Nitroreduction of 2,4-dinitrotoluene in vitro by cytochrome P-450 induced H4IIE cells.

Conditions have been established for H4IIE rat hepatoma cell cultures in which effects of cytochrome P-450 induction on the metabolism of a munitions wastestream pollutant can be studied. Under these conditions, the polychlorinated hydrocarbon 2,3,4,7,8-pentachlorodibenzfuran (PCDBF) induced cytochrome P-450 (1A1) aryl hydrocarbon hydroxylase (AHH) activity over a wide range of concentrations without significant cytotoxic effects. The munition pollutant 2,4-dinitrotoluene (2,4-DNT) did not induce AHH activity itself, but its metabolism was considerably altered when applied to PCDBF induced cultures. Production of amino nitrotoluene isomers was greatly enhanced in induced cultures as compared to uninduced controls, as was the conversion of radiolabeled 2,4-DNT to relatively more polar metabolites. To some extent, the results with H4IIE cells parallel those reported for animals exposed to 2,4-DNT after induction of cytochrome P-450 AHH activity. The preliminary findings suggest that with further development and validation, H4IIE cultures could be of use in characterizing metabolites that result from exposure to chemical mixtures involving a P-450 (1A1) inducer.

Perceived Usefulness of the Collection of Subclinical and other Disease Entities Detected at Slaughter.

Based on a survey of 1820 Ontario pork producers and 16 veterinary members of the Ontario Swine Practitioners Association, condemnation/demerit data, while viewed as potentially valuable, are seldom, if ever, utilized in the provision of herd health programs. We found, however, that: 1) 89.4 percent (SD 1.04 percent) of producers and all veterinarians would use the disease information made available by a computerized system that would collect and report on subclinical and other disease entities detected during the slaughter of hogs; 2) Iesion diagnosis should be as detailed as possible and report on severity of disease; and 3) with the exception of those producers who ship larger numbers of hogs to market for which reports were wanted for each kill, monthly reports would be adequate.Written comments by producers expressed concerns about confidentiality of individual herd data, costs for the information/service, and veterinary expertise in the interpretation of findings.

Direct measurements of urinary estrone conjugates during the normal menstrual cycle of the gorilla (Gorilla gorilla).

A direct immunoassay for urinary estrone conjugates (estrone sulfate and estrone glucuronide) was used to assess the preovulatory estrogen rise in normal gorilla menstrual cycles. Immunoreactive estrone conjugates in samples concomitantly assessed for total estrogen immunoreactivity reflected similar profiles throughout the cycle; however, the speed and resolution of the direct assay for conjugates indicate this method to be more accurate in monitoring ovulation than the measurement of total immunoreactive estrogens. In a single conceptive ovarian cycle, urinary estrone conjugate continued to rise in the luteal phase, indicating that this test may also be useful for detecting early pregnancy. The application of this technique provides clear profile of ovarian function in gorillas as well as in other primate species.

Isolation of Streptococcus suis using a selective medium.

A selective medium containing tryptic soy agar, 5% defibrinated bovine blood, crystal violet, nalidixic acid and gentamicin significantly improved the isolation rate of Streptococcus suis from tonsilar tissue of slaughtered pigs. Ninety-five percent of the S. suis isolates identified in Guelph were confirmed as S. suis in Copenhagen, but only six out of 21 isolates typed as capsular serotype 2 in Guelph were confirmed to possess serotype 2 antigen in Copenhagen. Sixty-four percent of the S. suis isolates were not typable within the current scheme of capsular serotypes from 1 to 13 and type 1/2.

Streptococcus suis in slaughter pigs and abattoir workers.

The detection and identification of Streptococcus suis type 2 in 8.1% of 347 pig herds of southwestern Ontario revealed that the infection is widespread in this area. A herd suspected to be infected showed a carrier rate of 9.7% among the 62 animals sampled. These subclinical carriers represent a potential source of infection for slaughterhouse workers. From studies of contamination of hands and knives, it was concluded that eviscerators involved in removing the larynx and lungs from the carcasses have a significantly higher (p less than or equal to 0.05) risk of exposure to Streptococcus suis than other abattoir workers.

