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===Clinical Signs===

===Clinical Signs===

Canine distemper is characterised by a biphasic fever, with the first peak 3-6 days post-infection and the second peak several days later and intermittently thereafter. The second peak of pyrexia is usually associated with the onset of other clinical signs. These initially include conjested conjunctiva and nasal mucosa leading to serous ocular and nasal discharges that become mucopurulent. The animal is depressed and anorexic, and vomiting, diarrhoea and pneumonia commonly follow. These gastrointestinal and respiratory signs are often complicated by secondary bacterial infections, as CDV is highly immunosuppressive. Lesions may occur on the retina and optic neuritis can develop. Some strains of CDV cause hyperkeratosis of the footpads and the nose, and retinal lesions and optic neuritis can occur. In neonates, hypoplasia of the tooth enamal is common following infection, causing "distemper rings". Pustular dermatitis may also be seen on the abdomen of infected puppies. In pregnant animals, transplacental infection can result in abortions, stillbirths, or the birth of persistent excretors of virus, depending on the stage of gestation.

Canine distemper is characterised by a biphasic fever, with the first peak 3-6 days post-infection and the second peak several days later and intermittently thereafter. The second peak of pyrexia is usually associated with the onset of other clinical signs. These initially include congested conjunctiva and nasal mucosa leading to serous ocular and nasal discharges that become mucopurulent. The animal is depressed and anorexic, and vomiting, diarrhoea and pneumonia commonly follow. These gastrointestinal and respiratory signs are often complicated by secondary bacterial infections, as CDV is highly immunosuppressive. Lesions may occur on the retina and optic neuritis can develop. Some strains of CDV cause hyperkeratosis of the footpads and the nose, and retinal lesions and optic neuritis can occur. In neonates, hypoplasia of the unerupted tooth enamel is common following infection, causing "distemper rings". Pustular dermatitis may also be seen on the abdomen of infected puppies. In pregnant animals, transplacental infection can result in abortions, stillbirths, or the birth of persistent excretors of virus, depending on the stage of gestation.

Many, but not all, infected dogs develop CNS signs after systemic disease but this is dependent on the strain of the virus. Either the white matter or the grey matter may be affected. Grey matter disease affects the cerebral coretx, brainstem and spinal cord, and may give a non-suppurative meningitis, seizures, stupor, hysteria or ataxia. Dogs with grey matter disease may die within 2-3 weeks, recover, or alterntatively progress to white matter disease. In this, mutlifocal lesions mean that the signs are variable: cerebellovestibular signs are common, as well as spinal cord paresis, ataxia and occasionaly myoclonus. Once white matter disease has developed, some dogs die with a non-inflammatory, demyelinating disease 4-5 weeks after intial systemic infection. Other animals may recover with minimal injury to the CNS but may still suffer neuromuscular tics or "chewing gum" seizures.

Many infected dogs develop CNS signs after the initial systemic disease, but this is dependent on the strain of the virus. Either the white matter or the grey matter may be affected. Grey matter disease affects the cerebral coretx, brainstem and spinal cord, and may give a non-suppurative meningitis, seizures, stupor, hysteria or ataxia. Dogs with grey matter disease may die within 2-3 weeks, recover, or progress to white matter disease. In this, mutlifocal lesions mean that the signs are variable: cerebellovestibular signs are common, as well as paresis, ataxia and myoclonus. Once white matter disease has developed, some dogs die with a non-inflammatory, demyelinating disease 4-5 weeks after intial systemic infection. Other animals may recover with minimal injury to the CNS but may suffer neuromuscular tics or "chewing gum" seizures for life.

Although canine distemper is often fatal, in some cases an increased production of virus-neutralising antibodies promotes the recovery of the animal. However, CDV can persist in the uvea, CNS, lymphoid organs and footpads despite elimination from most organs and the blood. This can result in "old dog encephalitis" in dogs that recovered from acute canine distemper years previously. In this, several neurological episodes occur over weeks to months, and end in the death of the dog.

Canine distemper is often fatal, but an increased production of virus-neutralising antibodies can promote the recovery of the animal. However, CDV can persist in the uvea, CNS, lymphoid organs and footpads despite elimination from most organs and the blood. This can result in "old dog encephalitis" in dogs that recovered from acute canine distemper years previously. In this, several neurological episodes occur over weeks to months, and usually culminate in the death of the dog.

===Laboratory Tests===

===Laboratory Tests===