Mycoplasma in Tortoises: Symptoms, Testing, Treatment and Carrier Risk

By Dr Duncan Houston

A runny nose, swollen eyelids or bubbles around a tortoise’s nostrils should never be dismissed as a simple cold.

Mycoplasma is one important cause of chronic upper respiratory tract disease in tortoises. It can produce rhinitis, conjunctivitis, blocked nostrils, appetite loss and progressive weight loss. However, many other infections and husbandry problems can produce almost identical signs.

The challenge is that an infected tortoise may look unwell one week and apparently normal the next. Some tortoises carry detectable Mycoplasma without showing obvious disease, while others develop severe inflammation and chronic respiratory damage.

Quick Answer

Mycoplasmosis in tortoises most commonly causes nasal discharge, bubbles around the nostrils, swollen eyelids, eye discharge, conjunctivitis, reduced appetite and weight loss.

Diagnosis usually combines a reptile examination with PCR testing of a nasal lavage or respiratory swab. Antibody testing can show previous exposure but does not prove that the tortoise is currently shedding bacteria or clinically ill. Treatment may control signs and reduce bacterial burden, but no protocol guarantees complete eradication, and recurrence is possible. (Merck Veterinary Manual)

Mycoplasma in Tortoises at a Glance

Question	Practical answer
What does it usually cause?	Chronic or intermittent upper respiratory tract disease
Most common signs	Nasal discharge, bubbling, watery eyes, swollen eyelids, conjunctivitis and appetite loss
Can an infected tortoise look healthy?	Yes
Does a positive PCR mean the tortoise is sick?	Not necessarily. It confirms that Mycoplasma DNA was detected
Does a positive antibody test mean active infection?	No. It indicates an immune response or previous exposure
Can antibiotics guarantee a cure?	No
Can signs return later?	Yes
Should positive animals live with negative animals?	No
Is every runny nose caused by Mycoplasma?	No
When is it an emergency?	Laboured breathing, severe weakness, blocked nostrils, collapse or rapid deterioration

What Is Mycoplasma?

Mycoplasmas are extremely small bacteria that lack the rigid cell wall found in most bacterial species.

That missing cell wall affects treatment. Antibiotics that work primarily by disrupting bacterial cell-wall production, such as penicillins and cephalosporins, do not directly target Mycoplasma. Drugs used against reptile mycoplasmosis are instead selected from antimicrobial classes that act on other bacterial functions, most commonly tetracyclines or macrolides. (microbiologyresearch.org)

In tortoises, Mycoplasma organisms attach to the respiratory lining and can produce chronic inflammation, excessive mucus, epithelial damage and progressive blockage of the nasal passages. Experimental infection studies confirmed that M. agassizii can directly cause upper respiratory tract disease in desert and gopher tortoises. (ASM Journals)

Which Mycoplasma Species Affect Tortoises?

Mycoplasma agassizii

M. agassizii is the best-characterised cause of mycoplasmal upper respiratory tract disease in tortoises.

It was first studied intensively in North American desert and gopher tortoises but has since been detected in numerous captive and free-ranging tortoise species, including Mediterranean tortoises. It can cause chronic rhinitis, conjunctivitis, swollen eyelids and thick nasal exudate. (ASM Journals)

Some modern publications use the updated name Mycoplasmopsis agassizii. Both names refer to the same clinically important organism, and many diagnostic laboratories and veterinary references continue to use Mycoplasma agassizii. (Nyas Pubs)

Mycoplasma testudineum

M. testudineum is also associated with chronic rhinitis and conjunctivitis in tortoises.

Studies of infected desert tortoises found inflammatory changes within the nasal cavities consistent with upper respiratory disease. Its lesions may sometimes be less diffuse or severe than those caused by M. agassizii, although disease expression varies between individuals. (USGS)

Mycoplasma testudinis

M. testudinis has been isolated from tortoises but has not been consistently associated with clinical respiratory disease.

This is an important reminder that finding a Mycoplasma organism does not automatically prove it is the cause of the patient’s signs. Species-level identification and clinical context matter. (Sage Journals)

What Signs Does Mycoplasma Cause in Tortoises?

