Presentation of postweaning Escherichia coli diarrhea in southern Ontario, prevalence of hemolytic E. coli serogroups involved, and their antimicrobial resistance patterns

Post-weaning Escherichia coli diarrhea (PWECD) in Ontario was investigated using a case-control study involving 50 Ontario nurseries. The clinical signs and the impact on productive parameters were determined by means of a producer survey. The hemolytic E. coli serogroups involved in PWECD (O149:K91:K88) were examined in this study. Based on a polymerase chain reaction test, the hemolytic E. coli from 82% of the case herds were positive for 3 enterotoxins (STa, STb, and LT), those from 12% of the case herds were positive for STb and LT only, and those from one herd (6%) were positive for 3 enterotoxins, as well as for verotoxin and F18 pili. The E. coli involved in disease were resistant to multiple antibiotics. Case farms commonly used a wide variety of antibiotics either in the feed or water, or as injectable drugs. The most common antibiotic used to treat PWECD on the study farms was apramycin, but evidence of resistance to this antibiotic was noted. The PWECD problem was commonly seen within a week of weaning but onset of diarrhea was reported as late as the grower-finisher stage. Growth rate was poorer in case herds and mortality was higher than in control herds, demonstrating that PWECD is an economically important disease in Ontario.     

Comparison of diagnostics techniques in an outbreak of infectious laryngotracheitis from meat chickens

Various diagnostics techniques were compared for their ability to detect infectious laryngotracheitis (ILT) during an outbreak in chickens aged between 4 and 21 wk. Gross lesions ranged from excess mucus to accumulation of fibrinonecrotic exudate in the larynx and trachea. Syncytial cells with intranuclear inclusion bodies were found in sinus, conjunctiva, larynx, trachea, lung, and air sac. Virus isolation in chicken embryos was attempted in every case. Negative-stain electron microscopy detected herpesvirus in only 6% of the cases. Yet, isolation of ILT virus in the chorioallantoic membrane was presumed by histology in >20% of the samples and confirmed by fluorescent antibody (FA) in 35% of the embryos inoculated with conjunctivas or tracheas from affected birds. Overall, results from histology and FA tests were highly correlated. FA test has the advantage over histology of being diagnostically specific for ILT virus. Polymerase chain reaction was the most sensitive test and detected the viral DNA even in cases where histology and FA were negative. ILT virus DNA was quantified by real-time polymerase chain reaction (Re-Ti ILTV). Histologic and FA results from larynx and trachea were negative if the concentration of the viral DNA was < or =4 of log10. A viral DNA concentration higher than log10 4, as determined by Re-Ti ILTV, was required for clinical ILT to be manifested.     

The effects of starving and feeding on Dover sole (Solea solea,Soleidae, Linnaeus, 1758) stress response and early larval development

In the view of an urgent necessity to improve the quantity and the quality of farmed fish species, there is a strong need to improve our basic knowledge on the effects of first feeding during the developmental stages of fish larvae. High mortality, mainly due to food deprivation or inappropriate food quality, has been observed in many larval fish species, but knowledge about the morphological, biochemical and molecular processes related to this topic is still poorly understood. The understanding of the early larval ontogeny as well as the larval nutritional requirements and the molecular and cellular mechanisms elicited by fish larvae during food deprivation and starvation are thus of primary importance. At this regard, this study investigates, in Dover sole larvae, the effects of starvation and starving/re‐feeding procedures at a morphological, histological, biochemical and molecular level. The results evidenced that starved larvae progressively decrease in growth, lipid content, affected their gastrointestinal tract and muscle development and increased cortisol and heat shock protein 70 levels. On the contrary, starved and re‐fed larvae showed, after the restoration of a favourable feeding condition, a compensatory growth. In conclusion, this is the first study analysing through a multidisciplinary approach the effects of food deprivation on the development of an important economic species, the Dover sole.     

The ecosystem services concept: a new Esperanto to facilitate participatory planning processes?

Landscape Ecology - Several case studies investigated the role of ecosystem services in participatory planning processes. However, no systematic study exists that cuts across a large number of...     

Serological tests in relation to the viability,fertility and localization of hydatid cysts in cattle,sheep, goats and swine

A serological study of intermediate hosts (cattle, sheep, goats and swine) of Echinococcus granulosus was carried out by means of the indirect haemaglutination (IHA) and flocculation with latex (LA) tests, relating them with the organs invaded, and the fertility and viability of the cysts.In cattle a sensitivity of 75% and 21.05% of non-specific reactions was given by IHA, while the LA gave 66.7 and 17.54%, respectively. In the sheep, the IHA gave 79.16 and 20%, and the LA, 75 and 15%. In the goat, the IHA gave 76 and 22%, and the LA 71.43 and 16%. Finally, in the pig, the IHA gave 75 and 22%, and the LA, 66.6 and 14.16%.The IHA was more sensitive in detecting hepatic cysts in the cow, and pulmonary cysts in the goat, while in the sheep and the pig there were no significant differences. The LA was more sensitive in detecting hepatic cysts in the cow, goat and pig, while there were no significant differences in sheep.The differences in serum titers by the IHA and the LA tests with respect to the viability and the fertility of the cysts in the hosts, were not significant.     

