A review of respiratory agents associated with disease of sheep, cattle and pigs in Australia and overseas.
Explore the source record for details and available documents.
SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
History and syndromes of pneumonia, encephalitis, arthritis, and mastitis are reviewed. Occurrence, etiology, pathogenesis, transmission, diagnosis, treatment, and prevention of these diseases are discussed.
Explore the source record for details and available documents.
For the estimation of the diagnostic value of plasma concentrations of total bile acids and ammonia in liver disease healthy controls (n = 23) as well as animals sick with different diseases were examined. The reference values for total bile acids and ammonia in the plasma of sheep range from 18-166 mumol/l and 15-64 mumol/l, respectively. While animals with chronic copper poisoning (n = 18), vitamin E/selenium deficiency (n = 15) and with diseases not affecting the liver (n = 8) did not show significant differences in concentrations of total bile acids and ammonia from those of the healthy controls, this could be proven for animals with severe hepatopathy or hepatoencephalopathy. Furthermore, some of the latter group showed increased ammonia concentrations in the liquor cerebrospinalis and multifocal vacuolation of the central nervous system. The determination of total bile acids and ammonia in the diagnosis of liver disease in sheep would also be useful. The hepatoencephalic syndrome should therefore be considered as possible differential diagnosis in animals showing neurological signs.
This review describes the pathogenesis of a slowly progressive disease complex caused by naturally occurring nononcogenic retroviruses in sheep and goats. In nature, infections are usually clinically silent, but disease may manifest itself after prolonged incubation periods. Clinically, this is seen as dyspnea, progressive paralysis, and/or progressive arthritis. In all organs the basic lesion is inflammatory with infiltration and proliferation of lymphocytes, plasma cells, and macrophages. Other organ-specific pathologic changes such as primary demyelination in the central nervous system and degeneration of cartilaginous structures in joints accompany inflammation. The viruses infect tissue-specific macrophage populations in vivo. Viral replication in these cells is restricted to minimal levels but continues indefinitely in the animal as a result of either failure to induce specific neutralizing antibodies or antigenic drift when neutralizing antibodies develop. Consistent low-grade viral replication sets the pace for disease by providing continuous antigenic stimulation for the inflammatory cellular immune response or antibodies that localize in the target tissues. These cells and immune complexes may have adverse effects on indigenous cell populations.
Explore the source record for details and available documents.
Plastic tags containing 8.5 per cent w/w cypermethrin or 10 per cent w/w permethrin reduced the severity of damage caused to sheep by the headfly Hydrotaea irritans. A similar pattern of protection extended from the tagged ewes to their untagged lambs. Tags containing 8.5 per cent w/w fenvalerate failed to reduce the level of headfly damage in gimmers.
The temporal development of the CSF abnormalities was examined in visna, a chronic neurological disease caused by a persistent viral infection of sheep. Two types of changes were observed. During the first 30 to 40 days there was an intense mononuclear pleocytosis associated with high protein and proportionately elevated IgG. Later, there was a persistent slight pleocytosis associated with mildly elevated protein which had an increased proportion of IgG and antivisna antibody. These later cellular and protein changes are similar to those found in a number of chronic neurological diseases of man.
Many cobalt-deficient sheep develop liver lesions known as ovine "white liver" disease, but the etiology of these changes is controversial. It has been suggested that cofactors are required for development of liver damage in cobalt-deficient sheep. In this study, one group of lambs (n = 5) was fed a diet low in cobalt (4.5 micrograms/kg) while a group of control lambs (n = 4) received the same diet after it had been supplemented with cobalt (1000 micrograms/kg). All cobalt-depleted lambs had reduced growth rate, anorexia, lacrimation, and alopecia, and they eventually became emaciated (mean body weight at end of study: 83% of initial body weight). Plasma concentrations of bilirubin and serum activity of glutamate-oxaloacetate transferase were elevated in these animals, while plasma concentrations of vitamin B12 were reduced (less than 220 pmol/L from day 42). Fatty degeneration of the liver associated with reduced concentrations of vitamin B12 (14.5 pmol/g) was seen in these animals at necropsy at 196 days. Microscopic liver lesions included accumulation of lipid droplets and lipofuscin particles in hepatocytes, dissociation and necrosis of hepatocytes, and sparse infiltration by neutrophils, macrophages, and lymphocytes. Ultrastructural hepatocytic alterations included swelling, condensation and proliferation of mitochondria, hypertrophy of smooth endoplasmic reticulum, vesiculation and loss of arrays of rough endoplasmic reticulum, and accumulation of lipid droplets and lipofuscin granules in cytoplasm of hepatocytes. No liver lesions were seen in control lambs. The results of this study indicate that cofactors are not a prerequisite to development of hepatic damage in cobalt-deficient sheep. Reduced activities of the vitamin B12-dependent enzymes, methylmalonyl CoA mutase and methionine synthase, and lipid peroxidation are of likely pathogenetic importance in the development of the lesions.
Explore the source record for details and available documents.
Bronchoalveolar lavage fluid was collected postmortem from the lungs of 113 sheep, and total and differential cell counts were analysed in relation to the presence of gross and microscopic lung pathology. The diffuse lung diseases, maedi and adenomatosis, were both characterised by an increase in overall cellularity and by increases in the percentages of lymphocytes and neutrophils, respectively. Focal parasitic lung disease was characterised by an increase in the percentage of eosinophils and mast cells. Consolidated lung lesions were characterised by a slight increase in cellularity but no change in the differential cell profile. In regions of parasitised and consolidated lungs without lesions the differential cell profile was consistent with focal lung pathology, although the slight increase in cellularity observed in the consolidated regions was not observed in the regions without lesions. A decision tree was developed to facilitate the interpretation and indicate the likely predictive capacity of the differential cytology of the fluid.
Explore the source record for details and available documents.
The use of counter-immunoelectrophoresis (CIEP) in the diagnosis of Johne's disease was investigated in flocks of sheep in Iran and Libya. In 50 sheep with no history of paratuberculosis none had antibodies to Mycobacterium paratuberculosis. Animals vaccinated as neonates were either negative or had reciprocal titres (RT) of less than 4 at 18 months of age unless exposed to infection. Among 105 non-vaccinated adults in an infected flock 91% had antibodies. Twenty-one animals that either died or were slaughtered were autopsied. Eight animals with RT of 8 or above and one with RT of 4 had gross lesions with demonstrable acid-fast organisms. Two animals with RT of 2 had clinical disease while three with RT of 4 and one with RT of 2 had histopathological lesions only. All animals found negative for M. paratuberculosis infection had RT of 2 or below. The critical interpretation of the test is discussed.
Sheep affected by broken mouth periodontal disease (P.D.) were examined over a twelve month period for different clinical parameters. It is suggested that P.D. in sheep is an episodic phenomenon similar to human P.D., and that only a few animals with signs of P.D. may undergo clinically significant destruction over a yearly period. No single parameter could reliably predict future deterioration in other parameters.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.