Foot abscess is just one of the possible results of infection by Fusiformis. This necrobacillosis can also cause lesions in the mouth, throat, umbilicus, liver and lungs of deer.
How does the problem spread?
The organism is part of the normal flora (or make-up) of the deer’s intestine. It is present in faeces and survives well in soil and mud. When it enters into the deer’s body through damaged skin or mucous membrane problems can start. Toxins produced by the bacterium kill good cells in the tissue, disrupting blood supply.
The problem is exacerbated by stress bought on by events like cold weather, mixing mobs or yarding.
What are the symptoms?
The disease shows up in four key ways:
- Cuts to the feet or lower legs can lead to infected limbs, especially in cold muddy conditions. Foot abscess will develop above the claw area. Dermatitis may be seen as well as infected swollen joints, ligaments and tendons. Deer will become lame and may lag behind the mob.
- Abrasions or injuries of the mouth (due to thistles, damage from foreign objects or teething) can lead to mouth or throat infections. Deer will have swollen heads and/or tongues, salivate excessively and young deer can be unable to suckle or feed.
- After feeding ad lib grain the lining of the stomach can be damaged, opening it up to fusobacteriosis* of the wall of the rumen or reticulum. These are the first two stomachs. Deer may lose their appetite.
- The bateria can be spread by blood in the body, taking the infection to the liver, lungs and brain. A fever can develop, indicating infection. When deer lag behind the mob, it may indicate that foot abscess has spread to the lungs.
All of these will cause slowing growth rates or weight loss.
Effect on deer production
If the condition becomes widespread and established in the liver and lungs of an animal then a fever will result. The deer will lose their appetite, suffer respiratory distress and in some cases die. The disease can become widespread among the mob.
In the case of foot abscess the foot area above the claw will be swollen and discharge pus. Feet abscess and mouth lesions are quite obvious but culture of the organism should be done to confirm the cause. An ELISA (blood test) can be used to detect antibodies. Autopsies will show pus-filled liver and lung abscesses. The rumen will be ulcerated.
Control and treatment
The two management strategies are to minimise the risk of the disease occurring, and then treat with antibiotics if the disease is confirmed. A veterinarian can advise on both.
Ways to minimise the risk:
- Minimise the chance of deer being injured through removing sharp objects in yards and paddocks. Make sure yard surface is smooth, not sharp.
- Protective matting in sheds and transport trucks can reduce the chance of foot abrasion and injury. Always check deer for the days following transportation.
- Provide optimal feed and make sure deer don't suffer from other animal health conditions.
- Reduce stress, particularly from over-crowding in muddy conditions.
- Cleaning of surfaces in the deer shed with disinfectant will reduce the presence of bacteria.
- Remove thistles from pasture to reduce the chance of mouth injuries.
- Vaccinating against tetanus and clostridial diseases may be useful. The vaccine for Fusobacterium necrophorum is no longer available in New Zealand.
Ways to treat foot abscess:
- INDIVIDUAL: In early cases of foot abscess, treat with injectable antibiotics and cleanse the area with hydrogen peroxide. Applying an oily antibiotic mastitis cream has been successful in treating deep-seated abscesses in red deer feet.
- HERD: Deer with symptoms should be treated with antibiotics. If several deer show symptoms then preventative treatment with antibiotics of all deer in the mob (even those without symptoms) is useful. If the infection moves to other parts of the body with lesions developing, treatment is usually futile.
Ways to treat oral abscesses and/or fever;
- Treat with antibiotics. High doses of penicillin, tetracyclines and sulphonamides have been used successfully.
In all cases a veterinarian can advise on the best treatment method and ways to reduce risk.
*Information on Fusobacteriosis is available in a convenient DINZ Deer Fact sheet (September 2015).