The comparative pathogenicity of four serovars of Actinobacillus (Haemophilus) pleuropneumoniae

The pathogenicity of 2 isolates of each of serovars 7, 3, 1 and 2 of Actinobacillus pleuropneumoniae was tested by intranasal inoculation into 60, 6-week-old large white pigs. Four dose rates varying from 0.27 to 560 x 10(6) organisms per pig with 10-fold serial dilutions were used. Surviving pigs were necropsied 7 days after inoculation. The proportion of pigs dying and developing gross lesions following infection was significantly greater for pigs given serotype 1 than for each of the other 3 serotypes, which did not differ significantly from each other. Twelve of 16 pigs given either of the 2 isolates of serovar 1 died after acute illness and 1 of 44 pigs given either of the 2 isolates each of serovars 7, 3 and 2 died. Pigs given serovar 1 showed high temperatures, severe respiratory distress, frothy haemorrhagic nasal discharge and weight loss. Lung lesions were produced in all 16 pigs given serovar 1, in 7 of 14 pigs given serovar 7, 7 of 14 pigs receiving serovar 3 and in 5 of 16 pigs given serovar 2. The lethal infections were characterised by a severe acute fibrinohaemorrhagic necrotising pleuropneumonia, whereas non-lethal cases had lung lesions ranging from necrotising purulent pleuropneumonia to abscessation. Significant differences between isolates in proportions of tissues culture positive for A. pleuropneumoniae for serovars 7 and 2, but not for serovars 3 and 1 suggested that isolates may vary in virulence within serovars, but more detailed studies are needed to clarify this point.     

The toxicity of Castanospermum australe seeds for cattle

Two calves given a mean of 16.1 g and 16.4 g ripe Castanospermum australe seeds/kg body weight daily for 13 and 16 days respectively developed haemorrhagic gastroenteritis. The first calf died. The second calf had mild myocardial degeneration and necrosis and mild nephrosis at necropsy. Two calves given a mean of 16.8 g unripe C. australe seeds/kg body weight daily for 18 days remained clinically normal and had mild gastritis at necropsy. The activity of alpha-glucosidase was reduced in the mononuclear cells of peripheral blood and in skeletal muscle. This was attributed to the presence of the indolizidine alkaloid, castanospermine, in the seeds. The toxin causing the gastroenteritis and other lesions is unknown.     

Morbillivirus infection in two common porpoises (Phocoena phocoena) from the coasts of England and Scotland.

Two common porpoises (Phocoena phocoena), one found stranded on the Isle of Sheppey, Kent, and the other in the Moray Firth, Scotland, in late 1990, were examined post mortem. Lesions of diffuse bronchointerstitial pneumonia were present in both animals; they were characterised by the infiltration of alveoli with leucocytes, macrophages and multinucleate syncytia, the necrosis of bronchial and bronchiolar epithelium, focal proliferation of type II pneumocytes and occasional acidophilic cytoplasmic inclusions in alveolar macrophages and syncytia. Lymphoid depletion was apparent in the spleen, thymus and lymph nodes of both porpoises. Other changes in the Isle of Sheppey porpoise included severe dacryoadenitis. Marked pharyngitis, oesophagitis and balanoposthitis were present in the Moray Firth porpoise. Immunoperoxidase staining revealed the presence of morbillivirus antigen in a range of epithelia from both porpoises. This is the first report of morbillivirus infection in cetaceans from the coast of Great Britain.     

Occurrence of organochlorine residues in Australian meat

In spite of several quality control procedures used by Australia to ensure the wholesomeness of export meat, a number of pesticide residue violations were identified in the Australian product exported to the USA in May 1987. The pesticides involved were the organochlorines, dieldrin and heptachlor. The problems were caused by the persistence of organochlorines in soils and their illicit use or contamination of storage facilities. Animals grazing contaminated pasture, ingesting contaminated feed or held in contaminated yards over a period, bioaccumulated residues in their adipose tissues which eventually exceeded maximum residue limits (MRL) and caused violations. Though there was no immediate public health risk, the Australian Quarantine and Inspection Service (AQIS) of the Commonwealth Department of Primary Industries and Energy (DPIE), acted expeditiously to determine and eliminate the factors causing these problems, which threatened Australia's beef export industry worth in excess of two billion dollars annually. An overall strategic plan, "The Integrated Action Plan", was formulated and implemented by AQIS with the assistance of the relevant Departments of the States and the Northern Territory (NT), meat processing and export industries and livestock producer bodies. As a result of this action, the likely sources of contamination were identified and controlled. The National Residue Survey (NRS) was enhanced, a National Residue Data Base (NRDB) was established and a centralised computer system interactive with abattoirs, laboratories and animal health authorities developed. The cattle farm identity tail tag system already in place, capable of tracing cattle to the farm of origin was refined and trace back systems for sheep and pigs were utilised.(ABSTRACT TRUNCATED AT 250 WORDS)