Efficacy of doramectin against naturally acquired nematode infection in Iberian swine

Studies were carried out to determine the therapeutic efficacy of doramectin, administered intramuscularly at a dose of 300 microg/kg live weight, against naturally acquired helminths of extensively farmed Iberian pigs. The first study (slaughter study) evaluated, through necropsy of the study animals, the product's efficacy against gastrointestinal and pulmonary nematodes (Ascaris suum, Oesophagostomum dentatum and Metastrongylus sp.) whilst the second, faecal egg count reduction study, (FECR study) evaluated the drug's efficacy only against gastrointestinal helminths (A. suum, Trichuris suis and Oesophagostomum sp.).The first study used 20 animals divided into two equal groups of 10 on the basis of body weight and faecal egg count. One group constituted saline treated controls and the other was doramectin treated. On Day 14 post treatment half of the animals in each group were necropsied and the number of parasites present counted. On Day 15 the remaining half of each group underwent the same procedure. The second study was carried out with 40 animals divided equally into two groups of 20. This study determined the effect of doramectin treatment on faecal egg counts as an indicator of parasite burden.The first study demonstrated an efficacy of 100% against adult Metastrongylus sp. and A. suum, whilst the efficacy against O.dentatum was 96.3%. The second study indicated that at Day 21 post treatment there was a 100% reduction in egg counts in faeces in comparison to untreated controls.     

Molecular epidemiology of environmental MRSA at an equine teaching hospital: introduction,circulation and maintenance

The role that environmental contamination might play as a reservoir and a possible source of Methicillin-resistant Staphylococcus aureus (MRSA) for patients and personnel at equine veterinary hospitals remains undefined, as the environment has only been monitored during outbreaks or for short periods. Therefore, the objectives of this study were to determine the monthly presence, distribution, and characteristics of environmental MRSA at an equine hospital, and to establish patterns of contamination over time using molecular epidemiological analyses. For this purpose, a yearlong active MRSA surveillance was performed targeting the environment and incoming patients. Antimicrobial susceptibility testing, SCCmec typing, PFGE typing, and dendrographic analysis were used to characterize and analyze these isolates. Overall, 8.6% of the surfaces and 5.8% of the horses sampled were positive for MRSA. The most common contaminated surfaces were: computers, feed-water buckets, and surgery tables-mats. Ninety percent of the isolates carried SCCmec type IV, and 62.0% were classified as USA500. Molecular analysis showed that new pulsotypes were constantly introduced into the hospital throughout the year. However, maintenance of strains in the environment was also observed when unique clones were detected for 2 consecutive months on the same surfaces. Additionally, pulsotypes were circulating throughout several areas and different contact surfaces of the hospital. Based on these results, it is evident that MRSA is constantly introduced and frequently found in the equine hospital environment, and that some contact surfaces could act as “hot-spots”. These contaminated surfaces should be actively targeted for strict cleaning and disinfection as well as regular monitoring.     

Effect of storage on wall-bound phenolics in green asparagus

The cell walls of green asparagus spears have been analyzed for their phenolic and carbohydrate composition as modified by postharvest storage. Esterified phenolic components were released by sequential alkaline hydrolysis and identified and quantified by diode array HPLC. Significant quantities of ferulic acid (FA) and its derivatives were found to increase at least 3-fold during storage, particularly in walls from the lower parts of the stem, where accompanying changes in sugar composition were also observed. In fresh asparagus, >60% of the total FA was in the form of diferulic acid, and this increased to approximately 70% after 3 days of storage. The main FA dehydrodimers were 8-8-, 8-O-4-, and 8-5-diferulates. These have been detected in other monocotyledonous and dicotyledonous plants, but as a smaller proportion of the total FA. The possible roles phenolic esters might have in relation to the mechanical, textural, and wound-response properties of asparagus spears are discussed.     

Mouse epidermal development: effects of retinoic acid exposure in utero

Epidermal morphogenesis was studied in vivo following prenatal exposure to retinoic acid (RA). In pregnant mice, a single oral dose of RA on day 11.5 of gestation failed to induce histological changes in fetal epidermal development except in epidermal thickness. Epidermal thickness increased from 16.5 days post-coitum (dpc) onwards, and temporal and spatial epidermal modifications in keratins K5 and K14 related to proliferative activity of keratinocytes were observed. An RA effect on cell proliferation was supported by a statistically significant increase in the number of epidermal S-phase cells, containing BrdU-incorporated DNA in RA-exposed mice compared with nonexposed animals. The prolonged in utero action of RA on epidermal proliferative activity in fetuses and newborns suggests a long-term RA effect that may play a role on the development and evolution of diseases in adult skin.