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For tortoise, terrapin and turtle care and conservation


Stephen J. Divers, BSc, BVetMed, CBiol, MIBiol, MRCVS.

From BCG Newsletters 120 (Nov/Dec 1997), 121 (Jan/Feb1998), 122 (Mar/Apr 1998) and 123 (May/June 1988), reprinted from an original article which first appeared in The Reptilian, with kind permission of Mantella Publishing.


The cool wet spring appears to have caused havoc with the captive tortoise population in the UK, so I thought that an article on tortoise respiratory disease would be a good idea.


The respiratory system of tortoises may at first glance appear a little strange; after all, everything is encased within that large bony shell and these animals have to move their limbs to breathe. But take a step back and consider the similarities between tortoises and mammals:

  • Air enters through the nose or mouth
  • Air enters the windpipe (trachea) situated at the back of the mouth (glottis)
  • Air passes down the trachea which divides into two main airways (bronchi)
  • One bronchus supplies the left lung and the other the right lung

Now this is where things change a little between mammals and tortoises. In mammals the bronchus then sub-divides until it terminates in microscopic air sacs called alveoli, and it is across the walls of these alveoli that oxygen and carbon dioxide are exchanged. However, tortoises lack this sophistication; instead, the bronchi terminate in a honeycomb-like lung. The overall effect of the lack of subdivision and the lack of tiny alveoli in the tortoise lung means it is not as efficient as that of mammals. That does not really matter because the respiratory demands of a tortoise are about 7 times less than those of a mammal. Air that is breathed out from the lungs follows a similar but reversed path from the lungs to the outside.

The other major difference between mammals and tortoises is how breathing is achieved. Inhalation is achieved by increasing the lung volume, which causes a decrease in lung air pressure, and as a result air is sucked in. During exhalation, the lung volume is decreased causing lung air pressure to increase and so air is forced out of the lung.

How is this achieved?

In mammals, the ribs and muscular diaphragm are responsible.

  • Mammalian inhalation: the intercostal muscles and diaphragm contract causing the chest to increase in volume and air to be sucked in.
  • Mammalian exhalation: the intercostal muscles and diaphragm relax causing the chest volume to decrease and air to be forced out.

But this cannot work in a tortoise! The ribs of the tortoise are fused to the inner surface of the shell and cannot move. The tortoise also lacks a muscular diaphragm, having only a thin membrane to separate the lungs from the rest of the body cavity. The lungs themselves are fixed to the upper part of the carapace. In tortoises, the shell represents a fixed volume, but by pulling the limbs in and out the pressure inside the shell (coelomic cavity) can be altered.

  • Tortoise inhalation: the limbs are extended, resulting in a decrease in soft tissue and a decrease in lung pressure within the coelomic cavity, and so air is sucked into the lungs.
  • Tortoise exhalation: the limbs are retracted into the shell, causing an increase in soft tissue and pressure within the coelomic cavity which forces air out of the lungs.


It is also important to realise that because tortoises lack a muscular diaphragm, they cannot cough. This has important medical repercussions, as once infection develops the tortoise cannot cough up infected material from within the lungs, and so infection tends to accumulate and make matters worse.

One last important point to bear in mind is that because there is no muscular diaphragm to divide the chest from the abdomen in tortoises (unlike mammals), any disease affecting the abdomen can also affect the lungs. For example:

  • Overweight tortoises will have a lot of coelomic fat which will squash the lungs, necessitating extra respiratory efforts compared with a lean tortoise.
  • Peritonitis (coelomitis) can easily spread to the lungs through the very thin diaphragm.
  • Distension of the intestines (e.g.gaseous bloat) or the reproductive tract (e.g. egg bound) will also reduce the volume.

Normal tortoise

In the normal tortoise at rest, there should only be slight movement of the forelimbs as the animal breathes. When undisturbed, breathing movements may only occur 4-8 times per minute; but be careful, as soon as your tortoise sees you this may increase as part of the normal fright/flight reflex. There should be no discharge from the nose, and the mouth should be closed. When the mouth is opened, the lining (mucous membranes) should be pale pink and there should be no discharge emanating from the opening to the windpipe (glottis) which is located at the base of the tongue.

Abnormal tortoise

Tortoises with respiratory disease may be lethargic, weak and anorexic. They will often have an increased respiratory rate at rest. During respiration the limb movements will usually be more exaggerated, and audible gurgling or hissing noises will frequently be noticeable. There may be a discharge from the nose, and the mucous membranes may be pale grey or, in severe cases, blue. Examination of the mouth may also reveal the presence of discharge bubbling up from the glottis. In very severe cases the tortoise may fully extend the neck and perform open-mouthed breathing as it craves air.


