Shortly after the commencement of a widespread Pleuro-Pneumonia outbreak early in 1957, a phone call was received from a stock-owner in the Spring Hill area reporting a suspected case of Pleuro-Pneumonia on his property. The owner, questioned briefly over the phone, gave the following history:
The affected animal was a Hereford-cross yearling steer in fat condition. It had seemed well until the previous day; how it was obviously sick and had developed a cough. This steer had been bred by the owner and although the latter had introduced some cattle over the previous months, these were doing well and none of them had appeared sick at any stage.
A prompt visit was paid to this holding as the ramifications of the P.P.C. outbreak were so complex and the nature of the outbreak on some of the holdings concerned was so unusual, that the mere mention of a sick beast was sufficient to place one on guard. On arrival the owner was questioned more closely but could enlarge little on the history and symptoms already recorded. However, he did recall that the steer had shown evidence of diarrhoea and a slight nasal discharge. As soon as the owner had noticed the animal coughing, he separated it from the remainder of the herd, and placed it in a paddock on its own, just prior to 'phoning.
An inspetion was made of the main herd but no evidence of unthriftiness or sickness was noticed. Most of the cattle were in good to fat condition and at the time of the inspection, were grazing a nutritious, dry pasture comprising natural grasses with a heavy growth of trefoil. There were a few ex-Queensland cattle in the herd but as far as could be ascertained none of the more recently purchased cattle could have had contact in saleyards or elsewhere with those responsible for the P.P.C. outbreak. Having inspected the herd, the owner and writer then entered the paddock to examine the sick animal and after a search, it was found dead, on its side, with little evidence of struggling prior to death. The general appearance of the carcase suggested that the animal could not have been dead more than a few hours.
The lungs showed extensive pneumonic areas with varying stages of red and grey hepatisation. There were some pleuritic adhesions present but no appreciable quantity of pleuritic fluid, and there was no pronounced distention of the inter-lobular septa. The general appearance throughout the body suggested an acute septicaemic or toxaemic condition; the lymph nodes being engorged, with an extensive subserous and submucous petechiation. The liver was orange-coloured and the gall bladder grossly distended with a dark brown, viscid bile. The mucous membrane of the abomasum, small intestines and large intestines was congested.
Pipettes of liver, kidney, spleen, heart and lung, together with other specimens, were forwarded to Glenfield Research Station for examination, and the Director of Veterinary Research advised in his report on the examination of these specimens that no organisms were recovered from the pipettes of heart, kidney, liver or spleen. However, a pure culture of Pasteurella haemolytica was recovered from the pipettes of lung tissue. The D.V.R. remarked that this was of interest as it had not previously been identified at Glenfield.
About the middle of January, 1957, an owner reported a mortality in ewes which over the previous week had resulted in the loss of three in a flock of 1,200. The ewes concerned were in good condition and had been grazing excellent dry pasture containing a mixture of perennial rye, clovers and phalaris.
An inspection was made of the flock, which, apart from one sheep, appeared to be in very good order and free from any obvious signs of disease. The one exception had been noticed by the owner, who said that the symptoms exhibited in this ewe were quite typical of those shown in earlier cases.
Walking in circles, champing of jaws, keratitis and conjunctivitis. In the case examined, the head was dorsi-flexed, but held to the right side. The animal had reached the stage where it was unable to stand unassisted. When raised to its feet, it would turn on its axis and then fall on to its right side. If turned on to its left side, the ewe would kick and struggle until it rolled over, on its back, to the right side. Temperature-103.2°. Respiration normal. After the completion of the examination, the ewe was destroyed.
No significant pathological changes were present but there was some congestion of the meningeal vessels. A diagnosis of Listeriosis was made on the basis of symptoms, history and post-mortem appearance, and pipettes of brain, kidney, liver and heart were forwarded to the Veterinary Research Station for examination.
In due course, advice was received from the Director of Veterinary Research that no organisms were recovered from the pipettes of kidney, liver and heart blood; but that a small diphtheroid was a constant organism in growths obtained from pipettes of brain tissue. This organism was identified as Corynebacterium pyogenes. The D.V.R. was of the opinion that in view of the circumstances of its isolation, this organism was quite possibly responsible for the condition.
There appears to be no record of organisms other than Listeria producing typical circling disease. The writer has seen cases of Listeriosis associated with circling and feels that, on a clinical basis, such cases could not be differentiated from the condition reported here.