Early or Mild Signs

Early disease may produce:

• Clear nasal discharge

• Tiny bubbles at the nostrils

• Watery eyes

• Mild eyelid swelling

• Redness at the inner corner of the eye

• Intermittent conjunctivitis

• Mild appetite reduction

• Occasional rubbing of the nose or face

• Discharge that appears only after activity or handling

These signs may come and go. A tortoise that looks normal during one examination may have shown discharge several days earlier. (FWC)

More Established Disease

As inflammation progresses, owners may notice:

• Thick or stringy nasal mucus

• White, yellow or caseous material blocking the nostrils

• Persistent eye discharge

• Marked swelling around the eyes

• Eyelids that become partly sealed

• Reduced sense of smell and interest in food

• Open-mouth breathing

• Noisy breathing

• Lethargy

• Progressive weight loss

• Dehydration

• Reduced activity or abnormal basking behaviour

A tortoise may have severely blocked nasal passages without visible dripping because the discharge has become trapped inside the nares. The absence of a wet nose therefore does not rule out advanced disease. (ASM Journals)

Severe Chronic Disease

Severe disease may cause:

• Complete blockage of one or both nostrils

• Destruction or distortion of nasal tissues

• Significant ocular disease

• Inability to eat normally

• Marked muscle loss

• Profound weakness

• Secondary bacterial or fungal infection

• Lower respiratory involvement

• Eventual death from chronic debilitation

Experimental studies have demonstrated damage to the respiratory epithelium and prolonged recovery of viable organisms from infected tortoises. (ASM Journals)

Does Mycoplasma Always Cause Nasal Discharge?

No.

Clinical expression varies substantially between infected tortoises. A tortoise may show:

• Eye changes without obvious nasal discharge

• Nasal discharge only during certain seasons

• Positive PCR results without visible illness

• Previous exposure on antibody testing without current signs

• Chronic nasal inflammation despite an apparently dry nose

In one field study, mild eyelid swelling was much more common than obvious nasal discharge among affected gopher tortoises. (Wiley Online Library)

A tortoise with no discharge can therefore still be infected, while a tortoise with discharge may have an entirely different disease.

Is Every Runny Nose Caused by Mycoplasma?

No. “Upper respiratory tract disease” describes a clinical syndrome, not one specific diagnosis.

Important alternatives include:

Possible cause	Other clues
Testudinid herpesvirus	Oral plaques, stomatitis, regurgitation, severe systemic disease
Other respiratory viruses	Collection outbreaks, sudden disease or mixed infections
Bacterial rhinitis or pneumonia	Purulent discharge, systemic illness or abnormal lung imaging
Intranuclear coccidiosis	Chronic nasal disease, oral-nasal fistulas or systemic signs
Fungal infection	Granulomatous lesions, chronic plaques or poor treatment response
Nasal foreign material	One-sided discharge, sudden onset or repeated sneezing
Dust or substrate irritation	Signs linked to a dusty or excessively dry enclosure
Oral or dental disease	Mouth inflammation, facial swelling or abnormal eating
Vitamin or nutritional disease	Eye swelling, poor growth and broader epithelial abnormalities
Overheating or severe stress	Temporary frothing without true rhinitis
Abscess or tumour	Unilateral swelling, distortion or progressive obstruction
Poor environmental temperature	Reduced immunity, inactivity and secondary respiratory infection

Chelonian respiratory disease frequently involves more than one organism. Mycoplasma, herpesviruses, ferlaviruses and other agents have been detected together, and Mycoplasma should not be blamed for every clinical sign simply because one PCR result is positive. (Sage Journals)

Can a Healthy-Looking Tortoise Carry Mycoplasma?

Yes.

A tortoise can carry detectable Mycoplasma without showing nasal discharge, eye swelling or appetite loss.

A recent study of captive tortoises in Portugal detected M. agassizii DNA in 52 of 78 valid samples, including many animals that appeared clinically healthy. This does not mean all captive tortoises are infected, but it demonstrates that silent carriage within collections can be substantial. (Lusófona University)

Another quantitative PCR study detected M. agassizii DNA in an entire sampled captive desert tortoise group, yet not every PCR-positive tortoise had developed detectable antibodies. The researchers interpreted some animals as colonised rather than demonstrating the full immune pattern expected with established disease. (ScienceDirect)

The practical consequence is straightforward:

A tortoise does not have to look sick to present an infectious-disease risk to another tortoise.

