Experimental production of fatal mucosal disease in cattle

Three outbreaks of mucosal disease were investigated. Careful examination of 47 cattle that were persistently viraemic with bovine virus diarrhoea virus (BVDV) revealed no clinical disease, no or low levels of BVDV antibody and only non-cytopathic virus in their blood. The four animals with mucosal disease all showed clinical disease and both cytopathic and non-cytopathic virus in their blood. Following post mortem examination, there were particularly high levels of cytopathic virus in gut tissue. A hypothesis for the induction of mucosal disease is suggested. It states that animals become persistently infected with non-cytopathic virus following in utero infection and when, in post natal life, they become superinfected with a cytopathic virus, then mucosal disease ensues. The experimental reproduction of mucosal disease in support of this hypothesis is described.     

Cardiopulmonary effects of medetomidine in sheep and in ponies

Medetomidine was administered intravenously to six sheep at 5, 10 and 20 μg kg⁻¹ and to one horse and four ponies at 5 and 10 μg kg⁻¹. In both species medetomidine resulted in significant decreases in heart rate and cardiac output and, initially, in an increase in arterial blood pressure. In the ponies this increase in blood pressure was followed by a significant and prolonged decrease, but in the sheep the secondary decrease in blood pressure was not statistically significant. In the sheep, the three doses of medetomidine resulted in profound and significant decreases in arterial oxygen tensions, which were significantly dose related, but in the ponies the arterial blood oxygen tensions were not significantly decreased. In both species medetomidine caused a small but significant increase in arterial blood carbon dioxide tensions.     

Using the Tools of the Information Age to Enhance Research and Management of the Southern Pine Beetle

The Southern Pine Beetle (SPB) is a major pest in southern U.S.A., Mexico, and Central America. Enormous resources in terms of funding, personnel, and effort have been allocated for research and development of pest management tools for this pest over the past century. Access to information from journal articles, reports, fact sheets, etc. does require some effort and is often incomplete and difficult to obtain. The emergence of the Internet now allows rapid access to information from diverse sources. We have created a comprehensive website entitled, 'The Southern Pine Beetle Internet Control Center' (SPBICC) (www.spbicc.vt.edu). The goal of the site is to provide all available resources on SPB to anyone with access to the Internet. It is also designed to increase communication among researchers and professionals to help advance the management of this pest. The site is interactive, which permits constant updating without contacting a webmaster. Attributes of the site include background information in the form of fact sheets, reviews, and government handbooks; an interactive diagnostic identification key for SPB and other bark beetles; a searchable expertise directory; a calendar of SPB-related events; a discussion forum; an online SPB spot growth predictive model; a searchable bibliographic database; a webcrawler designed to search for SPB-related websites, and more. Web-based tools were developed to integrate relational databases as the functional base of this site. The dynamic nature of the SPBICC makes it a powerful tool and a model for development of websites for other major agricultural or forest pests.     

Epidemiological associations between characteristics of registered broiler chicken flocks in Canada and the Salmonella culture status of floor litter and drinking water

A Canada-wide flock management survey of 294 randomly selected commercial broiler chicken flocks was conducted during 1989-1990. The prevalence of flocks that yielded Salmonella from cultures of floor litter or drinking water, and the prevalence of floor litter samples that yielded Salmonella, were significantly associated (p < 0.05) with the age of the flock and the region of Canda in which the flock was located. Culture of Salmonella from the drinking water was significantly associated (p < 0.05) with the type of drinker used, the dead bird disposal method, and the region of Canada in which the flock was located. There was a significantly greater risk (p < 0.05) of contamination of drinking water with Salmonella from trough drinkers (odds ratio = 7.99) and plastic bell drinkers (odds ratio = 6.10) than from nipple drinkers. No significant associations were found between pest control, restrictions on visitors, clean-out methods, or water sanitization and the culture of salmonellae from floor litter or drinking water.     

The renin‐angiotensin‐aldosterone system and its suppression

Chronic activation of the renin‐angiotensin‐aldosterone system (RAAS) promotes and perpetuates the syndromes of congestive heart failure, systemic hypertension, and chronic kidney disease. Excessive circulating and tissue angiotensin II (AngII) and aldosterone levels lead to a pro‐fibrotic, ‐inflammatory, and ‐hypertrophic milieu that causes remodeling and dysfunction in cardiovascular and renal tissues. Understanding of the role of the RAAS in this abnormal pathologic remodeling has grown over the past few decades and numerous medical therapies aimed at suppressing the RAAS have been developed. Despite this, morbidity from these diseases remains high. Continued investigation into the complexities of the RAAS should help clinicians modulate (suppress or enhance) components of this system and improve quality of life and survival. This review focuses on updates in our understanding of the RAAS and the pathophysiology of AngII and aldosterone excess, reviewing what is known about its suppression in cardiovascular and renal diseases, especially in the cat and dog.