A thorough clinical examination may reveal the signs stated above and give the veterinary surgeon an indication that respiratory disease might be present. In a quiet consulting room it is also possible to auscultate the lungs using a stethoscope. However, just like human medicine the diagnosis requires X-rays and laboratory investigation.


Radiography provides a two-dimensional black/white image of the animal using a beam of X-rays. Bone is most dense and appears white while air is least dense and appears black; various soft tissues are represented by shades of grey. The lungs of a normal tortoise look dark but the presence of any infection (pus) causes the lungs to become more opaque. An increase in visceral volume (fat, eggs etc.) reduces the lungs so although they may be clear, they are smaller than normal. As X-rays are only two-dimensional images, it is important to take at least two different views so that any problems can be pinpointed in the animal. For example, if there is a localised area of infection in only one lung it is essential to:

  • Take one side/side (lateral) X-ray to ascertain whether the problem is near the front of the lung or near the back of the lung.
  • Take a front/strongack (anterior – posterior) X-ray to ascertain whether the problem is in the left or right or both lungs.

Lung wash

In many cases a lung wash is vital as it provides material for:

  • Bacterial and fungal culture to determine the best choice of anti-microbial drug
  • Microscopy to determine the presence of any lung parasites, inflammatory changes or, more rarely, cancer.

The lung wash is performed in the sedated or anaesthetised tortoise. A sterile catheter is inserted down the trachea and into the lungs. A small volume of sterile water is instilled and then aspirated into a syringe. On most occasions not all the water is recovered, but that does not matter as being sterile it will be absorbed without causing pneumonia. If the X-rays demonstrate a problem with just one lung it is important to ensure the catheter is placed down the correct bronchus. This can easily be achieved by using a curved stylet to direct the catheter into the correct lung.

Blood tests

Blood tests are quite useful; in particular, a haematology assessment enables the clinician to determine whether the tortoise is responding to an infectious disease, and if so, is the disease overwhelming the tortoise? Certain antibiotic and anti-fungal drugs can put an extra strain on the tortoise’s liver or kidneys, and so it is also important in many cases to ensure that these organs are working adequately before starting therapy. This is achieved by blood biochemistry which looks for indications of liver damage and kidney disease.

Other diagnostic procedures

There are a number of other diagnostic procedures that can be used in special circumstances:

  • Endoscopy can be used to actually look inside the lung and take biopsies
  • CT scans and MRI imaging are expensive but provide excellent images.


There are several conditions that cause respiratory compromise and disease; these include:


  • Bacterial pneumonia
    • often caused by Gram-negative bacteria such as Pseudomonas, although Mycoplasma and Mycobacterium have also been diagnosed as primary diseases
    • requires aggressive antibiotic therapy administered either orally, by injection or administered directly into the diseased lung by nebulisation or intrapulmonary injection
    • lung abscessation may require surgical removal
    • other supportive measures include providing a suitable thermal environment, adequate ventilation, anti-inflammatory medication, fluid therapy and occasionally nutritional support
  • Fungal pneumonia
    • often caused by Candida albicans although Aspergillus fumigatus is not uncommon
    • often secondary to prolonged treatment with broad spectrum antibiotics (e.g. Baytril)
    • requires aggressive anti-fungal therapy administered either orally, by injection or directly into the diseased lung by nebulisation or intra-pulmonary injection
    • fungal granulomas may require surgical removal
    • other supportive measures include providing a suitable thermal environment, adequate ventilation, anti-inflammatory medication, fluid therapy and occasionally nutritional support
  • Viral pneumonia
    • often caused by Herpesvirus infection although there may be other, as yet unidentified, viruses capable of causing respiratory disease
    • very few anti-viral drugs are available, but acyclovir has been used with some success against Herpesvirus infections. Therapy is given either orally or by injection
    • other supportive measures include providing a suitable thermal environment, adequate ventilation, anti-inflammatory medication, fluid therapy and nutritional support
  • Parasitic pneumonia
    • a rare condition in tortoises caused by metazoan or protozoan parasites