Does a Positive PCR Mean the Tortoise Is Sick?

Not automatically.

PCR detects genetic material from the organism. It may indicate:

• Active infection with clinical disease

• Active shedding without visible disease

• Early colonisation before signs develop

• Persistent low-level infection

• Detection of an organism that is not currently causing the main clinical problem

PCR does not directly measure tissue damage, pain or the severity of respiratory disease.

A positive PCR becomes more clinically meaningful when it occurs alongside:

• Compatible nasal or ocular signs

• Progressive weight loss

• Inflammatory lesions

• High organism load

• Repeated positive results

• Transmission to exposed animals

• Exclusion of important competing diagnoses

Does a Positive Antibody Test Mean Active Disease?

No.

Serology measures the tortoise’s immune response to the organism. A positive antibody result generally indicates previous exposure or infection, but it does not prove that the bacterium is currently being shed.

Antibody responses in tortoises can be extremely slow. In one long-term exposure study, Mycoplasma DNA was detected within weeks, while specific antibodies were not detected until approximately 60 to 85 weeks after exposure in some animals. (PubMed)

This creates several possibilities:

• PCR positive and antibody negative during early infection

• PCR positive and antibody positive during established infection

• PCR negative and antibody positive after previous exposure

• Clinical signs despite a temporarily negative PCR

• Subclinical exposure identified only by serology

Maternal antibodies can also persist in hatchlings born to seropositive females and may complicate interpretation for more than a year. (PubMed)

How Should PCR and Serology Be Interpreted?

Result	Possible interpretation
PCR positive, signs present	Mycoplasma is likely contributing, but coinfections and other disease still need consideration
PCR positive, no signs	Subclinical colonisation or infection is possible
PCR negative, signs present	Mycoplasma is not excluded. Shedding may be low, intermittent or poorly sampled
Antibody positive, PCR negative	Previous exposure or persistent immune response without current detection
Antibody negative, PCR positive	Early colonisation or infection before seroconversion
Both negative	Infection is less likely, but timing and sample quality still matter
One negative test after treatment	Does not prove eradication

No single result should be interpreted without the tortoise’s clinical signs, exposure history, collection status and previous test results.

How Does Mycoplasma Spread Between Tortoises?

Direct close contact appears to be the most important route.

Transmission risk increases during:

• Courtship

• Mating

• Fighting

• Nose-to-nose contact

• Shared hides or burrows

• Prolonged cohabitation

• Contact with heavy nasal discharge

Experimental work found that the likelihood of transmission depended on both contact duration and the amount of Mycoplasma being shed by the infected tortoise. Animals with a high organism load could transmit infection even during relatively short interactions. (BES Journals)

Asymptomatic carriers may also contribute to transmission, particularly in breeding groups, rescue centres and mixed-species collections where contact is close and prolonged. (Frontiers)

Can It Spread Through Equipment?

Direct transmission has stronger supporting evidence than indirect environmental transmission because mycoplasmas are generally fragile outside a host.

However, fresh nasal discharge can contaminate:

• Food bowls

• Water dishes

• Hides

• Transport boxes

• Weighing equipment

• Examination surfaces

• Hands and gloves

• Cleaning tools

Dedicated equipment remains sensible because even if Mycoplasma survives poorly after drying, respiratory secretions can be moved immediately between animals, and other more environmentally resistant pathogens may be present at the same time.

Can Different Tortoise Species Infect One Another?

Yes.

M. agassizii has been identified across multiple tortoise genera and species. Mixing Mediterranean, African, South American or North American tortoise species creates opportunities for pathogen transmission between hosts with different susceptibility and immune histories. (Sage Journals)

Mixed-species tortoise housing should be avoided for more than one reason:

• Different temperature and humidity requirements

• Different diets

• Different parasite burdens

• Different herpesviruses and respiratory organisms

• Difficulty identifying which animal is shedding

• Increased chronic social stress

The fact that two tortoises tolerate each other behaviourally does not make them medically compatible.

What About Mycoplasma in Snakes?

