of tuberculin tests that are a prerequisite for movement of cattle between environmentally different states in Australia. A. w. D. LEPPER, CSIRO, Division of Animal Health, Animal Health Research Laboratory, Private Bag No. 1, P.O. Parkville. Victoria. 3052 15 July 1977
References Lepper, A. W. D., Newton-Tabrett, D. A., Corner, L. A., Carpenter, M. T., Scanlan, W. A., Williams, 0. J., and Helwig, D. M. (1977)-Aust. vet. 1. 53: 208. U.S. Roswurm, J. D. and Konyha, L. D. (1973)-Proc. Anim. H. Assoc. 11: 368. Rushford, B. H. (1964)-Aust.
vet.
J . 4 0 411.
ISOLATION OF EQUINE RHINOVIRUS TYPE 1
The established viral causes of equine respiratory disease in Australia are equine herpesvirus type 1 (EHVI), possibly EHV2 and EHV3, and equine adenovirus. The isolation of equine influenza, equine arteritis and equine rhinovirus (EVR), which are significant causes of equine respiratory disease in other parts of the world have not been reported here. Limited serologic data indicate that neither equine influenza virus (F. Warburton, personal communication) nor equine arteritis virus (Akashi et a1 1975) is present in Australia. This note records the isolation of ERV type 1 (ERV1). A 4-year-old, non-pregnant, thoroughbred mare was one of a group of 53 horses flown from Eire to Australia in late December, 1975. The horses which originated from various parts of the United Kingdom and Eire, were assembled in Eire and flown directly to Australia. Fifteen days after arrival the mare ceased eating suddenly, became very lethargic, and showed swelling in the legs. The horse's temperature was 39.6"C, the heart rate and respiratory rate were elevated and urine and faecal flows slowed. The mare remained ill for 7 days after which an uneventful recovery was made. On days 16, 17 and 18 temperatures of 41.4"C, 41.0"C and 40.0"C respectively were recorded. Nasal swabs (right and left nostrils) were obtained on day 19 and were broken off into medium 199. On days 20 and 21 in addition to the signs already noted the mare showed sweating and pawing. On day 22 there was abdominal pain and an exploratory abdominal paracentesis was performed. Fluid which appeared as blood was obtained. The nasal swabs and a serum-buffy coat mixture from the abdominal fluid were submitted to the laboratory. The nasal swabs were pooled and both samples were then filtered through 0.45 pm membrane filters and inoculated onto monolayers of equine foetal kidney cells. Thirty six hours after inoculation foci of cytopathology were present in all inoculated cultures and by 48 hours 80 to 100% of cells showed cytopathic changes. Details of the isolation and characterisation of the virus will be reported elsewhere. Viruses isolated from the pooled nasal swabs and from the abdominal fluid were the same. Briefly summarised, the virus was not inactivated by chloroform but was inactivated after 1 hr at room temperature in media at pH 4, 5 and 6.
The virus was not stabilised by M MgCI*. Replication was not inhibited by bromodeoxyuridine and by immunofluorescence microscopy and thin section electron microscopy it was established that the virus replicated in the cytoplasm where it formed paracrystalline arrays. Under one step growth conditions mature virus production began at about 14 hours post inoculation. Virus appeared to be released soon thereafter such that maximum levels of cell free virus were attained about 16 hours post inoculation. In negatively stained immune electron micrographs the diameter of the virus was 24.8 zk 0.61 nm and its density in caesium chloride was 1.456 g/ml. The virus did not agglutinate human 0, guinea pig, chicken or equine red blood cells at room temperature. These properties were consistent with the identification of the virus as ERV. Using specific antiserum prepared in rabbits it was shown that the virus, designated ERV 397/76, was in fact ERVl. A total of 355 equine serums collected from horses of various ages and breeds primarily in Victoria but also in New South Wales, South Australia, Northern Territory and Tasmania were examined for ERVl 397/76 neutralising antibody. 47.9% of these serums contained such antibody. Some of the serums that contained antibody were collected as early as 1965. This is the first report of the occurrence of ERVl Australia. The serologic data indicate that the virus is widely distributed and that it has been present in Australia at least since 1965. Serological data (Studdert unpublished) indicate that ERVl is associated with some episodes of acute upper respiratory tract disease of horses in Australia. We are grateful to Drs G. J. Mooney, J. W. Macaulay, P. R. Harvey and B. H. Rushford for facilitating the examination of the original samples. Dr G. R. Thompson, The Royal Veterinary College, London, and Dr W. A. Geering are thanked for supplying antiserums. Financial support was provided by the University of Melbourne Equine Research Fund. M. I. STUDDERT, L. J. GLEESON, School of Veterinary Science, University of Melbourne, Parkville, Victoria, 3052 31 March 1977 References Akashi, H., Konishi, S. and Ogata, M. (1975hJa p. J. vet. Sci. 38: 71.
