Brain tumours in two Bactrian camels: a histiocytic sarcoma and a meningioma.

Primary brain tumours were identified in two Bactrian camels (Camelus bactrianus) living at the Zoological Society of London's two zoos. Histology and immunohistochemistry were used to diagnose a histiocytic sarcoma in a 16-year-old female and a fibroblastic meningioma in a 13-year-old male. Before one died and the other was euthanased both camels had shown progressive neurological signs, including circling and ataxia.

Experimental respiratory disease in dogs due to Bordetella bronchiseptica.

Young dogs of two age groups, six weeks and 12 weeks respectively, were infected by aerosol with a strain of Bordetella bronchiseptica which had been isolated from a dog with pneumonia. Clinical respiratory disease characterised by coughing and in some cases purulent nasal discharge was induced in both groups of infected dogs and also in dogs kept in contact. B bronchiseptica was recovered from the nasal cavity, trachea, bronchi and lung parenchyma of infected and contact animals. At necropsy, masses of Gram-negative bacteria were found trapped in the cilia of the respiratory epithelia and there was an exudate containing neutrophils in the mucosae of the respiratory tract at all levels. A close similarity was noted between the lesions produced in the dog and those described in pertussis infection in man. Experimental respiratory disease in the dog due to B bronchiseptica may offer a model system for the study of the human disease.

Vaccination against Bordetella bronchiseptica infection in dogs using a heat-killed bacterial vaccine.

A group of eight-week-old dogs was inoculated with a heat-killed suspension of Bordetella bronchiseptica by the intramuscular route on two occasions at an interval of two weeks. All vaccinated animals developed high circulating agglutinin titres by two weeks after the second inoculation at which time the vaccinated dogs and a comparable group of unvaccinated animals were challenged by exposure to an aerosol of live B bronchiseptica. Both vaccinated and unvaccinated dogs subsequently developed clinical respiratory disease characterised by persistent coughing but the onset of disease in vaccinated animals was delayed by up to five days when compared with the controls. B bronchiseptica was isolated from the nasal cavity, tracheobronchial tree and lung parenchyma of vaccinated and control dogs.

Vaccination against canine bordetellosis using an aluminum hydroxide adjuvant vaccine.

Six collie dogs, eight weeks old, were inoculated intramuscularly with an aluminium hydroxide adjuvanted preparation of killed Bordetella bronchiseptica; the inoculation was repeated after two weeks. Two weeks after the second inoculation, the vaccinated dogs and a comparable group of six unvaccinated animals were challenged by exposure to an aerosol of pathogenic B bronchiseptica. All six unvaccinated control dogs developed respiratory disease characterised by persistent coughing. In contrast, four of the vaccinated dogs remained free from clinical respiratory disease while, in the other two dogs, disease was less severe and of shorter duration than in controls. At necropsy, there were only slight changes in the lungs of vaccinated dogs but in controls there was a severe tracheobronchitis with areas of exudative pneumonia. Bacteriological examination showed a marked reduction in the numbers of B bronchiseptica isolated from the respiratory tract of vaccinated animals compared with controls. An aluminium hydroxide adjuvant vaccine may be of value in controlling naturally occurring respiratory disease in dogs in which B bronchiseptica is involved.

Studies on canine parvovirus infection: preparation of challenge virus.

Two techniques, adsorption on to hydroxylapatite and density gradient centrifugation, were investigated as prospective methods for the large scale purification of canine parvovirus from faecal suspensions. Adsorption with hydroxylapatite successfully removed virus from faecal material. However, the resultant virus was contaminated and some virus was left behind in the faecal suspension. Repeated adsorption with hydroxylapatite appeared to result in some damage to the virus particles. In contrast, density gradient centrifugation provided a simple, economical method of purification which yielded uncontaminated, infectious virus. The final method, using both isopyknic and rate zonal centrifugation is described.

Patterns of cilia formation in the lower respiratory tract of the dog: a scanning electron microscopic study.

A scanning electron microscopic study of the distribution of ciliated cells in the tracheobronchial tree of 25 dogs whose ages ranged from four hours to six months was carried out. In newborn puppies, only the dorsal wall of the trachea was completely ciliated while the lateral and ventral walls showed patchy ciliation. This pattern of cilia formation persisted until five days of age when the whole tracheal wall was found to be completely ciliated. The bronchus of newborn puppies was uniformly poorly ciliated but almost complete ciliation was achieved by two days. Likewise, large and small bronchioles of newborn animals had few cilia and, although the number of ciliated cells had increased by two days, complete ciliation was never observed regardless of the age of the dog. No ciliated cells were found in the respiratory bronchioles of any of the 25 dogs.

Canine bordetellosis: chemotherapy using a sulphadiazine-trimethoprim combination.

Respiratory disease was induced in young dogs by exposure to an aerosol of Bordetella bronchiseptica. The affected dogs were then treated with a sulphadiazine-trimethoprim combination by daily subcutaneous injection for five days. There was marked improvement in the clinical, bacteriological and pathological features of the respiratory disease during and immediately after the treatment period but treated dogs relapsed a few days after chemotherapy was stopped. The use of a sulphadiazine-trimethoprim combination over a longer period of time may be of value in the treatment of dogs with respiratory disease associated with B bronchiseptica.