Effect of chlorination of drinking water on experimental salmonella infection in poultry.

The type of drinker used for poults influenced the level of free available chlorine (FAC) in chlorinated water as well as the total plate count, fecal coliform count, and number of salmonellae in chlorinated and non-chlorinated drinking water. Nipple drinkers maintained higher levels of FAC in drinking water than Swish-cups, Swish-cups maintained higher levels than MarkIII, and MarkIII maintained higher levels than trough drinkers. The level of FAC retained in the water in trough drinkers was insufficient to exert a bactericidal effect against coliforms and salmonellae. Chlorination of drinking water and the resulting diminished number or absence of salmonellae in the drinking water did not lower the number of salmonellae per gram of cecal contents in challenged or unchallenged but exposed poults. The number of salmonellae per gram of cecal contents decreased significantly (P less than 0.01) in poults between 14 and 21 days of age, irrespective of whether or not the poults drank chlorinated water.

Practical aspects of competitive exclusion for the control of Salmonella in turkeys.

In laboratory trials, a fourth-passage culture of adult chicken cecal contents was protective against challenge with Salmonella typhimurium in turkey poults raised on wood-shavings poultry litter. The culture was not protective against pre-treatment exposure to hatchery-introduced S. bredeney and was inhibited in poults that had received an antibiotic injection at the hatchery. The inhibitory effect of the hatchery antibiotic could be avoided if the cecal-culture treatment was delayed by 3 to 4 days after antibiotic injection. Under field conditions, there was a significant reduction in the salmonella contamination of turkeys and their environment when cecal culture was given to poults raised on wood-shavings litter sprayed with a quaternary ammonium compound. When used alone, both the cecal culture and the litter disinfectant were ineffective in preventing the establishment of S. heidelberg infection. Further studies are required to confirm the possibility of a synergistic effect between the two treatments. For the control of salmonella in turkeys, use of cecal cultures may be limited by the interference of antibiotics and by their failure to protect against pretreatment exposure to salmonella.

Thermoregulatory responses to central injections of excess calcium in monkeys.

In unanesthetized monkeys (4-8 kg), artificial cerebrospinal fluid (ACSF) containing excess (greater than 1.3 mM) amounts of Ca2+ was infused at 20 microliters/min for 5 min into the cerebral ventricles. Core and skin temperatures, respiratory gas exchange, heart rate, and sweat rate were monitored. At 22 degrees C, intracerebroventricular infusions of 13-39 mM Ca2+ produced a dose-related hypothermia associated with a dose-related fall in metabolic rate and heart rate and a rise in average skin temperature. General body sweating was not initiated, and respiratory water loss was unaffected; however, exercise activated sweating and elevated it from 0.05 to 0.22 mg X (cm2 X min)-1. At 35 or 40 degrees C, infusion of 26 mM Ca2+ failed to influence ongoing general body sweating; however, subsequent exercise increased sweat rate by 63%. Heart rate was unaffected. At 15 degrees C metabolic rate increased 50%. After infusing 26 mM Ca2+, metabolism decreased 6% and core temperature declined 0.8 +/- 0.24 degrees C. Skin temperatures continued to fall, heart rate fell, and sweating was not initiated. In contrast, infusing ACSF increased metabolism 11% and core temperature fell only 0.18 +/- 0.14 degrees C. The inability of exogenous Ca2+ to 1) initiate sweating at 22 degrees C, 2) elicit vasodilation at 15 degrees C, 3) initiate or stimulate sweating at 35 or 40 degrees C, or 4) lower core temperature at 35 or 40 degrees C argues against a set-point function for this cation.

Epidemiology of Haemophilus pleuropneumoniae infection in pigs: a survey of Ontario Pork Producers, 1981.