Mycoplasmas are also detected in snakes, particularly pythons, but the clinical relationship is less clearly defined than it is in tortoises.

A 2025 study tested 640 snakes and detected genetically diverse mycoplasmas across pythons, boas, colubrids, elapids and vipers. Positive results were especially common in pythons, but clinical information was unavailable, so the study could not establish whether each detected organism was pathogenic, commensal or incidental. (PubMed)

Earlier pathology work identified Mycoplasma in occasional snakes with pneumonia, but viruses, other bacteria and husbandry problems were also commonly present. A positive snake PCR should therefore not be interpreted using tortoise rules. (PubMed)

A snake with respiratory signs may require testing for:

• Ferlavirus

• Reptarenavirus or inclusion body disease

• Nidovirus

• Bacterial pneumonia

• Fungal disease

• Parasites

• Mycoplasma

• Environmental and temperature problems

What About Crocodilians?

Mycoplasma can cause much more severe systemic disease in crocodilians.

Mycoplasma crocodyli has been associated with exudative polyarthritis, progressive lameness, swollen joints and pneumonia in Nile crocodiles. Mycoplasma alligatoris caused fatal pneumonia, polyserositis, arthritis and bloodstream infection during outbreaks in American alligators. (PubMed)

These diseases are biologically and clinically different from classic tortoise rhinitis. Treatment and biosecurity protocols must therefore be designed for the species and syndrome involved.

How Worried Should You Be?

Lower Immediate Concern

The tortoise:

• Has no respiratory signs

• Is eating normally

• Maintains a stable weight

• Has no known exposure

• Has a single uncertain or low-level test result

• Is housed alone

Action: Discuss the result with a reptile veterinarian. Repeat or complementary testing may be more useful than immediate medication.

Moderate Concern

The tortoise has:

• Occasional clear nasal moisture

• Mild watery eyes

• Intermittent eyelid swelling

• Slight appetite reduction

• A known exposure to a positive tortoise

• A positive PCR without systemic illness

Action: Isolate the tortoise and arrange a reptile veterinary appointment within several days. Begin daily weight and symptom monitoring.

High Concern

The tortoise has:

• Thick nasal discharge

• Repeated bubbling

• Swollen or sealed eyelids

• Complete appetite loss

• Progressive weight loss

• Blocked nostrils

• Noisy breathing

• Marked lethargy

• Failure to improve after previous antibiotics

Action: Seek same-day reptile veterinary assessment.

Critical

The tortoise has:

• Open-mouth or laboured breathing

• Severe respiratory effort

• Collapse

• Minimal responsiveness

• Inability to extend or support the head normally

• Completely blocked nostrils

• Severe dehydration

• Rapid deterioration

• Blue, grey or extremely pale oral tissues

• Profound weakness

Action: Attend an exotic veterinary emergency service immediately.

When Is This an Emergency?

Seek urgent veterinary care when your tortoise develops:

• Open-mouth breathing outside a brief handling response

• Marked extension of the head and neck to breathe

• Repeated gasping

• Severe bubbles or mucus obstructing both nostrils

• Collapse

• Inability to walk or support the body

• Complete refusal to eat with progressive weakness

• Rapid weight loss

• Severe eye swelling or inability to open the eyes

• Blood from the nose or mouth

• Neurological abnormalities

• Rapid decline over several hours

A tortoise with respiratory distress may deteriorate during excessive handling. Keep the animal calm and minimise repeated attempts to clean or examine the mouth.

What Should You Do Right Now?

1. Isolate the Tortoise

Move the affected tortoise away from every other reptile.

Use dedicated:

• Bowls

• Hides

• Weighing equipment

• Cleaning tools

• Gloves

• Transport containers

Care for healthy or negative animals first and the affected tortoise last.

2. Maintain the Correct Temperature Range

Keep the tortoise within its species-appropriate preferred temperature range.

Appropriate warmth supports:

• Immune function

• Gastrointestinal activity

• Medication metabolism

• Appetite

• Mucociliary respiratory function

Do not overheat the enclosure. A sick tortoise still needs a cooler retreat and should never be placed directly against an unregulated heating device.

