매추리 유래 가금 adenovirus인 QBV로 부터 CsCl을 사용한 균질밀도분배원심분리법으로 AAAV의 분리를 시도하였으며, 분리된 바이러스의 순수성을 전자현미경 및 혈청학적인 방법을 통하여 증명하였으며 순수 분리된 AAAV를 항원으로 사용한 혈청반응을 개발하였다. 즉, CsCl의 밀도 1.38 및 $1.42gm/cm^3$의 분획들은 순수한 AAAV이었으며 $1.42gm/cm^3$의 분획은 토끼에서 양성혈청제조용 면역원으로 1.38 및 $1.42gm/cm^3$의 분획은 혈청반응용 표준항원으로 사용하였다. AAAV 표준항원 및 가토 양성혈청계는 MDV, IBDV, ITV 및 "helper"인 가금 adenovirus와의 교차반응이 없었으며 혈청학적인 특이성이 인정되었다. 또한 상기 혈청학적 반응을 이용하여 AAAV의 동정은 물론 AAAV에 대한 닭의 항체검출을 가능하게 하였다.

순수하게 분리 정제된 AAAV를 "helper"인 가금 adenovirus와 공동으로 11일령의 계태아에 감염시켰으며 토끼 유래 특히 항혈청을 사용하여 AAAV의 증식성을 추시하였다. AAAV의 증식은 "helper"와의 공동감염인 경우에만 인정되었으며 "helper"의 양과 AAAV의 증식은 서로 일치하였으나, AAAV와의 공동감염인 경우 "helper"의 증식은 억제되는 경향을 보였다. 이 시험에 공여된 7주의 가금 adenovirus중 6주는 AAAV의 증식을 위한 "helper"능을 부여하였으며 "helper"로써의 기능은 계태아에서의 증식성과 일치하였다. 계태아에 순화된 (CELO) 바이러스를 "helper"로 하여 계태아에서의 AAAV의 증식을 조사한바, $10^5$ PFU의 CELO 바이러스를 "helper"로 하였을 경우 접종후 5일에 최고에 달하였다.

In order to know the effects of thyroid hormone on the bursa of Fabricius in chicken, the bursae were studied with the light microscope after administration of thyroxine(TX) or propylthiouracil(PPT). Macroscopically, the bursa of TY-treated group showed increase in size and thickened folds. while those of the PPT-treated group decrease in size, compared with those of control group. In the light microscopic studies, the bursa of Fabricius of the TX-treated group showed active cell-divisions in the medulla, and increased number of pyroninophilic large lymphocytes and plasma cells containing PAS positive materials in the cytoplasms. On the other hand, the bursa from PPT-treated group revealed decreased number of lymphocytes, significant increase of necrotic lymphocytes in the follicles, and the proliferation of the interfollicular connective tissues. A large number of pyroninophilic lymphocytes and plasma cells were also appeared in the spleen of the TX-treated group.

The outbreak of viral encephalomyelitis (Talfan disease) in suckling piglets was diagnosed pathologically for the first time in Korea. The clinical signs of affected sucklings were very high morbidity without death, and fever ($39^{\circ}C$ or higher) with incoordination of the rear limbs and paresis, while no specific gross lesions were observed at autopsy. Histopathological changes were confined to the nervous system, and were of the nature of a nonsuppurative and nondemyelinating encephalomyelitis which is usual for the viral encephalitis. It was characterized by perivascular cuffing, meningitis, neuronal degeneration, neuronophagia and glial nodules in the brain and spinal cord.

The outbreak of hepatosis dietetica from 2 different herds of pigs was diagnosed for the first time in Korea. The livers from 5 affected pigs showed yellow atrophy, necrotic foci and ecchymotic hemorrhages anatomically, and hemorrhagic necrotic hepatitis histopathologically.

1. In adult ICR-SLC mice, significant increase in the occurrence of the Tyzzer's disease was noted when the reticuloendothelial system was blockaded with the carbon particles. The most suitable bloakading time was 2 hours before inoculating Tyzzer's organisms, the route was intraperitoneal and the dose was 3mg/body. 2. Survival rate of the experimental group ICR-SLC suckling mice receiving BCG ($3{\times}10^8$) 6 days prior to intraperitoneal inoculation of Tyzzer's organisms was 80 percent, but the control group was 17%. 3. In comparing the survival rate of the nude/nude mice with the nude/+ mice, the former congenitally thymus deficient mice are 11 percent, but the latter are 67 percent.

This experiment was undertaken to determine the causative agent of bovine mastitis induced by yeast-like fungi and to know its therapeutic effect. California mastitis test, somatic cell counting and pH titration as well as cultural examination were performed continuously for the quarter milk and the feces obtained from the diseased cattle from November, 1979 to February, 1980. As a result, the causative agent was identified as Candida krusei and intramammary infusion of Nystatin was effective in the udder. Candida krusei was isolated from the feces.

