| Disease Agents |
- Predisposing factors that may lead to foot diseases in captive
elephants include lack of exercise, lack of regular foot care and
inspection, nail and sole overgrowth and lack of trimming, inappropriate enclosure surfaces (hard
unyielding substrates contribute to the development of foot
problems, for example by trauma and by lack of opportunity for
digging), constant direct
contact with dirty and wet surfaces in which pathogens can proliferate,
malnutrition, excess
feeding/insufficient exercise leading to overweight elephants which
put more stress on their feet, arthritis and inherited poor foot
structure.
(B22.34.w12, B454.1.w1,
B454.16.w16)
- The aetiological agents are unknown. Several organisms have been
isolated from the lesions, including Proteus
spp.,
Escherichia coli
and Pseudomonas
spp..
However, it is unlikely that these are the primary pathogens.
Anaerobic bacteria such as Bacteroides fragilis may be
involved. (B22.34.w12)
- During an outbreak of ulcerative pododermatitis in free-ranging Loxodonta africana
- African Elephants a variety of bacteria were isolated.
The most consistent isolate was Streptococcus agalactiae. Dichelobacter
nodosus, a bacterium involved in domestic ruminant foot problems,
was only isolated in two cases. The most likely aetiology was
considered to be traumatic injury of the sole, with secondary
bacterial infection. (J62.64.w2)
Further information on Disease Agents has only been
incorporated for agents recorded in species for which a full Wildpro "Health
and Management" module has been completed (i.e. for which a comprehensive literature
review has been undertaken). Only those agents with further information available are
linked below:
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| Further Information |
- Ulcerative pododermatitis affecting one or more feet (always a front
foot if only one foot was involved), was reported in thirteen adult
free-ranging Loxodonta africana
- African Elephants bulls from the Kruger National Park,
South Africa. (J62.64.w2,
D301.3.w3)
Susceptibility/Transmission
- Predisposing factors that may lead to pododermatitis in captive
elephants are lack of exercise, lack of regular nail and sole trimming,
inadequate enclosure surface, constant direct
contact with dirty and wet surfaces, and lack of inspection of the sole.
(B22.34.w12, B454.1.w1)
- In free-ranging elephants, body mass (increasing the risk of damage
from standing on objects) and the presence of multiple stumps of
vegetation which might cause sole wounds able to act as portals of entry
for bacterial infection were
considered to be contributory to the development of the disease. (J62.64.w2)
Gross pathology:
- Large ulcers
in the sole of the affected feet. (J62.64.w2)
[Data includes findings from clinical examination of anaesthetised
animals as well as from post mortem examination.]
- Each affected foot contained a single, focal, well-demarcated
ulcer, round to oval, about 200 x 240 mm diameter. Ulcers were
about 20 mm deep. The surface of the ulcer was covered with a
necropurulent exudate, malodorous, mixed with soil and other
debris. The surface was raw, yellowish-red, crusted with pus and
bled freely when lightly scarified. This purulent reaction reached
a depth of 2mm below the surface. In some cases ulcers dissected
between the keratinised sole and the foot cushion, with the space
being filled with tissue debris, exudate and soil. (J62.64.w2)
- Where a single foot was affected, the nails of the affected foot
were overgrown and distorted, those of the opposite foot showed
excessive wear. (J62.64.w2)
- In some cases ulcers had reached the nail junction, resulting in
onychia and paronchyia and loss of affected nails.
- Some lesions appeared to be healing. (J62.64.w2)
- In one euthanased animal, all four feet were affected and in the
hind feet, the ulcers had reached sufficient depth to expose the
third phalanx. There was an ascending subcutaneous infection
causing limb swelling, and septic arthritis of the phalangeal
joints. Draining sinus tracts were present 30 to 70 mm up the
foot. and skin was lost as far as 100 mm up the lateral side of
the feet. (J62.64.w2)
- Lymph nodes draining affected legs were severely swollen. (J62.64.w2)
- In one animal affected on all four feet there was severe
swelling and oedema of the prepuce. (J62.64.w2)
Histopathology:
- Severe chronic active, ulcerative, bacterial pododermatitis
complicated by hypersensitivity (in one animal) and septic vasculitis. (J62.64.w2)
Treatment:
- Rubber gloves should be worn while carrying out treatments. (B22.34.w12)
- Drainage of any pocket, tract or groove, daily if necessary; all the devitalised tissue should
be debrided.
- Note: Trimming a severely infected foot should be performed under
anaesthesia and is usually a laborious and long procedure. (B22.34.w12)
- Tetanus vaccination should be given if the elephant has not been
vaccinated. (B22.34.w12)
- Once drainage has been established, the foot should be soaking
repeatedly in an antibiotic solution or with a disinfectant, such as chlorhexidine,
povidone iodine or 5% copper sulphate. Dimethyl sulfoxide (DMSO)
may be added to the foot soaking solution. (B22.34.w12,
P1.1996.w2)
- Systemic antibiotics (given orally or parenterally) are recommended if the bone or joints are
involved. (B22.34.w12)
- Note: Anaerobic bacteria may be involved. This should be
considered in choosing an appropriate antibiotic. (B22.34.w12)
- Protection of the foot from environmental
contamination may be required. Specially constructed boots, made of canvas
or leather, are fitted to keep the foot dry and clean. The boots also
need to allow application of disinfectant solution to the infected
foot. (B22.34.w12,
P1.1996.w2)
- N.B. If the digital cushion is involved, healing may be slow,
since the tissue is avascular, and it will be difficult to maintain
drainage, since the elastic tissue expands to block any drainage
window produced. (B22.34.w12)
- For cases extending to cause osteomyelitis or suppurative arthritis,
surgical removal of the affected bone may be required. N.B.
"the surgery is difficult and the aftercare horrendous."(B22.34.w12)
- Note: Infrared-thermography may be used to monitor the
efficacy or otherwise of treatments. (P6.4.w4)
- Euthanasia may be required for severe cases (J62.64.w2)
or chronic cases which are unresponsive to treatment. (B336.53.w53)
Prevention:
- Substrate, hygiene and exercise:
- Provision of appropriate, clean and dry, substrates. (B10.49.w21,
B214.3.7.w3,
B336.53.w53)
- A lightly brushed concrete floor is recommended, as it provides an
adequate surface: deep brushed concrete floors tend to
accumulate faeces and urine where bacteria can grow. (J4.171.w5)
- Regular exercise, preferably on natural substrates. (B454.5.w5)
- Adequate hygiene. (B454.5.w5)
- Foot/nail trimming:
- Adequate regular foot trimming. (P5.39.w1)
- Excess sole should be trimmed regularly using a Swiss hoof cutting knife
and an abrasive pad. (P1.1996.w2)
- Trimming of the nails with equine hoof nippers and/ or a rasp at
least every two months, if the substrate is not abrasive enough and/or
the animal is inactive. (B22.34.w12)
- Nails should be trimmed carefully with an abrasive pad or hoof
rasp, so that the distal tips do not bear any weight when the elephant
foot is weight bearing. (P1.1996.w2)
- Nutrition:
- Adequate nutrition is recommended to maintain foot
health. Biotin,
protein and trace elements, such as
zinc,
selenium
and arsenic are some of the nutrients to consider. (B454.3.w3)
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