MYELOMALACIA IN AFGHAN HOUNDS
Cockrell et a/ (1973) reported a myelomalacic disease characterised by ataxia and progressive hind limb para452
lysis in 7 Afghan Hounds. They suggested that the cause may be anoxia or ischemia. McGrath (1974) Australian Veterinary
Journal, Vol. 53, September, 1977
suggested that the disorder is a familial metabolic disorder involving vitamin B12 metabolism rather than ischemia. This paper records the presence of the disease in Australia. In addition to the 10 Melbourne cases reported below, the disease has also been diagnosed in Sydney (W. J. Hartley personal communication) and New Zealand (8. R. Jones unpublished data). The clinical signs in the 10 Afghan Hounds at the Veterinary Clinical Centre, Werribee, were similar to those of the dogs described by Cockrell et a[ (1973). The age of onset of this slowly progressive condition varied from 3 to 11 months of age with a course of 3 to 12 weeks. Both male and female animals were affected. The first clinical signs observed in all cases were hind limb weakness and difficulty rising from a recumbent position, followed by hind limb ataxia, hypermetria and occasional knuckling on to the dorsal surface of the hind paws or collapse of the hindlimbs. There was often abduction and over extension of the hind limbs while walking, and in 2 dogs a “bunny hopping” gait was seen. Rarely, forelimb ataxia and hypermetria were observed. The hindlimb ataxia progressed to paralysis which was spastic in 2 dogs. Urinary and faecal incontinence were present at the stage of paralysis. Pain was not a feature of the condition but one dog was hyperaesthetic to palpation of the mid-thoracic spine. All dogs retained normal sensation to pin prick on the skin of the hind limbs, back, flanks and forelimbs even when hindlimb paralysis was complete. Early in the course of the disease a proprioceptive deficit could be demonstrated in the hind limbs. Hindlimb spinal reflexes that were normal in the early stages became exaggerated later and a crossed extensor reflex could often be elicited. Forelimb and cranial nerve reflexes were normal. N o significant abnormalities were observed in plain radiographs of the vertebral column or in myelograms. Haematology, blood chemistry, cerebrospinal fluid analysis and cell count were normal. The disease was observed in closely related dogs and more than one puppy of a litter were often affected. Also, the progeny of different matings of the same sire and dam developed the disease suggesting that there is an inherited predisposition to develop the condition. The dogs were destroyed at the stage they became paraplegic and were necropsied. Lesions in all dogs were similar and confined to the central nervous system. In the spinal cord, lesions were usually found between the second cervical and fourth lumbar vertebrae and were visible, in formalin-fixed tissue, as greyish softenings of the white matter. Lesions in the upper cervical segments were usually confined to the dorsal white fasciculi, in the thoracic segments to ventral and lateral fasciculi and in lumbar segments
to the ventral fasciculi, Occasionally in the lower cervical segments both dorsal and ventral fasciculi were affected. Histological examination showed that the lesions were always symmetrical and characterised by leucomalacia. Severely affected areas were clearly demarcated from the surrounding tissues and showed loss of normal architecture, swelling and fragmentation of myelin sheaths, astrocytosis and numerous gitter cells. Blood vessels in these areas were prominent with perivascular accumulation of astrocytes and gitter cells, and hypertrophy of endothelial nuclei. In many of the larger foci, the central areas were undergoing liquefaction. The cranial and caudal limits of the spinal cord lesions (cervical and lumbar segments) consisted of swollen myelin sheaths with little axonal swelling and astrocytosis was either mild or absent. Myelin sheaths were often swollen to approximately 10 times their normal diameter and many contained normal axons. Blood vessels in these areas contained hypertrophic endothelial nuclei. There was minimal involvement of grey matter even in the mid-thoracic segments where the white matter lesion was extensive. In areas of grey matter adjacent to affected white matter, there was a slight increase in glial cell numbers and mild central chromatolysis of neurons. No morphological abnormalities were detected in the meningeal blood vessels. The changes observed in sections of the brain in 4 dogs were small foci of malacia confined to the caudal brain stem and medial olivary nucleus. The lesions observed in our cases were similar to those reported by Cockrell et a1 (1973) except that our cases showed no meningeal vascular abnormalities or lesions of the ventral suinal arterv and in addition lesions were detected in {he brain &em. B. R. JONES, Department of Veterinary Clinical Sciences, Maisey University, Palmerston North, New Zealand. R. B. RICHARDS, Regional Veterinary Laboratory, Department of Agriculture, Albany, 6330, Western Australia. 