There are numerous factors that impact the pulmonary health of cetaceans.
These may include age, immune status, concurrent illness, neoplasia, inhalation of debris,
bacteria, or fungi, hematogenous spread of disease, exposure to irritating or caustic agents,
etc. Cetaceans may be more prone to some forms of respiratory disease as a result of their
unique anatomy. Many terrestrial species appear to depend on variations in the nasal pharynx
such as the conchae and turbinates to help trap inhaled debris before it enters the larynx. The
efficiency of the upper respiratory system, even in terrestrials can be overloaded or
compromised by numerous factors such as excessive numbers of pathogenic organisms or a
compromised immune system.
Air flowing through the upper respiratory system in cetaceans encounters
little anatomic resistance before entering the glottis. From the glottis inhaled air must make
an almost 90 degree turn before entering the trachea. The floor of the larynx, when expanded on
exhalation then inspiration, exposes numerous folds and recesses that may be capable of trapping
larger particles carried by the normally high velocity airflow. Smaller particles may remain
suspended in the air column and gain access to the lower respiratory system. The potential air
velocity may be compromised by decreased activity or resting behavior in cetaceans. This may
also result in increased exposure to debris, bacteria or fungi.
Symptoms of respiratory disease include dyspnea, tachypnea, respiratory
noise, exercise intolerance, inappetence, depression, and behavioral changes. Diagnosis of
pulmonary disease can be aided by numerous methods that include physical exam with signs of
respiratory compromise, auscultation, bloodwork, respiratory cultures, radiographic examination,
computerized radiographs, thoracic ultrasound, blood gases, and pulmonary endoscopy.
Some infectious agents such as Pseudomonas aeruginosa and many fungi
may result in pathology primarily involving the trachea, bronchi, lungs, pleura and associated
Other pathogens such as Zygomycetes fungi and Nocardia may be spread
by the vascular system localizing in many different tissues including the brain, joints or skin.
The pulmonary relationship to these sites may be difficult to determine initially and these
organisms are often very resistant to therapy.
Treatment approaches are similar to other species. There may be numerous
complicating factors including unknown etiology, unknown portal of entry, location of the
primary site, resistance to therapy, diagnostic difficulty, rapid onset of signs, and in some
cases rapid death. Pulmonary infections with fungi may linger for extended periods resulting in
large lesions that appear resistant to therapeutic approaches. Pulmonary conditions involving
inhalation of non-infectious debris may result in chronic pulmonary symptoms since antibiotic
agents may not be effective.
Prevention may play the biggest role in pulmonary disease in cetaceans.
Recognizing the potential ease of access to the cetacean respiratory system, personnel must do
all that is possible to decease exposure to any dust, aerosol, or poor air quality. Some
cleaning techniques around exhibits, while increasing efficiency, may result in decreased air
quality. In an outdoor environment this will include the elimination of exposure to pressure
washing that aerosolizes dirt and debris, blow packs that redistribute dirt and leaves,
mechanized brushes, dirt left behind on road surfaces that could be blown by the wind,
construction and excavation activity, dirt mounds exposed to the wind, and air conditioner
systems. Exhaust from combustion engines should also be avoided. Sprinkler systems that form
spray or mist may aerosolize infectious agents as well as contaminants. Watering systems should
be of a non-spray variety. Indoor environments must be monitored for air contaminants such as
fungi and bacteria. Properly sized filters should be used in air circulation systems, to more
efficiently trap contaminants, and changed routinely. Air exchange rates should be adequate to
avoid the air becoming stale or heavy with chemical odors. Pressure washing should not be used
indoors near cetaceans.
Chemical exposure should also be closely monitored. Cleaning solutions such
as chlorine products may result in a range of effects from pulmonary irritation to fatality and
should be avoided near the animals. Inexperienced animal personnel should be educated to the
potential hazards of chemicals such as disinfects when joining the staff. Other departments such
as horticulture or park personnel who are responsible for cleaning should also be educated to
the potential respiratory problems the animals face so there is more cooperation in their
long-term health care.