Brain abscess associated with a penetrating foreign body.

Oropharyngeal foreign bodies are not infrequently encountered in dogs and are usually associated with dysphagia. In this case an oropharyngeal foreign body resulted in nervous signs as a result of penetration of the cranial cavity and the development of a brain abscess.

Progressive haematoma of the maxillary sinus in a horse.

A nine-and-a-half-year-old three quarters thoroughbred gelding was presented with unilateral epistaxis. The cause was a destructive, progressive haematoma in the left maxillary sinus. In all previous reports of progressive haematomata in the equine nasal cavity, the site of origin has been the ethmoidal labyrinth. Surgical removal of the progressive haematoma resulted in an apparent cure.

Diseases produced by feline caliciviruses when administered to cats by aerosol or intranasal instillation.

Specific pathogen free cats were infected by two feline calicivirus isolates of different plaque type, an extra-large plaque (ep) former and a minute plaque (mp) former. A comparison was made of the disease produced when these isolates were administered by either aerosol or direct intranasal instillation. With both isolates, aerosol infection produced lesions and gave rise to virus replication throughout the respiratory tract. The effects of intranasal infection were more confined to the upper respiratory tract and oropharynx. By both routes of infection the disease produced by the mp virus was clinically and pathologically less severe than that produced by the ep virus.

Unusual vascular ring in a cat: left aortic arch with right ligamentum arteriosum.

A young kitten was presented with regurgitation of food at weaning. Episodes of respiratory distress and cyanosis were also present. The cause of food regurgitation was a perioesophageal vascular ring caused by left descending aorta and a right ligamentum arteriosum. This type of vascular ring has not previously been described. There was also anomalous development of the right subclavian artery and a large ventricular septal defect. The respiratory distress and cyanosis was most probably caused by a combination of tracheal compression by the vascular ring and a polycythaemia associated with the ventricular septal defect. Surgical correction was not attempted.

Vaccination against canine bordetellosis: protection from contact challenge.

Eight collie-cross pups, eight weeks old, were inoculated intramuscularly with an aluminum hydroxide adjuvanted preparation of killed Bordetella bronchiseptica; the inoculation was repeated after two weeks. Two weeks after the second inoculation, the vaccinated dogs and a control group of four unvaccinated animals were placed in contact with a group of five pups of similar age which had been experimentally infected with a pathogenic strain of B bronchiseptica by an aerosol method. All four unvaccinated control dogs as well as all five experimentally infected dogs developed a respiratory disease characterised by persistent coughing. Six of the vaccinated dogs remained free from clinical respiratory disease while disease was less severe and of shorter duration in the remaining two than in controls. Only slight changes were found in the lungs of vaccinated animals at necropsy while in the controls there was a severe tracheobronchitis. There was a marked reduction in the numbers of B bronchiseptica isolated from the respiratory tract of vaccinated animals when compared with controls. An aluminium hydroxide adjuvanted vaccine may be of value in controlling naturally occurring canine respiratory disease in which B bronchiseptica is involved.

Canine parvovirus: interaction between passive immunity and virulent challenge.

Two groups of puppies, one passively immunised by the administration of hyperimmune serum and the other with natural maternally derived antibody, were inoculated orally with virulent canine parvovirus of faecal origin. Serum antibody titres declined more rapidly in both groups after challenge than before. The dogs became clinically affected but the onset of clinical signs, seroconversion and faecal excretion of virus was delayed when compared to controls. It is postulated that this rapid decline of antibody was due to its sequestration by virus after the initial phase of viral replication in the lymphoid tissues. These findings have important implications. The incubation period of the disease is prolonged, making it more difficult to estimate accurately the time of infection in clinically affected animals. Furthermore, the more rapid decline of maternally derived antibody, which could occur in endemically infected premises, may complicate immunisation programmes based on the isolation and segregation of puppies in anticipation of a predicted decline in maternally derived antibody before vaccination.

Experimental reproduction of acute lesions of porcine pleuropneumonia with a haemolysin-deficient mutant of Actinobacillus pleuropneumoniae.

The role of the heat-labile haemolysin of Actinobacillus pleuropneumoniae in acute porcine pleuropneumonia was examined. A virulent strain was compared with an isogenic haemolysin-deficient mutant in experimental infections. The pigs which received the virulent strain showed clinical signs of acute respiratory disease whereas the animals infected with the mutant strain appeared to be less severely affected. At post mortem examination, both groups showed similar acute pulmonary lesions and pleurisy typical of A pleuropneumoniae infection. The bacterial antigen representing the haemolysin was detected in lung lesions infected with the parent strain but not in those infected with the mutant. These results demonstrate that the haemolysin of serotype 2 A pleuropneumoniae is not an essential factor for the production of the lesions of pleuropneumonia in pigs.

Canine parvovirus enteritis 3: Scanning electron microscopical features of experimental infection.