7 November 1975 References Cockrell, B. Y.,Hegristad, R. D., Flo, G. L. and Legendre, A. M. (1973)-J. Am. vet. med. Ass. 162: 362. McGrath, J. T. ( 1 9 7 4 M i t e d by Bailey, C. S. and Holliday, T. A. (1975) in Chapter 14 “Textbook of Veterinary Internal Medicine - Diseases of the Dog and Cat” W. B. Saunders, Philadelphia p. 420.
SALMONELLA DUBLIN IN DAIRY CATTLE Following the first report of Salmonella dublin infection in Australian cattle by Stewart and Hayston (1941), very few confirmed cases of S. duhlin disease in cattle were recorded in Australia prior to 1969. Hughes and Jones (1973) reported a marked rise in the number of S. dublin isolates referred to the Salmonella Reference Centre, Adelaide, and the Enteric Reference Centre, Melbourne, between 1969 and 1972. A total
Australian Veterinary Journal, Vol. 53, September, 1977
of 68 isolations of S. dublin were made during that period, the majority originating from Victorian cattle. By 1972, S. d u b h was the second most frequently reported cause of bovine salmonellosis, most cases being associated with S. typhimurium. The predominant clinical syndrome reported was diarrhoea and mortality in calves.
453
References Lepper, A. W. D., Newton-Tabrett, D. A., Corner, L. A., Carpenter, M. T., Scanlan, W. A., Williams, 0. J., and Helwig, D. M. (1977)-Aust. vet. 1. 53: 208. U.S. Roswurm, J. D. and Konyha, L. D. (1973)-Proc. Anim. H. Assoc. 11: 368. Rushford, B. H. (1964)-Aust.
vet.
J . 4 0 411.
ISOLATION OF EQUINE RHINOVIRUS TYPE 1
The established viral causes of equine respiratory disease in Australia are equine herpesvirus type 1 (EHVI), possibly EHV2 and EHV3, and equine adenovirus. The isolation of equine influenza, equine arteritis and equine rhinovirus (EVR), which are significant causes of equine respiratory disease in other parts of the world have not been reported here. Limited serologic data indicate that neither equine influenza virus (F. Warburton, personal communication) nor equine arteritis virus (Akashi et a1 1975) is present in Australia. This note records the isolation of ERV type 1 (ERV1). A 4-year-old, non-pregnant, thoroughbred mare was one of a group of 53 horses flown from Eire to Australia in late December, 1975. The horses which originated from various parts of the United Kingdom and Eire, were assembled in Eire and flown directly to Australia. Fifteen days after arrival the mare ceased eating suddenly, became very lethargic, and showed swelling in the legs. The horse's temperature was 39.6"C, the heart rate and respiratory rate were elevated and urine and faecal flows slowed. The mare remained ill for 7 days after which an uneventful recovery was made. On days 16, 17 and 18 temperatures of 41.4"C, 41.0"C and 40.0"C respectively were recorded. Nasal swabs (right and left nostrils) were obtained on day 19 and were broken off into medium 199. On days 20 and 21 in addition to the signs already noted the mare showed sweating and pawing. On day 22 there was abdominal pain and an exploratory abdominal paracentesis was performed. Fluid which appeared as blood was obtained. The nasal swabs and a serum-buffy coat mixture from the abdominal fluid were submitted to the laboratory. The nasal swabs were pooled and both samples were then filtered through 0.45 pm membrane filters and inoculated onto monolayers of equine foetal kidney cells. Thirty six hours after inoculation foci of cytopathology were present in all inoculated cultures and by 48 hours 80 to 100% of cells showed cytopathic changes. Details of the isolation and characterisation of the virus will be reported elsewhere. Viruses isolated from the pooled nasal swabs and from the abdominal fluid were the same. Briefly summarised, the virus was not inactivated by chloroform but was inactivated after 1 hr at room temperature in media at pH 4, 5 and 6.