3. Do Not Brumate a Clinically Ill Tortoise

A tortoise that is anorexic, underweight, dehydrated, actively discharging, breathing abnormally or undergoing treatment should not be placed into brumation.

A clinically normal PCR-positive tortoise requires individual veterinary assessment before planned brumation. Test positivity alone does not reveal current disease activity, but a tortoise entering brumation with uncontrolled illness may have very limited ability to compensate.

4. Weigh the Tortoise

Use an accurate gram scale and record:

• Date

• Weight

• Appetite

• Activity

• Nasal discharge

• Eye changes

• Breathing pattern

• Faecal and urate output

A progressive downward trend is more useful than relying on whether the shell still feels heavy.

5. Photograph the Signs

Take clear photographs or videos of:

• Both nostrils

• Both eyes

• Breathing

• Any bubbles or discharge

• The mouth where safely visible

• The enclosure

• Temperature readings

Respiratory discharge may disappear before the appointment, making records particularly useful.

6. Clean Only the Outside of the Nostrils

Visible discharge may be gently removed from the outer edge of the nostril using sterile saline-moistened gauze.

Do not:

• Insert cotton swabs into the nostrils

• Force the mouth open

• Flush the nose at home

• Push the tortoise’s head into the shell to express discharge

• Pick out deeply attached material

• Use peroxide, oils or essential oils

Nasal lavage must be performed in a way that avoids aspiration and excessive stress.

7. Do Not Give Leftover Antibiotics

Do not administer:

• Penicillin

• Amoxicillin

• Cephalosporins

• Leftover reptile antibiotics

• Bird respiratory medication

• Human antibiotics

• Medication prescribed to another tortoise

The drug, route, concentration and dosing interval depend on the tortoise’s species, temperature, hydration and diagnosis.

8. Arrange a Reptile Veterinary Examination

Tell the clinic:

• Species

• Age

• Weight

• Duration of signs

• Previous Mycoplasma tests

• Other reptiles exposed

• Recent purchases or breeding

• Brumation history

• Previous medications

• Temperature and humidity measurements

• Appetite and weight trend

How Do Veterinarians Diagnose Mycoplasma?

Physical Examination

The veterinarian will assess:

• Nasal passages

• Eyes and eyelids

• Mouth and choana

• Breathing pattern

• Body weight and muscle condition

• Hydration

• Shell and skeletal health

• Husbandry

• Exposure history

The entire tortoise must be examined. Nasal discharge may be the most visible problem while pneumonia, oral disease, metabolic disease or another infection is also present.

PCR Testing

PCR detects Mycoplasma DNA.

Samples may be collected from:

• Nasal lavage fluid

• Nasal swabs

• Oral swabs

• Choanal swabs

• Ocular material in selected cases

Nasal lavage often provides an excellent sample from the affected respiratory tissue, but the best technique depends on the species, laboratory and patient’s condition.

PCR is particularly useful during early colonisation because it may detect the organism before antibodies or clinical signs appear. (ScienceDirect)

Why Can PCR Be Negative in an Infected Tortoise?

Possible explanations include:

• Low organism load

• Intermittent shedding

• Sampling after treatment

• A superficial swab missing deeper material

• Poor sample collection

• PCR inhibitors

• Infection located outside the sampled area

Repeated testing or a different sample may be needed when clinical suspicion remains high.

Serology

ELISA testing detects antibodies produced against Mycoplasma.

It is most useful for identifying previous exposure and supporting population or collection-level screening. It cannot determine whether the organism is currently present in the nasal passages. (PubMed)

Interpretation becomes difficult when:

• Infection is recent

• Antibody production is delayed

• The tortoise is immunocompromised

• The patient is a hatchling with maternal antibodies

• The assay has not been validated for that exact tortoise species

Culture

Mycoplasma culture is difficult, slow and not available through every laboratory.

Culture has the advantage of confirming viable organisms and may support further strain or antimicrobial investigation, but contamination and the organism’s slow growth make it less practical than PCR for many clinical cases. (PubMed)

Bloodwork

Bloodwork does not diagnose Mycoplasma directly.

It may help evaluate:

• Dehydration

• Anaemia

• Inflammation

• White blood cell changes

• Liver and kidney function

• Nutritional status

• Safety of prolonged medication

A normal blood panel does not rule out significant upper respiratory inflammation.

