Bordetella bronchiseptica and toxigenic type D Pasteurella multocida as agents of severe atrophic rhinitis of swine.

Bordetella bronchiseptica and toxigenic type-D Pasteurella multocida were cultured from pigs in each of five herds diagnosed as having severe atrophic rhinitis (AR). B. bronchiseptica alone, P.

Serologic survey for Bordetella bronchiseptica in Nebraska specific-pathogen-free pigs.

The frequency of Bordetella bronchiseptica infection in Nebraska specific-pathogen-free (SPF) pigs was determined by serologic and bacteriologic cultural analysis. Serum samples from non-SPF herds were tested for comparison. A total of 1,282 of 1,397 (92%) of the SPF pigs tested had antibody to B bronchiseptica; 37 of 220 (17%) were culture-positive, and 67 of 4125 (1.

The effect of feeding Streptococcus faecium upon Escherichia coli induced diarrhea in gnotobiotic pigs.

Streptococcus faecium (Sf) was fed to gnotobiotic pigs to control colibacillosis. Three strains of Escherichia coli (Ec) were used. Strain 0:K103,987p:NM of Ec fed to pigs without Sf developed severe diarrhea which persisted for several days.

Effect of Streptococcus faecium C-68 in control of Escherichia coli-induced diarrhea in gnotobiotic pigs.

Streptococcus faecium was fed to prevent colibacillosis in gnotobiotic pigs. Three strains of Escherichia coli were used. With strain O:K103, 987P:NM in pigs fed S faecium before the E coli challenge exposure, the pigs exhibited less severe diarrhea, recovered earlier, and produced better weight gains than did pigs given E coli only.

Long-term effect of Bordetella bronchiseptica infection in neonatal pigs.

A total of 62 gnotobiotic pigs were inoculated with Bordetella bronchiseptica at 7 days of age. There were 25 noninoculated controls. Thirteen of the inoculated pigs were killed and 6 pigs which died were examined between 3 and 5 weeks after inoculations were done (group A).

Scanning electron microscopy of intestine of gnotobiotic piglets infected with porcine rotavirus.

The development of intestinal lesions caused by the porcine rotavirus were studied in six day old gnotobiotic piglets by scanning electron microscopy. The onset of diarrhea followed an incubation period of 17 to 31 hr. The first detectable lesion was observed in the ileum at 12 hr postinfection, a few hours before the onset of diarrhea.

Duration of Mycoplasma hyopneumoniae infection in gnotobiotic pigs.

Sixteen gnotobiotic pigs raised in flexible plastic isolators (four pigs per isolator) were inoculated with a culture of Mycoplasma hyopneumoniae. One pig was killed and underwent necropsy at weekly intervals for the following 16 weeks. Macroscopic lesions were observed in the lungs of 13 of 16 pigs and microscopic lesions were found in 14 of 16 pigs.

Neonatal calf diarrhea caused by a virus that induces villous epithelial cell syncytia.

Intestinal lesions caused by a virus serologically unrelated to the calf diarrheal rotavirus or coronavirus were studied in gnotobiotic calves. The virion purified from feces from infected calves was a fringed particle with a diameter of about 100 nm. The incubation period from time of inoculation per orum to onset of diarrhea in calves was as short as 8 hours.

Scanning electron microscopy of trachea and bronchi from gnotobiotic pigs inoculated with Mycoplasma hyopneumoniae.

Areas of trachea and right apical and right dorsal diaphragmatic bronchi from gnotobiotic neonatal pigs were examined by scanning electron and transmission electron microscopy at 7, 13, and 21 days after pigs were given intranasal inoculation of Mycoplasma hyopneumoniae. Similar areas were examined by scanning electron microscopy from 2 noninoculated neonatal pigs. Tracheal and bronchial lesions were observed in all inoculated pigs.

Patterns of shedding of human reovirus-like agent in gnotobiotic newborn piglets with experimentally-induced diarrhea.

Virus shedding patterns of neonatal gnotobiotic piglets infected with the reovirus-like agent of human infantile gastroenteritis were studied. Fecal viral counts were highest before or at the onset of diarrhea. In diarrheic piglets, viral particles were usually observed for only 1-2 days after the onset of diarrhea, and total duration of shedding was 2-6 days.

Diarrhea caused in gnotobiotic piglets by the reovirus-like agent of human infantile gastroenteritis.

One- to four-day-old gnotobiotic piglets were inoculated orally with a reovirus-like agent obtained from human infants with acute gastroenteritis. Diarrhea developed in the piglets two to seven days after inoculation and was reproduced for five serial passages in one sequence and for three passages in another. Nineteen of 21 inoculated piglets developed diarrhea; reovirus-like particles were observed in intestinal contents and/or fecal samples from 17 animals with illness and from two inoculated piglets that did not develop diarrhea.

Recovery of transmissible gastroenteritis virus from chronically infected experimental pigs.

Transmissible gastroenteritis (TGE) virus was reisolated from pulmonary and intestinal tissues from 6 of 9 chronically infected experimental pigs (principals) necropsied 30 to 104 days after inoculation. Tissue homogenates (lung and small intestine) from the principals were prepared and inoculated into 3- to 5-day-old gnotobiotic pigs. The virus reisolated from the tissue homogenates produced a milder disease on 1st passage and a more severe disease on 2nd passage.

Transferable drug resistance among Enterobacteriaceae isolated from cases of neonatal diarrhea in calves and piglets.

Fecal specimens were collected on 22 different Nebraska ranches and at the Department of Veterinary Science from young calves and pigs with neonatal diarrhea. Enterobacteriaceae isolated from these fecal specimens were screened for resistance to tetracycline, streptomycin, sulfamethizole, kanamycin, chloramphenicol, colistin, nitrofurantoin, and nalidixic acid. Of the 92 strains studied, 57 were resistant to one or more of these antimicrobial agents.

Protein metabolism in the developing brain: influence of birth and gestational age.

Incorporation of carbon-14-labeled phenylalanine into brain protein of newborn pigs falls sharply within 24 hours after birth. This decrease is related to the time of birth rather than the gestational age of the piglets, although the latter is also associated with a gradual decrease in brain protein synthesis.