The virus was not stabilised by M MgCI*. Replication was not inhibited by bromodeoxyuridine and by immunofluorescence microscopy and thin section electron microscopy it was established that the virus replicated in the cytoplasm where it formed paracrystalline arrays. Under one step growth conditions mature virus production began at about 14 hours post inoculation. Virus appeared to be released soon thereafter such that maximum levels of cell free virus were attained about 16 hours post inoculation. In negatively stained immune electron micrographs the diameter of the virus was 24.8 zk 0.61 nm and its density in caesium chloride was 1.456 g/ml. The virus did not agglutinate human 0, guinea pig, chicken or equine red blood cells at room temperature. These properties were consistent with the identification of the virus as ERV. Using specific antiserum prepared in rabbits it was shown that the virus, designated ERV 397/76, was in fact ERVl. A total of 355 equine serums collected from horses of various ages and breeds primarily in Victoria but also in New South Wales, South Australia, Northern Territory and Tasmania were examined for ERVl 397/76 neutralising antibody. 47.9% of these serums contained such antibody. Some of the serums that contained antibody were collected as early as 1965. This is the first report of the occurrence of ERVl Australia. The serologic data indicate that the virus is widely distributed and that it has been present in Australia at least since 1965. Serological data (Studdert unpublished) indicate that ERVl is associated with some episodes of acute upper respiratory tract disease of horses in Australia. We are grateful to Drs G. J. Mooney, J. W. Macaulay, P. R. Harvey and B. H. Rushford for facilitating the examination of the original samples. Dr G. R. Thompson, The Royal Veterinary College, London, and Dr W. A. Geering are thanked for supplying antiserums. Financial support was provided by the University of Melbourne Equine Research Fund. M. I. STUDDERT, L. J. GLEESON, School of Veterinary Science, University of Melbourne, Parkville, Victoria, 3052 31 March 1977 References Akashi, H., Konishi, S. and Ogata, M. (1975hJa p. J. vet. Sci. 38: 71.
MYELOMALACIA IN AFGHAN HOUNDS
Cockrell et a/ (1973) reported a myelomalacic disease characterised by ataxia and progressive hind limb para452
lysis in 7 Afghan Hounds. They suggested that the cause may be anoxia or ischemia. McGrath (1974) Australian Veterinary
Journal, Vol. 53, September, 1977
suggested that the disorder is a familial metabolic disorder involving vitamin B12 metabolism rather than ischemia. This paper records the presence of the disease in Australia. In addition to the 10 Melbourne cases reported below, the disease has also been diagnosed in Sydney (W. J. Hartley personal communication) and New Zealand (8. R. Jones unpublished data). The clinical signs in the 10 Afghan Hounds at the Veterinary Clinical Centre, Werribee, were similar to those of the dogs described by Cockrell et a[ (1973). The age of onset of this slowly progressive condition varied from 3 to 11 months of age with a course of 3 to 12 weeks. Both male and female animals were affected. The first clinical signs observed in all cases were hind limb weakness and difficulty rising from a recumbent position, followed by hind limb ataxia, hypermetria and occasional knuckling on to the dorsal surface of the hind paws or collapse of the hindlimbs. There was often abduction and over extension of the hind limbs while walking, and in 2 dogs a “bunny hopping” gait was seen. Rarely, forelimb ataxia and hypermetria were observed. The hindlimb ataxia progressed to paralysis which was spastic in 2 dogs. Urinary and faecal incontinence were present at the stage of paralysis. Pain was not a feature of the condition but one dog was hyperaesthetic to palpation of the mid-thoracic spine. All dogs retained normal sensation to pin prick on the skin of the hind limbs, back, flanks and forelimbs even when hindlimb paralysis was complete. Early in the course of the disease a proprioceptive deficit could be demonstrated in the hind limbs. Hindlimb spinal reflexes that were normal in the early stages became exaggerated later and a crossed extensor