Information about factors associated with the spread and the effect of pleuropneumonia was obtained from 418 pork producers in Ontario, who returned a mailed questionnaire. The overall herd prevalence of pleuropneumonia was 23.2%. The prevalence among herds with feeder pigs only was 34.3% and 16% among sow herds. The chance of pleuropneumonia breaking out in a herd was increased with increased traffic of pigs into the herd. The source of supplementary stock had an important effect on the chance of pleuropneumonia occurring. The highest risk resulted from introducing stock from salesbarns and the lowest from stock of health status known to the purchaser and supplied by one breeder only. Mortality, primarily among feeder pigs, and unthriftiness were the major effects of Haemophilus pleuropneumoniae infection. Stress, such as crowding or inclement climatic conditions, was associated with outbreaks of pleuropneumonia. This would suggest that the infection with H. pleuropneumoniae can be subclinical until stress precipitates the disease.

Evaluation of the complement fixation test for the diagnosis of pleuropneumonia of swine caused by Haemophilus pleuropneumoniae.

Evaluation of diagnostic sensitivity and specificity was based on test results of 346 sera from pigs known to be infected and 139 sera from pigs known not to be infected. All sera were tested with a monospecific antigen (serotype 1) and a polyspecific antigen (serotypes 1-5). The sensitivity of the polyspecific antigen was approximately 85% at serum dilution 1:2 and was significantly higher than the monospecific antigen at all serum dilution levels. The specificity of the two antigen preparations was not significantly different at any dilution and increased from approximately 78% to 1:2 to 100% at 1:128. When pigs from herds with unknown incidence of infection were studied, it was found that a high proportion seroconverted, presumably as a response to subclinical infection. However, the antibody titres waned rapidly. This indicated that seroreaction expresses current or recent infection. Thus, the complement fixation test provides a reliable means of diagnosing pleuropneumonia of pigs and might be useful as a tool to control this disease.

Urinary immunoreactive estrogen and pregnanediol-3-glucuronide during the normal menstrual cycle of the female lowland gorilla (Gorilla gorilla).

Urine samples were taken daily during 22 menstrual cycles of six normal adult female gorillas. Urine was analyzed for total immunoreactive estrogens (Et) and pregnanediol-3-glucuronide (PdG) and indexed by creatinine (Cr). An average cycle length of 32 ± 1 days (mean ± SE) with a range of 25-42 days is reported. Estrogen values range from 4 to 128 ng/mg Cr and show a midcycle peak and a midluteal rise. PdG values range from 0.01 to 2.4 µg/mg Cr and display a low, flat follicular phase followed by a luteal elevation. The follicular phase is 19.5 ± 1 days in length (range 11-30 days) and accounts for the variation in cycle length. The luteal phase is 12.3 ± 0.3 days long (range 10-14 days). In contrast to previous studies, PdG levels rise two days before the estrogen peak. The results from the present study are compared with information available on the gorilla, chimpanzee, and human. The accuracy of various alignment methods is discussed, as well as the importance of the methods presented in this study for the captive propagation of gorillas.

The application of the soluble antigen fluorescent antibody test for the diagnosis of avian influenza.

The application of the soluble antigen fluorescent test as a tool for serological investigation of influenza type A infection in wild birds was studied. The soluble antigen fluorescent antibody test is basically an indirect fluorescent antibody test except that an artificial matrix of cellulose acetate discs is used as a substrate for antigen and the test results are scanned and recorded by a fluorometer. THe influenza type A soluble antigen fluorescent antibody was obtained from concentrated and detergent disrupted virus particles, absorbed onto cellulose acetate discs. Anti-influenza sera were prepared in pheasants and ducks to A/turkey/Ontario/6118/67 and in pigeons to A/turkey/Ontario/6213/68. The antigen-antibody complex was detected by specific staining with monovalent or polyvalent fluorescein isothiocyanate conjugated rabbit anti-avian immunoglobulins. The soluble antigen fluorescent antibody test is a sensitive technique for the detection of specific influenza A antibodies in several avian species, and could be adapted for use in large scale surveys.

Vaccination against pleuropneumonia of pigs caused by Haemophilus pleuropneumoniae.

