Help, My Turtle Has a Respiratory Infection! 

Dogs and cats are by far the most popular pet in the UK, and many owners are familiar with the coughs, colds and sneezes that indicate a respiratory infection in these animals. But other animals, like turtles, can get respiratory infections too. What causes respiratory disease in turtles, tortoises and terrapins? What can you do about it? How do vets treat respiratory infections in these animals? If you’ve ever said, “help, my turtle has a respiratory infection!” then this article is for you. 

A Note on Names 

First, let’s clarify which animals we are talking about. In the UK, ‘turtle’ usually refers to the sea-dwelling reptile, and their land- and freshwater-based cousins are ‘tortoises’ or ‘terrapins’ respectively. This article will talk about the entire group of hard-shelled reptiles of the order Testudines. The group is often called the chelonians, which we will use going forward.  

Chelonian Respiratory System 

The respiratory system of chelonians differs quite a bit from other animals. Healthy chelonians breathe through their nostrils (nares). Air passes through the nares and down the trachea at the back of the throat. The trachea is short and flexible so that it remains functional when the head is retracted into the shell. The trachea divides into two bronchi, one for each lung. The lungs do not contain tiny air sacs (alveoli) like many animals, but instead have similar structures called ediculi and faveoli that perform a similar function – oxygen from inhaled air is exchanged for carbon dioxide from the blood within these structures, and the oxygen can then travel around the body.    

Because chelonians have a bony rigid shell around their body, the chest cannot expand and contract to assist in movement (breathing) of the lungs. They also have no diaphragm (the inside of a turtle is one cavity, called the pleuroperitoneal cavity (or coelom), contrasting to the thorax and abdomen in other species). Instead, chelonians pump the lungs via muscles in the groin, armpits and shoulders – this creates pressure changes that allows the lungs to inflate or deflate. In healthy turtles, the visible movement of breathing is subtle. When chelonians hibernate, the movement of the heart alone is sufficient to move the lungs and allow some breathing to take place, despite no other movement.  

It is important to remember that all chelonians require air to breathe. Even sea turtles must surface for oxygen (though some can go for hours without taking a breath). The normal respiratory rate for chelonians is around 4-8 breaths per minute. Not too relevant to today’s topic, but of interest, is that some sea turtles can perform cloacal respiration – this means they can absorb oxygen from the water via their cloaca (the common exit for urine and faeces). 

Symptoms of Respiratory Disease in Chelonians 

For keepers of chelonians, it is important to know the possible signs your chelonian has respiratory disease.  

Starting at the head, chelonians are obligate nasal breathers, so breathing with their mouth open is almost always a sign of respiratory distress. They may also have their head and neck stretched up and out too, to maximise oxygen intake. Some respiratory disease may cause fluid from the nostrils. However, because chelonians have their nostrils and mouth connected directly, the fluid can also occur due to mouth infection or even just salivation when eating. Similar fluid and swelling may be present from the eyes.  

A normal chelonian’s breathing is very hard to hear, even with a stethoscope – this means audible breathing is almost always abnormal. Noises you may hear include wheezing, gasping, crackling, gurgling or hissing. When a chelonian struggles to breathe, they may also move more in an attempt to increase their respiratory rate – if apparent, the respiratory rate may be above the normal 4-8bpm. Aquatic chelonia may swim abnormally or even struggle to float in a normal orientation.  

There are also many non-specific signs of disease that could indicate respiratory disease. These include lethargy, weakness, going off food and water, and pale or blue gums. Some infectious diseases can also cause changes to the skin, like depigmentation, ulceration or plaques.  

Investigation into Respiratory Disease 

Vets investigate respiratory disease in chelonians via several techniques. 

Initially, vets will want to ask questions about your chelonian’s environment, feeding and cleaning regimes and history, as well as details about when symptoms first developed, what they are, how serious they are, and if they have changed. This may help narrow down what kind of disease we are dealing with. 

From here, a clinical exam is performed. This will involve examining the chelonian from head to tail, focussing particularly on the nostrils and mouth for signs of disease. The heart and lungs can be auscultated (listened to) with a stethoscope, but remember this can be limited because of the shell.  

Blood samples can be taken from chelonians from the neck or tail vein commonly – this allows an assessment of red blood cell concentration for anaemia, checking white blood cells for infection, and specific tests for viruses. Parasites can be diagnosed by findings eggs or larvae in faeces or mouth swabs. The airways can also be sampled by flushing or swabs to identify bacterial, fungal or parasitic infections. Imaging via x-ray or CT can be very useful to view inside the chelonian, looking at the lungs and nearby structures. Finally, whole pieces of tissue may be able to be analysed via biopsy, surgery or post-mortem.  

Respiratory Infections 

There are many organisms that can cause respiratory infections in chelonians. 

Bacterial 

As in humans and other organisms, chelonians carry bacteria in healthy numbers on their skin and in their airways, called commensals. These commensals usually cause no harm, and may even benefit the organism by protecting them from pathogenic organisms, creating certain useful chemicals and ‘training’ the immune system. However, if the chelonian’s immune system is not sufficient to control the commensals, they can become opportunistic pathogenic bacteria, leading to disease. This may occur during times of illness or stress, if the environment is too hot or cold, the humidity is wrong, or if the chelonian has insufficient food or poor water quality. This often makes opportunistic respiratory infections in chelonians a preventable husbandry issue.  