Radiographs and CT

Imaging may be recommended when the veterinarian is concerned about:

• Pneumonia

• Chronic sinus disease

• Facial or nasal masses

• Foreign material

• Bone changes

• Other causes of weight loss

• Lower respiratory disease

Routine radiographs are less useful for superficial rhinitis than for evaluating the lungs and wider body.

Testing for Other Pathogens

Depending on species and signs, the veterinarian may also recommend testing for:

• Testudinid herpesviruses

• Ferlavirus

• Picornaviruses or topiviruses

• Intranuclear coccidia

• Bacterial culture

• Fungal disease

• Parasites

Coinfections may explain why one tortoise becomes severely ill while another PCR-positive tortoise remains clinically normal. (Sage Journals)

Can Mycoplasma Be Cured?

There is no treatment proven to guarantee complete elimination of Mycoplasma from every infected tortoise.

Antimicrobial treatment may:

• Reduce organism burden

• Improve nasal discharge

• Reduce eye inflammation

• Restore appetite

• Support weight gain

• Reduce the immediate risk of transmission

However, infection can persist for prolonged periods, and discharge or bacterial shedding may recur after clinical improvement. Longitudinal research found evidence of multi-year infection and later reactivation in desert tortoises. (Cambridge University Press)

The phrase “lifelong carrier” is often used, but it is more accurate to say:

Complete clearance is difficult to prove, and a previously positive tortoise should continue to be treated as a potential carrier unless a reptile infectious-disease specialist advises otherwise.

How Is Mycoplasma Treated?

Treatment is individualised according to the tortoise’s species, severity, hydration, concurrent disease and test results.

Antibiotic Therapy

Current reptile references describe tetracyclines and macrolides as commonly used antimicrobial classes for reptile mycoplasmosis. Clarithromycin has been pharmacokinetically studied in desert tortoises, while doxycycline and other related drugs are also used in reptile medicine. (Merck Veterinary Manual)

The veterinarian must decide:

• Which antimicrobial is most appropriate

• Oral, injectable or local route

• Dosing interval

• Treatment duration

• Whether combination therapy is justified

• How liver and kidney function will be monitored

There is no universal evidence-based rule that every tortoise requires 45 to 60 days of injectable antibiotics.

Long courses may be appropriate in selected patients, but forcing one protocol onto every species and severity risks undertreatment, toxicity, injection-site injury or unnecessary antimicrobial exposure.

Nasal and Ocular Treatment

A reptile veterinarian may use:

• Sterile nasal lavage

• Choanal flushing

• Removal of obstructive exudate

• Prescribed eye medication

• Nebulisation

• Local antimicrobial therapy

• Saline humidification

These procedures may improve airflow and remove material that systemic medication penetrates poorly.

They should not be attempted by owners without training because fluid can be aspirated into the lungs.

Supportive Care

Supportive care can be just as important as the antibiotic.

It may include:

• Species-appropriate warmth

• Fluid therapy

• Nutritional support

• Assisted feeding when safe

• Oxygen

• Analgesia

• Treatment of dehydration

• Management of ocular damage

• Correction of vitamin or dietary deficiencies

• Reduction of handling stress

A recent Horsfield tortoise case was managed using respiratory flushing, systemic and topical medication, nebulisation, pain relief, fluid support, warmth and nutritional support rather than antibiotics alone. (Magma Online Library)

Treating Coinfections

Antibiotic therapy directed at Mycoplasma will not treat:

• Herpesvirus

• Ferlavirus

• Intranuclear coccidia

• Fungal disease

• Foreign bodies

• Tumours

• Nutritional disease

Failure to improve should trigger reassessment rather than simply extending or increasing the same medication.

Should an Infected Tortoise Be Euthanised?

A positive PCR or antibody result alone is not a reason for euthanasia.

Tortoise mycoplasmosis researchers have specifically warned that overinterpreting diagnostic results has led to undesirable management decisions involving clinically healthy animals. (USGS)

Euthanasia may become appropriate when there is:

• Uncontrolled respiratory distress

• Severe irreversible tissue destruction

• Profound chronic wasting

• Inability to eat

• Repeated treatment failure

• Serious concurrent disease

• Poor and declining quality of life

The decision should be based on the individual tortoise’s welfare, not simply the presence of an organism.