A strain of Haemophilus pleuropneumoniae was isolated from a pig with pleuropneumonia from a herd where this condition was frequent. A formalin inactivated culture of this isolate was used as antigen in two vaccine preparations: A and B. Vaccine A had peanut oil + arlacel 80 + tween 80 as adjuvant and vaccine B had aluminum hydroxide gel as adjuvant. Twenty pigs were vaccinated twice with vaccine A and 19 with vaccine B. Twenty additional pigs were not vaccinated. All pigs were transferred to the herd. Eleven pigs in the nonvaccinated group developed pneumonia and seven of these died within eight days after exposure. None of the vaccinated pigs had signs of pneumonia. It is concluded that the vaccines prevented the acute form of pleuropneumonia due to H. pleuropneumoniae.

Prevalence of reovirus 1, 2 and 3 antibodies in Ontario racehorses.

The sera of 2596 thoroughbred and standardbred racehorses from Ontario were examined by hemagglutination-inhibition for antibodies to reovirus types 1, 2 and 3. The prevalence of antibodies differed between the standardbred and thoroughbred horses and varied with the age groups within the two populations. While reovirus 1 was the principal virus type infecting thoroughbreds, all three types seemed to infect standardbred horses. Differences of these findings with data from similar studies in Europe are mentioned and the epizootiological and pathological significance of these findings are discussed.

Epidemiology of equine upper respiratory tract disease on standardbred racetracks.

The outbreaks of upper respiratory tract infections in horses at Standardbred racetracks were investigated over a three year period. The most serious epidemics of respiratory disease occurred in the winter and spring seasons. Both influenza viruses and equine herpesvirus 1 were shown to be present in the horse population. The herpesvirus was associated with respiratory disease particularly in the winter but the equine influenza viruses apparently were responsible for the major epidemics of respiratory disease at these tracks. Younger horses, two or three years of age, were particularly susceptible to upper respiratory disease and showed the greatest rate of seroconversion to influenza viruses. Major outbreaks of respiratory disease occurred when the proportion of young horses which had not previously been exposed to epidemics of respiratory disease reached 30 to 40% of the population at the track. Most horses over four years of age appeared to develop resistance to the infections.

Sources of Salmonellae in broiler chickens in Ontario.

Sources of Salmonellae infecting broiler chicken flocks in Ontario were investigated from July, 1975 to April, 1976. Three broiler flocks were investigated on each of four farms which received chicks from a common hatchery. Samples of feed and new litter were preenriched in nonselective broth subcultured to Salmonella-selective enrichment broth and plated on Salmonella-selective differential agar. Samples of used litter, water, culled chicks, insects, mice, wild birds and environmental swabs were not cultured initially in the nonselective broth. Fecal samples from principal and occasional flock attendants were examined for Samonellae. Salmonella infection, as judged by contaminated flock litter was detected in six flocks on two of the farms while the flocks on the other farms remained negative. Salmonellae were isolated from 23 of 412 feed samples (nine serotypes), six of 35 new wood shaving samples (four serotypes), one of 29 pools of culled chick viscera (one serotype) and 44 of 267 used litter samples (14 serotypes). These results indicate that broiler chicken flocks were infected with diverse Salmonellae introduced in day old chicks, pelleted feeds, wood shavings and residual contamination from the preceding flock.

Salmonella investigation in an Ontario feed mill.

The frequency of Salmonella contamination of feedstuffs and finished broiler chicken feeds at an Ontario feed mill were investigated over a four-month period. Samples of feed ingredients and finished pelleted feeds were collected at various points during manufacture and cultured in trypticase soy broth prior to selective enrichment for isolation of Salmonella. Salmonella contamination was found in 4.3% of 93 finished pelleted broiler feeds examined. The contamination appeared to result primarily from the incorporation of contaminated animal protein ingredients into the feed. Meatmeal and the broiler, premix, which contained meatmeal as a filler, were most frequently contaminated followed by feather meal. Pelleting failed to eliminate the Salmonellae from the feeds. The methods used failed to detect Salmonella in the environment of the feed mill or its delivery trucks. Recommendations for control are made.