A group of 10-week-old puppies was orally inoculated with canine parvovirus of faecal origin. Scanning electron microscopy was used to study and compare the surface topography in both control and inoculated animals. In control dogs the villi were tall and finger-like in shape and numerous irregular transverse circumferential grooves were present on the surface. At higher magnification, the outlines of individual epithelial cells and depressions, interpreted as goblet cells, could be discerned. In the inoculated dogs, scanning electron microscopy changes were first seen at six days after inoculation. The small intestinal mucosa was covered by a thick layer of mucus. The underlying villi were stunted and had lost their surface features. In some instances there was loss of the luminal epithelium, exposing the lamina propria. In addition, there was dilation of the circumvillar basins and the crypt mouths. There appeared to be regenerative changes by day 7 after inoculation. The surface of the small intestinal mucosa was still covered by a thick layer of mucus. Where villi could be discerned, they were short and pointed and transverse grooves could be seen on their surface. There was some hypertrophy of the intervillus ridges. The changes in the surface topography of the small intestinal mucosa following canine parvovirus infection are compared to those seen in enteric infections in other species and the similarity of the lesion to that seen following sublethal irradiation is discussed.

Canine parvovirus enteritis 2: Pathogenesis.

Two groups of puppies, eight and 10 weeks of age, were inoculated orally with canine parvovirus of faecal origin. The patterns of faecal excretion of virus, antibody production and systemic viral localisation following inoculation were studied. Faecal excretion of virus was first apparent at day 3 after inoculation, was present most frequently and in greatest quantity at days 4 to 7 after inoculation and fell sharply thereafter. Serum antibody was first detected at day 5 after inoculation with high titres in all samples from day 7 onwards. Virus isolation from serum samples revealed a non-cell associated viraemia at days 3 and 4 after inoculation. Immunocytochemical examination, using both immunofluorescence and immunoperoxidase techniques, first revealed antigen in the thymic cortex at day 1 after inoculation and in the germinal centres of the lymph nodes and the splenic white pulp from days 2 and 3. Viral antigen was first detected in the intestines at day 4 in individual cells in the proliferative zone of the crypt epithelium. From day 5 onwards, the amount of antigen present in the lymphoid tissue decreased so that by days 7 and 8, only a trace was present. There was widespread specific staining in the small intestinal mucosa at day 6, but little antigen was present by day 7. Virus was present in the bone marrow of some dogs killed at days 5 and 6.

Canine parvovirus enteritis 1: Clinical, haematological and pathological features of experimental infection.

The effect of oral infection of puppies, eight and 10 weeks old, with canine parvovirus of faecal origin was studied. Clinical signs of enteric disease were first apparent at five days after inoculation and persisted during days 6 and 7 after inoculation. The severity of clinical signs varied from transient dullness and anorexia to emesis, dysentery and death. Changes in haematological parameters were first found at day 3 after inoculation when a relative lymphopenia was observed. A profound neutropenia developed in severely affected dogs after the appearance of clinical enteric disease. Post mortem examination revealed thymic atrophy in all dogs killed on day 4 after inoculation. Macroscopic changes in the small intestine were apparent only in animals examined during the phase of severe enteric disease and consisted of thickening, rigidity and congestion of the small intestines. Microscopically there was lymphocytolysis in the thymic cortex and the germinal centres of the lymph nodes from days 2 and 3 after inoculation respectively and this rapidly resulted in depletion of these tissues. There was repopulation of lymph nodes from day 7 after inoculation but significant thymic regeneration was not apparent during the course of this study. In the small intestine, necrosis of crypt epithelium, atrophy of villi and, in some areas, complete collapse of mucosal architecture were found but the extent of these changes varied along the length of the small intestine and between individuals. Regenerative intestinal changes were observed in those animals surviving the acute phase of enteric dysfunction. The variable severity of clinical and enteric lesions, together with the factors which may affect the expression of clinical disease, are discussed.

A study of dogs with kennel cough.

A detailed study of a population of dogs with kennel cough was undertaken. Twenty-seven (77 per cent) of a total of 35 dogs had pathological evidence of respiratory disease in the form of tracheobronchitis with, in some animals, exudative pneumonia. A variety of viral and bacterial agents were isolated from the respiratory tract of diseased dogs but Bordetella bronchiseptica and canine parainfluenza virus SV-5 appeared to be the most significant organisms recovered.

Aortic valvular dysplasia in a calf.

Aortic valvular dysplasia, a congenital abnormality not previously reported in cattle, was diagnosed in a calf with a pulsating mass at the base of its neck, an enlarged area of cardiac dullness and a loud (grade IV/V) systolic cardiac murmur. Electrocardiography and thoracic radiography demonstrated that the left atrium and ventricle were enlarged. Dysplasia of two aortic valve cusps and post stenotic dilatation of the ascending aorta were identified by echocardiography and confirmed post mortem.

Encephalitis in dogs associated with a batch of canine distemper (Rockborn) vaccine.

During a period of seven months in 1982-83 cases of postvaccinal encephalitis were recorded in dogs in various parts of Britain after the administration of a particular batch of combined distemper/hepatitis vaccine. Detailed investigations of one of these cases revealed that the distemper component was responsible and the vaccine virus was recovered from the brain of an affected dog.