reflex could often be elicited. Forelimb and cranial nerve reflexes were normal. N o significant abnormalities were observed in plain radiographs of the vertebral column or in myelograms. Haematology, blood chemistry, cerebrospinal fluid analysis and cell count were normal. The disease was observed in closely related dogs and more than one puppy of a litter were often affected. Also, the progeny of different matings of the same sire and dam developed the disease suggesting that there is an inherited predisposition to develop the condition. The dogs were destroyed at the stage they became paraplegic and were necropsied. Lesions in all dogs were similar and confined to the central nervous system. In the spinal cord, lesions were usually found between the second cervical and fourth lumbar vertebrae and were visible, in formalin-fixed tissue, as greyish softenings of the white matter. Lesions in the upper cervical segments were usually confined to the dorsal white fasciculi, in the thoracic segments to ventral and lateral fasciculi and in lumbar segments
to the ventral fasciculi, Occasionally in the lower cervical segments both dorsal and ventral fasciculi were affected. Histological examination showed that the lesions were always symmetrical and characterised by leucomalacia. Severely affected areas were clearly demarcated from the surrounding tissues and showed loss of normal architecture, swelling and fragmentation of myelin sheaths, astrocytosis and numerous gitter cells. Blood vessels in these areas were prominent with perivascular accumulation of astrocytes and gitter cells, and hypertrophy of endothelial nuclei. In many of the larger foci, the central areas were undergoing liquefaction. The cranial and caudal limits of the spinal cord lesions (cervical and lumbar segments) consisted of swollen myelin sheaths with little axonal swelling and astrocytosis was either mild or absent. Myelin sheaths were often swollen to approximately 10 times their normal diameter and many contained normal axons. Blood vessels in these areas contained hypertrophic endothelial nuclei. There was minimal involvement of grey matter even in the mid-thoracic segments where the white matter lesion was extensive. In areas of grey matter adjacent to affected white matter, there was a slight increase in glial cell numbers and mild central chromatolysis of neurons. No morphological abnormalities were detected in the meningeal blood vessels. The changes observed in sections of the brain in 4 dogs were small foci of malacia confined to the caudal brain stem and medial olivary nucleus. The lesions observed in our cases were similar to those reported by Cockrell et a1 (1973) except that our cases showed no meningeal vascular abnormalities or lesions of the ventral suinal arterv and in addition lesions were detected in {he brain &em. B. R. JONES, Department of Veterinary Clinical Sciences, Maisey University, Palmerston North, New Zealand. R. B. RICHARDS, Regional Veterinary Laboratory, Department of Agriculture, Albany, 6330, Western Australia. 7 November 1975 References Cockrell, B. Y.,Hegristad, R. D., Flo, G. L. and Legendre, A. M. (1973)-J. Am. vet. med. Ass. 162: 362. McGrath, J. T. ( 1 9 7 4 M i t e d by Bailey, C. S. and Holliday, T. A. (1975) in Chapter 14 “Textbook of Veterinary Internal Medicine - Diseases of the Dog and Cat” W. B. Saunders, Philadelphia p. 420.
SALMONELLA DUBLIN IN DAIRY CATTLE Following the first report of Salmonella dublin infection in Australian cattle by Stewart and Hayston (1941), very few confirmed cases of S. duhlin disease in cattle were recorded in Australia prior to 1969. Hughes and Jones (1973) reported a marked rise in the number of S. dublin isolates referred to the Salmonella Reference Centre, Adelaide, and the Enteric Reference Centre, Melbourne, between 1969 and 1972. A total
Australian Veterinary Journal, Vol. 53, September, 1977
of 68 isolations of S. dublin were made during that period, the majority originating from Victorian cattle. By 1972, S. d u b h was the second most frequently reported cause of bovine salmonellosis, most cases being associated with S. typhimurium. The predominant clinical syndrome reported was diarrhoea and mortality in calves.
453