What Is the Prognosis?

More Favourable Prognosis

The outlook is generally better when:

• Signs are identified early

• The tortoise continues eating

• Weight remains stable

• Nasal obstruction is limited

• No pneumonia is present

• Husbandry is appropriate

• Treatment can be administered reliably

• Coinfections are absent or treatable

Guarded Prognosis

The prognosis becomes more guarded with:

• Chronic blocked nostrils

• Marked ocular damage

• Severe weight loss

• Complete anorexia

• Pneumonia

• Repeated relapses

• Multiple concurrent pathogens

• Inability to maintain appropriate temperatures

• Poor response to treatment

Some tortoises remain stable for years after clinical recovery. Others experience recurrent discharge during stress, relocation, breeding or periods of physiological challenge.

How Should a Positive Tortoise Be Managed Long Term?

A previously positive tortoise should generally:

• Remain separated from confirmed-negative tortoises

• Have dedicated bowls and equipment

• Be weighed regularly

• Receive routine reptile veterinary examinations

• Be monitored closely before breeding or relocation

• Avoid unnecessary stress

• Receive immediate assessment if discharge returns

• Not be released into the wild

One negative PCR after treatment should not automatically be interpreted as permanent clearance.

How Often Should Follow-Up Testing Be Performed?

There is no universal requirement to test every two months for one year.

Follow-up should be based on:

• Severity of disease

• Treatment used

• Clinical improvement

• Collection risk

• Breeding plans

• Previous PCR and serology results

• Whether exposed tortoises remain in the household

A recheck may involve:

• Repeat examination

• Body-weight review

• Repeat PCR

• Bloodwork

• Imaging

• Assessment of exposed animals

Serial results are usually more meaningful than one isolated test.

How Should New Tortoises Be Quarantined?

Quarantine should be measured in months rather than a few days for high-risk acquisitions, but there is no single duration that guarantees freedom from Mycoplasma.

A meaningful quarantine plan includes:

• Complete physical separation

• Dedicated equipment

• Baseline body weight

• Repeated respiratory examinations

• PCR testing where appropriate

• Serology where validated

• Monitoring through environmental and seasonal changes

• Investigation of any nasal or eye sign

• No breeding or group introduction until reviewed

Because PCR may become positive before antibodies and because clinical signs can be intermittent, release from quarantine should depend on repeated assessment rather than one negative test obtained immediately after arrival. (PubMed)

How Should the Environment Be Cleaned?

Mycoplasmas are relatively fragile outside the host, but cleaning remains essential because fresh secretions and other pathogens can contaminate equipment.

A practical cleaning process is:

1. Remove the tortoise.

2. Remove all faeces, food, mucus and organic material.

3. Wash hard surfaces with detergent and water.

4. Apply a reptile-safe disinfectant according to its label.

5. Maintain the required contact time.

6. Rinse where required.

7. Allow the enclosure and equipment to dry fully.

8. Use separate equipment for positive and negative animals.

There is no reason to prescribe one universal 0.15% bleach concentration. Household bleach strengths vary, and different coexisting pathogens may require different products, concentrations and contact times.

Porous items that cannot be cleaned properly may need to be discarded.

Is Mycoplasma Zoonotic?

The tortoise pathogens M. agassizii and M. testudineum are not currently recognised as human pathogens.

Normal reptile hygiene still matters because tortoises and their environments may carry Salmonella and other organisms capable of infecting people.

Wash your hands after handling:

• The tortoise

• Nasal discharge

• Bowls

• Substrate

• Enclosure equipment

• Medication syringes

Immunocompromised people should avoid direct contact with respiratory secretions and contaminated cleaning materials.

Common Mycoplasma Mistakes

Assuming Every Runny Nose Is Mycoplasma

Respiratory viruses, other bacteria, coccidia, foreign material and husbandry problems can produce the same sign.

Assuming a Positive PCR Proves Clinical Disease

PCR confirms organism DNA, not whether that organism is causing the entire clinical syndrome.

Assuming a Negative Antibody Test Rules Infection Out

Antibodies may take months to become detectable.

