CASE 1. Did the deadly Meloidosis bacteria infect this rabbit?

"Put the rabbit to sleep." Mr Tan said in an authoritative tone as he fished out a white rabbit from a pink plastic carrier cage.  "It has cancer of the mouth."  His 10-year old daughter was with him and had no choice.

A big black globular lump of 3 cm in diameter,  hard as a pebble on the shores of the Pasir Ris Beach protruded from the commissures of the left side of its mouth.

Yellow pus could be seen on the inner side. The outer area was enveloped by a big hard skin.  There was no need to talk much as the pragmatic client had decided that it would be too costly to operate. A brand new replacement rabbit would cost less.

"Could it have developed from an original wound inside the mouth or the root of the tooth?" I asked the senior veterinary surgeon.  "Was this an infected skin tumour or an encapsulated gangrenous abscess?  The blood supply could have been cut off, resulting in the blackened skin discoloration.  Or was it a potent bacteria able to kill all tissues under the skin, resulting in a black lump of necrotic (dead) tissue under the skin?"  

Nature sometimes present the veterinarian challenging problems to solve.  

"Rabbits are well known to have hard abscesses. This looked like an encapsulated abscess commonly found in the internal organ of sheep and caused by one of the deadliest bacteria in the world," the senior vet replied.  "The bacteria is said to be present in the soil and causes Meloidosis in sheep and as well as killing people."

As a new graduate, it was good to have a senior to consult.  He continued to warn me, "This bacteria forms cheesy or thick pus-like abscess in the internal organs of sheep and is well documented in sheep medicine.

"Do rabbits get infected too?" I asked.
"No reported cases," the senior vet replied. "The rabbit could be infected by a  lethal tissue destroying bacteria like Group A Streptococcus (GAS) bacteria which eats flesh and had got in from the tooth root?"

In that case, should the vets mess around with this dangerous bacteria?

Could the lump be removed by cutting it off?  Would the rabbit then die?  Was it wise to cut it off?  How much it would cost?  A replacement white rabbit cost around $20.00 and the veterinary treatment might cost ten new rabbits and more if there was surgery and anaesthesia. 

"You can't save all the sick rabbits in this world," the senior said. 

"Maybe, just this one. He's a young rabbit".  It was not the age but the cost of treatment that affects the profitability of a private practice. Should not all private business look at cutting down expenses as the cost of living and rentals in Singapore inevitably become more expensive as it progresses to being a developed country.      

How much was the cost of compassion towards one rabbit?  It was not much but if the veterinarian saves all such cases, it could be a big amount. 

An antibiotic injection was given and the rabbit was placed under observation.  The rabbit was eating well but avoided the hard rabbit feed pellets.  Water melon was greatly appreciated.  Twelve days later, he stopped eating much. He began to lose weight.  He would die soon as he lost a lot of weight and was not eating or drinking. 

In this life and death situation, should I operate?  Should the rabbit be put out of suffering with one lethal injection?  The jaw lump must have been very painful. His life was in a veterinarian's hands.  Would he live if he was operated?   Would his suffering be prolonged?

A pain killer was given.  The lump came off the jaw area and exposed a big hole.  There was no need to put it under anaesthesia. Young healthy creatures have excellent healing powers.  The wound closed within seven days. 

Within twenty days, there was a small hole and new tissue had bridged the gaping hole. The rabbit had an excellent appetite and put on much weight.  

It was fortunate that no nasty scars could be seen. It would be too expensive to send the necrotic tissue for laboratory analysis.  The bacteria causing dead tissue under the skin would most likely be the GAS or Clostridium bacteria entering the lower cheek from the tooth root. These flesh eating micro organisms thrive well and multiply deep in the skin as they dislike oxygen.  They are called anaerobic bacteria as they cannot survive in the presence of oxygen.  In human medicine, the treatment of necrotising fasciitis would be a combination of intensive antibiotic injections, surgery to remove the dead tissue, fluid therapy and pure oxygen.  

