Hi Pinkstergirl,
The causative organism in Mud Fever and Rain Scald is Dermatophilus congolensis, a Gram-positive bacterium which has some fungus-like characteristics in that it produces branching filaments. This bacterium is found in the soil and is fairly widespread in Britain and Ireland and extremely prevalent in tropical climes. The disease it causes is also known as cutaneous streptothricosis and usually occurs in or after prolonged wet weather; other predisposing factors being insect or tick bites, or wounds caused by thorns, or even over-enthusiastic grooming of the lower limbs while they are wet or not sufficiently dried after hosing down. These factors are the route by which the baterium enters the dermis or top layer of skin. As well as affecting the legs, it also causes lesions to appear on the back and the belly.
The condition is predominantly seen in mild, wet winters, although it may occur in wet summers.
Horses with long, unkempt coats or heavy feathering on the legs are particularly at risk. Where it occurs along the dorsal midline, gently pulling the
raised tufts of hair will reveal greeny grey pus at the base of the tuft. Where it occurs on the limbs the skin will be cracked and fissured, and may cause lameness or, at least, a disinclination to move.
Poor hygiene in poorly cared for horses at grass is causative so improved hygiene is a priority in prevention/cure. Horses should not be allowed to stand in muddy conditions while the weather is wet without some access to shelter. In the case of stabled animals the legs should be thoroughly cleaned by cold hosing (warm water would encourage the pores to open, thus increasing the risk of entry by the bacterium), after which they should be properly dried (preferably by bandaging or the application of sawdust). Great care must then be taken not to damage the underlying skin by overzealous brushing.
Where the disease is established in the lower limbs any long hair shielding the lesions should be carefully removed and burned and the clipper blades sterilised after use. Prolonged, carefull treatment by systemic antibiotics may be necessary. Washing with mild soap and tepid water, thorough drying and application of topical atibiotics may prevent mild cases progressing.
PREVENTION IS BETTER THAN CURE.
Good general husbandry with consideration for shelter in prolonged wet and muddy conditions and regular inspections for wounds or skin parasites, along with gentle cold hosing and thorough drying of the skin should help to prevent this painful condition. The application of barrier creams or lotions is not widely recommended because of the risk of 'trapping' the causative bacterium next to the skin while creating favourable conditions for its mutiplication.
Incidentally, the condition is sometimes found when rugs are removed/changed irregularly, the bacterium having been present on the coat before the rug was put on, and finding the conditions favourable thereafter.
CAUTION!.....care must be taken by the carer of the affected animal lest the bacterium enters the hands via sratches or open wounds thereon; ideally gloves should be worn when treating.
DERMISOL cream is effective in treating most cases if applied after following the advice above re. cleaning of affected areas.....(obtainable from your vet.).
A mild solution of tea tree oil or tincture will cleanse and is antibacterial too.
