In vitro effects of a mixture of Escherichia coli heat-stable enterotoxins (STa and STb) on isolated jejunum of 3-week-old male pigs were studied, using everted intestinal sac techniques. Heat-stable enterotoxins increased chloride secretion and chloride absorption in everted intestinal sacs. The increase of secretory flux was greater than that for absorptive flux. Vasoactive intestinal peptide (6 x 10-9M) increased chloride secretion, but had no effect on chloride absorption. Neither vasoactive intestinal peptide nor pilocarpine (10-5M) had additive effect to ST. Secretory effects of ST were not blocked by atropine 2 x 10-5M), clonidine (10-6M), or morphine (4.2 X 10-6M).

The present study was conducted to investigate the Bordetella bronchiseptica infection in Youngnam swine herds during the period of August 1986 to July 1987 and some properties of the organisms isolated from these Korean swine. B. bronchiseptica was recovered from 25 of 70 (35.7%) growing pigs of 4 to 10 weeks of age and from 12 of 13 (92.3%) herds. From 115 slaughter pigs, 58(50.4%) pigs were culture positive and the pigs from 13 of 14 (92.9%) herds were found to be infected with B. bronchiseptica. The majority of biochemical and cultural properties of B. bronchiseptica isolated from Korean swine were identical to those of the standard strain employed and some 97.6% of the isolates showed the characters of phase I organism on primary isolation.

The first outbreak of aujeszky's disease (AD) was identified from piggery located at the southern part of Korea in July, 1987. This piggery suffered from a significant economic loss caused by unexpected piglet mortality and reproductive failure. Etiologic viral agents were isolated from tonsil and spleen of the infected piglets, and the isolates produced a typical cytopathic effect of herpesvirus with giant cell formation when inoculated in many different cells. Subsequently the field isolates were characterized as suid herpesvirus I by cross-neutralization test and indirect fluorescence assay utilizing specific monoclonal antibody, and proved to be a pathogenic strain of AD virus(ADV).

The present study was done to demonstrate ADV antigens in frozen and paraffin sections from ADV-infected pigs and cell cultures by using of the IGS method. Tissue specimens from 3 young pigs infected with ADV-phylaxia strain and of 2 healthy pigs were used. Fibroblastic cells originated from pig brain and BHK cells were grown and confluent monolayers were infected with the virus. Two monoclonal antibodies and a specific hyperimmune serum to ADV were used as the source of primary antibodies for both the IGS and immunoperoxidase methods. Application of the IGS method yielded a black fine granular reaction in positive areas, and the results were superior to those obtained using the immuno-peroxidase technique for all cases tested. The IGS method might be useful in the detection of various viral antigens in tissue sections

The In vitro drug susceptibility of 83 strains of Bordetella bronchiseptica recoverd from Korean pigs with atrophic rhinitis was investigated by the use of disk diffusion method. The majority of the organisms were highly resistant in order of prevalence to penicillin (98.7%), ampicillin(91.5%), streptomycin (90.3%), triple sulfa (83.1%), and trimethoprim/sulfamet-hoxazole (70.7%) while none of them were resistant to gentamicin, only 3.6% to colistin, chloramphenicol and kanamycin and 6.0% to tetracycline. The percentage of the organism resistant to bicozamycin, cephalothin and neomycin were 34.9%, 34.1% and 18.4%, respectively. A high prevalence of multiple drug resistance was observed and the 3 most common resistant patterns among 35 patterns noted were Am Pc Sm Sss Sxt(26.5%), Am Cf Pc Sm Sss Sxt(12%) and Am Bm Pc Sm Sss Sxt(9.6%) patterns

A porcine parvovirus inactivated vaccine was prepared and inoculated to 7 piglets and also 8 guinea-pigs, and their serum antibodies were titrated. Twenty-two field serum samples of unvaccinated sows were also tested by SN and HI methods. It was observed that SN test was superior over HI test. Therfore, it is suggested that the SN test could well be used in the detection of serum antibody for PPV in vaccinated pigs