Note for Biology students:   Oxygen therapy is used in human medicine to treat necrotising fasciitis.  In Singapore, the Hyperbaric Medicine Branch of the Republic of Singapore Navy's Naval Medicine and Hyperbaric Centre used to be the only place to get such treatment.  Its primary role is to treat navy divers who suffer from decompression illness. It treats many recreational divers and other conditions which benefit from oxygen therapy such as carbon monoxide poisoning, gas gangrene in wounds infected by anaerobic bacteria, diabetic ulcers, compromised skin grafts, radiation tissue damage for cancer patients and burns.  In 2001, the Tan Tock Seng Hospital will start a hyperbaric medicine centre. 

Hyperbaric oxygen acts as a drug as some types of bacteria such as those eating flesh, will die if exposed to oxygen.  The patient is given 100% oxygen at 2 to 3 times the normal atmospheric pressure (sea level pressure) while kept in an enclosed oxygen pressure.  Oxygen is at a low level in flesh eating tissues and is needed by the cells to sustain life. The oxygen is more easily absorbed by the cells deprived of oxygen when the patient is put under high atmospheric pressure. 

Note:
Cells die in 2 different ways.
1. Apoptosis.  Programmed cell death.  The cell is gradually disassembled from within, then engulfed and digested by the white blood cells.  An example is an aging cell.

2. Necrosis. A frenzied form of killing the cell, releasing cell's total contents including toxic chemicals and enzymes and damaging surrounding cells, causing inflammation manifested by redness and swelling of the tissue cells.  An example is bacterial infection of the cell.

CASE 2.  Will the rabbit die on the operating table?

"What is your advice?" Mr Loo asked. His wife's rabbit had a huge black elbow and there was another smaller one under the skin.  I had given the rabbit an anti-inflammatory injection ten days ago and the growth had dried up.  The skin around the growth looked the healthy pink colour and was not weepy.  The rabbit had stopped licking it but it was a matter of time when the rabbit had to lick it to relieve itself of the persistent pain and redness.

"Much depends on how deep your pocket is," I replied. "This rabbit is very thin and it may just die on the operating table to remove its lump or a few days after the surgery."  In that case Mr Loo would have paid the $200  operation bills and get a dead rabbit.

Rabbits are inexpensive pets. Therefore, the pragmatic owners think in terms of replacement costs as ten times cheaper than veterinary costs.  

"How long does a rabbit live?" Mr Loo asked.  That was a question I did not anticipate. If the 6-year-old rabbit was at the end of its life span, then it would not be worth the money to treat it.

"8 - 12 years." I replied. "A healthy one live longer."  If this rabbit survived the operation, it could have 2 - 6 years of life. Would 2 years of quiet companionship be worth the $200?

Rabbits are seldom demonstrative in their emotions, unlike dogs. I guessed Mr Loo was not bonded to it. If the veterinary fees were lower than the replacement fee, he would go for the risk of surgery. 

So, should it be euthanased?  I had not expected to see Mr Loo after the first visit as many rabbit owners are pragmatic and seldom give such cases a second chance to live.

"You can save on veterinary bills by taking the rabbit home after surgery," I suggested. "I prefer to observe it for another  3 days. If the stitches are not chewed of, the wound will heal very well in 10 - 14 days."  The cost of warding it would be $10 per day.

It was a hard economic decision.  Mr Loo said, "My wife wanted the rabbit operated."  So, it was a sentimental decision. Now, should I risk operating the rabbit? Would there be sufficient skin to stitch up the big hole after removal of the growth? Would the rabbit chew off the stitches and make a bigger hole?  And more costs and trauma to the wife?

The rabbit was operated and as at day 2, it was behaving itself and eating.

The 6-year-old rabbit now has a huge itchy skin growth. It lost a lot of weight and may die on the operating table. Should the owner put it to sleep or spend $200 to operate? A new rabbit costs 10% of the veterinary fees
The rabbit had 2 encapsulated abscesses under the elbow skin and several small ones. Dogs do lick skin growths too and it is always LESS costly to consult your vet earlier than much later.