The occurrence of Clostridium difficile in fecal samples of dogs and cats

Fecal samples of 150 dogs and 175 cats originating from different veterinary practices were investigated for assessing the occurrence of Clostridium (Cl.) difficile by using a selective medium for cultural isolation. From dogs without enteric symptoms 7 (9.3%) of 75 samples were positive for Cl. difficile, with 2 strains being cytotoxic for bovine embryonic lung fibroblast cells, which could be neutralized by Cl. difficile-antitoxin. In samples of 75 dogs with enteric symptoms Cl. difficile could be isolated in 2 cases (2.7%). In cats 9 (9%) of 100 fecal samples deriving from animals without enteric symptoms contained Cl. difficile, while in 75 cats with enteric symptoms, the isolation rate was 6.7% (5 strains). Of either group only 1 Cl. difficile-strain showed cytotoxicity for tissue culture. The results of this study allow to conclude, that in contrast to the significance for man Cl. difficile is neither for dogs nor for cats an important enteric agent. However these pets can harbour and shed strains of Cl. difficile, even cytotoxigenic ones, in faeces. In view of these findings the possibility of occasional human infections by household dogs or cats needs attention and further investigation.     

Infectious laryngotracheitis in the niagara peninsula: a case control study

The method(s) of spread of infectious laryngotracheitis in poultry flocks is uncertain. Based on an outbreak of the disease in the Niagara Peninsula in the summer of 1982, managers of infected (case) flocks and noninfected (control) flocks were interviewed to compare their management practices. The data were statistically analyzed; however, the results are not conclusive since only thirteen farms were involved in the outbreak. The results do suggest the following: farms with previous infectious laryngotracheitis infected flocks are more likely to have future outbreaks than are infectious laryngotracheitis-free farms, sanitation procedures of people entering the barns (changing boots and coveralls) appears to be related to infection status and air inlet location on the barn may be associated with infection. These items should be examined more thoroughly in future outbreaks.     

Analysis of the relationships among O(3) uptake, conductance, and photosynthesis in needles of Pinus ponderosa

We studied the effects of O(3) uptake on conductance (g(wv)) and photosynthesis (A) in needles of ponderosa pine (Pinus ponderosa Laws.) seedlings exposed for 70 days to one of three O(3) regimes-Low-O(3) (0.1 micro mol mol(-1) daily peak), High-O(3) (0.2 micro mol mol(-1) daily peak), and Low/High-O(3) (alternating 2 days Low-O(3) and 2 days High-O(3)). Seedlings exposed to charcoal-filtered air served as controls. Total O(3) exposures, expressed as ppm-h (the sum of the average hourly concentration in ppm ( micro mol mol(-1)) over the exposure period), were 77, 135, 105 and 4 for the Low-O(3), High-O(3), Low/High-O(3) and control treatments, respectively. Conductance (g(wv)) declined to about 60% of the value in control seedlings by Day 6 in seedlings in the High-O(3) treatment and by Day 37 in seedlings in the Low/High-O(3) treatment, but g(wv) did not decline at all in seedlings in the Low-O(3) treatment. At the end of the 70-day experiment, cumulative O(3) uptake, calculated from measured g(wv) values and assuming an internal O(3) concentration of zero, was 12.2, 13.5, and 14.7 mmol m(-2) for seedlings in the Low-O(3), Low/High-O(3), and High-O(3) treatments, respectively; however, O(3) uptake was reduced by 0, 24, and 36%, respectively, from that expected if there had been no decline in g(wv). With increasing total O(3) exposure, A declined, but the reduction was not strictly cumulative, i.e., A measured on Days 49 and 70 was similar for a given treatment even though both total O(3) exposure and uptake had increased. At the end of the experiment, A at near saturating CO(2) (1000 micro mol mol(-1)) and saturating photosynthetic photon flux density was reduced by about 25, 40 and 50% in seedlings in the Low-O(3), Low/High-O(3) and High-O(3) treatments, respectively, compared to the control seedlings. The ratio of internal to external CO(2) concentrations, an indicator of relative change in stomatal limitation of A, did not change over time and did not differ among treatments, suggesting that A and g(wv) decreased in parallel. After 40-60 days without O(3), A of seedlings in all O(3) treatments was not significantly different. Our data indicate that O(3)-induced stomatal closure was a result of reduced A and that decreased g(wv) reduced O(3) uptake to a rate that needles of ponderosa pine could tolerate without exhibiting further reductions in gas exchange capacity.     

Effect of large palpable ovarian follicles on response to prostaglandin administration in dairy cows with corpora lutea

We examined the response to exogenous prostaglandin F2α in cattle with or without palpable structures believed to be ovarian follicles. All animals had ovarian structures diagnosed by palpation as corpora lutea. The cows were placed into two groups: those with follicles which were estimated by the palpators to be ≤13 mm diameter (n=60); and cows with no palpable follicles or with follicles <13 mm diameter (n=133). Comparisons of proportion in estrus within five days, days to estrus, and milk progesterone levels failed to show significant differences between the groups.