What you need to know about mudfever
What is Mud Fever?
Mud fever is a condition commonly associated with wet conditions which is why it is named so.
What is the cause?
The bacterium responsible is Dermatophilus congolensis. This bacterium is found everywhere in soil and its spores are activated by moisture which is why we tend to see the effects mainly at wet times of year. However, the name may lead us to think that those horses affected are kept knee-deep in mud and this is often not the case.
Why do some horses seem prone?
The bacterium cannot cause mud fever alone. It requires a breakdown in the skin's natural barrier. This is usually achieved by constant wetting of the skin causing it to become chapped or small abrasions or wounds which allow the bacterium to gain access. Unfortunately for some horses, they are genetically more at risk to having poor skin barrier function in the first place which may explain why different horses kept in the same field for the same amount of time may suffer to different extents.
What are the signs?
The appearance of mud fever can vary from a few small scabs to a severe skin inflamation causing severe lameness and a swollen limb. The typical area affected is the back of the pasterns but it can extend further up the limbs and around to the front of the legs as well as at the back.
How is mud fever diagnosed and treated?
The appearance alone is often diagnostic but occasionally cases may require skin scrape samples of the affected areas for the bacterium to be identified using microbiology techniques in the lab.
Treatment varies depending on severity but generally involves washing of the skin with an antibacterial shampoo such as Hibiscrub. The area is best clipped so that the shampoo effectively penetrates the affected area and it helps to leave the shampoo on for 5 minutes before rinsing. After shampooing topical creams are then applied to act locally against the bacteria and to promote healing. Oral medication may include anti-inflammatories and antibiotics depending on the severity.
How can it be prevented?
- There are plenty of barrier greases on the market which may help the 'bug barrier' during grazing time. Keeping the hair in the pastern area short as well as thoroughly drying legs when they get wet will also help to protect against bacterial invasion.
- Rather than hosing legs off when coming in from the field, allow the mud to dry and then brush off. If this is not practical, ensure that legs are very dry afterwards.
- Avoid horses standing in muddy gateways wherever possible.
- Avoid applying boots and bandages to wet skin as this will cause tiny micro-abrasions which contribute to a compromised skin barrier and may allow bacteria to invade.
- Act early if you believe your horse is affected to hopefully prevent very sore legs or a lameness.
