A seroepizootiologic study of five viruses in a swine-evaluation station.

This serologic study was done to gain information on the spread, maintenance, and effect upon performance of five porcine viruses. Blood samples were taken from two groups of 8- to 11-week-old pigs from a large number of Indiana swine herds in a performance-testing station 1 week after entry, 7 weeks after entry (one group only), and at slaughter. The sera were tested by indirect fluorescent antibody tests for antibodies to transmissible gastroenteritis virus (TGEV), swine influenza virus (SIV), hemagglutinating encephalomyelitis virus (HEV), porcine adenovirus (PAV), and pseudorabies virus (PRV). Seroconversions to TGEV, HEV, and PAV occurred in a group of pigs entered in May and slaughtered in August (group 1). In the group that was entered in October and slaughtered in January (group 2), pigs developed antibodies to SIV, HEV, and PAV, but not to TGEV. Only 1 of the 434 pigs tested had antibodies to PRV, and there were no seroconversions to this virus. The only statistically valid effect of infection on performance was found in group 1 pigs, which had seroconverted to TGEV during the first 7 weeks of their stay. These pigs gained 0.077 kg less per day than pigs that did not develop antibodies to TGEV during that period. The pattern of serologic reactions was indicative of a relatively slow spread of these viruses in the groups. We interpret this as supporting the concept that a relatively slow spread of these viruses through large groups of pigs kept under conditions that are less than optimum for virus spread may be an important means of their interepizootic survival.     

Antibiotic resistance and transferable antibiotica resistance Escherichia coli isolated from calves on a modern farm with therapeutic problems and unsatisfactory management conditions.

On a farm with therapeutic problems and unsatisfactory management conditions, the occurrence of antibiotic resistance and transferable antibiotic resistance has been studied in E. coli isolated from calves which were 5 and 30 days old. Strains with resistance to up to seven antibiotics as well as transferable resistance against up to five antibiotics were recorded. On an average, 4.2 strains with different patterns and 4.0 different strains with transferable resistance were isolated from each calf. The corresponding figures previously found for healthy control calves were 1.6 and 1.1 strains, respectively. Resistance and transferable resistance were most common against sulphonamide and penicillin.     

Plasma concentration of sulphadimethoxine in pigs after multiple dosing and during injections of Escherichia coli endotoxin

The effect of endotoxin induced fever on the steady state concentration of sulphadimethoxine in pigs has been studied.Sulphadimethoxine 20 mg/kg b.wt. was injected at 9 a.m. in an ear vein each day for eleven days. From day 6 until the end of the experiment, endotoxin fromEscherichia coli 1.5 g/kg b.wt. was injected at 9 a.m. and at 3 p.m. The plasma concentration versus time curves were calculated by means of a computer program, assuming a two-compartment model. During the endotoxin injections the plasma concentrations were simulated and compared with those calculated.It was not possible to show any clinically significant changes in pharmacokinetics of sulphadimethoxine after the start of endotoxin injections.     

Gastrointestinal colonization by salmonellae and pathogenic Escherichia coli in monoxenic and holoxenic chicks and poults

Chicks monocolonized by either salmonellae or pathogenic strains of Escherichia coli had persistent and undiminished colonization of all levels of the gastrointestinal tract and frequently had bacteremia during test periods ranging to 35 days. Poults monocolonized by salmonellae or Arizona hinshawii 7:"1,7,8 developed a similar pattern of colonization. Conventionally reared chicks and poults had rather variable colonization by these pathogens, and it was most persistent in the ceca. Groups treated with a native protective microflora were infrequently colonized. Differences in colonization are explainable by lack of competing bacteria in the monocolonized group and by various degrees of protection provided by microflora colonizing the other groups.     

A histopathological survey of adult bovine terminal ilea

A histopathological survey of 945 abattoir-derived adult bovine terminal ilea was conducted. All samples showed changes interpreted as chronic enteritis. Sixty-nine percent had glandular epithelium within submucosal Peyer's patches. Thirty-eight percent showed dense focal lymphoid aggregations within the mucosa and twenty-seven percent showed sub-mucosal abscessation and granulomata. Evidence of coccidial and nematode parasitism was common. Four percent had Johne;s disease.     

Fossil land mammal from antarctica

A fossil land mammal, apparently the first found in Antarctica, belongs to the extinct marsupial family Polydolopidae. The fossils were recovered from rocks about 40 million years old on Seymour Island, in the northern Antarctic Peninsula. The newly discovered marsupials support theories that predicted their former presence in Antarctica and strengthen proposals that Australian marsupials perhaps originated from South American species that dispersed across Antarctica when Australia still was attached to it, prior to 56 million years ago.