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R C Cutlip

Publications and source records attributed to R C Cutlip.

124 records · Page 7Linked to original sources
PubMed1970

Electron microscopy of cell cultures infected with a chlamydial agent causing polyarthritis of lambs.

McCoy cell cultures infected with the agent of ovine chlamydial polyarthritis were examined with the electron microscope. The agent was seen as small dense particles (250 to 450 nm) with an eccentric nucleoid and a multilaminated cell wall, as large (800 to 1,200 nm) granular particles surrounded by two unit membranes and as intermediate particles. Replication, which occurred throughout the cytoplasm, was initiated by phagocytosis of a small dense particle and terminated by rupture of the plasma membrane. Upon entering a cell, the small dense particles developed into large granular particles which divided by binary fission. Daughter particles either repeated the division or condensed to form new small dense particles.

Journal Article↗
PubMedDate not supplied

Response of turkey poults to aerosolized spores of Aspergillus fumigatus and aflatoxigenic and nonaflatoxigenic strains of Aspergillus flavus.

Groups of 3-week-old turkey poults were exposed to aerosols containing spores of either Aspergillus fumigatus or aflatoxigenic or nonaflatoxigenic strains of Aspergillus flavus. Approximately 5 X 10(5) spores of A. fumigatus/gm of lung tissue killed about 50% of the turkey poults with A. funigatus, whereas doses approximating this level with either of the A. flavus strains did not cause any mortalities for up to 8 weeks postexposure. Fungi were isolated from lung tissue of 60% of the birds surviving for 8 weeks after exposure to spores of A fumigatus, but A. flavus was isolated from lung tissue from only 20% of the birds 8 weeks after exposure to either A. flavus strain. Almost all birds exposed to A. fumigatus developed precipitating antibodies, whereas none of the birds exposed to A. flavus developed precipitating antibodies. The lesions in the lung tissue from birds exposed to A. fumigatus were larger, were more numerous, and involved a greater percentage of tissue than was observed in lung tissue from birds exposed to A. flavus. There were no apparent differences in pathogenicity between the A. flavus strains. Aflatoxin was not detected in tissues from birds exposed to the aflatoxigenic strain of A. flavus, and there were no signs of aflatoxigenic when sections of liver from these birds were examined histopathologically.

Aerosols↗
PubMedDate not supplied

Pasteurella haemolytica complicated respiratory infections in sheep and goats.

Respiratory infections which commonly occur in sheep and goats often result from adverse physical and physiological stress combined with viral and bacterial infections. Inevitably, Pasteurella haemolytica pneumonia occurs as a result of these interactions. In this review, we present recent advances in research on the complex etiology of pneumonia involving P. haemolytica. Initially stress, induced by factors such as heat, overcrowding, exposure to inclement weather, poor ventilation, handling and transport is a major predisposing factor. Respiratory viruses including parainfluenza 3 (PI-3) virus, adenovirus type 6 and respiratory syncytial virus (RSV), and to a lesser extent bovine adenovirus type 2, ovine adenovirus types 1 and 5, and reovirus type 1 cause respiratory infections and pneumonia. More importantly these viruses also dramatically increase the susceptibility of sheep and goats to secondary P. haemolytica infection. Primary infection of the lower respiratory tract, with Mycoplasma ovipneumoniae and Bordetella parapertussis can increase the susceptibility of sheep and goats to secondary P. haemolytica infection. It is possible that initial infections with viral or primary bacterial agents break down the antimicrobial barrier consisting of beta defensins and anionic peptides found in epithelial cells, resident and inflammatory cells, and serous and mucous secretions of the respiratory tract. Loss of barrier integrity may release P. haemolytica from its usual commensal status. Once in the lung, P. haemolytica becomes opportunistic. To grow and colonize, P. haemolytica uses extracellular products like O-sialoglycoprotein endopeptidase, neuraminidase and RTX leukotoxin, as well as cell-associated products such as capsular polysaccharide, lipopolysaccharide, outer membrane proteins, proteins involved in iron acquisition and a periplasmic superoxide dismutase. In lambs and kids, pneumonic pasteurellosis can be acute, characterized by fever, listlessness, poor appetite and sudden death. Sheep and goats that survive the acute stage may recover or become chronically affected showing reduced lung capacity and weight gain efficiency and sporadic deaths may occur. This infection is detrimental to sheep and goats throughout the world and flocks and herds of small ranches, dairy operations, or large feedlots are all affected.

Animals↗