Alpaca & facial eczema
Facial Eczema and alpacas - summer and autumn risk
Alpacas are very susceptible to the toxic effects of facial eczema spores and high risk periods occur during the summer and autumn.
The spores, produced by the fungus Pithomyces chartarum, are broken down in the digestive tract releasing the sporidesmin toxin. The toxin is absorbed into the circulation and reaches the liver where it is metabolised, releasing potent free radicals that damage liver cells. Once damaged, the liver irreversibly loses its full metabolic capacity. Consequently, noxious compounds accumulate in the bloodstream.
Photodynamic chemicals are some of the noxious compounds. They accumulate in the skin, react with UV light damaging blood vessels and skin cells, hence the typical skin lesions seen. Additionally, in severe cases, complete liver failure and death are also seen.
What are the key conditions favouring fungal growth?
Preventing fungal growth and accumulation of spores is by far the most effective way to safeguard your animals against the disease. It is important to know that the key conditions favouring fungal growth are:
- Accumulated dead litter at the base of the sward, in summer/autumn
- Warm, moist conditions especially in north-facing slopes
- Grass base temperature greater than 12oC for more than 2-3 days
- Once produced, the spores remain a risk if you have a contaminated pasture
What are the signs of Facial Eczema in alpacas?
The usual symptoms seen in other species affected with Facial Eczema include:
- Skin swelling, crusting and oozing
- Decreased production/growth rates
- Sudden death
Alpacas are reasonably stoic animals and may not show the subtle early signs that other species do until the liver damage is very severe. As they are very susceptible to this disease and severe liver damage as a species, early diagnosis and treatment are highly recommended. Diagnosis is obtained via a blood sample for analysis of liver-specific enzyme or via post-mortem.
Use fungicide sprays to prevent fungal growth. This method is most effective before spore levels rise to dangerous levels, as it prevents further spore formation but does not remove spores already present on the pasture.
Minimise litter accumulation at the base of the sward
- Efficient pasture grazing
- Use other grazing species to graze excess pasture
- If you are considering mowing pasture, think of a way to remove the dead matter
- If you mow, but can not remove dead grass, use a set of chain harrows (a set of interlocked chains/metal spikes) to stir and expose the dead matter, hence minimizing fungal growth. Chain harrows come in all sizes and there will be one suitable for your property
- Identify higher risk paddocks
- Monitor spore levels by carrying out spore counts and manage accordingly
Assist in the prevention of free-radical damage to the liver, the most practical and effective option is:
- Supplementation of 2g of elemental zinc per 100 kilo liveweight per day. Start supplementation about 3 weeks before the danger period and carry out for approximately 100 days. The best response in alpacas is achieved by mixing zinc oxide with molasses which helps to mask the bitter taste. Other options exist but are generally not as effective
- Homoeopathic remedies can also be added to the water but should be used in conjunction with and not as a substitution for zinc.
Treatment of affected animals
The damage to the liver is generally permanent but some degree of regeneration can occur.
- Remove from contaminated pasture
- Provide shelter from sunlight, complete darkness is best
- Reduced protein feeds
- Use protective, nourishing skin creams to soothe sensitive areas
- Minimize stress by making water and feed easily accessible to the animal
- Liver-specific supportive homoeopathic treatments are available
Other treatments may be possible but will depend on age, condition and pregnancy status of animals.
In summary, manage your pastures adequately, start zinc supplementation early, be aware of the district spore count levels and contact us as soon as possible if you suspect any animal is affected.
For more information on this disease, please refer to our Facial Eczema page