Cyclophosphamide(CY)가 마우스 및 가토(家兎)의 P. multocida 야외분리균주(野外分離菌株)의 호흡기관내(呼吸器管內) 인공감염(人工感染)에 대한 감수성(感受性)에 미치는 영향(影響)을 연구(硏究)하였다. 체중(體重) Kg당(當) 300mg CY를 주입(注入)한 마우스와 150mg CY를 처리(處理)한 가토(家兎)는 P. multocida의 호흡기관내(呼吸器管內) 인공감염(人工感染)에 대해서 높은 감수성(感受性)을 보였다. 또한 CY 처리(處理)는 일시적(一時的)으로 말초혈액(末梢血液) 중에 있는 총백혈구수(總白血球數)와 단핵백혈구수(單核白血球數)의 감소(減少)를 야기(惹起)했고, 비장(脾臟)의 백수(白髓)와 적수(赤髓)에 있는 임파구(淋巴球)의 소실(消失)을 초래(招來)했다. CY 주사(注射)된 가토(家兎)는 접종(接種)된 균주(菌株)에 대한 항체형성능력(抗體形成能力)의 저하(低下)를 나타냈다. 얻어진 결과(結果)는 가토(家兎)에 있어서 면역기능(免疫機能)의 저하(低下)와 호흡기질병(呼吸器疾病) 발생(發生) 간(間)의 상호관계(相互關係)에 대해 고찰(考察)하였다.

Antimicrobial susceptibility of 157 Gram-negative bacilli (90 Escherichia coli. 30 Enterobacter aerogenes, 18 Klebsiella pneumoniae, 12 Proteus spp., 3 Pseudomonas aeruginosa and 4 Alcaligenes faecalis) isolated from infected bovine udders was determined by the plate dilution method. Gentamicin and oxolinic acid at a concentration of $12.5{\mu}g/ml$ were very active to all of 157 Gram-negative bacilli tested, and 98% of these strains were susceptible to nalidixic acid at a concentration of $25{\mu}g/ml$. Most of the 90 Escherichia coli strains were inhibited by chloramphenicol, ampicillin and carbenicillin and carbenicillin at a concentration of $12.5{\mu}g/ml$. None of the Klebsiella pneumoniae strains were inhibited at a concentration of $50{\mu}g/ml$ of ampicillin and carbenillin, whereas all the species of Proteus resisted a concentration of $50{\mu}g/ml$ or higher tetracycline. All the 3 strains of Pseudomonas aeruginosa were highly resistant to streptomycin, kanamycin, Ampicillin, chloramphenicol, tetracycline and nalidixic acid.

Incidence of avian infectious diseases in breeder chickens was followed serologically. Serum samples were collected during the period of 1978~1979 from breeders throughout country and tested for the presence of antibodies against Salmonella pullorum(SP), Mycoplasma gallisepticum(MG), Avian Infectious Bronchitis virus(AIBV), Infectious Bursal Disease virus(IBDV) and Egg Drop Syndrome Virus(EDS). The tests used serum plate agglutination for SP and MG, immuno-diffusion for AIBV and IBDV and hemagglutination-inhibition test for EDS virus. The results are summarized as follows: 1. Individuals and Hocks incidence rate of Avian Infectious Bronchitis virus were 16.9% and 55.3%. 2. Individuals and Hocks incidence rate of Infectious Bursal Disease virus were 50.1% and 66.4%. 3. Individuals and Hocks incidence rate of sal. pullorum were 17.2% and 65.9%. 4. Individuals and flocks incidence rate of M. gallisepticum were 36.2% and 63.2%. 5. Individuals and flocks incidence rate of Egg Drop Syndrome (BC 14) virus were 14.1% and 46.3%.

From November 1978 to April 1979, there occurred among cows many cases of abortion, premature birth, stillbirth and congenital arthrogryposis or hydranencephaly in Kyongki-do province in Korea. Epizootics recurred between February and May, 1980 in the same area. Six calves born at 8 or 10 months of gestation were examined by means of pathology and one of the calves was examined by serological test. And a survey on local occurrence of the disease in other than Kyongki-do province, was conducted. 1. At necropsy, some calves showed distinct lesions such deformities of the limbs and the vertebrae as arthrogryposis or scoliosis. Other calves revealed arthrogryposis and partial or total deficience of the cerebral hemispheres with hydranencephaly. 2. In the calves with deformities the skeletal muscle showed histologically severe hypoplasia of the muscle fibers with cellular infiltration. In the central nervous system of the calves with hydranencephaly there were minute cystic cavitation and the decrease of ventral horn cells of the spinal cord in the number. 3. Similar epizootics were also observed in the same season in the other several provinces such as Chungoheongnam-do, Kangwon-do and Jeonrabuk-do. 4. Anti-Akabane virus antibody was detected in precolostral blood from the calf with arthroglposis and hydranencephaly syndrome. 5. On these findings of the disease it was diagnosed as Akabane disease presenting the first report on the epizootics in Korea.