  • Obesity
    • a common condition in which tortoises present a high ‘Jackson’s Ratio’ due to being overfed over a prolonged period of time
    • treatment involves a slow weight reduction programme, but care is necessary to prevent clinical fatty liver syndrome (hepatic lipidosis)
  • Egg binding
    • large numbers of eggs may cause a transient respiratory compromise which is of no concern unless the tortoise fails to lay eggs normally
    • dystocias are usually responsive to oxytocin therapy
  • Poor husbandry (ventilation and thermal environment)
    • a very common condition, especially in juvenile tortoises housed in glass vivaria where poor ventilation results in stagnant air
    • poor thermal environment often results in immuno-suppression and secondary bacterial infections, which must be treated with appropriate antibiotics
    • other supportive measures include providing a suitable thermal environment, adequate ventilation, anti-inflammatory medication, fluid therapy and occasionally nutritional support
    • improvements in husbandry, especially ventilation, are essential to prevent recurrence
    • housing tortoises outside, weather permitting, provides superior ventilation
  • Drowning in freshwater ponds
    • tortoises wander or fall into garden ponds from which they cannot escape
    • affected animals may have been submerged for minutes or even hours
    • good chances of recovery if emergency veterinary treatment is instigated (evacuation of lung fields, respiratory stimulants)
    • secondary bacterial infections are a common complication and so prophylactic antibiotic cover is advisable
    • other supportive measures include providing a suitable thermal environment, adequate ventilation, anti-inflammatory medication, fluid therapy and occasionally nutritional support
  • Cancer (rare)
    • primary (benign and malignant) growths are possible but very rare
    • secondary spread from other cancers (e.g. liver, muscle) is also possible
    • surgery offers the best chance of recovery but once diagnosed the condition is often far advanced
    • chemotherapy is a largely untried option
    • supportive measures include providing a suitable thermal environment, adequate ventilation, steroidal anti-inflammatory medication, fluid therapy and nutritional support

The specific treatment of respiratory disease obviously depends on the cause of the disease and how serious the problem is. In cases of severe compromise (e.g. drowning, severe pneumonia) it is often necessary to place the tortoise in an oxygen-rich atmosphere. There are a large number of medications that can be used to treat respiratory diseases. These medications can be given by the conventional methods, e.g. orally by stomach tube or by injection. However, it has become apparent that in certain situations a more direct method is more effective.

At the Exotic Animal Centre we have been using two other approaches:

  • Nebulisation
  • Intrapulmonary injection


This method involves placing the tortoise in a high oxygen environment. The oxygen also acts as a carrier for an aerosol of active drug, often an antibiotic or anti-fungal medication. As the animal breathes, so the active drug, in the form of minute droplets, is breathed into the lung directly into the area of infection. This method is particularly useful because it permits the use of drugs that would be considered dangerous if administered by injection (e.g. Neomycin aminoglycoside) or not absorbed and hence ineffective in the lungs if dispensed by stomach tube (e.g. Nystatin anti-fungal).

Intrapulmonary injection

This method is particularly useful when dealing with focal, discrete infections involving one lung. Radiographs are used to pinpoint the infection, and then a hole is drilled through the carapace of the anaesthetised tortoise directly above the site of infection. A sterile catheter is inserted into the area, and capped using an injection port to prevent any communication between the lung and outside. The injection port and catheter are tissue bonded to the shell to form an air and water tight seal. Medication can then be injected directly into the site of the infection, which means the concentration of drug at the infection site is much greater than would be achieved by oral or standard injection methods. Alternatively, the same lung drug concentration can be achieved using a smaller intrapulmonary dose than oral or standard injection dose. This is especially important when using potentially toxic drugs.


The prevention of disease is what we should really all be aiming for and there are four cardinal rules:

  • Maintain a suitable thermal gradient, paying particular attention to the species-specific preferred optimum temperature zone and the provision of a basking area provided by an overhead radiant heat source.
  • Maintain good ventilation. Far too many vivarium set-ups have little or no ventilation. A strip of ventilation mesh should extend across the whole of the back wall and ventilation panels should be present at both sides. Avoid using glass aquaria, especially for juveniles, but if they are used the entire top of the enclosure should consist of wire mesh. The ideal situation is to maintain tortoises in large garden enclosures, climate permitting, and this goes for the tropical as well as subtropical and temperate species.
  • Maintain a suitable humidity. The Testudo species will be quite tolerant of humidity ranges between 25-28%, but some tropical forest species such as the red-footed tortoise (Geochelone carbonaria) will do better at a higher sustained humidity, often approaching 95%. Inappropriate humidity for a prolonged period of time will predispose to respiratory disease and so efforts must be made to maintain a suitable level by regular spraying, humidifiers, humidity chambers, sprinkler systems etc.
  • Maintain an effective quarantine protocol. New additions to a collection should be maintained well away from the existing collection for at least three months and preferably six months.