected in broilers and layers at different age groups. The results obtained were summarized as follows ; 1. Of a total of 1,035 chicken sera from 1.16 flocks 617 samples of sera were detected as positive(59.6%) and 95 flocks of a total flocks as positive(81.9%). 2. Proportion of positive sera by age were 92.3 %(88.9~100%) at 1 to 2 weeks of age, 56.4%(16.7~77.8%) at 3 to 9 weeks of age, 85.0%(50.0~100%) at 10 to 14 weeks of age and all tested sera were positive at over the 15 weeks age. 3. In each broiler and layer chicken 63.6% and 68.4% chicks possessed positive sera respectively. 4. Neutralizing antibody titer in age group was various from 1:10 to 1:6,400 and mean titer was 1:400 to 1:800.

• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.101-109
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• 2000

Duck viral hepatitis is an acute, highly infectious viral disease of young dacklings aged from two days to three weeks. The significant lesion associated with the disease was enlarged liver including necrotic foci and numerous hemorrhagic spots. We have isolated five strains of duck hepatitis virus (DHV) from field cases showing about 20% mortality with a sign of opisthotonos. When a-day-old ducklings were intramuscularly inoculated with one of the isolates, 92% of the birds were died within 5 days. We attempted to develop an attenuated strain of duck hepatitis virus (DHV) using one of the isolates by serial chicken embryo passages. The propagation of DHV in chicken embryos was carried 140 passages. The virus titer increased gradually from the $21^{st}$ through the $50^{th}$ passage, but there was no significant increase of virus titer in subsequent passages after then. Through the serial passages, the virulence of the virus for chicken embryos was gradually increased but decreased for ducklings. The pathogenicity of the virus for ducklings was preserved up to the $21^{st}$ passage but disappeared at the $50^{th}$passage. An attenuated Korean isolate which was passaged 140 times in chicken embryos gave good protection in ducklings against both challenge infection to a Korean virulent strain and to a DHV-DRL strain, a type 1 reference strain of DHV, which indicated that the Korean isolates could be classified as DHV type 1. And the above results suggest that an attenuated Korean isolate can be used for developing a live DHV vaccine.

• Korean Journal of Veterinary Service
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• v.14 no.2
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• pp.148-153
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• 1991

To investigate epidemological sitution of bovine viral diarrhea infection, serological survey in cattle being raised in Young Dong province were conducted. Bovine sera collected ramdomly from August 1990 to December 1990 were tested for bovine viral diarrhea virus serum neutralizing antibody titers. The results were as follows 1. BVDV SN antibody levels were considerably varies and positive rate was 58(108 heads out of 186) 2. BVDV SN antibodies to breeds of cattle was various and positive rates showed that diary cattle, beef, native cattle(Korean) were 67.52%, 59.38%, 27.00％ respectively followed in that order. 3. In the regional prevalence of BVD SN antibodies in cattle, Alpine(92％) was the highest, Young Dong south(59%) middle(44%), and North 30% followed in that order 4. In the age relatated prevalence of BVD SN antibodies, the younger than 6 month old group was the highest 65.7%, and older than 25 month old group was also at 62.2％. Then, 7 to 12 moth old group and 13 to 24 month old group showed to 58.5%, 52.1％ respectively. 5. The geometric mean titer (log2) of 108 cattle serum samples showing positive BVD SN antibodies was 4.3. 6. In the geometric mean titer(log2) according to age, younger than 6 month old group (5.2) was the highest, then 7 to 12 month old group 2.8(SD=1.94 standard deviation) was lowliest.