Variola caprina

Variola caprina (Goat Pox) is a contagious viral disease caused by the pox virus which affects goats. The virus usually spreads via the respiratory route or sometimes through abraded skin and is most likely to occur in crowded stock. Sources of the virus include Cutaneous lesions, Saliva , Nasal Secretions and Faeces. There are two types of the disease; the Papulo-vesicular form and Nodular form ('stone pox'). The incubation period is usually between 8-13 days but may be as short as 4 days.

It is thought the same virus spreads Sheep pox. European sheep breeds are highly susceptible to Sheep Pox. In dried scabs the virus may be present for up to 6 months. In endemic areas morbidity rate 70-90% and Mortalitiy rate 5-10% (but may reach nearly 100% in imported animals).

Resistant animals may show only a mild form of the disease, which may be missed as only a few lesions are present, usually around the ears or the tail.

Classification

* Other names: Goat Pox
* Virus family: Poxviridae
* Genus: Capripoxvirus

pread of Goat Pox

Goat Pox is seen in Africa north of the equator, the Middle East, Central Asia and India.Goat Pox may be spread between animals by:
* Direct contact
* Indirect transmission by contaminated implements, vehicles or products (litter, fodder)
* Indirect transmission by insects (mechanical vectors) has been established (minor role)
* Contamination by inhalation, intradermal or subcutaneous inoculation, or by respiratory, transcutaneous and transmucosal routes

Clinical signs

*Initially rapid onset of fever, salivation , nasal discharge and conjunctivitis.
* After a few days skin lesions erupt which first develop into vesicles, pustules and then scabs .The scabs are hairy, dark coloured and may take up to 6 weeks to heal. These are often in hair or wool-free areas such as the udders, perineum, inguinal area, scrotum, muzzle, eyelids and axillae.
* Small, red spotty areas appear on udders and teats which may form scabs. The orifices of the teats may become infected and cause mastitis.
* Affected skin is senstive.
* Internal lesions in the lungs may cause respiratory distress.
* Depression
* Polynoea
* Oedema of eyelids, photophobia, Rhinitis and lacrimation
* Nodules develop in the lungs causing bronchopneumonia
* Anorexia

The Papulo- vesicular form

* Papules become a white-grey colour, desiccate and form crusts that are easy to remove Papules are 0.5-1.5cm diameters and are hard to touch. The papules become depressed, gray and necrotic. May be surrounded by an area of hyperemia.
* Rarely, papules may transform into large, fluid-filled vesicles. After rupture of vesicles, a thick crust covers the lesions

The Nodular form

* Papules give rise to nodules involving all the layers of the skin and the subcutaneous tissue.
* Necrosis and sloughing of the nodules leaves a hairless scar.

econdary problems

* Septicaemia
* Abortion (rare)
* Infections
* Fly strike
* Digestive localisation

References

[http://www.defra.gov.uk/animalh/diseases/notifiable/goatpox/index.htm defra]

[http://www.oie.int/eng/maladies/fiches/a_A100.htm OIE]

[http://www.cfsph.iastate.edu/factsheets/pdfs/sheep_and_goat_pox.pdf cfsph]