Exotic Diseases

Return to Exotic Diseases Index

Click on the images on this page to see a larger image and more information

Species Infected

infects sheep only

Clinical Signs

• dependent on age of animal
• incubation 5-7 days

young sheep

• fever, marked prostration, rhinitis, conjunctivitis
• within 2 days lesions appear
• some mortality can occur before this
• cutaneous lesions often accompanied by lesions on nares, lips, buccal cavity
• slow healing 5-6 weeks
• high morbidity, mortality 50% or more

adult sheep

• minimal skin lesions frequently under tail
• mortality low, about 5%
• can be higher in ewes if udder affected
• secondary mastitis develops

Lesions

• classical pox cycle: erythema, papule, vesicle, pustule, exudation
• found on hairy areas of skin
• systemic lesions associated with high mortality
• trachea, subpleural
• vagina
• alimentary tract accompanied by a haemorrhagic enteritis

Pathogenesis

• main source of virus - skin lesions
• main source of infection - through skin abrasions
• inhalation also possible by contact
• arthropod role may exist
• viraemic - maximal skin titres of virus 10-14 days and may be detected up to 1 month

Aetiology

• Capripoxvirus (Poxviridae)
• closely related to goat pox virus and lumpy skin disease virus
• resistant to desiccation, acidic, alkaline conditions
• survives for months in environment

Epidemiology

• environmental resistance of virus important
• 2 disease patterns:

     1.  endemic areas: low level of infection and morbidity results in increased numbers of
          susceptible stock - epidemic with high mortality follows
     2.  margins of endemic areas: susceptible stock allows severe outbreaks of morbidity
           and mortality to occur complicated by other factors such as husbandry practices
           and intercurrent disease

Differential Diagnoses

     1.  severe atypical orf infection
     2.  dermatophilosis
     3.  bluetongue
     4.  photosensitisation
     5.  sheep scab