There are some true pathogenic bacteria that cause respiratory disease too. The most significant is Mycoplasma, which can be spread between chelonians in close contact. Usually those that are already under stress are more vulnerable. Antibiotics can clear the infection, but the animal usually remains vulnerable to relapses life-long.  

Generally, most of these bacterial infections cause similar symptoms, thus sampling of the airways to culture the bacteria is essential to get a diagnosis and treatment plan. 

Viral 

Viruses are another common cause of respiratory infections in chelonians, and the most common is Herpesvirus. It mainly causes upper respiratory tract symptoms, and distinguishing it from Mycoplasma is difficult. As well as the classic symptoms of respiratory infection, Herpesvirus can also cause shell and skin, gastrointestinal, liver, and brain disease. The reduction of the immune system can also allow secondary bacterial infections to occur at the same time. As with Mycoplasma, chelonians infected with Herpesvirus should be considered carriers of the virus for life, and they may have recurrence of symptoms during times of stress. Treatment is mainly supportive, though there are some anti-viral drugs that may show some benefits. Herpesvirus can be fatal.  

Ranavirus is another viral disease of chelonians that primarily causes inflammation of the blood vessels, but this can lead to inflammation and damage of the lungs secondarily. Other viruses that can cause respiratory disease include Adenovirus, and Paramyxovirus. 

Fungal  

Respiratory infections from fungi can occur and again are common when the chelonian is already unwell or immunosuppressed. Importantly, they can occur after inappropriate antibiotic use, so care must be taken while treating bacterial infections not to cause a fungal infection. Common fungal pathogens include Aspergillus, Candida and Penicillum. As well as respiratory signs, they can form fungal plaques or granulomas on the mouth or in the lungs. Treatment requires oral, inhaled or systemic anti-fungal drugs, supportive care, and sometimes surgical removal of the plaques.   

Parasitic 

Unlike dog or cat lungworm, primary parasitic infections in chelonians are rare. However, non-respiratory parasites, such as Coccidia, ascarid roundworms or flukes may migrate into the lungs and cause damage. Treatment of these conditions is controversial, and there is even evidence that killing the organisms may lead to pneumonia due to inflammation. 

Other Respiratory Diseases 

Remember that a chelonian with respiratory disease may not have an infection (or it may be secondary to another primary problem), so consider these conditions as well. 

Hypovitaminosis A (low vitamin A) is a condition seen primarily in aquatic turtles. In the wild, their diets are high in vitamin A, but captive diets may be deficient. This can lead to reduced immune system, mild ocular discharge and abscessation, and secondary bacterial respiratory disease. Animals can be treated with injections of vitamin A, then correction of the diet long-term.  

Drowning is, unfortunately, not uncommon in chelonians, such as free-roaming pets in gardens with fishponds. Although tortoises may be able to hold their breath for 10 minutes or more, any longer can lead to aspiration of water and damage to the lungs. In the worst case this can be fatal, but if found quickly, treatment is often effective. Treatment is removal of the fluid from the lungs, drugs to open the airways and antibiotics to prevent secondary infection. Similarly, aquatic turtles that are placed in water too cold for them may become hypothermic, which can cause respiratory slowing. In the worst case, this could also lead to drowning. 

Trauma, such as from dog bites, falling from height or being hit by a car may damage the lungs directly, leading to disease. However, even if these events do not directly affect the lungs (remember their shells are designed to protect the organs), blunt force trauma may cause bruising or bleeding within the lungs, which can lead to disease or even death. Secondary infections are, again, common, so any trauma should indicate the need for swabbing for bacterial and fungal culture, antiseptic cleaning and antibiotics. 

Cancers of the respiratory tract are rare in chelonians. They either arise directly from the respiratory tract or spread via malignancy from other areas.  

Other rare respiratory diseases include respiratory arrest due to toxin exposure, idiopathic pulmonary fibrosis (the lungs become firm and inelastic), and congenital malformations of the lungs. Reported cancers include lymphomas, sarcomas, fibroadenomas and fibropapillomas. There is some evidence that viral infections, from Herpesvirus and others, may cause cancers as well. Surgery may be a treatment option, but many cancers are not noted until they are advanced.  

Non-Respiratory Disease 

It is also important to consider non-respiratory disease when a chelonian has respiratory symptoms – because there is no diaphragm, and thus no separation from abdominal and thoracic organs, disease of any organs may affect the lungs too.  

For example, infection of the coelom (coelomitis or peritonitis), such as from damage to the intestines or bladder, can easily spread to the lungs and cause pneumonia. Enlargement of organs, such as the reproductive tract from ovarian follicles or egg-stasis, the bladder due to blockage and distention, and the GI-tract from constipation or foreign body blockage, may physically compress the lungs, resulting in ineffective respiratory. Even obesity can cause reduced respiratory efficiency due to excess fat compressing the lungs.  

Any chelonian with respiratory disease should also be checked for non-respiratory disease first, via a thorough clinical examination, before focussing on the respiratory tract itself.