Abstract. Five dogs 2 to 8 years old with old dog encephalitis were compared to five other dogs, 4 to 8% years old, with prolonged multifocal demyelinating distemper encephalitis. The dogs with old dog encephalitis had a diffuse panencephalitis involving most areas of the central nervous system with relative sparing of the cerebellum. The clinical signs were related to the cortical and subcortical lesions. The other dogs had severe focal necrotizing lesions mostly in the cerebellum and in the vicinity of the fourth ventricle; clinical signs were related to brainstem and spinal cord lesions. Viral isolation attempts were unsuccessful in the dogs with old dog encephalitis. In two dogs with multifocal encephalitis, canine distemper virus was isolated in tissue culture. The differences in lesions, clinical signs and observations in v i m indicate differences in pathogenesis between old dog encephalitis and multifocal demyelinating distemper encephalitis although both diseases may be caused by the same agent.

The N-chloramine compound 3-chloro-4,4-dimethyl-2-oxazolidinone (agent I) has been compared with calcium hypochlorite as to its efficacy as a bactericide for the treatment of water. The study included concentration, contact time, pH, temperature, and water quality as controlled variables. The species of bacteria tested were Staphylococcus aureus, Pseudomonas aeruginosa, and Shigella boydii. In general, for highly pure, demand-free water, calcium hypochlorite was the more rapid disinfectant at a given total chlorine concentration, although for water containing a controlled amount of organic load, agent I was the better disinfectant. The differences in efficacy of each of the two disinfectants can be attributed primarily to their different stabilities in water at various controlled conditions.

The bactericidal efficacies of three organic N,N'-dihalamine disinfectants in the class of compounds termed imidazolidinones were determined for combinations of pH, temperature, and water quality treatments by using Staphylococcus aureus and Shigella boydii as test organisms. The compound 1,3-dibromo-4,4,5,5-tetramethyl-2-imidazolidinone was found to be the most rapidly acting bactericide, especially under halogen-demand-free conditions. The mixed N,N'-dihalamine 1-bromo-3-chloro-4,4,5,5-tetramethyl-2-imidazolidinone was found to be intermediate in terms of rate of disinfection, while the compound 1,3-dichloro-4,4,5,5-tetramethyl-2imidazolidinone was observed to be the slowest acting bactericide. When overall effectiveness was judged on the basis of stability of the disinfectants along with rates of disinfection, the mixed halamine was considered to exhibit great potential for use as a disinfectant in an aqueous solution.

Abstract. An epornitic of canary pox occurred in white-crowned sparrows (Zonotrichia leucophrys gambelli) , golden-crowned sparrows (Zonotrichia atricapilla) , and house sparrows (Passer domesticus), which had been caught in the wild and were being studied in laboratories. Of 900 exposed birds, 100 died naturally with the disease and 200 with clinical signs, and their 600 cage mates were killed. The earliest lesion was proliferative dermatitis around the eyes and beak. Next, severe ulcerative dermatitis, often with secondary bacterial and mycotic infections, developed under the wing; rhinitis, pneumonia, pleuritis, and peritonitis occurred in advanced cases. Histologically, there were eosinophilic, sudanophilic, cytoplasmic inclusions in epithelial cells and in subepidermal lymphoreticular cells. The isolated virus produced 100% mortality when inoculated into white-crowned sparrows, house sparrows, and canaries but only local cutaneous reactions in pigeons, turkeys, and chickens.Wild passerine birds are increasingly used in biomedical research. Among the potential diseases in such species, canary pox is probably the most serious threat, since it is highly infectious [3, 271, produces almost 100% mortality in affected birds [3,7, 231, and may occur in a latent form with the virus being shed from lesions for up to 13 months [18]. It may thus be introduced from the wild into stocks of laboratory-maintained birds, with devastating results.The canary poxvirus is one of the four major subgroups of the avian poxviruses ; the other three are fowl poxvirus, pigeon poxvirus, and turkey poxvirus [3,5,8, 13, 351. These three viruses usually cause a cutaneous disease of high morbidity but variable mortality [8]. Large pocks with umbilicated centers form on the skin. Within the cutaneous lesions, which are generally confined to the epidermis, there are pronounced hypertrophy and hyperplasia of epithelial cells. The cytoplasm of these cells often contains Bollinger bodies, that is, large eosinophilic inclusions composed of clusters of viral particles [8,24].

No abstract

Two N-halamine compounds, 3-chloro-4,4-dimethyl-2-oxazolidinone and 1,3-dichloro-4,4,5,5-tetramethyl-2imidazolidinone, were compared with free chlorine as to their effects on selected membrane functions of intact Staphylococcus aureus cells. Free chlorine was found to cause a loss of permeability control, as measured by the efflux of potassium from the cells and a dramatic increase in hydrogen ion permeability, and to affect cell respiration in a nonreversible fashion, as measured by oxygen uptake. The two N-halamines were found to have very little effect on permeability to either potassium or hydrogen ions but were both found to dramatically inhibit respiration in a reversible manner. It is proposed that the first step in the disinfection process by these N-halamines is an inhibition of respiratory enzymes that, if not reversed, ultimately leads to a loss of cell viability.

No abstract

No abstract