Date: 24-AUG-1994 20:54 Expires: 30-SEP-2022 10:29
Subject: Bad Breath
In 1985 I began to wonder about the lousy breath in some humpback whales. At that time the off-hand official explanation was that the stench arose from food bits rotting in the baleen. That was very unlikely because the esophagus is isolated from the trachea in whales. There is no true oro-pharynx in whales. So the smell was coming from the blowhole and that meant the bronchial tree might be infected.
In my office, when I suspected a strep throat, it was routine to take a swab from the throat of the patient and test for the suspect bacteria. How do you do that for a whale ? Simple take the mountain to Mohammed.. I placed an agar plate on a bent coat hanger frame. Stuck the holder on a bamboo pole and put the plate over blowhole of the whale.
Whales cannot cough or sneeze, if they did they would likely drown. Instead of coughing whales rely on the explosive and volumetrically large tidal volume of their breaths to clear the bronchial tree. In effect each breath is a cough and the mist generated contains a true random sample of bacteria present in the lungs and bronchi.
The results from the first few smelly whales were negative nothing grew on the incubated plates. Finally one wonderful humpback (#385 Nevus) swam along the rail of the boat my son and I were on and coated my agar plate and arm with goop. The sample was sent to the lab with the unusal instructions to incubate the plate until something grew. Strongly pathogenic bacteria grow full colonies in 24 hours. Almost all pathogens show up in 48 hours. This wimpy bug took 240 hours to show up. It was a dark diptheroid bacteria with strict preference for blood agar.
To make a very long story short, the isolated organism was a previously undiscovered species of diptheroid that needs pressure to grow quickly. Dr. Linda Schlater of the Animal and Plant Health Inspection Service lab in Ames,Iowa called me one day to ask what she was doing "wrong" with the bug in her lab. She finally asked if there was a factor in the ocean environment that might affect both the whales and the bugs. It was a "EUREKA" moment. It had to be pressure! The effective pressure increases at one atmosphere for every 30 feet of depth. We quickly designed a modified 1950's pressure cooker from the kitchen and grew the samples in increasing steps of pressure until the cooker blew up.
The result of all of this is a non fatal form of diptheria in humpbacks. Humpbacks that dive too long and too deep develop diptheria and the pathognomonic bad breath of that disease. All of the whales found with bad breath were older than one and younger than three years. These are whales that are beginning to fend for themselves and are at the bottom of the social ladder.
Calves do not exhibit bad breath because they have no need to feed themselves and don't have to dive deeply. Adult whales have learned to assert themselves and elbow their way to the food. The whales with the greatest metabolic needs are nursing females. They are larger than males and will aggressively occupy preferred feeding areas. I define a preferred feeding area as rich in food and relatively shallow. Unaggressive whales are quickly driven off to less desirable feeding areas where food may be as plentiful but is found deeper. This means more work for the food but also means that the whale is under increased whole body pressure for longer periods of time. The bacteria will then grow more aggressively and cause diptheria. The disease causes an erosion of the mucosal lining of the trachea and the development of a pseudomembrane in the airway. The stench from the rotting tissues is the source of bad breath.
Fortunately the whale does not usually die from the episode. The whale probably feels poorly and tries to rest. That means spending long stretches of time at the surface. The effective pressure would then drop to one atmosphere and the bacteria could not grow at pathogenic rates. The disease triggers it's own cure.
Any questions? Please send me an email here at the "ASK" forum.
Dr. Tom Ford (firstname.lastname@example.org)
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