Treating With Penicillin or Amoxicillin

Mycoplasmas do not possess the cell-wall target these drugs are designed to attack.

Using One Antibiotic Course for Every Tortoise

Species, temperature, hydration and disease severity affect drug choice and dosing.

Returning a Recovered Tortoise to a Negative Group

Clinical improvement does not prove microbiological clearance.

Brumating an Actively Ill Tortoise

An anorexic, dehydrated or respiratory-compromised tortoise should be stabilised and assessed rather than placed into dormancy.

Treating Only the Nose

A tortoise may also have eye disease, pneumonia, oral disease, metabolic problems or another infection.

Stopping Monitoring When Discharge Disappears

Signs can be intermittent, and weight loss may continue after the nose looks dry.

How Can Mycoplasma Be Prevented?

Keep Tortoises Individually or in Stable Tested Groups

Avoid introducing unfamiliar tortoises directly into established collections.

Quarantine Every New Arrival

Do not rely on the animal looking healthy on arrival.

Do Not Mix Species

Mixed-species housing increases infectious-disease and husbandry risk.

Use Dedicated Equipment

Keep separate:

• Bowls

• Hides

• Cleaning tools

• Weighing containers

• Transport boxes

• Medication equipment

Monitor Body Weight

Regular weighing may detect deterioration before dramatic respiratory signs appear.

Maintain Correct Husbandry

Provide:

• Species-appropriate temperature

• Suitable humidity

• Correct UVB

• Balanced diet

• Clean water

• Adequate enclosure space

• Shelter from extremes

Good husbandry cannot prevent every exposure, but it helps the tortoise maintain immune function and cope with chronic infection.

Test Before Breeding, Sale or Transfer

Respiratory screening is particularly important before:

• Breeding

• Rehoming

• Group housing

• Moving animals between facilities

• Introducing animals into conservation collections

Never Release Pet Tortoises Into the Wild

A pet tortoise may introduce Mycoplasma, herpesvirus or another pathogen into a vulnerable wild population even when the animal appears healthy.

Frequently Asked Questions

Can a tortoise recover from Mycoplasma?

Yes. Many tortoises improve clinically with appropriate medication, supportive care and husbandry. However, complete elimination is difficult to prove, and recurrence or intermittent shedding remains possible.

Does a positive PCR mean my tortoise needs antibiotics?

Not automatically. The veterinarian should consider clinical signs, organism load, previous results, exposure risk and other possible diseases before deciding whether treatment is appropriate.

Can a Mycoplasma-positive tortoise live with a negative tortoise?

It is not recommended. An apparently healthy positive tortoise may still shed the organism and infect a susceptible animal.

Should a Mycoplasma-positive tortoise be allowed to brumate?

An actively ill, underweight, dehydrated or recently treated tortoise should not be brumated. A clinically normal positive tortoise requires an individual pre-brumation assessment by a reptile veterinarian.

Can humans catch tortoise Mycoplasma?

The recognised tortoise-associated species are not known human pathogens. Standard hygiene remains important because reptiles can carry other zoonotic organisms.

Final Thoughts

Mycoplasma is an important cause of respiratory disease in tortoises, but it is not the only cause of a runny nose.

The most important principles are:

1. Clinical signs may be mild, intermittent or absent.

2. A dry nose does not rule out blocked nasal passages.

3. PCR detects the organism, not the severity of disease.

4. Serology identifies an immune response, not necessarily current shedding.

5. Early infection may be PCR positive and antibody negative.

6. Coinfections are common enough to matter.

7. Treatment may control disease without proving eradication.

8. Positive animals should remain separated from negative animals.

9. Sick tortoises should not be placed into brumation.

10. Breathing difficulty, collapse or complete nasal obstruction requires urgent care.

The real goal is not simply to make the nasal discharge disappear. It is to restore breathing, appetite and body condition while preventing the organism from moving silently through the rest of the collection.

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ASK A VET™ can help you organise weight trends, respiratory videos, PCR or antibody results, treatment records and exposure histories while you work with a reptile veterinarian. A tortoise with laboured breathing, collapse, severe weakness or completely obstructed nostrils still requires immediate hands-on veterinary care.