Observations on swamp fever in sheep

Authors: Scott D
Publication: New Zealand Veterinary Journal, Volume 33, Issue 11, pp 191, Nov 1985
Publisher: Taylor and Francis

Animal type: Livestock, Production animal, Ruminant, Sheep
Subject Terms: Integument/skin/wool/hair/fur/feather, Photosensitivity, Toxicology, Disease/defect, Poisoning - plant
Article class: Correspondence

---

Abstract: ‘Swamp fever` is the name given in the Mackenzie Country to a primary photosensitization of sheep that occurs in small outbreaks in some seasons. Affected animals show the classical signs of photosensitivity, viz. red to black oedematous swelling of nose, lips and ears, often followed by skin sloughing and secondary infection. It occurs sporadically, although primarily confined to the mid-altitude country of Canterbury and Otago. Usually only a few percent of a flock are affected and ultimately recover. Death may occur on occasions. It is associated with swamps or tarns that dry out. The causative agent is thought to be a plant toxin. The prime suspect was the native Hypericum japonicum, though its scarcity made that doubtful. Outbreaks occurred in the autumn of 1985, and one was investigated in detail. This was at Godley Peaks Station, Lake Tekapo in late May, following an exceptionally dry autumn. A mob of 3300 Merino wethers was grazing four adjacent paddocks of 90 ha, with less than 1% swampy areas, for the first time on 24 May. Four days later about 170 sheep showed clinical signs…

---